ETL-600 Instructional Manual...Last Revision Date: 12/12/11 ETL-600 EYE & HEAD TRACKING LABORATORY OPERATING INSTRUCTIONS 21 Cabot Road Woburn, MA 01801 Tel. 781-932-1199 Fax: 781-932-1155ISCAN

Last Revision Date: 12/12/11

ETL-600 EYE & HEAD TRACKING LABORATORY

OPERATING INSTRUCTIONS

21 Cabot Road

Woburn, MA 01801

Tel. 781-932-1199

Fax: 781-932-1155

Email: [email protected]

ISCAN ETL-600 Instructions

TABLE OF CONTENTS i

Pages 1 - 2

Pages 3 - 5

Pages 7 - 18

Section 1: ETL-600 Components

Computer System ........................................................................................................... 1

Eye Imaging System ....................................................................................................... 2

Head Tracker Subsystem ............................................................................................... 2

Global View Camera Subsystem .................................................................................... 2

Laser Pointer Subsystem ............................................................................................... 2

Optional Computer Display Interface ............................................................................ 2

Section 2: ETL-600 Overview

Figure 2.1: ETL-600 Standard Configuration ........................................................... 3

Figure 2.2: Component Positioning ............................................................................ 4

Section 3: System Set Up

Part A: Setting Up the ETL-600 With the Tabletop Computer .................................... 7

Figure 3.1: ETL-600 Lab Set-up ................................................................................. 7

Figure 3.2: Computer Hook-up ................................................................................... 9

Part B: Setting Up the Global View Camera & Laser Pointer Subsystems................. 10

Figure 3.3: Global View & Laser Pointer Set-up ....................................................... 10

Part C: Setting Up the Global View Camera ................................................................. 11

Part D: Setting Up the Laser Pointer............................................................................. 11

Figure 3.4: Back of Pan/Tilt Unit ............................................................................... 12

Part E: Setting Up the Head Tracker Subsystem.......................................................... 13

Figure 3.5: Set-up of Head Tracker ............................................................................ 13

Part F: Hooking Up the Headset .................................................................................... 15

Figure 3.6: ETL-600 Headset...................................................................................... 15

Figure 3.7: Computer Chassis Front View................................................................. 17

Figure 3.8: Windows Start-up Screen & ETL-600 Icon............................................. 18


TABLE OF CONTENTS ii

Pages 19 - 28

Pages 29 - 36

Section 4: Obtaining Eye & Scene Images

Figure 4.1: LSW Main Window ..................................................................................19

Figure 4.2a: Enlarging the Eye Image ......................................................................20

Figure 4.2b: Enlarging the Scene Image ...................................................................21

Figure 4.3: Threshold Zero Settings for Eye 1 ..........................................................21

The Eye Image Landmarks ............................................................................................22

Figure 4.4: The Eye Imaging Camera Matrix & Eye Landmarks ...........................22

Figure 4.5: Eye Image With Matrix & Gate On ........................................................23

The Scene Imaging Camera Matrix ...............................................................................23

Figure 4.6: Scene Monitor Matrix & POR Indicator with Data Display .................24

Obtaining Good Eye Images With the Headset ............................................................24

Figure 4.7: Eye/Illuminator/Mirror Orientation .......................................................25

Figure 4.8: Image of the Eye, High-contrast Pupil/CR .............................................25

Figure 4.9: Tilting the Mirror In/Out ........................................................................26

Figure 4.10: Tilting the Eye Camera In/Out .............................................................27

Figure 4.11: Eye Image With Glasses .......................................................................27

Figure 4.12: Eyeglasses Adjustments ........................................................................28

Section 5: Tracking the Eye

Figure 5.1: Eye Tracking Controls Panel ..................................................................29

Part A: Threshold ............................................................................................................30

Figure 5.2: Pupil Threshold Adjustment ...................................................................30

Figure 5.3: Corneal Reflection Threshold Adjustment .............................................31

Figure 5.4: Corneal Reflection Crosshair with Threshold ........................................32

Figure 5.5: Pupil and CR Crosshairs On with Threshold Display Off ....................32

Figure 5.6: Good Tracking Eye Image with Threshold ............................................33

Figure 5.7: Eye Image Gate .......................................................................................34

Figure 5.8: Aux 1 Controls Panel ...............................................................................34

Adjustment of the Scene Camera ...................................................................................35


TABLE OF CONTENTS iii

Pages 37 - 48 Section 6: Calibrating the Eye to the Scene

Overview of Point-of-Regard Calibration Procedure ....................................................37

Overview of Eye Angle Calibration Procedure ..............................................................37

Point-of-Regard Calibration ...........................................................................................37

Setting Up the Calibration Targets ...............................................................................38

Figure 6.1: Calibration Procedure .............................................................................38

Checking the Eye & Scene Images ................................................................................39

The Point-of-Regard Calibration Procedure ..................................................................39

Figure 6.2: RK-630 POR Scene Image........................................................................39

Figure 6.3: Symbol of Point Of Regard ......................................................................39

Figure 6.4: POR Data Display ....................................................................................40

Figure 6.5: POR Calibration Control Panel with Large Scene Image .....................40

Figure 6.6: Center Calibration Point .........................................................................41

Figure 6.7: Upper Left Calibration Point ..................................................................42

Figure 6.8: Upper Right Calibration Point ...............................................................43

Figure 6.9: Lower Left Calibration ............................................................................43

Figure 6.10: Lower Right Calibration .......................................................................44

Figure 6.11a: POR Output Active After Calibration ................................................44

Figure 6.11b: POR Tracking Enabled After Calibration ..........................................45

Calibration Auxiliary Controls .......................................................................................45

Figure 6.12: POR AUX Panel Settings for Monocular Operation ............................45

Storing a Calibration Model ...........................................................................................46

Figure 6.13: LSW Window With the Save Selection ................................................46

Figure 6.14: Save Calibration File Name ..................................................................47

Recalling a Calibration Model ........................................................................................47

Figure 6.15: Open Calibration File ............................................................................48

Figure 6.16: POR Output Active ................................................................................48


TABLE OF CONTENTS iv

Pages 49 - 72 Section 7: Eye Angle Calibration

Part A: Mapping of the Planar Surfaces ........................................................................ 49

Figure 7.1: 3D Mapping of Multiple Planar Surfaces .............................................. 49

Figure 7.2a: Multiple Planar Surfaces (Viewed from Above) ................................... 50

Figure 7.2b: Multiple Planar Surfaces (Partial View) .............................................. 51

Figure 7.3: Environment Planes Layout Icon ........................................................... 52

Figure 7.4a: Environment Planes Layout Editor for Plane 1 .................................. 52

Figure 7.4b: Measurements to Establish the Relationship of

Magnetic Source to Plane 1 ........................................................... 53

Figure 7.5: Environment Planes Layout Editor for Planes 2 & 3 ............................ 54

Part B: Registration of Planar Surfaces with the Global View Scene Monitor ............ 55

Figure 7.6: Monitor Schematic .................................................................................. 55

Figure 7.7: Global View Monitor ............................................................................... 56

Figure 7.8: Video Display Unit Control Panel .......................................................... 56

Figure 7.9: Center Point Registration ....................................................................... 57

Figure 7.10: Upper Left Point Registration .............................................................. 57

Figure 7.11a: Upper Right, Lower Left, Lower Right Points Registration ............. 58

Figure 7.11b: Clearing the Active Item Box............................................................... 58

Figure 7.12a: Global View Image Display of Multi-Plane Area ............................... 59

Figure 7.12b: VDU Control Panels for Multiple Planes Registration ..................... 59

Figure 7.13: Matching Z Coordinates ........................................................................ 60

Part C: Verification of Head Vector Intersection with Planar Surfaces ...................... 62

Figure 7.14: Global View Scene Image Display ........................................................ 62

Figure 7.15: LSW Window with Mannequin Head Data .......................................... 63

Figure 7.16: Eye Angle Calibration Controls Panel ................................................. 64

Figure 7.17: ETL-600 Boresight in Center Plane 1 .................................................. 65

Figure 7.18: Movement of the Head Vector Intersection Indicator ......................... 66

Part D: Eye Angle Calibration ....................................................................................... 67

Figure 7.19: Boresight in Center Plane 1 .................................................................. 67

Figure 7.20: Eye Angle Calibration Center ............................................................... 68

Figure 7.21: Laser Pointer Inside Center of the Indicator ....................................... 68

Figure 7.22a: Left Calibration Point ......................................................................... 69

Figure 7.22b: Right, Top & Bottom Calibration Points ............................................ 70

Figure 7.23: Graph A in the LSW Window ............................................................... 71

Eye Sensor Measurements ............................................................................................. 71

Figure 7.24: AUX1 Tab & Panel ................................................................................ 71

Figure 7.25: Safety Glasses Headset, Two Views ..................................................... 72


TABLE OF CONTENTS v

Pages 73 - 80

Pages 81 - 100

Section 8: Graph Display Controls

Figure 8.1: Graph Control & Display Area ............................................................... 73

Graph Display Parameters Labels & Descriptions ....................................................... 75

Section 9: LSW Software Features and Functions

Part A: Blink Monitoring................................................................................................. 81

Figure 9.1: Blink Monitor Configuration Panel ........................................................ 82

Figure 9.2: Blink Controls Enabled ........................................................................... 82

Figure 9.3: Blink Control Panel ................................................................................. 83

Part B: ISCAN Analog Outputs ..................................................................................... 84

Selecting Analog Outputs ............................................................................................... 84

Figure 9.4: Analog Output Control Panel ................................................................. 84

Figure 9.5: Select Analog Output Parameters .......................................................... 84

Figure 9.6: Analog Output Parameters & Graph Displays ...................................... 85

Configuring the Analog Outputs .................................................................................... 86

Figure 9.7: Analog Inputs & Outputs Control Panel ................................................ 86

Part C: Serial I/O ............................................................................................................ 87

Example of How to Use Serial Port ............................................................................... 87

Figure 9.8: Serial I/O Configuration Panel ............................................................... 87

Figure 9.9: Serial Output Controls Panel ................................................................. 88

Part D: Digital I/O .......................................................................................................... 89

Figure 9.10: ISCAN Digital I/O Connector ............................................................... 89

Figure 9.11: Digital I/O Configuration Panel ........................................................... 90

Figure 9.12: Digital Output Controls Panel .............................................................. 90

Figure 9.13: Digital Output Bit Selection ................................................................. 91

Part E: Recording Data .................................................................................................. 92

Figure 9.14: Data Recording Control Panel .............................................................. 93

Figure 9.15: Data Recording Parameters Bank ........................................................ 93

Recording Configuration Panel ...................................................................................... 94

Figure 9.16: Recording Configuration Panel ............................................................. 94

Example of Recording and Reading Data ...................................................................... 96

Figure 9.17: Data Recording Controls Info ............................................................... 96

Figure 9.18: Save TDA Data in File .......................................................................... 97

Figure 9.19: Saving Data as Test.TDA ...................................................................... 97

Figure 9.20: Open WordPad ....................................................................................... 98

Figure 9.21: Test.TDA Data ....................................................................................... 99


TABLE OF CONTENTS vi

Pages 101 - 106

Pages 107 - 110

Pages 111 - 116

Pages 117 - 118

Section 10: Recording Data for Analysis by ISCAN’s PRZ Software

Figure 10.1: Loading VDU.H2A & VDU.V2A into Bank 1 .......................................101

Part A: Image Registration for PRZ ...............................................................................101

Figure 10.2: Image Registration, Upper Left ............................................................102

Figure 10.3: Defining the Anchor Points....................................................................102

Part B: Recording a Data Run .......................................................................................103

Figure 10.4: Start Recording ......................................................................................103

Figure 10.5: Quit Recording .......................................................................................103

Part C: Storing the Eye/Head Plane Intersection Data in a Fixation File ..................104

Figure 10.6: Select Save Fixation File .......................................................................104

Figure 10.7: Open Fixation File .................................................................................104

Figure 10.8: Identifying a Fixation File ....................................................................105

Figure 10.9: Saving a Fixation File ...........................................................................105

Section 11: PRZ Overview

Task Configuration .........................................................................................................107

Scope & Study Context ...................................................................................................107

Stimulus Images .............................................................................................................107

Master Registration Image ............................................................................................108

PRZ/DQW Workflow .......................................................................................................108

Figure 11.1: PRZ/DQW Workflow Diagram ..............................................................109

Figure 11.2: PRZ File Definitions Table ....................................................................110

Section 12: Saving & Retrieving Configuration Settings

Saving Definition Files ...................................................................................................111

Figure 12.1: Save LSW Settings ................................................................................111

Figure 12.2: Saving a Unique .def File ......................................................................112

Retrieving LSW Settings Via Definition Files ..............................................................112

Figure 12.3: Open LSW Settings in File Menu .........................................................112

Figure 12.4: Selecting a Saved .def File ....................................................................113

Factory Definition File ...................................................................................................113

Figure 12.5: Factory .def ETL-600 Settings ..............................................................114

Section 13: IR Irradiance & Safety


TABLE OF CONTENTS vii

Pages 119 - 128 Section 14: ETL-600 Appendices

Appendix A: Single Plane/Computer Screen Stimulus Operation .......................119

Figure A.1: ETL-600 Single Plane Configuration .....................................................119

Part A: Setting Up the Single Plane/Computer Monitor Connections .........................120

Figure A.2: ETL-600 Computer Hook-up ..................................................................120

Part B: Changing the Title of the Monitor to VDU Monitor ........................................121

Figure A.3: Changing the Name of the Monitor .......................................................121

Part C: Entering the Planar Surface Coordinates ........................................................121

Part D: Alignment of the VDU Display Borders ...........................................................122

Figure A.4: VDU Controls Panel ...............................................................................122

Figure A.5: Selecting Left Border for Alignment ......................................................122

Figure A.6: Selecting Right, Top, & Bottom Borders for Alignment .......................123

Part E: Verification of the Head Intersection ...............................................................124

Part F: Eye Angle Calibration ........................................................................................124

Appendix B: Additional ISCAN Head-mounted Units .............................................125

Figure B.1: Headband-mounted Monocular System ................................................125

Appendix C: Serial I/O ....................................................................................................127

Auxiliary Serial Output Formats ...................................................................................127

ISCAN Serial Output Format (ASCII) ..........................................................................127

Binary Output Format ...................................................................................................127

Remote Serial Controls ...................................................................................................128

Remote Serial Command Bytes .....................................................................................128


Section 1: ETL-600 Components 1

Section 1: ETL-600 Components

The ISCAN ETL-600 Head & Eye Tracking Laboratory contains all components necessary

to measure head and eye movements of a human subject and to calculate point-of-gaze and

target plane intersection coordinates with respect to the working environment.

The ETL-600 components include the following subsystems:

1. Personal computer chassis with the following accessories:

• AC line cord for PC operation at either 120VAC or 230VAC

• 17” LCD monitor

• AC line cord for monitor operation at either 120VAC or 230VAC

• Keyboard

• Mouse

• 6 1’ BNC cables

• 6’ phono cable

• Phono/BNC adaptor

The PC also contains the follow circuit cards and software:

Component

SG-100 camera control card

RK-826PCI monocular eye

tracker

RK-630PCI calibration

subsystem

Video Display Unit (VDU) PCI

card

3-channel video display card

3 serial ports

LSW Line of Sight (LOS) and

Target Intersection software

PRZ Analysis software

Function

Supplies power to head-mounted cameras and

illuminator; outputs eye and scene video channels

Tracks eye position from head-mounted eye imaging

camera

Calculates real-time point of gaze; superimposes gaze

point over scene from head-mounted scene imaging

camera

Accepts video input from a stand-alone global field of

view camera or a VGA/NTSC converter from a host

PC monitor display

Displays the eye, scene and VDU images in real time

on the PC monitor

One port interfaces with the magnetic head tracker;

two ports used for input/output data transfer from

the ETL-600

Allows the system operator to monitor eye and head

tracker functions and calibrate the subject to

generate eye/head line-of-sight vectors with respect

to their working environment; records and saves eye

movement and head movement data for analysis

Allows the operator to analyze the head/eye data for

quantitative representations of fixation times, pupil

size, blinks, and scan path information with respect

to planar surfaces in the working environment


Section 1: ETL-600 Components 2

2. Head-mounted Eye/Scene Imaging System, comprised of the following items:

• Miniature eye camera

• Infrared illuminator

• Scene camera

• Magnetic sensor (20’ range, for head tracking)

• Plastic safety goggle, headband or spectacles frame

• 15’ SG-100 camera control card connecting cable (also called the umbilical cable)

3. Head Tracker Subsystem:

• Patriot/FasTrak/Liberty Magnetic Head Tracker Control Unit

• 20’ Magnetic source

• Floor mount for source

• Power supply for magnetic tracker, 120VAC or 230VAC

• Serial interface cable (for PC serial port 1 interface)

• Tape measure

4. Global View Camera Subsystem

• Color video camera

• 12VDC camera power supply

• AC line cord for 120VAC or 230VAC

• Floor tripod camera mount

• 25’ BNC connecting cable (for VDU input)

5. Laser Pointer Subsystem

• 2-axis motorized mount with laser pointer

• 25’ cable with hand controller for mount

• 6VDC power supply

• AC line cord for power supply, 120VAC or 230VAC

• Tripod floor mount for laser pointer mount

6. Optional Computer Display Interface

• VGA-to-NTSC converter

• +12VDC power supply for VGA-to-NTSC converter

• AC line cord for VGA-to-NTSC converter operation at either 120VAC or 230VAC



3


The ISCAN ETL-600 Eye & Head Tracking Laboratory tracks the eye and head movement

of a human subject in real time and generates point-of-gaze data with respect to the head-

mounted scene camera. The ETL-600 also calculates line-of-sight vector data using

combined eye and head position and displays the intersection point of the line-of-sight

vector as an indicator superimposed over a global view scene display, with up to 20 planar

surfaces in the subject’s surrounding environment.

