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TobiiPro Glasses 2
Practical User Manual for scientific
experiments
Peter Slijkhuis
Department of Geo-Information Processing
Faculty ITC
and
Department of Cognitive Psychology and Ergonomics
Faculty of Behavioural, Management and Social Sciences
University of Twente
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Table of Contents How do the Tobii Glasses 2 work? ................................................................................................................. 3
1. TobiiPro Glasses 2 Components ................................................................................................................ 4
1.1. The head unit ...................................................................................................................................... 5
1.2. The Recording Unit ............................................................................................................................. 6
1.3 TobiiPro Glasses 2 Carry Case ............................................................................................................. 7
1.4 The tablet and the researcher ............................................................................................................. 8
2. Participant selection and recommendations ............................................................................................. 9
2.1. Participant Selection ........................................................................................................................... 9
2.2. Weather conditions for outside testing .............................................................................................. 9
2.3. Recommendations for experiment and research .............................................................................. 9
3. Preparations before a data collection day ............................................................................................... 10
3.1. Charging batteries and preparing memory cards ........................................................................... 10
3.2. Check for Windows updates on the tablet ....................................................................................... 10
3.3. Check for updates on the controller software and the firmware of the glasses............................ 10
4. Data collection .......................................................................................................................................... 11
4.1. Preparing for recording .................................................................................................................... 11
4.2. Making recordings ............................................................................................................................ 11
4.3. How to fit the Tobii Glasses 2 Eye Tracker onto a test participant ................................................ 12
4.4. How to change the Nose Pad ............................................................................................................ 12
4.5. The Track Status ............................................................................................................................... 13
4.6. Checking the recording .................................................................................................................... 13
4.7. Turning the Glasses off .................................................................................................................... 13
4.8. After data collection.......................................................................................................................... 13
6. Analysis of the recordings with Tobii Glasses Analysis Software .......................................................... 14
6.1. Basic Operations ............................................................................................................................... 14
6.2. Creating a new project ...................................................................................................................... 14
6.3. Opening an existing project ............................................................................................................. 14
6.4. Importing data from Tobii Pro Glasses 2 ......................................................................................... 14
7. Replaying recordings and recording settings ......................................................................................... 15
7.1. Gaze data settings ............................................................................................................................ 15
8. Specific methods for analysis .................................................................................................................. 16
8.1. Qualitative Analysis ........................................................................................................................... 16
8.1.1. Observing behavior and Logging Events (Coding) ....................................................................... 16
8.1.2. Managing snapshots and mapping eye gaze ............................................................................... 17
8.1.2.1. Importing snapshots .................................................................................................................. 17
8.1.2.2. Mapping data onto a snapshot .................................................................................................. 18
8.1.2.3. Visualizing eye tracking data ..................................................................................................... 19
8.2. Quantitative Analysis ........................................................................................................................ 20
8.2.1. Metrics (Areas Of Interest) ............................................................................................................. 20
8.2.2. Eye tracking data ........................................................................................................................... 21
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How do the Tobii Glasses 2 work? Eye tracking has long been known and used as a method to study the visual attention of individuals. There are several different techniques to detect and track the movements of the eyes. However, when it comes to remote, non‐intrusive eye tracking the most commonly used technique is pupil center corneal reflection (PCCR). The basic concept is to use a light source to illuminate the eye causing highly visible reflections, and a camera to capture an image of the eye showing these reflections. For the TobiiPro Glasses 2, there are two cameras per eye to identify the reflection of the light source on the cornea (glint) and in the pupil. What is measured eventually are fixations and saccades in milliseconds. Combined with the measurement of the fixations and saccades, the glasses also record a video feed of what the participant is looking at, with a camera in the front of the glasses. It is also possible to use Think Aloud Protocol with the glasses thanks to the integrated microphone in the glasses.
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1. TobiiPro Glasses 2 Components The TobiiPro Glasses 2 system is made up of several components. Each component is briefly described
below.
The system includes:
1. The wearable eye tracker (glasses), from here on referred to as the head unit.
2. The recording unit, connected to the head unit via a HDMI cable. The recording unit contains the battery and stores the recorded data on an inserted SD memory card.
The recording unit is controlled from a tablet or computer running the TobiiPro Glasses controller
software.
3. The Dell Venue 11 Pro Windows tablet with Windows 8.1 (or later), from here on referred to as the
tablet. The software allows for managing participants, controlling the eye tracker and viewing both
real-time and recorded eye tracking data. The software connects to the eye tracker through an
Ethernet connection (either wireless or wired). No eye tracking data is stored on the tablet computer.