The subject may be seated or standing, wearing the head-mounted eye and scene cameras

and the head tracker sensor on a lightweight plastic head mount. The magnetic source and

sensor units are coupled via 20’ cables to the magnetic head tracker unit, and the eye and

scene cameras on the headset are coupled to the eye tracking personal computer via a 15’

cable. The magnetic head tracker unit is coupled to the eye tracking computer via a serial

data cable that carries the real-time six-degree-of-freedom head position data. The

magnetic source is mounted on a floor tripod and is generally placed behind the subject

with the subject staying within two feet in the front hemisphere of the source.

A schematic of a typical set-up is shown below:

Figure 2.1: ISCAN ETL-600 Standard Configuration



4

Planar surfaces surrounding the subject must be mapped with respect to the magnetic

source. The magnetic head tracker calculates the position in X, Y, and Z and Azimuth,

Elevation, and Roll of the head-mounted sensor with respect to the center of the source.

These measurements are in inches for X, Y and Z displacement of the sensor from the

source and in degrees of angle for the orientation of the sensor with respect to the source.

Figure 2.2: Component Positioning

The planar surfaces that are of interest to the operator must be entered into the line-of-

sight software as coordinate groups, defining a plane, with respect to the 0, 0, 0 origin of

the source. This mapping of planar surfaces may be used for multiple monitors, flat

surfaces, screens or areas of interest in a 360º arc around the subject.

Once the coordinate mapping of the surfaces has been completed, a rapid calibration

procedure is performed, using an operator-controlled laser pointer in conjunction with the

global view camera display. The operator instructs the subject to sequentially look at a

pattern of five calibration points within the field of view. After the calibration procedure,

the system outputs plane number and the X, Y location of the subject’s combined eye/head

line of sight within each plane in real time. The data shows precisely the point the subject

is looking at in the 3-dimensional workspace. The data may be stored for analysis or used

as a real-time control signal for man/machine interface and control experiments.



5

As an integrated eye/head tracking system, the ETL-600 is comprised of several discreet

functional parts. An outline of the steps necessary to successfully set up and operate the

system, and where each step can be found, is as follows:

! Setting up the system components and hooking up the cables (Section 3)

! Tracking the eye using the headset (Sections 4 and 5)

! Calibrating the eye data to the head-mounted scene camera (point of regard

calibration) (Section 6)

! Defining the planar surfaces surrounding the subject (Section 7)

! Registering the defined planar surfaces to the global view image of the subject’s

environment (Section 7)

! Verifying the head position data (Section 7)

! Calibrating the eye and head data (eye angle calibration) with respect to the planar

surfaces (Section 7)

! Recording the eye and head data (Section 7)

! Recording the eye and head tracking data for input to the PRZ advanced point-of-

regard analysis software (Section 10)



6

PAGE INTENTIONALLY LEFT BLANK


Section 3: ETL-600 Set-up

7

Section 3: Setting up the ETL-600

Part A: Setting Up the ETL-600 With the Tabletop Computer

After unpacking all the system components as listed in Section 1, please note that all

connectors are labeled so as to exactly match each end, cable to component. The following

step-by-step directions describe how to set up all the components as shown in Figure 3.1

below.

Figure 3.1: ETL-600 Lab Set Up



8

Hooking up the PC chassis and Monitor:

! Connect the VGA cable between the 17"PC LCD monitor and the VGA output port of

the computer chassis labeled "CONNECT PC VGA MONITOR HERE ONLY"

! Connect the AC line cord to the 17" PC VGA monitor.

! Connect the mouse to an open USB port in the back of the eye tracker PC chassis.

! Connect the keyboard to an open USB port in the back of the eye tracker PC chassis.

! Connect the AC line cord to the power receptacle on the back of the eye tracker PC

chassis.

! Plug in the 17" PC VGA monitor line cord to an AC power source.

! Plug in the eye tracker PC power cord to an AC line source.

! Using the 1' BNC cable labeled "RK-826PCI VIDEO OUT" on one end and "EYE

MONITOR" on the other, connect the BNC output of the RK-826PCI Video Out

connector to the input of the Eye Monitor on the 3 channel video display card.

! Using the 1' BNC cable labeled "RK-630PCI OPER VIDEO OUT" on one and "SCENE

MONITOR" on the other, connect the BNC Operator Output on the RK-630PCI

Autocalibrator card to the input of the Scene Monitor on the 3 channel video display

card.

! Using the 1' BNC cable labeled "VDU2PCI OPER VIDEO OUT" on one end and "VDU

MONITOR VIDEO IN" on the other, connect the BNC output of the VDU2 Operator

Output to the input of the VDU Monitor on the 3-channel video display card.

! Using the 1' BNC cable labeled "EYE CAMERA VIDEO OUT" on one end and "RK-

826PCI VIDEO IN" on the other, connect the BNC output of the Eye Camera Output

on the bottom slot SG-100 card to the input of the RK-826PCI eye tracker card directly

above it.

! Using the 1' BNC cable labeled "SCENE CAMERA VIDEO OUT" on one end and "RK-

630PCI SCENE VIDEO IN" on the other, connect the BNC output of the Scene

Camera Output on the bottom slot’s SG-100 to the Scene Video Input of the RK-

630PCI Autocalibrator card in the third slot of the computer.

! Using the 25' BNC cable labeled "VDU2 SCENE VIDEO IN" one end and "GLOBAL

VIEW OUT" on the other, connect the VDU2 Scene Video Input cable to the VDU card

in the fifth slot up from the bottom in the PC. The other end of the cable will be

connected to the output of the global view camera described in the set up following.

! Connect the serial cable to the COM 1 serial port of the PC, labeled "HEAD TRACKER

SERIAL INPUT". The other end of the serial cable will be connected to the RS-232

output on the head tracker control unit.

! Connect the Eye Imager cable to the input on the SG-100 card in the bottom PCI slot

in the PC, labeled "EYE IMAGER IN". A yellow label also reads "CONNECT EYE

IMAGER HERE ONLY".



9

A schematic diagram showing all the eye tracker PC chassis connections are shown in

Figure 3.2 below.

Figure 3.2: Diagram of Back of Computer with All Cables Hooked Up



10

Part B: Setting Up the Global View Camera and Laser Pointer Systems

The global view camera must be set up to view the operational field of view of the subject.

The global view imagery, in conjunction with the laser pointer subsystem is used to

quickly calibrate the subject to one of the planar surfaces within the field of view.

The global view camera should be mounted on a tripod and positioned so that the system

operator can see a clear in focus image of the subject's working environment. For example,

if the subject is viewing a display of two computer monitors, the field of view of the global

camera should be adjusted to clearly encompass the active areas of both monitors. The

front surface of the monitor that is most directly in front of and normal to the subject will

be designated Plane 1. The laser pointer subsystem should also be positioned so that the

laser can be positioned by the system operator to cover the entire surface of the Plane 1.

Figure 3.3 shows the relative positions of the global view camera and laser pointer with

respect to a subject viewing three planar surfaces.

Figure 3.3: Schematic of Global View and Laser Pointer Set Up



11

Part C: Setting up the Global View Camera

! Attach the global view scene camera to the global view tripod assembly.

! Plug in the global view scene camera power supply to the back of the global view

camera. Plug in the camera power supply into a wall AC source.

! Connect the end of the 25' BNC cable labeled "GLOBAL VIEW CAMERA OUT" to the

video output connector on the back of the global view camera. The other end of the 25'

BNC cable has already been attached to the VDU2 Scene Video Input on the back of

the eye tracker PC.

Part D: Setting up the Laser Pointer

! Attach the pan/tilt unit containing the laser pointer to the Laser Pointer Tripod.

! Connect the +6VDC power supply to the input connector on the front side of the

pan/tilt unit labeled "PTU POWER IN". Plug in the +6VDC power supply into a wall

AC outlet. Turn on the power switch on the back of the pan/tilt unit. The power switch

is the rightmost of the two switches on the back panel of the pan/tilt unit. The left

switch should be set at 0 degrees, all the way down, and the right power switch should

be set in the middle position at the M position. The green POWER ON LED will be

illuminated when the pan tilt is powered up. Figure 3.4 shows photos of the Laser

Pointer set up, and a schematic of the back of the pan/tilt unit.



12

Figure 3.4: Back of Pan/Tilt Unit

! Plug in the pan/tilt hand controller on its 25' cable. Position the hand controller so the

system operator can easily move the position of the laser pointer while watching the

ISCAN eye tracker LSW software control screen.

! Turn on the laser pointer by pushing the pointer body into the cylindrical tube it is

mounted on. The pushbutton will be pushed on and the laser pointer output should be

visible within the work area of the subject. Make sure that the tripod head is

positioned so that the range of the pan and tilt unit, when used with the hand

controller, covers the surface of the primary surface (plane1) that will be used for

subject calibration.



13

Part E: Setting up the Head Tracker Subsystem

The ETL-600 is provided with one of three models of Polhemus Head Tracker Systems.

The most common version of the head tracker is the Patriot, a single sensor, 60Hz, six

degree of freedom magnetic head tracker. The Patriot Magnetic source is a 2" cube that

contains the transmitter coil, and the sensor head tracker unit is mounted onto the ISCAN

headset along with the miniature eye and scene cameras.

The magnetic source is normally mounted onto a floor tripod that should be positioned

behind the subject's head at about the same height as the sensor. The source has a bubble

level attached to it and the tripod should be adjusted so the bubble level is centered. Keep

the subject within approximately 1' of the magnetic source and operate the source and

sensor away from any ferrous or metal objects that can interfere with the magnetic field.

A photo of the source and sensor set up is shown in Figure 3.5

Figure 3.5: Set-up of Head Tracker

! Connect the thick gray head tracker source cable to the front panel connector of the

Patriot labeled "SOURCE".

! Connect the thin gray head tracker sensor cable coming from the ISCAN headgear to

the front panel connector on the Patriot labeled "SENSOR 1".

! Connect the AC line cord to the Polhemus +5 power supply.



14

! Plug in the +5VDC output of the Polhemus power supply to the connector on the back

panel of the Patriot labeled "DC IN". Plug in the AC line cord of the power supply to

an AC wall source. The Polhemus power supply supports a 120VAC - 230VAC input

range.

! Connect the serial cable to the back panel connector on the Patriot labeled "RS-232".

The other end of the serial cable has already been connected to the COM 1 head

tracker serial input on the eye tracking computer.

! Look at the back panel of the Patriot and make sure that all the DIP switches in the

"CONFIG" panel are all in the OFF or DOWN position.

The head tracker subsystem is now completely assembled and ready to go.



15

Part F: Hooking Up Headset

The following directions describe the step-by-step procedure for connecting the headset

and head tracker unit to the eye tracker computer.

The headset is comprised of a miniature eye imaging camera and a miniature scene

imaging camera, all mounted onto a plastic safety glasses frame.

Figure 3.6: ETL-600 Headset

The safety glasses are designed to fit over most normal spectacle frames. The eye camera

views the subject's eye via a plastic hot mirror that passes visible light but reflects a near

infrared image of the eyes into the cameras. The eye is illuminated by a low-level near



16

infrared light emitting diode (LED) and the LED is positioned next to the eye camera to

properly reflect the light off of the plastic mirror to illuminate the eye area.

The eye camera is mounted on a moveable post that allows it to be twisted up and down.

The plastic mirror is mounted on a thin adjustable rod so it can also be tilted up and down

to image the eye at its optimal angle of view.

There is also a lanyard strap in the back of the safety glasses to comfortably secure the

headset to the head. Do not remove this strap. At the very least, it prevents the headset

from falling off the subject's head and becoming damaged.

! Initially have a person other than the system operator put the headset on. Secure the

head set to the subject with the strap on the back of the head. Plug in the thin black

cable connector labeled "EYE CAMERA OUT", the other end of this cable has already

been connected to the SG-100 card in the eye tracker PC. Attach the silver clip on the

cable end to the subject's clothing to act as a strain relief for the headset.

At this point all the system components are hooked up and the ETL-600 system is ready

for initial operation.

If the system is provided with the tower PC chassis, please note that the computer chassis

is normally configured for 120VAC power input for use in North America and Japan. If the

system is shipped to the rest of Asia or to Europe, the power supplies are configured for

230VAC and a label above the power receptacle will indicate this. If it is necessary to

switch the PC for 120VAC or 230VAC input, unsnap the front cover and push up the

voltage selection switch as shown in Figure 3.7 below.



17

Figure 3.7: Computer Chassis Front View and With Front Panel Removed

To power up the tabletop PC, press the power button on the top front of the PC chassis as

shown in Figure 3.7 above. The power switch for the 17" PC VGA LCD monitor is located

on the front of the monitor.

WARNING: Do not apply 230VAC to the PC chassis if the voltage selection

switch reads 110V. This will result in damage to the computer power supply

and possibly the eye tracking circuit cards.



18

! Turn on the tabletop PC and monitor.

! Turn on the head tracker. The power switch for the Patriot is located on the back

panel of the control unit, next to the power supply input connector.

! Make sure that the global view camera is powered up.

! Make sure that the laser pointer is on and that the pan/tilt unit is moving in response

to commands from the pan/tilt hand controller.

The eye tracker PC will start up and after a brief interval, a Windows 7 screen will appear

that should look something like that shown in Figure 3.8 below.

Figure 3.8: Win 7 Start Up Screen With ETL-600 Icon

Note that there is an ETL-600 icon on the Windows 7 start up screen. Double clicking on

this icon opens the ISCAN LSW Data Acquisition Software.



19

Section 4: Obtaining Eye and Scene Images

With the ISCAN LSW software main window now open, and a subject wearing the

headgear, this section will discuss the tools and techniques involved in obtaining clear, in-

focus images of the eye and adjusting the scene camera.

Figure 4.1 below shows the ISCAN LSW window, configured for monocular eye tracking.

The eye tracking control panel for the eye is located in the upper left quadrant of the LSW

control window and is labeled "1" in Figure 4.1.

Figure 4.1: LSW Main Window



20

Note that there is a control panel for the eye labeled "EYE 1." The ETL-600 is normally set

up with Eye 1 as the subject's left eye. At the bottom of the LSW window are panels

labeled "EYE MONITOR"(5), "SCENE MONITOR"(6) and "GLOBAL VIEW

MONITOR"(7). The video signal from the head-mounted eye camera runs through the RK-

826PCI Eye Tracker card and is displayed on the eye monitor. The video from the head-

mounted scene camera runs through the RK-630PCI Autocalibrator card and is displayed

on the scene monitor.

In the upper right hand corner of each monitor display there is a small click box. Clicking

on this box will expand the monitor image to fill in the area of the graph display controls

(9). In addition, clicking on the monitor expansion box will automatically bring up the

associated control panel for that enlarged image.

For example, clicking on the Eye Monitor box will expand the eye image coming out of the

RK-826PCI 2 and also bring to the forefront the Eye 1 control panel. If the Scene Monitor

is expanded, a calibration control panel will automatically appear in the Auxiliary

Controls Panel area (3). Figure 4.2 shows the corresponding selection of the eye and scene

images with their associated control panels.

Figure 4.2A: Enlarging the Eye Image



21

Figure 4.2B: Enlarging the Scene Image

Set the pupil and corneal reflection threshold levels to zero, for Eye 1. (There will be a

detailed discussion of the threshold functions later in the manual.) Click on the Eye 1

panel tab and use the mouse to drag the both the pupil and corneal reflection threshold

sliders to the lowest point of the slider controls. The number zero should be seen in both

boxes below the sliders, as shown in Figure 4.3 below.

Figure 4.3: Threshold Zero Settings for Eye 1



22

The Eye Image Landmarks

The eye monitor will present images of the left eye of the subject when the eye camera

unit has been properly adjusted to obtain clear, in focus images of the subject's eye. The

images will be adjusted to look similar to those shown in Figure 4.3 above. Again, note

that both the pupil and corneal reflection threshold levels for Eye 1 are set to zero at this

time.

The high contrast eye image shown in Figure 4.3 is the result of the system operator

properly aligning the position of the head mounted eye camera and the infrared reflecting

hot mirror in front of the eye. Figure 4.4 has an expanded view of an eye image to clearly

show the eye landmarks. With the eye illuminated by the infrared (IR) light source

mounted on the headset, the pupil appears as a dark hole, or sink to the infrared light.

The IR illuminator also generates a bright spot off of the cornea, (the curved anterior

portion in front of the pupil). This bright spot is called the corneal reflection.

Figure 4.4: The Eye Imaging Camera Matrix and Eye Landmarks

Eye images similar to that shown above in Figure 4.4 are input to the RK-826PCI eye

tracker card that detects the dark pupil and bright corneal reflection data present in the

eye images. To track the eye in real time, the RK-826PCI eye tracking card processes the

video signal representing the eye images generated by the eye imaging camera. The

images of the eye contain dark video information corresponding to the pupil of the eye and

bright video information corresponding to the corneal reflection.

In the RK-826PCI eye tracker card, electronic circuitry generates voltage levels that are

continuously compared to the dark pupil and bright corneal reflection signals present in

the eye images. These voltage levels are called the PUPIL THRESHOLD and CORNEAL

REFLECTION THRESHOLD respectively. First, the operator manually adjusts the pupil

threshold level to discriminate the dark video information present in the image that

corresponds to the pupil signal. When the threshold display control button is enabled, the

dark pupil information that is discriminated by the pupil threshold level is displayed as a

bright overlay on the eye image. See Figure 4.5.



23

The operator then manually adjusts the CR threshold level to discriminate the bright

video information present in the image containing the corneal reflection. When the

threshold display control button is enabled, the bright CR information that is

discriminated by the CR threshold level is displayed as a black overlay on the eye image.

Figure 4.5 shows the eye landmarks being tracked as seen on the LSW eye monitor panel.

Figure 4.5: Eye Image With Matrix and Gate On

Once the operator has adjusted the pupil and corneal reflection thresholds to encompass

the pupil and corneal reflection targets, the operator enables a TRACK ACTIVE feature

that initiates automatic tracking of the pupil and corneal reflection over the eye image

area displayed on the monitor.

Another feature shown in Figure 4.5 above is the IMAGE GATE. This box is a two

dimensional window displayed on the eye image display monitor. The eye threshold and

eye tracking functions are only active inside the gated area. The size and position of the

image gate is adjustable by the system operator and can help to isolate the eye landmarks

for tracking in extremely cluttered eye images. The image gate can be turned on or off.

When the image gate is turned off, the eye tracker is active over the eye camera's full field

of view.

The video eye image display monitor over which each eye is tracked, is represented by a 0

- 511 pixel horizontal by 0 - 255 TV line vertical matrix. All pupil and CR position data

and image gate data is with respect to this grid. For example, if the pupil is in the center

of the eye image display monitor, the coordinates of the pupil position generated by the

RK-826PCI eye tracker would be 255 horizontal and 128 vertical. The coordinates for the

upper left corner of the eye image display monitor are 0H, 0V and the lower right corner of

the display is 511H, 255V.

The Scene Imaging Camera Matrix

The miniature color scene camera is mounted on the headset facing forward between the

eyes to capture a real time view of the world in front of the subject. The video from the

scene camera runs through the RK-630PCI Autocalibrator and is displayed on the scene

monitor in the LSW software window. The RK-630PCI Autocalibrator takes the eye

position data from the RK-826PCI Eye Tracker and transforms the raw eye position

signals into a point of regard indicator that is superimposed over the scene video.



24

The scene image display over which the subject's point of regard is presented is

represented by a 0 -511 pixel horizontal and 0 - 511 TV line vertical matrix. All point of

regard position data is with respect to this grid. Figure 4.6 shown below illustrates the

main landmarks present in the point of regard image shown on the scene monitor.

Figure 4.6: Scene Monitor Matrix and Point-of-Regard Indicator With Data Display

For example, if the subject was looking at a point directly in the centre of the scene image,

the coordinates of the point of regard would be 255H, 255V. The upper left corner of the

scene monitor display is 0H, 0V and the lower right is 511H, 511V.

Also shown in figure 4.6 above is the real time data display that shows the current

horizontal and vertical point of regard coordinates, the pupil diameter and a real time

elapsed time clock. The operator can turn off this display so as not to obscure any portion

of the scene image.

Obtaining Good Eye Images With the Headset

Have a cooperative human subject sitting relatively still, wearing the headset. At this

time, preferably select a subject that is not wearing eyeglasses. Adjustments of the

headset to compensate for subjects wearing glasses will be covered at the end of this

section.

The eye camera is a miniature television camera that is designed to capture clear, in focus

images of the eye. The eye is illuminated by a low level infrared light-emitting diode

(LED) that is positioned next to the eye camera, and the LEDs should be kept free from

dirt or mechanical obstructions.



25

Figure 4.7: Eye/Illuminator/Mirror Orientation

As shown in Figure 4.7, the plastic hot mirror is positioned in front of the subject's eye at a

roughly 45 degree angle, reflecting an infrared image of the eye into the eye camera. The

IR illuminator, mounted next to the eye camera, points downward to illuminate the eye

area, also reflecting off the hot mirror.

Figure 4.8 below shows typical eye images as seen by the head mounted camera, reflected

off of the hot mirror.

Figure 4.8: Image of the Eye, High-Contrast Pupil/CR

For optimal eye imaging the mirror should be free from dust, dirt or fingerprints. keep it

clean by blowing off dust with compressed air and cleaning it periodically with glass

cleaner and a soft cloth. The hot mirror is adjustable and can be tilted inwards and

outwards in order to center the eye image with respect to the eye camera.



26

There are two main ways to adjust the position of the eye image with respect to the

camera, and hence center the eye image on the eye monitor displayed in the LSW software

window.

First, tilt the hot mirror slightly up and down to see the eye image move up and down in

the eye monitor. Note that pushing the hot mirror in, towards the bottom of the eye will

push the eye image down on the eye monitor. Similarly, pushing the hot mirror up, away

from the bottom of the eye will push the eye image up on the eye monitor.

Figure 4.9 illustrates what happens when the hot mirror is tilted in this manner.

Figure 4.9: Tilting the Mirror In/Out

Adjust the position of the mirror to center the eye image in the field of view of the eye

camera.

Similarly, leaving the hot mirror in a fixed position and twisting the eye camera inwards

or outwards, will result in the same type of eye position adjustment. Figure 4.10

illustrates what happens when the camera is twisted in this fashion.



27

Figure 4.10: Tilting the Eye Camera In/Out

Note that when the eye camera is twisted inwards (towards the eye), the eye image moves

up on the eye monitor. Similarly, when the eye camera is twisted outwards (away from the

eye), the eye image moves down on the eye monitor.

Adjust the balance between the mirror position and the camera position so the eye is

centered in its eye monitor display.

SUBJECTS WITH EYE GLASSES

Subjects wearing eyeglasses may require particular adjustments due to the additional

bright reflections off of the front surface of the lenses from the IR light source illuminating

the eye. These bright reflections may obscure or interfere with the eye landmarks and

make the pupil or corneal reflection unable to be tracked by the RK-826PCI eye tracker.

Figure 4.11 shows the type of eye image that can result if the eye camera and mirror are

not properly aligned.

Figure 4.11: Eye Image With Glasses



28

With subjects wearing eyeglasses, generally tilt the eye camera inwards, towards the eye,

raising the position of the eye on the eye monitor. Then tilt the hot mirror outwards, until

the eye drops back down to the center of the monitor and the glare spots from the IR

illuminator move downwards, off the pupil area.

Figure 4.12 below demonstrates the adjustments required to obtain clear pupil and

corneal reflection images with subjects wearing eyeglasses.

Figure 4.12: Eyeglasses Adjustments



29


The eye tracker controls are located in the upper left hand side of the LSW main software

window. (See Figure 4.1) The control panel is configured for monocular eye tracking and

consists only of controls for Eye 1. The control panel contains all the functional

adjustments necessary to threshold and automatically track the pupil and corneal

reflection eye landmarks.

Figure 5.1 Eye Tracking Controls Panel

As shown in Figure 5.1 above, there are controls for the following functions:

A. Threshold: displays the threshold level of the detected pupil and corneal

reflection areas

B. Pupil Threshold Slider: Controls the threshold level for the pupil

C. CR Threshold Slider: Controls the threshold level for the corneal reflection

D. Pupil X-Hairs: Enables the pupil crosshair display on or off

E. CR X-Hairs: Enables the corneal reflection crosshair display on or off

F. CR Limit: Turns on and off a pre-set search limit for the corneal reflection

G. Image Gate: Turns on and off a two-dimensional image gate; eye tracking is

active only inside the gate boundaries

H. Auto: Enables automatic thresholding of pupil and corneal reflection



30

A. Threshold

The threshold function is enabled when the threshold box is checked. This function

displays on the eye monitor a bright overlay on the pupil, the level of which is controlled

by the pupil threshold slider (B) on the right side of the control panel. It also displays a

dark overlay on the bright corneal reflection; its level is controlled by the CR slider (C).

The eye tracker also has an automatic threshold mode (H), in which the eye images are

automatically processed by the eye tracker to select the optimal pupil and corneal

reflection threshold levels. The baseline settings for the automatic threshold controls for

the pupil and corneal reflection can still be adjusted via their respective slider controls,(B)

and (C).

Become familiar with the manual threshold adjustment procedure before using the auto

threshold mode. For optimal tracking of the eye, the pupil threshold level should first be

adjusted so the dark areas corresponding to the pupil are completely filled in with the

bright threshold overlay. Adjust the pupil threshold slider (B), up until the pupil is filled

in with the bright overlay. Watch the eye image carefully and adjust the pupil threshold

slider until the level looks like that in Figure 5.2 below

Figure 5.2: Pupil Threshold Adjustment



31

Next, the CR threshold control must be adjusted to detect and fill in the small bright

corneal reflection with the dark overlay. The images below in figure 5.3 show the proper

level of the CR threshold, adjusted using the CR threshold slider control (C). Note that

there is a dark threshold overlay covering the bright corneal reflection when the CR

threshold is properly adjusted. The following eye images also illustrate CR threshold

levels that are too high and too low.

Figure 5.3: Corneal Reflection Threshold Adjustment

When the pupil and corneal reflection threshold levels have been set in the proper range,

enable Track Active Figure 4.1 (4). If the Pupil X-Hairs and CR X-Hairs functions are

enabled, Figure 5.1 (D) and (E), turning on track active control enables eye tracking and

graph display functions. With both Track Active and the Pupil and CR X-Hairs on, you

should see a black cross hair centered on the pupil. The black pupil cross hair is displayed

on top of the bright threshold overlay.



32

The corneal reflection cross hair is also displayed, superimposed over the dark corneal

reflection threshold overlay. The eye image should look like the image shown in figure 5.4

below.

Figure 5.4: Corneal Reflection Crosshair with Threshold

The Pupil X-Hair function turns on and off the pupil cross hair. If the crosshair is present

and is solidly locked on the center of the pupil as the subject looks around, the pupil is

being properly tracked by the RK-826PCI eye tracker card. Note that the pupil cross hair

appears dark when the threshold function is enabled and turns bright when the threshold

function is turned off.

The CR X-Hair function turns on and off the corneal reflection crosshair. If the crosshair is

present over the center of the corneal reflection and is solidly locked onto the corneal

reflection as the subject looks around, the CR is being properly tracked by the eye tracker

circuit card. Note that the CR crosshair appears bright when the threshold function is

turned on and it changes to a dark crosshair when the threshold function is turned off.

Figure 5.5: Pupil & CR Crosshairs with Threshold Display Off



33

The image below in Figure 5.6 shows what a good eye image looks like with the threshold

and crosshair functions enabled. As the subject looks around the center +/-20 degrees of

visual angle the pupil and corneal reflection crosshairs should be solidly tracking their

respective targets.

Figure 5.6: Good Eye Tracking Image

The CR Limit function Figure 5.1 (F) enables a user programmable search area around

the pupil for detection of the corneal reflection. This function can be used if there are other

bright corneal reflection candidates in the eye image that might compete for detection as a

corneal reflection target. This function is normally disabled in system operation. The

system operator can define the search area for the corneal reflection based on a percentage

of distance form the pupil center. To adjust the CR limit, click on the AUX 1 or the AUX 2

tabs just to the right of the Eye 1 and Eye 2 control panels. The CR % numbers can be

adjusted to detect the corneal reflection within a plus/minus percentage of the pupil

horizontal and vertical size. The default detection area is 150% of the pupil horizontal size

and 150% of the pupil vertical size.

The Image gate function, see Figure5.1 (G), turns on or off a user adjustable two

dimensional window on the eye monitor display within which the pupil and corneal

reflection threshold and tracking functions are active.

The operator can adjust the top, bottom, left and right sides of this two-dimensional box or

gate over the full extent of the eye imaging area. Figure 5.7 shows the eye image with the

image gate feature turned both on and off.

IMPORTANT: getting a good trackable eye image is possible with

virtually every subject by using a combination of the camera and

mirror position adjustments and by adjusting the pupil and corneal

reflection threshold levels. In addition, adjustment of the span of the

image gate may help to eliminate some eye image artifacts.



34

Figure 5.7: Eye Image Gate

The video eye image area over which the eye is tracked is represented by a 0 - 511 pixel

horizontal by 0 - 255 TV line vertical matrix. All pupil and corneal reflection position data

and image gate position data is with respect to this grid. The horizontal edges of the image

gate can be adjusted between 0 - 511 pixels and the top and bottom edges between 0-255

TV lines.

To move the position of the image gate, click on the AUX 1 or AUX 2 panels just to the

right of the EYE 1 and EYE 2 control panels, in the Eye Tracking Controls area in the

DQW software window. Figure 5.8 shows the typical settings in the AUX panel.

Enter 3 digit numbers with the keyboard or use the mouse to scroll the numbers

associated with the left/right/top/bottom boundary settings, as shown in figure 5.8.

Figure 5.8: AUX Control Panel



35

In addition, in the eye tracking AUX control panels, there are settings for the maximum

and minimum pupil and corneal reflection area limits. These minimum and maximum

values enable the operator to spatially filter the eye images to detect the pupil and corneal

reflections that may be in the presence of dark shadows or bright reflections that might

compete with the desired targets for recognition by the eye tracker electronics. The

standard pupil and corneal reflection area limit settings are shown in figure 5.8 above.

At this point, if the pupil and corneal reflection are both robustly tracked by the eye

tracker, the next procedure is the alignment of the scene camera.

Adjustment of the Scene Camera

The scene camera is positioned between the eyes above the nose, on the headset, facing

outwards. The scene camera is mounted on a tilt mechanism that allows the operator to

move the scene camera up and down to align the scene image with the subject's central

field of view. The scene camera is press-fit into a ring holder that also allows rotation of

the camera to straighten out the scene image if necessary.

! Tilt the scene camera to line up the center of the scene image as displayed on the

scene monitor with the center of the subject's field of view.

! If required, rotate the scene camera to straighten the scene image displayed on the

scene monitor.



36



Section 6: Eye/Scene Calibration

37

Section 6: Calibrating the Eye to the Scene

The ETL-600 system incorporates two distinct calibration procedures. The first calibration

procedure is called the point-of-regard calibration, which maps the eye position data to the

matrix of the head-mounted scene camera. The second calibration procedure is called the

eye angle calibration, which combines both the eye and head position data and maps them

to the global view camera’s image matrix.

Overview of Point-of-Regard Calibration Procedure

The point-of-regard calibration procedure can be performed either before or after the eye

angle calibration procedure. The point-of-regard calibration procedure maps the eye

position data calculated by the RK-826PCI eye tracker to the matrix of the head-mounted

scene camera.

The subject is instructed to view five calibration points within the field of view of the head-

mounted scene camera, resulting in a real-time indicator, superimposed over the video

display from the head-mounted scene camera, indicating precisely where in the image the

subject is looking. The point-of-regard calibration is covered in detail in this section.

Overview of Eye Angle Calibration Procedure

The eye angle calibration procedure combines both the eye and head position data and

maps them to the image matrix displayed by the global view camera. The global view

scene camera is fixed, generally to the side of the subject, and views a wide-angle image of

the subject’s visual field that includes the planar surfaces of interest to the experimenter.

The subject is instructed to look at five calibration points that are calculated by the

ISCAN software to be projected on a planar surface in front of the subject. The system

operator manually moves a laser pointer to superimpose the red laser spot precisely over

the position of each calibration point, as shown on the global view camera display. The

result of this calibration procedure is a real-time indicator superimposed over the global

view display showing precisely where the subject’s head and eye are pointing. This

calibration procedure precisely shows the subject’s combined head and eye position (also

called the line of sight or LOS) as it intersects with the planar surfaces surrounding the

subject.

Before the eye angle calibration can commence, the system operator must identify the

coordinates of the planar surfaces with respect to the 0X, 0Y, 0Z origin of the head tracker

source. These same planar surfaces also are to be defined with respect to the global view

camera matrix and this complete eye angle calibration procedure is described in detail in

Section 7.

Point of Regard Calibration

After the scene camera is properly aligned and the eye is tracked robustly while connected

to the eye tracking computer, a simple calibration procedure has been devised that first

instructs the subject to look at 5 points within the field of view, as seen by the operator on

the scene monitor display, to correlate the eye data to the scene image display. This

calibration procedure results in a point of regard output in which an indicator is

superimposed over the scene image showing precisely the subject's real-time point of gaze.



38

Wearing the headset, the subject will be instructed to complete a calibration procedure

that involves looking at a series of 5 calibration targets mounted on a flat surface, such as

a wall or work area.

The five calibration targets should include a center calibration point and four outer points,

positioned at ±8 to ±10 degrees of visual angle with respect to the center.

The subject will then be verbally instructed by the operator to look at the 5-point

calibration target pattern mounted on the flat surface at a distance of about 3 to 5 feet

from the subject. The system operator must manually line up an indicator to be

superimposed over each of the 5 calibration points and enter the raw eye position data for

each point. After this calibration procedure, the subject is free to move about in their

environment, and the point of regard is represented as that same indicator moving about

over the scene monitor display.

Setting Up the Calibration Targets

The calibration points are 5 high contrast stick-on targets that can be affixed to a wall,

computer screen or other flat surface. The typical eye to calibration point distance should

be set for the approximate range of the eye to stimulus distance expected in the

experimental set up. Set up the targets as shown in Figure 6.1 below, attaching the

stickers (supplied) to the front of the monitor.

Figure 6.1: Calibration Procedure

After the calibration points have been set up as described above, the subject should put on

the headset, and clip the cable to an article of clothing for stability.

Have the subject sit in the chair positioned approximately 2 to 5 feet from the calibration

targets. Ask the subject to look in the general area of the calibration targets on the surface

facing the subject.



39

Checking the Eye and Scene Images

Verbally instruct the subject to keep their head relatively still and look at the center

calibration target. Make sure that all 5 of the calibration targets are clearly visible in the

scene image and that the pupil and corneal reflection eye landmarks are robustly tracked

as the subjects looks at each calibration point in turn. Only after this quick check of the

eye and scene data, can the calibration procedure begin.

The Point of Regard Calibration Procedure

The ETL-600 is now set up to allow the operator to perform a calibration of the eye data.

The monocular eye tracker position data (represented by the positions of the pupil and

corneal reflection cross hairs on the eye monitor display) will be transformed into point of

regard coordinates by the calibration procedure.

In the calibration procedure, the eye position data will be related mathematically to the

known calibration points visible in the scene monitor display.

A calibration model will be constructed by the RK-630PCI Autocalibrator processor that

relates the subject's eye position data to coordinates in a matrix superimposed over the

scene video display, yielding real time point of regard position. The point of regard is

represented as an indicator that moves over the images of the scene.

Figure 6.2: RK-630 POR Scene Image

The scene image is represented by a 0 -511 pixel horizontal by 0 - 511 TV line vertical

matrix. The point of regard indicator is comprised of a cross symbol that represents the

position of the subject’s left eye, as shown in Figure 6.3 below.

Figure 6.3: Symbol of Point of Regard

The point of regard indicator is drawn by the RK-630PCI as a combination of

black and white symbology so it can be visible to the system operator when

superimposed over scene images that contain both bright and dark scene content.



40

The data display feature overlaid on the operator monitor output of the RK-630PCI

indicates pupil diameter in pixels, horizontal and vertical point of regard within the 0 -511

matrices and a real time 60Hz elapsed time clock that may be used to time events or to

synchronize the recorded video output with stored point of regard data in the eye tracker

computer.

Figure 6.4: POR Data Display

Performing the Point of Regard Calibration

Click on Track Active and then click on the Scene Monitor expansion box to the upper

right of the Scene Monitor display. This enlarges the scene image so it can be clearly

viewed by the operator. In addition, clicking on the expansion box calls up the P.O.R.

Calibration Controls, directly below the Eye Tracking Controls panel. (In some older

software versions it may be necessary to manually click on the Options button to cycle

through the panel selections until the P.O.R Calibration Controls appear).

Figure 6.5: POR Calibration Control Panel with Large Scene Image

The POR Calibrator starts up in the RESET mode. In the RESET mode, the operator can

move the point-of-regard indicator over the area of the scene monitor display by using the

mouse to place the cursor inside the gray pseudo-screen area, clicking and dragging the

operator’s active calibration point, thereby moving the POR indicator in the scene monitor.

Make sure that the subject's eye is open and that the center calibration point is clearly

visible in the scene image.

Click the POR Calib button in the POR Calibration Control panel, and the status box

below POR Calib will read CENTER.

Verbally instruct the subject to keep the head relatively still and to look at the center

calibration target.

Position the cursor in the gray calibration pseudo-screen and click and drag to line up the

POR indicator, as viewed on the expanded scene monitor display, directly over the center

calibration target. Precise positioning of the indicator is achievable using the rollers on the

numeric display directly below the pseudo-screen.



41

Confirm that the subject's eye images are similar to those shown in Figure 6.6 below,

appearing to look straight ahead at the center point of the calibration targets. Make sure

as well that the pupil and corneal reflections are properly tracked as indicated by the

position of the related cross hairs. If necessary adjust the pupil and corneal reflection

threshold levels for proper tracking and position the image gate to more tightly encompass

the eye landmarks, as described in section 5 above.

Once the eye is properly tracked and the POR indicator is lined up over the center

calibration target, enter the center calibration point by right clicking on the mouse while

the cursor is in the gray pseudo-screen box. If the subject inadvertently blinks or closes

their eye as the data is entered, this may result in the input of bad data to the calibration

model. If this happens, click on RESET and start the calibration procedure over or use the

SELECT control to go to the CENTER point again.

Figure 6.6: Center Calibration Point

As soon as the calibration point has been entered, the status box will indicate UPPER

LEFT and the upper left calibration indicator will be circled in the pseudo-screen.

Now, while keeping their head still, instruct the subject to shift their fixation and stare at

the upper left calibration target.

Watch the eye images carefully to see the subject shift their fixation to the upper left

calibration target and then, with the operator’s cursor positioned in the gray pseudo-

screen, click and drag the POR indicator exactly over the upper left calibration target as

shown in Figure 6.7. If necessary, use the roller controls below the pseudo-screen to

precisely position the indicator over the upper left calibration target.

Again, make sure that the eye is clearly visible and is properly tracked.



42

Enter the upper left calibration point by right clicking in the gray pseudo-screen.

Figure 6.7: Upper Left Calibration Point

After entering the upper left point, the calibrator will automatically indicate the UPPER

RIGHT in the status box and the circle in the pseudo-screen will move to encircle the

upper right calibration point.

Instruct the subject to fixate the upper right target and carefully watch the eye image

until you see the subject's fixation shift to the upper right calibration target. Move the

calibration indicator so it is exactly overlaid on the upper right calibration target, again

making sure that the eye landmarks are being properly tracked. With the operator’s

cursor in the pseudo-screen, right click the mouse to enter the upper right calibration

point.



43

Figure 6.8: Upper Right Calibration Point

Repeat the above steps for the LOWER LEFT and LOWER RIGHT calibration points.

Refer to Figures 6.9 and 6.10 for representations of the LSW screens at these points.

Figure 6.9: Lower Left Calibration



44

Figure 6.10: Lower Right Calibration

After successful entry of all 5 calibration points, click on RESET in the POR Calibration

Controls panel. At this juncture, the 5 point calibration model is calculated by the RK-630

Autocalibration system and the POR OUT button should become active, and ready to be

enabled.

Click on the POR OUT button. If the 5 point calibration was successful, and the subject is

still at the 3 to 5 foot distance from the calibration targets, the point of regard indicator

generated by the calibration model should be overlaid onto each of the calibration targets

when the subject is instructed to look at them in turn. When satisfied with the results of

the calibration, the operator should now peel off the calibration stickers.

Figure 6.11a: POR Output Active After Calibration



45

Figure 6.11b: POR Tracking Enabled After Calibration

A BNC "T" is provided with the system to tee off the RK-630PCI Operator Video Output

for recording purposes.

Note that after the calibration has been completed and POR OUT enabled, the POR

calibration indicator can also be manually offset by the operator using the horizontal and

vertical roller controls below the gray calibration pseudo-screen. This function can be used

to fine tune the output as necessary without re-calibrating the subject.

This completes the standard point of regard calibration procedure for the ETL-600.

Calibration Auxiliary Controls

The tab labeled "AUX 1" to the right of the main POR Calibration Controls panel allows

the operator to adjust various parameters relating to the POR calibration system. Figure

6.12 describes the various parameters that can be adjusted below.

Figure 6.12: POR AUX Panel Settings for Monocular Operation

SOURCE refers to how the data from the eye is gathered and displayed as a point of

regard indicator, “A” mode meaning the signal from the left eye.

The ICON setting controls the representation of the point of regard indicator. The default

mode is SYMBOL, a stylized plus shown in Figure 6.3. XHAIR is a full screen cross hair.

EDGE HAIR is a bright pip within dark borders displayed at the right and bottom edges of

the scene monitor display.

POR Avg denotes the number of video field averaging of the point of regard indicator. The

POR Avg is selectable from 1 to 24 video fields.



46

Storing a Calibration Model

Once a successful calibration model for a subject has been calculated by the calibration

and offset procedure, the operator can save this model to be run again with the same

subject.

After a successful calibration of the recorder output, to save a calibration model, disable

Track Active and click on the file menu in the upper left hand side of the LSW software

window.

From the file menu, select "SAVE ISCAN POR CALIB FILE AS..."

Figure 6.13: LSW Window With the Save Selection

The SAVE POR CALIBRATION FILE window will open and the operator should direct

the SAVE IN location to be the ISCAN LSW folder.

Type an identifying file name, making sure to have a .pcl file-type suffix, and click on the

SAVE button.



47

Figure 6.14: Save Calibration File Name

Recalling a Calibration Model

To open a previously saved calibration file, disable Track Active and click on the file menu

in the upper left of the LSW software window.



48

Figure 6.15: Open Calibration File

Select "OPEN ISCAN POR CALIB FILE..." from the drop down file menu.

The OPEN ISCAN POR CALIB FILE window will open and select the appropriate .pcl file

by double clicking on it.

The calibration file will be automatically loaded into the calibrator.

Now, when the POR Calibration Control panel is brought up, either by clicking through

the OPTIONS button or expanding the scene image display, the POR OUT control will be

active as shown in Figure 6.16 below, and able to be turned on by the operator.

Figure 6.16: POR Out Active

Enable Track Active and then click on the POR OUT control button to run the recalled

calibration model.


Section 7: Eye Angle Calibration

49


This procedure is the most complicated part of the ETL-600, as it involves measuring and

entering data to correspond to the position of the planar surfaces surrounding the subject.

The ETL-600 is normally used to automatically calculate where the combined eye and

head vector (the LOS) of the subject intersects various planar surfaces that surround the

subject in a real-world environment. The subject might be seated in a car or aircraft

cockpit, in a power plant simulator, or surrounded by a grouping of computer monitors.

The ETL-600 is used to display exactly where, at what time, and for how long the subject

looks at objects of interest to the experimenter in the surrounding work area. The planar

surfaces can include instrument clusters, radar screens, consoles, windows, or any group

of objects that can be reduced to planar surfaces.

Part A: Mapping of the Planar Surfaces

The planar surfaces must be mapped with respect to an origin point, at location 0X, 0Y,

0Z. This origin point is the center of the magnetic source cube, and the X, Y, and Z axes

are shown in Figure 7.1.

Figure 7.1: 3D Mapping of Multiple Planar Surfaces



50

The directions of the X, Y, and Z axes follow the right-hand rule:

" The X-axis is positive in front of the magnetic source pointing towards the first planar

surface and negative out the back of the source.

" The Y-axis is positive pointing out of the left side of the source and negative going out

of the right side of the source.

" The Z-axis is positive exiting the top of the source, and negative pointing towards the

bottom, of floor of the room.

The first planar surface is called Plane 1, and should be specified as the planar surface

most central and normal in the subject’s field of view.

An example using three planes is shown in Figures 7.2a and 7.2b. A 26” diagonal

computer monitor is positioned in front of the subject and is defined as Plane 1. Plane 2 is

a 17” diagonal computer monitor positioned to the right-hand side of the 26” monitor and

tilted inwards at a 45° angle. Plane 3 is a 17” diagonal computer monitor positioned to the

left-hand side of the 26” monitor and tilted inwards at a 45° angle. (The diagram in Figure

7.2b shows only Planes 1 and 2.) The center of magnetic source cube is positioned 41” in

front of the right edge of the monitor. The height of the magnetic source is adjusted so the

center of the source is 44” from the floor.

Figure 7.2a: Multiple Planar Surfaces (Viewed from Above)



51

Figure 7.2b: Multiple Planar Surfaces (Partial View)

Note that the X, &Y, and Z coordinates of the planar surface, in this case a computer

monitor, are measured at the edges of the active LCD monitor area. Once the X, &Y, and Z

coordinates have been measured, using the supplied tape measure, they must be entered

into the ISCAN Environment Planes Layout Editor.

To enter the coordinates of the planar surfaces into the ISCAN Environment Planes

Layout Editor , follow the steps below:

Disable Track Active, and click on the multi-color planar surface icon on the top icon row

at the top of the LSW software as shown in Figure 7.3.



52

Figure 7.3: Environment Planes Layout Icon

The ISCAN Environment Planes Layout Editor panel will come up, shown in Figure 7.4a.

Figure 7.4a: Environment Planes Layout Editor for Plane 1

Using the rollers to the right of the Total Planes box, enter the number of planar surfaces

to be designated. (In this example we are using 3.) Select the first plane to edit as 1. Select

Calib Plane as 1.



53

Plane 1 should be designated as the planar surface in front of and normal to the subject.

Plane 1 is always used as the calibration plane for the eye angle calibration.

Figure 7.4b: Measurements to Establish the Relationship of Magnetic Source to Plane 1

Using the tape measure provided, measure the distance of the center of the magnetic

source cube to the front surface of plane 1. (Note: all measurements must be in inches.) If

plane 1 is perpendicular to the table it is sitting on, this distance can be entered into all of

the four X coordinates. In the example shown in Figure 7.5a, the X distance for the upper

left, upper right, lower left and lower right coordinates is 41.00”.

Since the center of the source cube is positioned on a line with the right edge of the

monitor designated as Plane 1, the Y coordinates of the upper right and lower right points

will be 0.00, and should be so entered.

The distance of the upper left and lower left points on the Plane 1 monitor from the center

of the source is 23.00” in the positive Y direction and can be entered as 23.00 for the upper

left and lower left Y coordinates.

The center of the source is measured as 44” from the floor. The upper left and upper right

coordinates of the monitor are measured to be 48” from the floor. To get this number we



54

first measured the distance to the tabletop from the floor as 31”. The top edge of the

monitor is an additional 17” from the surface of the table. Therefore, the Z coordinates for

the upper left and upper right coordinates is 4.00”.

The lower left and lower right coordinates of the monitor are measured as 4” up from the

surface of the table, 35” from the floor, a difference of -9.00” from the center of the source.

Therefore the lower left and lower right Z coordinates are both -9.00”.

Refer back to Figure 7.4a to see the ISCAN Environment Planes Layout Editor with these

coordinates entered.

Using the mouse and computer keyboard, now manually enter the X, Y, and Z locations for

the edges of the upper left, upper right, lower left and lower right coordinates for the first

planar surface into the manual plane coordinate entry boxes. Again, make sure all

measurements are entered as inches.

The Edit Plane Info controls at the left hand side of the Manual Plane Coordinate Entry

panel can be used to fine-tune the X, Y, and Z position of the planar surface, once the

coordinates have been manually entered. For example, once the properly measured

coordinates of a planar surface have been manually entered, and it becomes necessary to

move the position of the magnetic source slightly closer or farther away from the plane in

the X direction, you can set the Increment in inches to values of 0.25” and click on the Left

X Pos arrow to move the plane farther away from the 0,0,0 origin of the magnetic source.

Enter the coordinates for Planes 2 and 3 as shown in Figure 7.5b below.

Figure 7.5: Environment Planes Layout Editor for Planes 2 & 3

After all of the plane coordinates have been entered, click OK to get back to the ISCAN

LSW Main Screen.



55

Part B: Registration of Planar Surfaces with the Global View Scene Monitor

The next required mapping procedure is to register the positions of the mapped planar

surfaces with the global view scene camera.

The global view scene camera should be positioned to the side of the subject’s work area to

view all the planar surfaces. In this example, we have a 3-monitor display. The center

monitor is a 26” diagonal, and both of the side monitors are 17” diagonal LCD monitors.

Adjust the position of the global view camera to encompass all the planar surfaces. Adjust

the focus and iris settings of the lens to present a clear, in-focus image of the environment

a shown in Figure 7.6.

Figure 7.6: Monitor Schematic

To register the positions of the planar surfaces to the global view scene image, first click

on the box to expand the global view monitor so it can be seen clearly by the system

operator. Figure 7.7 shows the global view scene camera output displayed on the global

view monitor.



56

Figure 7.7: Global View Monitor

Note that when the global view monitor is expanded to fill the graph areas, the video

display unit controls appear in the Auxiliary Control panel. In older versions of the LSW

software, it may be necessary to click on the Options button until the VDU controls

appear. The VDU Control panel is shown in detail in Figure 7.8.

Figure 7.8: Video Display Unit Control Panel

To begin the registration procedure, select the VDU2 panel for Global View, and select

Plane 1 in the Plane # box by clicking on the roller arrows. With Plane 1 selected, click on

the top roller arrow of the Active Item box to select the center plane registration point.

Center will appear in the Active Item box, and 5 small registration squares will appear in

the gray pseudo-screen area. The center registration square is circled, indicating that the

registration point indicator must be positioned by the operator over the geometric center of

the first planar surface, as seen in the global view monitor display.

Use the mouse to click on and drag the circled registration square, and move it around in

the gray pseudo-screen area until the registration point indicator is positioned over the



57

geometric center of Plane 1 in the Global View Monitor. After the indicator is positioned as

shown in Figure 7.9, releasing the mouse button registers the center point. Now left-click

on the Active Item up arrow to select the upper right registration point.

Figure 7.9: Center Point Registration

Again position the cursor in the gray pseudo-screen. Click and drag until the upper left

registration point indicator is precisely over the upper left corner of the active area of the

planar surface. See Figure 7.10.

Figure 7.10: Upper Left Point Registration

Repeat this procedure for the upper right, lower left, and lower right points, as shown in

Figure 7.11.



58

Figure 7.11a: Upper Right, Lower Left, Lower Right Points Registration

Once the first plane has been registered, so that all four corner points and the center point

have been ascertained, click on the Active Item box so that it is cleared, as shown in

Figure 7.11b. This allows registration to move to the next plane.

Figure 7.11b: Clearing the Active Item Box

The entire procedure must be repeated for all subsequent planar surfaces.



59

In the Global View Image display, as seen in Figure 7.12a, there are three planar surfaces,

Plane 1, Plane 2, and Plane 3. For this example, Plane 2 is the right-most 17” computer

monitor, and Plane 3 is the left most.

Figure 7.12a: Global View Image Display of Multi-Plane Area

Click on the Up roller next to the Plane # box to increment the Plane number. Figure

7.12b shows each of the video display unit controls with Plane 1, Plane 2, or Plane 3

selected. As described above for Plane 1, align the center, upper left, upper right, lower left

and lower right registration points in the corresponding corners of the planar surfaces.

Figure 7.12b: VDU Control Panels for Multiple Planes Registration

When each of the planes has been registered with respect to the global view monitor

image, the LSW software can then mathematically calculate the intersection of the 6-

degree-of-freedom head position data coming from the Polhemus head tracker, and display

the intersection of the head vector with the planar surfaces on the global view image.

Once the planar coordinates for the surfaces of interest have been entered, it is a good idea

to check the measurements a second time for accuracy and uniformity. For example, in

reviewing the data for the three planar surfaces entered in this instructional

configuration, the Z coordinate for the lower left and lower right points for all three planes

must be -9”, the same for all the monitors since the bottoms of all the monitors are aligned

as shown in Figure 7.13.

They are all the same height with respect to the center of the magnetic source, the origin.

A quick check of the coordinate data should show up any inconsistencies in data entry or

measurement.



60

Figure 7.13: Matching Z Coordinates



61

When the system operator is confident that the data is properly entered in the ISCAN

Environment Planes Layout Editor, and each of the planes has been registered in the

global view video display unit controls panel, it is time to actually run the head tracker

with the LSW software and verify that the head data is properly interfaced to the LSW

program, and that it is properly intersecting the planar surfaces as measured and input to

the LSW program. After the head position data is verified, the system operator can

commence with the eye angle calibration.



62

Part C: Verification of Head Vector Intersection with Planar Surfaces

At this point, exit from the LSW program. To exit from the program, disable Track Active,

click on the file menu in the upper left hand side of the LSW screen, and select the exit

command. Click the OK button to confirm program exit. The Windows 7 start-up screen

with the ISCAN ETL-600 icon is now visible.

Have a test subject put on the headgear, adjust the rear lanyard strap for a comfortable

tight fit, and clip the cable clips to the subject’s clothing to stabilize the headgear and

cables.

Have the subject sit in front of the magnetic source, keeping the head tracker sensor on

the right-hand side of the head within about a foot or so of the source. While looking at the

scene monitor in the LSW control window, adjust the tilt and/or rotation of the scene

camera as necessary to encompass the center monitor (Plane 1). Review Section 6 if

necessary. (If no subject is available, put the headgear on the mannequin head and

position it on a box or some books to put it in the same physical space as a human subject

would be positioned in front of Plane 1.)

The global view monitor display should show the subject seated in front of the center

monitor, and the other two planar surfaces should also be visible to the greatest extent

possible. (The subject will inevitably block a portion of the view.) See Figure 7.14.

Figure 7.14: Global View Scene Image Display

Turn on the Polhemus head tracker. (If it is already on, turn it off and then on.) Observe

the Sys Status LED on the front right of the head tracker panel. It should flash a few

times red, and then turn green, indicating successful power-up.



63

Only after the head tracker green status LED is on, double-click on the ISCAN LSW icon.

After the LSW program opens, click on Track Active. Immediately, graphical data should

appear in Graph B, showing the real-time measured positions of the head X, Y, Z and

Azimuth, Elevation, and Roll data. The LSW window will appear as in Figure 7.15 below.

Figure 7.15: LSW Window with Mannequin Head Data.

Note that the head position numbers are appearing as stable values, indicating there is

minimal movement between the head sensor and the source.

Click the Options button until the Eye Angle Calibration controls panel is visible in the

Auxiliary Controls panel.



64

Figure 7.16: Eye Angle Calibration Controls Panel

The eye angle calibration panel should open in the Reset mode. Below the Calibrate

button is an operator-selectable angle in degrees. This is normally set in the five to eight

degree range and represents the plus/minus eye angle in degrees that the subject will be

instructed to look at for the eye angle calibration

The Angle Out control button is disabled (grayed-out), but will become enabled after the

calibration procedure has been completed.

The Boresight Head button establishes a center location on the first planar surface that

corresponds to where the subject should be instructed to begin the eye angle calibration

procedure. The Boresight command basically “zeroes out” the position of the head sensor

with respect to its position to the source origin and positions. The intersection of the head

vector at the center of Plane 1 is, in most cases, the center of the screen directly in front of

the subject.

Click the Boresight Head button once and watch to see whether the head position

indicator appears on the global view monitor as shown in Figure 7.17.



65

Figure 7.17: ETL-600 Boresight in Center Plane 1

If the head position intersection indicator is not exactly in the center of Plane 1, click the

Boresight Head button one or two more times to adjust it closer to the center position.

Once the head position intersection indicator has appeared at the center of Plane 1 in

response to the Boresight Head command, instruct the subject to move his or her head

linearly pointing towards the multiple planar surfaces, or just rotate the mannequin head

to point at the surfaces. As the head is rotated, the head position intersection indicator

should move linearly over the mapped planar surfaces, as shown in Figure 7.18 below.

NOTE: If there is no indicator appearing anywhere within Plane 1,

even though everything is set up as described above, check first that

all the head tracker output is visible in Graph B, and verify that

they respond to real head movements. If the head position graphs

are not moving, exit the LSW program and re-start the Polhemus

head tracker before opening the LSW program again. Otherwise,

check that the planar coordinates have been measured correctly and

have been properly entered into the plane editor panel.



66

Figure 7.18: Movement of the Head Vector Intersection Indicator

Tilting the head up will also move the target head intersection indicator up in the global

view display, while tilting the head down will have the opposite effect.

As the head moves between the planar surfaces, the head vector indicator should

disappear at the edge of one monitor, and re-appear at the active area of the adjacent

monitor. This test of the head intersection with the planar surfaces confirms that the

planar coordinates have been properly entered, and that the registration points of the

planar surfaces to the global view monitor have been properly aligned over each plane.

Upon successful completion of this step, the operator can proceed to the eye angle

calibration.



67

Part D: Eye Angle Calibration

The eye angle calibration procedure involves prompting the subject to look at five points of

known degree of visual angle with respect to the head position vector. Upon completion of

the eye angle calibration, the combined eye and head vector intersection with the planar

surfaces will be superimposed over the global view monitor as a real-time indicator, in

place of the head-only vector seen by the operator and described in the previous section.

The angular magnitude of each of the five calibration points will be summed with the head

vector, and the operator will be shown the precise point that the subject should look at,

superimposed over the global view monitor. The five calibration points are arranged in a

cross pattern: Center, Left, Right, Top, and Bottom.

With the human subject seated in front of plane 1 and facing normal to the plane, enable

Track Active. Enlarge the global view monitor, then click the Options button until the eye

angle calibration controls panel is visible. With the subject’s head and eyes pointing

straight at the center of Plane 1, click the Boresight Head button several times in

succession until the head intersection indicator is in the center of Plane 1 as shown in

Figure 7.19.

Figure 7.19: Boresight in Center Plane 1

Click on the Calibrate button in the eye angle calibration controls, and five calibration

points will show up in the gray pseudo-screen, as shown in Figure 7.20.



68

Figure 7.20: Eye Angle Calibration Center

The first calibration point is the center, as indicated in the dialog box directly below the

gray pseudo-screen, next to the Enter Cal button. The center calibration point is also

circled in the gray pseudo-screen.

The position of the center calibration point that the subject should look at is projected onto

the operator’s global view monitor (ISCAN’s point-of-regard symbol discussed in Section 6,

and used here as the subject’s eye and head vector intersection indicator), and the system

operator must instruct the subject to look at that precise point on the screen of the Plane 1

surface. Note that the indicator moves as the subject moves his head, so the subject should

be instructed to make every effort to remain relatively still during the calibration process.

There are two methods for directing the subject where to fixate. If the Plane 1 computer

has its own mouse, the operator can use that mouse to line up the indicator for the Plane 1

monitor precisely at the indicated point on the screen as shown on the global view

monitor. Alternatively, the operator can position the laser pointer precisely so that its red

dot is superimposed over the open control area in the indicator that is seen on the global

view monitor image.

Figure 7.21: Laser Pointer Inside Center of Indicator



69

The operator must carefully position the laser spot or indicator so it is within the open

center area of the indicator (see Figure 6.3), to correlate the eye position data with the

center calibration point.

Make sure that the eye parameters are properly tracked (Section 5, Tracking the Eye)

when instructing the subject to fixate the indicator or red dot. Click the Enter Cal button

or right-click the mouse positioned in the gray pseudo-screen area to enter the center

calibration point eye position data.

As soon as the center point is entered, the circle will jump to the left calibration point, and

the dialog box will read Left. The indicator’s position on the global view monitor will move

to the left by the increment in degrees selected by the operator. (In this example, the

calibration increment is 5 degrees.) The operator must again line up either the mouse or

the laser spot to be visible to the subject at exactly the point on the Plane 1 surface

covered by the center of the left calibration indicator on the global view monitor.

As soon as the operator has lined up the laser dot or indicator with the left calibration

point on the global view monitor, instruct the subject to look at it, check that the eye

parameters are being tracked, and right-click the mouse in the gray pseudo-screen to

enter the left calibration point.

Figure 7.22a: Left Calibration Point

The circle in the pseudo-screen will then surround the right calibration point, and the

dialog box will increment to Right. Follow the same steps as above for the Right, Top, and

Bottom calibration points.



70

Figure 7.22b: Right, Top, and Bottom Calibration Points

Click on the Reset button. This will cause the eye angle model to be calculated by the LSW

software, making the Angle Out control available for selection.

Click on the Angle Out control button, and the combined eye and head vector intersection

point with the planar surfaces will be displayed on the global view monitor as a real-time

indicator. Instruct the subject to fixate some easily defined points within the planar

surfaces to ensure that the calibration is good. One quick test is to move the laser spot

over the planar surfaces, ask the subject to look at it, and verify that the eye and head

vector intersection indicator is properly indicating the subject’s eye and head position.

At this juncture, the ETL-600 should be successfully calculating the eye and head position

of the subject’s viewing the planar surfaces in the surrounding environment.

Graph A, shown in Figure 7.23 below, displays the real-time plane number (PlnIntNum1),

in this example either 1, 2, or 3, and the X and Y locations over each of the planes. For

example, PlaneInt H1 is the X location of the planar surface in units between 0 and 511,

and PlaneInt V1 is the Y location of the planar surface in units between 0 and 511.

These three data packets identifying the plane number and X,Y location on the plane at

which the subject is looking can be output via the serial port to a host computer for real-

time operations or stored in the ISCAN eye tracking computer for off-line analysis.



71

Figure 7.23: Graph A in the LSW Window

Eye-Sensor Measurements

The eye angle calibration controls also contain an AUX1 tab. Clicking on the AUX1 tab

opens a panel that allows the operator to enter the precise X, Y, and Z offset (in inches) of

the subject’s left eye with respect to the position of the head position sensor, as shown in

the diagram in the AUX1 tab.

Figure 7.24: AUX1 Tab and Panel

Using the roller controls at the right-hand side of the X, Y, and Z data boxes, the operator

can dial in the appropriate values for the X, Y, and Z location of the subject’s left eye with

respect to the center of the head position sensor, along with the distance of the center of

the nose to the sensor. The nose-sensor distance becomes an important parameter when

the system is optionally configured for binocular eye tracking.

The X dimension in inches represents the distance the eye is from the center of the sensor,

in side view. The positive axis of the X direction is how forward the eye is to the sensor in

a side view.

The Y dimension, in inches, represents how far to the left or right the left eye is positioned

with respect to the sensor, looking straight on at the subject. The positive axis of the X

direction is to the right side of the sensor, viewed straight on, facing the subject.



72

The Z direction, in inches, represents the height of the left eye, with respect to the head

position sensor, looking at the subject straight on. The positive axis of the Z direction is to

the top of the sensor, as viewed straight on, facing the subject.

The negative value for the Z direction in Figure 7.24 indicates that the eye is 1.5” below

the level of the sensor, in the safety glasses headset.

Figure 7.25: Safety Glasses Headset, Two Views



73


The graph displays are located in the center of the LSW software window. The graphs

allow the operator to display and view any of the parameters associated with eye tracking,

input/output operations, or other auxiliary functions.

Any of the signals displayed in the graphs can be manipulated by the controls on the right

hand side of the graph displays to adjust their scale and position.

The main features of the graph display and control panel can be seen in Figure 8.1 below.

Please note that Track Active must be enabled for display of graph data.

Figure 8.1: Graph Control & Display Area

The parameter list box shows the parameter selected by the operator for display. Clicking

the green box to the left of the parameter display brings up a list of all parameters that

can be shown in the graphs. The list of allowable graph parameters depends on what

auxiliary functions might have already been selected by the operator running in the LSW

software.

For example, if the LSW software has been configured to monitor blinks [Section 9(A)],

then parameters relating to blink count and blink state will be available for graph display.



74

If the blink monitoring subsystem has not been enabled, these parameters will not be included in

the graph parameter selection list.

Double-click on the desired parameter to load it into the parameter display box.

To the right of the graph parameter display box is a numerical representation of the parameter

value. Further to the right is the graph color selection control panel. Clicking on the colored box

brings up a color panel display. Clicking on any of the color boxes will change the color of the

graph to the selected color.

Clicking on the Activation button enables all graph scaling control functions for this selected

graph parameter.

The scaling controls include a default button that automatically scales the graph to a default

value. For example, if the pupil horizontal position (PupilH1) is activated and the default button

is clicked, the scale of the graph defaults to the full screen range of the horizontal pupil position

matrix, 0 – 511.

- Gain Controls: The in and out buttons amplify or reduce the gain of the signal as shown on

the graph, with a corresponding increase or decrease of graph resolution as shown on the

scale on the left hand side of the graph display.

- Offset Controls: The up and down buttons shift the position of the signal up or down with

a corresponding shift in the position numbers (scale) on the left hand side of the graph

display.

- Invert Control: Clicking on the INV button inverts the polarity of the signal on the graph.

- Center Control: Clicking the CTR button automatically centers the signal on the graph

display.

- Center Control for Two Signals simultaneously: Clicking the Center A/B button,

positioned between the two graphs, centers two signals, each one that is activated in each

graph.

After the scaling of the graphs has been completed, the scaling controls for the graph parameter

can be de-activated by clicking the No Active Param Scale button. The analog output signals

remain scaled with the values loaded into the scaling controls.

Note that the range of an analog output signal is represented full-scale over the entire height of

the graph. For example, the +/- 5-volt range of the analog output signal will encompass the full

scale from top to bottom of the graph.

Please note in Figure 8.1 that the Activation

button for the graph scaling functions to the

left of the green parameter selection button.



75

A large number of parameters are available within the LSW software for recording or viewing

depending upon the particular hardware and software configuration.

Following is a table defining the representations of the most often encountered possible

parameters. Note that many of the listed parameters will NOT be available in your setup, but

might become active if other hardware or system configurations become operational.

In both the binary (.dqw) and ASCII (.tda) file versions, parameters appear as strings. Each file

type has a different set of string listings as shown in the appropriate columns below.

Parameter Label Parameter (.dqw) Param (.tda) Description

....................... PRM_NULL N/A No Selected Parameter

Eye Tracker #1

.Pupil.H1........ PRM_PUPILH1 Pupil H1 Eye Pupil Horizontal Center Position

.Pupil.V1........ PRM_PUPILV1 Pupil V1 Eye Pupil Vertical Center Position

.Pupil.D1........ PRM_PUPILD1 Pupil D1 Eye Pupil Horizontal Diameter

.Pupil.VD1....... PRM_PUPILVD1 Pupil VD1 Eye Pupil Vertical Diameter

.Pupil.A1........ PRM_PUPILA1 Pupil A1 Eye Pupil Area

.C.R..H1......... PRM_CRH1 C.R. H1 Eye Corneal Reflection Horiz. Position

.C.R..V1......... PRM_CRV1 C.R. V1 Eye Corneal Reflection Vertical Position

.P-CR.H1......... PRM_PCRH1 P-C.R. H1 Eye Pupil to Corneal Refl. Horiz. Difference

.P-CR.V1......... PRM_PCRV1 P-C.R. V1 Eye Pupil to Corneal Refl. Vertical Difference

.Blink.St1....... PRM_BLNKST1 Blnk St1 Eye Blink Status

.Blink.Cnt1...... PRM_BLNKCT1 Blnk Cnt1 Eye Blink Counter

Eye Tracker #2










.Blink.St2....... PRM_BLNKST2 Blnk St2 Eye Blink Status

.Blink.Cnt2...... PRM_BLNKCT2 Blnk Cnt2 Eye Blink Counter



76


Eye Tracker #3










Eye Tracker #4










Eye Trigger State

.Eye.Trig.0...... PRM_EYETRIG0 EyeTrig 0 Eye Trigger Status (Each Bit = 1 Trig State)

Point-of-Regard (P.O.R.) Calibrator #1

.POR.H1A......... PRM_PORH1A POR H1A Eye P.O.R. Horiz. Position (Source A)

.POR.V1A......... PRM_PORV1A POR V1A Eye P.O.R. Vertical Position (Source A)

.POR.RH1A....... PRM_POR_RH1A POR RwH1A Eye P.O.R. Raw Horiz. Position (Source A)

.POR.RV1A....... PRM_POR_RV1A POR RwV1A Eye P.O.R. Raw Vertical Position (Source A)

.POR.H1B......... PRM_PORH1B POR H1B Eye P.O.R. Horiz. Position (Source B)

.POR.V1B......... PRM_PORV1B POR V1B Eye P.O.R. Vertical Position (Source B)

.POR.RV1B....... PRM_POR_RH1B POR RwH1B Eye P.O.R. Raw Horiz. Position (Source B)

.POR.RV1B....... PRM_POR_RV1B POR RwV1B Eye P.O.R. Raw Vertical Position (Source B)

.POR.Mode1...... PRM_PORMODE1 POR Mode1 POR Mode of Operation (Reset/Calib/Output)

.POR.Hrs.1....... PRM_PORHRS1 POR Hrs1 Calibrator Video Data Display - Hours Value

.POR.Mins1...... PRM_PORMINS1 POR Mins1 Calibrator Video Data Display - Minutes Value

.POR.Secs1...... PRM_PORSECS1 POR Secs1 Calibrator Video Data Display - Seconds Value

.POR.Frms1...... PRM_PORFRMS1 POR Frms1 Calibrator Video Data Display - Frames Value



77


Point-of-Regard (P.O.R.) Calibrator #2

.POR.H2A......... PRM_PORH2A POR H2A Eye P.O.R. Horiz. Position (Source A)

.POR.V2A......... PRM_PORV2A POR V2A Eye P.O.R. Vertical Position (Source A)

.POR.RH2A....... PRM_POR_RH2A POR RwH2A Eye P.O.R. Raw Horiz. Position (Source A)

.POR.RV2A....... PRM_POR_RV2A POR RwV2A Eye P.O.R. Raw Vertical Position (Source A)

.POR.H2B......... PRM_PORH2B POR H2B Eye P.O.R. Horiz. Position (Source B)

.POR.V2B......... PRM_PORV2B POR V2B Eye P.O.R. Vertical Position (Source B)

.POR.RH2B....... PRM_POR_RH2B POR RwH2B Eye P.O.R. Raw Horiz. Position (Source B)

.POR.RV2B....... PRM_POR_RV2B POR RwV2B Eye P.O.R. Raw Vertical Position (Source B)

.POR.Mode2...... PRM_PORMODE2 POR Mode2 POR Mode of Operation (Reset/Calib/Output)

.POR.Hrs.2....... PRM_PORHRS2 POR Hrs2 Calibrator Video Data Display - Hours Value

.POR.Mins2...... PRM_PORMINS2 POR Mins2 Calibrator Video Data Display - Minutes Value

.POR.Secs2...... PRM_PORSECS2 POR Secs2 Calibrator Video Data Display - Seconds Value

.POR.Frms2...... PRM_PORFRMS2 POR Frms2 Calibrator Video Data Display - Frames Value

Head Tracker Input Parameters

.Head.X......... PRM_HEAD_X Head X Head X Position (in.)

.Head.Y......... PRM_HEAD_Y Head Y Head Y Position (in.)

.Head.Z......... PRM_HEAD_Z Head Z Head Z Position (in.)

.Head.Azim...... PRM_HEAD_AZ Head Azim Head Azimuth Angle (deg.)

.Head.Elev...... PRM_HEAD_EL Head Elev Head Elevation Angle (deg.)

.Head.Roll...... PRM_HEAD_RO Head Roll Head Roll Angle (deg.)

Auxiliary Serial Input Parameters

.Serial.In.0..... PRM_SERINP0 Ser Inp 0 Auxiliary Serial Input Byte

Auxiliary Digital Input Parameters

.Digit.In.1A.... PRM_DIGIN1A Dig Inp 1A Auxiliary Digital Input Byte (Card 1, Port A)

.Digit.In.1B.... PRM_DIGIN1B Dig Inp 1B Auxiliary Digital Input Byte (Card 1, Port B)

.Digit.In.1C.... PRM_DIGIN1C Dig Inp 1C Auxiliary Digital Input Byte (Card 1, Port C)












78


Auxiliary Digital Output Parameters

.DigitOut.1A.... PRM_DIGOUT1A DigOut 1A Auxiliary Digital Output Byte (Card 1, Port A)

.DigitOut.1B.... PRM_DIGOUT1B DigOut 1B Auxiliary Digital Output Byte (Card 1, Port B)

.DigitOut.1C.... PRM_DIGOUT1C DigOut 1C Auxiliary Digital Output Byte (Card 1, Port C)










Auxiliary Analog Input Parameters

.Anlg.In.1...... PRM_ANLGIN1 Anlg Inp 1 Auxiliary Analog Input #1 - Value








Eye Tracker #1 - Eye Angle Output Parameters (After Eye Angle Calibration)

.Eye.Azim.1....... PRM_EYE_AZ1 Eye AZ1 Eye Azimuth Angle (deg.)

.Eye.Elev.1....... PRM_EYE_EL1 Eye EL1 Eye Elevation Angle (deg.)

Eye Tracker #2 - Eye Angle Output Parameters (After Eye Angle Calibration)

.Eye.Azim.2....... PRM_EYE_AZ2 Eye AZ2 Eye Azimuth Angle (deg.)

.Eye.Elev.2....... PRM_EYE_EL2 Eye EL2 Eye Elevation Angle (deg.)



79


Head Tracking Parameters

.LOS.Org.X1....... Origin of Line-of-Sight Vector X

.LOS.Org.Y1....... Origin of Line-of-Sight Vector Y

.LOS.Org.Z1....... Origin of Line-of-Sight Vector Z

.LOS.Vect.X1....... X Component of the Directional Vector of the LOS

.LOS.Vect.Y1....... Y Component of the Directional Vector of the LOS

.LOS.Vect.Z1....... Z Component of the Directional Vector of the LOS

.LOS.Azim.1....... LOS Angle Azimuth

.LOS.Elev.1....... LOS Angle Elevation

PlnInt.X1....... X Coordin. of the Plane Intersection (in World Space)

PlnInt.Y1....... Y Coordin. of the Plane Intersection (in World Space)

PlnInt.Z1....... Z Coordin. of the Plane Intersection (in World Space)

PlnInt.H1....... Plane Int. Horiz. Coordinates in Plane Space 0-511

PlnInt.V1....... Plane Int. Vert. Coordinates in Plane Space 0-511

PlnInt.AvgH1....... Averaged Version of Above

PlnInt.AvgV1....... Averaged Version of Above

VDU.H2A....... XY Horizontal Location over VDUA

VDU.V2A....... XY Vertical Location over VDUA

VDU.H2B....... XY Horizontal Location over VDUB

VDU.V2B....... XY Vertical Location over VDUB

VDU.Hrs.2....... Hours Displayed on VDU Data Bar

VDU.Mins.2....... Minutes Displayed on VDU Data Bar

VDU.Secs.2....... Seconds Displayed on VDU Data Bar

VDU.Frms.2....... Frms Displayed on VDU Data Bar

Active.Run....... Which Run is Being Recorded



80



81 Section 9: LSW Software Features

Section 9: LSW Software Features and Functions

No description of ISCAN’s LSW software can be quite complete, as ISCAN continuously

works to add functions and improvements requested by researchers and system users. The

basic LSW software incorporates many different eye tracking functions, with the most

frequently used discussed in this section, as outlined below:

(A) A blink monitoring subsystem that registers and outputs blinks and can count the

number of blinks over a specified period of time;

(B) Analog outputs, consisting of three ±5VDC analog output channels with the

capability to expand to six analog output channels;

(C) Serial I/O, consisting of three serial ports for data input and output in real time;

(D) Digital I/O, consisting of four TTL digital inputs and four TTL digital outputs that

can be operator-configured for recording control, output of fixation signals, input of

marker pulses, and synchronization signals;

(E) Data recording capability to record up to two hours of 240 Hz, four hours of 120 Hz,

or eight hours of 60 Hz eye position data for post processing via Matlab or Excel.

Detailed descriptions of these functions follow.

Part A: Blink Monitoring

The ETL-600 has a built-in blink detection and counting feature. The detection algorithm

requires that the system operator set a template of the eye with the pupil fully visible to

the eye camera and the pupil position clearly tracked by the eye tracker.

The blink monitor subsystem continuously compares the incoming real time pupil extent

information to that of the template initially set by the operator. It then registers and

counts blinks based on a percentage of eye closure parameter, also operator selectable.

The blink state is represented by the graph parameter BlinkSt1 and is a digital “0” when

the eye is open and a digital “1” when the eye is closed (beyond the percentage of eye

closure setting).

The blink count is represented by the graph parameter BlinkCnt1 and is a real time

integer representing the number of blinks that have occurred since the template was set.

The operator can clear the blink count at any time manually or can enable a feature that

automatically clears the blink count at the start of a data recording episode.

To enable blink monitoring, disable Track Active in the LSW software and click on the

“Fork & Spoon” configuration icon [Figure 4.1 (9)] to display the ISCAN system

configuration panel. Click on the Blink/Fixation tab, and set the blink criteria in that

panel as shown in Figure 9.1 below:



Figure 9.1: Blink Monitor Configuration Panel

Enable the blink monitor, and set the percentage of eye closure to the desired level. In this

example it is set to 80%. This means that if 80% or more of the pupil size is obscured or

has disappeared, the subject has blinked. Enabling Clear Blink Count w/Record will reset

the blink count automatically to zero at the beginning of a recording event.

Click OK to return to the LSW window. Enable Track Active, and note the blink controls

that are now highlighted at the bottom of the eye tracker controls panel in the upper left

hand side of the LSW window.

Figure 9.2: Blink Controls Enabled

Have the subject fixate straight ahead and ensure that the eye landmarks are properly

tracked. Click on the Set button in the blink control panel.



Figure 9.3: Blink Control Panel

This captures a pupil extent template, based on the pupil size parameters calculated by

the eye tracking processor. Load the BlinkSt1 and BlinkCnt1 parameters into the graph

display, if desired. At the subject’s eye closes during a blink, the BlinkSt1 will change from

a “0” to a “1,” and the BlinkCnt1 number will increment by one integer.

Clicking on the Clear button in the blink control panel will set the blink count number to

zero.

The blink state and blink count monitoring can be selected for recording and/or real time

output via the digital outputs (see Section 9, Part D), analog outputs (see Section 9, Part

B), or serial ports outputs (see Section 9, Part C).



Part B: ISCAN Analog Outputs

The ETL-600 normally has three analog outputs. The outputs are generally assigned to

Pupil or Pupil – Corneal Reflection horizontal position, Pupil or Pupil – C.R. vertical

position, and pupil size, either horizontal or vertical diameter or pupil area. The output

range of the analog outputs is ±5 volts DC.

Selecting Analog Outputs

The ETL-600 is shipped with the three analog outputs enabled. Clicking through the

Options button will bring up the Auxiliary Output Control panel in the lower left hand

corner of the LSW Control Window.

The analog folder should be configured as shown in Figure 9.4 below:

Figure 9.4: Analog Output Control Panel

Clicking on the Parameter Control box to the right of the parameter selects and loads a

desired analog output parameter.

Double-clicking on the highlighted parameter selects that parameter as an analog output.

Figure 9.5: Select Analog Output Parameters



It is also important to add the same analog output parameters to the graph displays. For

example, if you have selected PupilH1, the pupil horizontal position, as an analog output,

make sure to add PupilH1 into one of the graph displays. This will allow for scaling of the

selected analog outputs over the ±5VDC range. See this example in Figure 9.6 below.

Figure 9.6: Analog Output Parameters & Graph Displays

See Section 8 for a detailed discussion of scaling the analog outputs.



Configuring the Analog Outputs

With Track Active disabled, click on the “Fork & Spoon” configuration icon [Figure 4.1 (8)],

then click on the Analog I/O tab to show the Analog Inputs and Outputs control panel as

shown in Figure 9.7 below.

Figure 9.7: Analog Inputs & Outputs Control Panel

Set the Analog Outputs so Output Active is checked, the Card Type is RK8X6PCI-0, and

the Volt Range is ±5VDC.

Click on OK to exit from the System Configuration window display.



Part C: Serial I/O

The ETL-600 eye tracking computer has three RS-232 serial ports labeled COM1, COM2

and COM3. These serial ports can receive and transmit RS-232 format data at rates up to

115K bytes/second (baud). In the ETL-600, the COM1 port is always dedicated to the head

tracker. Use COM2 or COM3 for external data communications.

IMPORTANT: always use a null modem serial cable when using the serial ports to

transfer data. A null modem cable has the data transmit pin on one end connected to the

data receive pin on the other so serial data transfer can be performed. The biggest problem

associated with a serial port data transmission is the failure to use a null modem cable.

Example of How to Use Serial Port

Connect a null modem serial cable into the COM2 port of the ISCAN eye tracking

computer.

Open the ISCAN LSW software, and with Track Active disabled click on the “Fork &

Spoon” configuration icon [Figure 4.1 (9)]. When the ISCAN System Configuration panel

appears, click on the Serial I/O tab. The Serial I/O configuration panel will appear as


Figure 9.8: Serial I/O Configuration Panel

Select Data I/O-0 in the COM2 port, a Baud rate of 57,600 or 115,200, and Output Active

for data output only. Enable Input Active only if data is being sent to the ISCAN eye

tracker computer.

Click OK to close the System Configuration panel.

Click on the Options button until the Serial controls appear in the Auxiliary Output

Controls panel, as in Figure 9.9 below.



Figure 9.9: Serial Output Controls Panel

Set the Data parameter to Raw…ASCII or Raw…Binary, depending on the type of output

data format required. See Section 14 Appendix A for more detail regarding the

ASCII/binary formats.

The data may also be selected as Scaled…ASCII or Scaled…Binary. These settings allow

for the serial output to be scaled just like the analog outputs, under graph control. See

Section 8 for a detailed discussion of scaling the analog outputs

Load the desired eye parameters to be output into the data boxes labeled 01 to 06. Note

that there are two available parameter banks that can be loaded with up to twelve

parameters in total. In the example shown in Figure 9.9, PlnInt.Num1, PlnInt.AvgH1, and

PlnInt.AvgV1 are loaded into Banks 01, 02, and 03 respectively.

Click on Track Active to enable serial output. With the other end of the null modem cable

hooked up to a data acquisition computer running a standard serial interface program

such as Hyperterminal or TeraTerm, the serial link can be confirmed and any

transmission or data format problems resolved. Make sure that the baud rate of the

receiving program matches the baud rate set in the ISCAN serial configuration panel.

Make sure that the data format in the receiving program is set to ASCII or binary, the

same as in the ISCAN data output format, and that a null modem cable is used.

For a more technically detailed discussion of serial data formats and ISCAN software

controls, see Section 14 Appendix A.



Part D: Digital I/O

The ETL-600 comes with a digital interface that contains four TTL inputs and four TTL

outputs. The TTL signal is OVDC digital low or “0” or +5 digital high or “1.”

The four TTL inputs and outputs are located on the 9-pin D-sub female connector on the 3-

analog output card, installed in the eye tracker PC. See Figure 3.2.

The pin-out of the digital I/O connector is shown in Figure 9.10 below.

Figure 9.10: ISCAN Digital I/O Connector

For normal ETL-600 applications, the digital I/O is configured for four separate input and

four separate output TTL lines.



With the Track Active disabled, click on the “Fork & Spoon” configuration icon [Figure 4.1

(9)]. When the ISCAN System Configuration panel appears, click on the Digital I/O tab.

The Digital I/O configuration panel will appear as shown in Figure 9.11 below.

Figure 9.11: Digital I/O Configuration Panel

These are the default settings for ISCAN’s digital I/O card. Click on OK to return to the

main LSW software window.

Click on the Options button to bring up the Auxiliary Output Controls panel as shown in

Figure 9.12 below.

Figure 9.12: Digital Output Controls Panel



Each of the four available output bits, digital bit 0, 1, 2, and 3, can be assigned a variety of

outputs. Click on the down arrow to the right of the Bit0 alphanumeric display box and a

drop-down list of available digital outputs parameters appears for selection as shown in

Figure 9.13 below.

Figure 9.13: Digital Output Bit Selection

In all cases Track Active must be enabled to have the digital data appear at output.

Manual:

Allows the operator to test the digital output line by manually toggling the bit high

or low by clicking on the H or L button next to the alphanumerical box. Track

Active must be enabled for the digital data to appear at the appropriate output.

Sync:

The sync output generates a TTL level sync pulse on the digital output line that is

synchronous with the vertical sync pulse of the eye camera. The sync pulse is

normally TTL low and goes high every V-Sync pulse.

Trig1A, B, C, D:

Selecting Trig1A, Trig1B, Trig1C, or Trig1D routes the selected Trigger1 signal to

the digital output. The trigger signal is associated with a Fixation Monitoring

subsystem that is not applicable to the ETL-600.

Trig2A, B, C, D:

As above, but routes the selected Trigger2 signal to the selected digital output.

Blink St1:

Selecting Blink St1 routes the blink state output (digital 0 if eye is open, digital 1

if eye is closed/blinking).

Record St:

Selecting Record St1 routes the data recording status out the selected digital port.

The recording state is low (digital 0) during recording and high (digital 1) when

recording has stopped.



Part E: Recording Data

The ETL-600 is configured to record up to 24 digital eye parameters simultaneously. The

recording function can be controlled by the PC mouse, serial commands, an external

switch, or via a TTL digital input.

A single data run is defined as one cycle of starting and stopping recording. The system

operator can set a limit to the number of runs that can be consecutively recorded and also

set a number of data points that can be recorded in a single run. The number of data

points depends upon the sample speed of the eye position data.

At 60 Hz, 60 data points are recorded every second, resulting in 3600 data points each

minute. If the number of points per run is set at 7200 with a Runs limit of 10, this results

in ten two-minute recordings.

The ETL-600 may also be configured with a 120/240 Hz high-speed eye tracker. With this

option:

At 120 Hz, 120 data points are recorded every second, resulting in 7200 data points each

minute. If the number of points per run is set at 7200 with a Runs limit of 10, this results

in ten one-minute recordings.

At 240 Hz, 240 data points are recorded every second, resulting in 14,400 data points each

minute. If the number of points per run remains set at 7200, with a runs limit of 10, this

results in ten 30-second recordings.

It is important to calculate a priori the expected length of time for recording and the

expected number of data points, and take into account the 120 or 240 Hz sampling

frequency.

The maximum number of data points that can be recorded by the standard ETL-600 is

2,000,000. This would result in a maximum continuous recording of just over 2 hours at

240 Hz, about 4! hours at 120 Hz, and about 8 to 9 hours at 60 Hz.

The Data Recording controls are in the lower left hand side of the LSW window, as shown

in Figure 9.14 below.



Figure 9.14: Data Recording Control Panel

In the example above, the sampling rate of the eye tracker is 120 Hz, and recording is set

for Internal, meaning a mouse click can be used to start recording. The Runs Limit is set

to 10, and the number of Points per Run is set to 20,800.

Clicking on the Bank 1 tab in the Data Recording Controls panel brings up the display of

the parameters that the operator has loaded for recording.

Figure 9.15: Data Recording Parameters Bank

There are three banks that can hold eight different parameters, resulting in a maximum

of 24 discrete parameters that can be recorded in each run. Clicking on the box to the right

of a parameter shows the drop-down list of all available data that can be loaded in for

recording. Double-click on the highlighted parameter on the list to enter it into the

alphanumeric display box as demonstrated above. The list of available parameters is

shown at the end of Section 8.



Recording Configuration Panel

To customize the recording for a specific application, disable Track Active and click on the

“Fork & Spoon” configuration icon [Figure 4.1 (8)] to bring up the system configuration

panels, then click on the Recording tab to display the Recording Configuration panel as

shown in Figure 9.16 below:

Figure 9.16: Recording Configuration Panel

(1) Recording Trigger: Internal, Serial, Switch, or Digital

(2) Sample Mode: All Points or ! Points

(3) Source: None, RK-8x6PCI-0, RK-632-PCI-0, or Par Port-0

(4) Lockout Samples:

(5) Trigger Edge: Leading or Trailing

(6) Points/Run Action: Stop Recording or Start New Run

(7) Points Run Limit

(8) Maximum Data Runs

(9) Maximum Data Points

(10) Toggle Data Bar

The Recording Trigger (1) is normally set to Internal. Internal allows for the starting and

stopping of data recording via the PC mouse.

Set the Recording Trigger to Serial mode for starting and stopping the recording via the

hex serial commands (Section 14, Appendix A).



Set the Recording Trigger to Switch mode if a pushbutton switch is used to enable

recording. Hook the switch up between Pins 1 and 9 on the ISCAN digital I/O 9-pin D-SUB

connector. Pin 1 is the switch input and Pin 9 is Ground (Figure 9.10).

Set the Recording Trigger to Digital if an external TTL digital signal is required to start

and stop recording. Recording starts with an active “low” (digital 0) TTL signal and stops

when it turns “high” (digital 1). Hook the digital TTL signal to Pin 1 of the 9-pin D-SUB

I/O connector and ground to Pin 9 (Figure 9.10).

The Sample Mode (2) is normally set to record all Points, but allows the operator to record

Half Points. In the ! Points mode, every other data point is recorded.

The Switch Trigger configurations are only used if the Switch mode has been enabled as

the Recording Trigger. Switch Trigger Source (3) may be any of the three active sources

listed above, and each is described in detail below:

Setting the Switch Trigger Source to RK-8xPCI-0 allows a switch to be connected

on Pin 1 of the 9-pin D-Sub female digital input connector on the back of the eye

tracker PC. Pin 9 of the 9-pin D-Sub connector is ground.

Setting the Switch Trigger Source to RK-632PCI-0 can only be done if an ISCAN

RK-630PCI calibration card has been installed in the ETL-600.

Setting the Switch Trigger Source to Par Port-0 allows a switch to be connected to

the PC parallel printer port on the back of the eye tracker PC between Pin 10 and

Pin 25. Pin 10 is the switch signal input, and Pin 25 is ground on the PC parallel

printer port.

Lockout Samples (4) is the amount of video fields during which a second switch slick is

ignored.

Trigger Edge (5) can be selected for the leading or trailing edge of the switch pulse to start

or stop recording.

The Points/Run Action (6) can be configured to Stop Recording or set to Start New Run.

The Points Run Limit (7) can be set to the maximum number of points expected in a single

run. After the limit has been reached, the recording automatically stops. This number also

is displayed in the LSW data recording control display.

The maximum number of data runs (8) is set at 400, and the maximum number of data

points (9) is set at 2 million. The system operator cannot change either of these limits.

The Toggle Data Bar (10) function is normally disabled.



Example of Recording and Reading Data

With the LSW window open and Track Active enabled, obtain a clear, trackable image of

the eye. Click on Start Record and after a short time, click on Stop Record.

The Pts Rec’d shows how many data points were recorded. In the example shown in Figure

9.17 below, there were 1022 data points recorded.

Figure 9.17: Data Recording Controls Info

The Delete All and Delete Last buttons are enabled after completion of a recording run.

Click on Delete All to delete all of the runs that may have been recorded. Click on Delete

Last to delete just the previous recorded run.



Disable Track Active. Click on File [Figure 4.1 (14)] in the LSW software window, and

scroll down to select Save ISCAN ASCII Data File as tab-delimited ASCII (TDA), as


Figure 9.18: Save TDA Data in File

The recorded data run will automatically be saved to the Documents folder in the PC.

Make sure to label the run as a .TDA file. In this example it is called Test.TDA, as shown


Figure 9.19: Saving Data as Test.TDA



Open the Documents folder in Windows, and verify that it has been saved as Test.TDA.

To open and view the data, use the WordPad application in the eye tracker PC. To find

Word Pad, click on the Windows Start Menu icon, scroll to Accessories, and click on

WordPad, as shown in Figure 9.20 below. When WordPad starts up, click on Open File,

and make sure that All Documents is selected in order to see all the .TDA files, as shown


Figure 9.20: Open WordPad

Double-click on your data file (in this example, Test.TDA) to open the file and view the

data. WordPad will format the data as shown in Figure 9.21 below.



Figure 9.21: Test.TDA Data





101 Section 10: Recording Data for PRZ

Section 10: Recording Data for Analysis by the ISCAN PRZ Software

When using the global view scene camera to capture an image of the subject’s work area, it

may be of interest to record the X and Y locations of the subject’s line of sight intersection

with the planar surfaces, and automatically analyze the fixation data with the ISCAN

PRZ analysis software.

The VDU.H2A and VDU.V2A parameters represent the location of the horizontal and

vertical gaze point of the subject, superimposed over the global view monitor area.

First, load the VDU.H2A and VDU.V2A parameters into the Data Recording Controls

panel. To do this, disable Track Active, and click on the Bank 1 tab in the Data Recording

Controls panel. Select the VDU.H2A and VDU.V2A for recording by clicking on the

selection boxes, as shown in Figure 10.1.

Figure 10.1: Loading VDU.H2A and VDU.V2A into Bank 1

The ISCAN PRZ software will read this gaze point data from a fixation file created by the

operator and the PRZ software will correlate the gaze point with the location of the planar

surfaces that were registered by the operator onto the image of the global view scene.

The operator can also take a digital photo of the subject’s scene field of view (similar to

that seen by the global view camera) and import this image as a bitmap into the PRZ

analysis software. The operator will also register four clearly identifiable features in this

new scene image, to “anchor” or match up the bitmapped image to that of the global view

camera.

Part A: Image Registration for PRZ

A step-by-step description of the image registration procedure for PRZ is as follows:

With Track Active disabled, click on the Options button until the Video Display Unit

Controls panel appears. Alternatively, click on the enlarge button for the global view

monitor, and the VDU Controls panel will come up automatically.

The Video Display Unit Controls panel contains three operator-selectable options: Single

Plane mode, Global View mode, and Image Registration mode.

Click on the Image Registration button as shown in Figure 10.2.



Figure 10.2: Image Registration, Upper Left

The four registration or anchor points will be visible in the gray pseudo-screen area, and

the upper left point will be circled. Click on the upper left point and drag it until the

associated indicator in the global view monitor is superimposed over an unambiguous

visible point on that monitor. In the example shown in Figure 10.3 below (a series of

screen shots), the operator places the four registration points on the upper left and lower

left corners of Plane 3, and the upper right and lower right corners of Plane 2.

Figure 10.3: Defining the Anchor Points



Once the upper left point is satisfactorily superimposed over a clearly definable target in

the global view image, release the mouse button to register the anchor point. Click on the

up or down arrow of the Active Item box to select the next point. Repeat the above

procedure for the upper right, lower left, and lower right registration points as shown in

Figure 10.3. The X and Y coordinates of each of these registration points are stored in the

fixation file that is described below, and are used to anchor the bitmapped image of the

subject’s work space to the global view monitor image, when using the PRZ analysis

software.

Part B: Recording a Data Run

Enable Track Active, set up the subject with the headgear, perform the eye angle

calibration (see Section 7), and press the Start Record button to record a data run, as

shown in Figure 10.4.

Figure 10.4: Start Recording

After the run is completed, click Quit Record. See Figure 10.5

Figure 10.5: Quit Recording



Part C: Storing the Eye/Head Plane Intersection Data in a Fixation File

Disable Track Active and click on the File menu. Select the drop-down “Save ISCAN

P.O.R. Fixation File As …” in the menu as shown in Figure 10.6.

Figure 10.6: Select Save Fixation File

The ISCAN P.O.R. Fixation file info box will open as shown in Figure 10.7 below.

Figure 10.7: Open Fixation File



Click on Continue, and enter a new ID# from between 100 and 200, and a Track ID, either

lower case n or letters a through f, as shown in Figure 10.8

Figure 10.8: Identifying a Fixation File

Click on Finish, and the “Save P.O.R Fixation File As” box will appear. Save the Fixation

file as a .fxn file. In the example below, it is called test.fxn, and it is saved in the

LSW1_00T folder, as shown in Figure 10.9.

Figure 10.9: Saving a Fixation File

After keying in test.fxn, click on the Save button, and the LSW Control screen will be

visible. The .fxn fixation data file will be recalled for analysis by the ISCAN PRZ program.

Running the ISCAN PRZ Advanced Analysis Program

The PRZ software will read the .fxn file and perform automated fixation analysis, generate

scan path data, and allow the operator to elicit various metrics from the eye and head

position intersection data.





107 Section 11: PRZ Overview

Section 11: PRZ Overview

One of the principal uses of eye tracking technology is to determine precisely where on a

stimulus or target image, a subject has fixated and to analyze the fixation patterns. To

make sense of the fixation data, it is essential to correlate fixations with the particular

image being seen and objects of importance within this image. In addition, it is often of

value to consolidate the resulting data over multiple trials and/or multiple subjects. The

ISCAN Point-of-Regard Analysis (PRZ) Software implements a methodology that allows

users to automate the fixation analysis process and report results.

Features of the software include:

# Image registration to allow data from different data collection and stimulus

presentation contexts to be combined;

# Creation of image sequences to define stimulus viewing order;

# Definition of elements of interest via easy-to-use drawing tools with full editing

controls;

# Ability to aggregate elements into “nets;”

# Seamless integration with ISCAN’s Raw Eye Movement Data Acquisition Software

(DQW);

# Analysis of each individual view of the stimulus images including scan paths and

data tables;

# Combined analysis of groups of subjects and/or groups of images including

population-based data tables and charts (professional version only).

Task Configuration

In order to properly make use of the PRZ methodology, the user must first identify the

scope of the study, the context in which stimuli will be presented, the particular stimulus

images to be used and the key elements within the images to be tested.

Scope and Study Context

The PRZ software has primarily been designed to accommodate studies in which one or

many still images are presented in sequence to a subject while their eye movements are

being monitored. Usually this is in the context of subjects seated and remotely viewing a

single fixed display, but head-mounted VR displays, multi-monitor environments, and

video stimulus presentations can also be analyzed. The PRZ methodology allows the

fixation data to be accurately consolidated even if an image is presented in more than one

context.

Stimulus Images

Depending on the image stimuli required or desirable for different studies, various image

formats, resolutions and display sizes may b e employed. For the purposes of stimulus

presentation, any images compatible with the chosen display context are acceptable, but it

is advisable to use the same image format and resolution for all of the images within any

particular study.



The PRZ software accepts image files in the BMP format only, but can accommodate any

resolution image in this format. The BMP format is used because it is found globally and

is completely loss-less. If the study context requires presentation of images in a format

other than BMP, a simple conversion process in any graphics program can be used to

produce an analogous set of BMP images for use in the PRZ program.

An important part of the preliminary work for any study is to determine the display

context and stimuli image characteristics to be used.

Master Registration Image

In addition to the various stimulus images prepared for the study, a master registration

image (MRI) must be created for the display context being employed. The MRI allows data

to be analyzed and consolidated from different subjects even if the image stimuli are

presented in different display contexts.

The MRI is a simple image containing four or five targets. The MRI must be of the same

size and resolution as the other stimulus images to be displayed in the study context. If

five targets are included, this image can also be used in each subject’s eye point-of-regard

calibration when eye data is being collected. As with the other stimulus images, an

analogous MRI in BMP format must be created using the same scaling and/or

reformatting process, for use in the PRZ software.

PRZ/DQW Workflow

The following steps outline the suggested workflow for preparing sets of individual image

stimuli, collecting fixation data and producing results using the PRZ software in

conjunction with ISCAN’s eye movement monitoring systems and data acquisition

software (DQW), as shown in Figure 11.1:

#



Figure 11.1: PRZ/DQW Workflow Diagram

1. Task Configuration: Complete the task configuration steps described above.

2. Image Registration: In the PRZ software image registration module, combine

each BMP stimulus image with registration points matched with the BMP

master registration image. Create a resulting registered image file (IGR) for

each image.



3. Image Sequencing: In the PRZ software image sequencing module, create one or

more sequences of registered stimulus images in the order(s) they will be

presented. Generate one or more sequence files (SEQs) to be used by the data

acquisition software.

4. Eye Point-of-Regard Data Collection: Using the DQW software, read in the

appropriate SEQ file generated in Step 3, and collect eye point-of-regard data

from one or more subjects while they view the stimulus images. Generate a

fixation file (FXN) for each subject’s viewing session.

5. Image Element Entry: Read the IGR images into the PRZ program element

entry module, and using the drawing tools outline each of the elements of

interest for the current image. Create “nets” to aggregate image elements for

analysis. Generate one or more element files (EMTs) describing the elements

and nets you’ve created for each image.

6. Individual Analysis: In the PRZ individual analysis module, read an EMT file

and a FXN file in which the subject viewed the image of interest. View and

report image scan paths and data tables scoring eye fixations on the elements

and nets defined.

7. Group Analysis: In the PRZ professional version only, a group analysis module is

available. Here multiple FXNs and EMTs may be grouped and analyzed as a

population. So, for example, where individual analysis will tell you what element

the subject fixated on first, group analysis will tell you what percentage of the

subject population fixated first on each of the elements defined. View and report

group data tables and bar charts.

Please note that Steps 4 and 5 above may be done in any order or in parallel.

Figure 11.2 is a summary table of the various file types discussed in this section.

Figure 11.2: PRZ File Definitions Table


Section 12: FACTORY.DEF Settings

111

Section 12: Saving & Retrieving Configuration Settings

The LSW software has a multitude of settings, allowing the program to be configured for

many different types of eye tracking applications. On program start up, the software

automatically loads the settings that are stored in a definition file, a file with suffix .def.

This definition file is updated each time the LSW program is closed, saving all parameter

and board changes that may have been made by the operator.

Saving Definition Files

To save a definition file, for a specific subject or to save the settings for those that were

used in a particular experiment, go to the file menu, with Track Active disabled, and click

on the "SAVE DQW SETTINGS FILE as..." as shown in Figure 12.1 below. (Note: the

DQW and LSW may be used interchangeably.)

Figure 12.1: Save LSW Settings

Call the file an easy to remember name, in this example Factory.def, and save it in the

LSW folder, an example of which is shown in Figure 12.2 below.



112

Figure 12.2: Saving a Unique .def File

Retrieving LSW Settings via Definition Files

To restore the LSW software settings you have previously saved, (i.e to open a settings

file), disable Track Active, click on the File menu and select "Open DQW Settings File" as


Figure 12.3: Open LSW Settings in File Menu

When the Open LSW Settings window appears, double click on the desired .def file. In the

example shown in Figure 12.4, factory.def is being selected.



113

Figure 12.4: Selecting a Saved .def File

The LSW program will now contain all the settings previously saved in the selected .def

file.

Factory Definition File

The Open Settings File window will also contain a factory.def backup file loaded by ISCAN

prior to system shipment. The factory.def file contains all the factory settings when the

ETL-600 was shipped. Double clicking on the factory.def file icon opens the DQW program

with these initial settings.

Very occasionally, something could occur in the Windows operating system that can

corrupt the definition file. If the LSW program is opened with no eye tracker, calibrator or

on screen video display card in the tower PC chassis, and then the program is closed

again, the LSW software definition file will save information indicating no cards are

present. In this case, open the factory.def file after the cards have been replaced in the PC.

In a more extreme case, if both definition files have been corrupted, the factory settings for

each of the 16 ISCAN system configuration screens are presented in Figure 12.5 below.

Manually enter the parameters shown in each of the configuration screens to restore the

system to its original settings. The system configuration panel can be opened by going to

the View menu and selecting System Configuration or by clicking on the "fork and spoon"

icon to the right of the File menu in the DQW software window.



114

Figure 12.5: Factory.def ETL-600 Settings



115

Figure 12.5: Factory.def ETL-600 Settings (cont’d.)



116

Figure 12.5: Factory.def ETL-600 Settings (cont’d.)


Section 13: IR Irradiance 117

Section 13: IR Irradiance and Safety

OSHA’s standard for safe levels of near-infrared radiation on the lens is 10 mW/cm2. The

IR LED illuminator has a total radiant output of 1.2 mW. The peak of this output is at 940

nm, and the half-power points are approximately 60 nm above and below this value. Even

if the entire output of the illuminator falls on the lens of the eye, the radiant flux striking

the lens or the retina cannot and does not exceed 1.2 mW/cm2 (0.29 mcal/sec/cm2). This

value is only 12% of the OSHA maximum radiation standard.

As to thermal levels, according to OSHA recommendations, white light of less than 1

cd/cm2 may be regarded of safe. A retinal exposure of 1.2 mW/cm2 of 940-nm light is the

equivalent of 0.06 cd/cm2 of white light. Therefore the IR LED illuminator exposes the

retina to only 6% of the OSHA maximum standard for thermal safety standard.

ISCAN thus certifies that the radiation and thermal levels of the IR LED illuminators

used in the Eye Tracking Laboratories fall well within OSHA recommendations.


Section 13: IR Irradiance 118



Section 14: Appendices 119

Section 14: ETL-600 Appendices

Appendix A: Single Plane/Computer Screen Stimulus Operation

The ETL-600 may be configured to monitor the combined eye/head gaze point of the

subject while using a single-plane computer monitor as the stimulus source.

Figure A.1 shows the basic component configuration for this type of application. Note that

this set-up uses a VGA-to-NTSC converter that is installed between the stimulus display

computer chassis and the VGA stimulus monitor. The ETL-600 will be configured to

display an indicator to the system operator where on the stimulus computer screen the

subject should fixate for each of the eye angle calibration points, and the laser pointer

calibration procedure is not required.

Figure A.1: ETL-600 Single Plane Configuration-



Part A: Setting up the Single Plane/Computer Monitor Connections

1. First connect the VGA output of the stimulus computer to the VGA In port on the

iMicro Gold converter, using the short black VGA cable provided.

2. Connect the VGA Output cable of the stimulus monitor to the VGA Output

connector on the iMicro Gold converter unit. Plug in the +12VDC power connector

into the iMicro Gold. Plug in the +12VDC power supply to a120 VAC or 230 VAC

wall power source. When powered up, the green indicator light on the converter

unit will be visible.

3. Connect the video output of the converter unit to the VDU2 Scene Video In on the

back of the ISCAN PC chassis, using the phono cable. Note that there is a phono-

to-BNC adapter installed on the cable end connected to the VDU2 Scene Video In

end. See Figure A.2

Figure A.2: ETL-600 Computer Hook-up-



Part B: Changing the Title of the Monitor to VDU monitor

When running the ETL-600 in this configuration mode, the operator may also want to

change the monitor displaying the VDU output to read “VDU Monitor” instead of “Global

View Monitor.” To change the text above the monitor, disable Track Active, and click on

the “Fork & Spoon” icon in the main LSW software window. When the ISCAN system

configuration panel comes up, select the OS Video Configuration and use the computer

keyboard to change the text in Chan 3 to read “VDU Monitor” as shown in Figure A.3

below.

Figure A.3: Changing the Name of the Monitor

Click on OK, and the LSW window will show the right hand monitor as “VDU Monitor.”

The VDU monitor displays the NTSC or television-format representation of the VGA

stimulus computer screen that is in front of the subject.

Part C: Entering the Planar Surface Coordinates

Using the ISCAN Environment Planes Layout panel as described in Section 7, enter the

planar surface coordinates for Plane 1, the stimulus computer monitor viewed by the

subject. Once the plane coordinates have been measured with respect to the magnetic

head tracker source and entered into the Planes Layout Editor, an alignment procedure is

required to match up the edges of the computer display as shown on the VDU monitor

with the coordinates entered into the Planes Layout Editor, specifying the plane.



Part D: Alignment of the VDU Display Borders

Click on the Options button to bring up the video display unit controls panel as shown in

Figure A.4.

Figure A.4: VDU Controls Panel

Click the Single Plane mode button in the controls panel, and set the Plane # for 1. Click

the Up arrow for the Active Item box, until “Left Border” appears in the box, as shown in

Figure A.5.

Figure A.5: Selecting Left Border for Alignment

The left border in the VDU gray pseudo-screen will appear as a red line. Click and drag

the red border until the indicator in the VDU monitor display is exactly positioned at the

left side of the computer screen display on the VDU monitor. Refer again to Figure A.5.



Once the indicator is lined up with the left border on the VDU monitor, click the Up arrow

roller again for the Active Item box. The right border marker will appear (as a red line), as

shown in Figure A.6.

Figure A.6: Selecting Right, Top, & Bottom Borders for Alignment



Use the mouse to click and drag the red right border in the gray pseudo-screen until it is

properly assigned with the right edge of the stimulus computer screen display as shown in

the VDU monitor display.

Repeat the above procedures for the top and bottom borders as shown in Figure A.6.

The alignment procedure described above “matches up” the measured plane coordinates

with the edges of the stimulus computer screen display, so the head and eye line-of-sight

intersection with the planar surface will be accurately represented on the VDU monitor

display.

Part E: Verification of the Head Intersection

This procedure is the same as that described in Section 7, Part C.

Part F: Eye Angle Calibration

This procedure is similar to that described in Section 7, Part D, with the only difference

being that instead of using the laser pointer to indicate the position of the calibration

points to the subject, the operator simply positions the stimulus computer mouse at each

of the 5 calibration points. The position of the stimulus computer mouse is clearly visible

to the operator on the VDU monitor showing the stimulus computer’s display, and the

operator can easily move the mouse to be superimposed with the indicated calibration

symbol appearing on the VDU Monitor display. Upon completion of the eye angle

calibration as in Section 7, Part D, the position of the VDU monitor’s symbol will represent

the real-time intersection of the head and eye line-of-sight vector with the planar surface

of the computer monitor.



Appendix B: Additional ISCAN Head-mounted Units

Like all ISCAN labs, the ETL-600 may be configured in a variety of ways to best suit the

research protocols for a given project. The headgear may need to fit in a more expansive or

in a more confined setting, to be steady with more or less physical activity, to fit adults or

children, to track the left or the right eye, etc.

Here is an example of a head-mounted configuration using a lightweight headband,

slightly different from that shown in Figure 3.6.

Figure B.1: Headband-mounted Monocular System






Appendix C: Serial I/O

Auxiliary Serial Output Formats

ISCAN Serial Output Format (ASCII)

When the ASCII format is specified, the serial output data packet consists of a single line

of ASCII character bytes terminated by /r/n bytes (carriage return/line feed characters).

Each data byte is 8 bits with 1 start bit, 1 stop bit and no parity. Data is streamed out

with no active handshaking. Each data value is separated by a /t (tab) character. Each

data value will appear in the format XXXX.X, where each X represents the ASCII

representation of numerals 0 -> 9. This data format can be read by any terminal

emulation program (e.g. "Hyperterminal").

Standard Point-of-Regard output will consist of one data packet for each sample at 60

samples per second. Each packet will consist of two (2) data values POR_H and POR_V

that are the horizontal and vertical coordinates of the eye point-of-regard. Each of the

POR data values varies from 0 to 511 with (0,0) being the upper left corner of the viewed

scene.

When the ASCII format is specified, the serial output data packet consists of a single line

of ASCII character bytes terminated by /r/n bytes (carriage return/line feed characters).

Each data byte is 8 bits with 1 start bit, 1 stop bit and no parity. Each data value is

separated by a /t (tab) character. Each data value will appear in the format XXXX.X,

where each X represents the ASCII representation of numerals 0 -> 9. This data format

can be read by any terminal emulation program (e.g. "Hyperterminal") but the number of

data bytes transmitted will be significantly greater than when using the binary format

(see below).

Binary Output Format

When the binary format is selected, the serial output data packet consists of a set of data

bytes in a specific packet format. Each data byte is 8 bits with 1 start bit, 1 stop bit and no

parity. Each data value is multiplied by 10 and encoded as 2 integer bytes (LSB/MSB) in

the packet. The packet format is shown below:

Byte Value (Hex)

0 0X 44 - Header Byte 1

1 0X 44 - Header Byte 2

2 0X ?? - Ch1 Parameter x 10 (LSB)

3 0X ?? - Ch1 Parameter x 10 (MSB)

4 0X ?? - Ch2 Parameter x 10 (LSB)

5 0X ?? - Ch2 Parameter x 10 (MSB)

.

. (Repeated for each parameter)

.



Remote Serial Controls

The DQW software also allows the user to remotely control data recording and send

synchronizing bytes to be incorporated in recorded data files.

To enable the serial input capability in DQW [see also Section 7((E)]:

• In the DQW "System Configuration" dialog, select the "Serial I/O" tab.

• Of the available COM channels, specify the COM port to be used as "Data I/O", the

baud rate to match the remote data sending system, and select "Input" as active.

• Click on "OK" to register changes to the system configuration.

• With the above steps completed, the DQW system is ready to receive serial commands

from a remote source. All DQW remote serial commands are single bytes between 128

and 255 (80 -> FF Hex).

• Whenever "Track Active" is enabled, the DQW system can receive and record any

single serial byte between 0 and 127 (00 and 7F Hex) as a synchronizing data marker.

These bytes are represented as parameter "SerIn0" wherever parameter selections are

made for display or recording in the DQW program.

• To trigger data recording via the serial port, in the DQW "System Configuration"

dialog, select the “Recording” tab and set the recording “Trigger” to “Serial.”

Remote Serial Command Bytes

Description of Data Recording Command Byte (Hex)

Start Recording 84 = 132 decimal

Quit Recording 88 = 136 decimal