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1.1. The head unit
The head unit is a highly sophisticated measuring device. It consists of several very sensitive sensors
and must be cared for as instructed for it to work properly. The head unit consists of the following parts:
1. High-definition scene camera– Captures a high-definition video of what is in front of the participant.
2. Microphone – Picks up sounds from the participant and its surroundings.
3. Eye tracking sensors – Records eye orientation e.g. the direction of the eye gaze.
4. IR illuminators – Illuminates the eyes to support the eye tracking sensors.
5. Micro HDMI connector – Connects to the recording unit via the supplied HDMI cable.
6. Cable guide – Guides the HDMI cable towards the participant’s back.
7. Protective lens – Both clear and tinted versions supplied
8. Nose pad— Exchangeable and available in different sizes.
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1.2. The Recording Unit
The recording unit is a small computer that controls the head unit (the eye tracking glasses). It records
and stores eye tracking data, sounds and scene camera video on a removable SD memory card. The
recording unit carries a replaceable and rechargeable Li-ion battery that supplies power to both the
recording unit and the head unit. The recording unit has several connectors and a power button and is
controlled from the controller software.
The recording unit consists of the following parts:
1. Power button & power indicator LED Touch
button that turns the recording unit on
and off. LED indicates power state and remaining
battery power. This button is very sensitive, do
not press it by accident or you will lose the
current recording data.
2. 3.5 mm connector for data synchronization
3. LAN port – Connects to a Windows tablet or computer running the controller software, via the
supplied Ethernet cable. The recording unit can
also be connected to the tablet or computer via
Wifi. 4. Connection status LED– Indicates connection to
the head unit and the controller software.
5. SD card Activity LED– Indicates if a SD memory card is present and if the recording unit is busy
writing on the SD memory card. 6. HDMI connector – Connects to the head unit via the supplied HDMI cable.
7. Micro USB connector – Connects to USB charger for powering the unit and charging the
battery. 8. SD memory card slot – Slot for SD memory
card for storage of recorded data. 9. Battery compartment – Holds the battery for
the recording unit and the head unit 10. Belt clip – For attaching the recording unit to
participant’s belt.
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1.3 TobiiPro Glasses 2 Carry Case TobiiPro Glasses 2 comes with a dedicated Carry Case that will accommodate the most important
components needed for data collection with Tobii Glasses 2. The Carry Case can be used
as a portable tablet rest, see illustration below. This however is not very comfortable for the researcher
and it is suggested to prepare everything beforehand and walk with only the tablet.
The case has space for the Head Unit, Recording Unit, SD memory cards, batteries, etc. See the
illustration and the table below for information about how to fit the equipment in the Carry Case.
a. Head Unit
b. Recording Unit
c. Protective Lenses (1 clear + 1 tinted, 1
should be attached to Head Unit)
d. Nose Pads in different sizes
e. Rechargeable Li-Ion batteries type 18650
f. SD memory cards + sleeves
g. Calibration Card
h. Microfiber cleaning cloth
i. Head Strap
j. USB memory stick with documentation and
software
k. Cable cord clip
l. HDMI A to HDMI D cable
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1.4 The tablet and the researcher
For the glasses to work, the tablet needs to be running the TobiiPro Glasses Controller software. You
can start and stop recording with the software and view the live feed of the glasses when close enough
to the glasses when recording, this should approximately be 20 meters. This means that the researcher
is always carrying the tablet when experimenting. When calibrating the glasses, it is possible to use the
calibration card in the carry case, but it may be more useful to use the sticker located on the back of
the tablet. This way you need not bring the card with you during the experiment.
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2. Participant selection and recommendations
2.1. Participant Selection
There are multiple things to keep in mind when selecting participants for your research.
1. No participant can partake in the experiment, whilst wearing other glasses.
. Solutions for this problem are gathering participants with no
visual impairments or use participants that have their visual impairment corrected with contact
lenses. Prescription protective lenses for the Tobii Glasses 2 are also a possibility, but, as of now, we
do not possess the prescription glasses, these are recommended to get. Contact lenses do not
interfere with the accurate tracking of
eye movements.
2. No fake eye lashes.
This causes the Tobii Glasses 2 to not accurately track eye movements. Solutions are to ask the
participants to take them off.
2.2. Weather conditions for outside testing
Whilst doing tests with the Tobii Glasses 2 outdoors, we came by a problem with sunlight interfering
with the eye measurements. The eye movements were not registered when walking in very bright and
sunny conditions (in summer). We think the reason for this is the infrared light that is used to measure
the eye movements is being overpowered by the infrared light of the direct sunlight. This was tried to
be counteracted by wearing a hat, using an umbrella and using a scarf, but without any positive effect.
Therefore, we were dependent on the weather conditions. It had to be cloudy with minimal sunlight
exposure for the glasses, but it could not rain for not wanting to damage the glasses. Tobii advised us
on always calibrating the glasses inside, because this was hard to do outside when sunny. You can use
the Track Status (see section 5.3. below) to see whether the glasses register the participants’ eyes or
not. These problems do not occur when doing experiments indoor.
2.3. Recommendations for experiment and research
1. When making an experiment involving mapping, that the field of focus is the size of a thumbnail at
an arm’s length. 2. Do not make tasks for the participants, that makes the participant multitask. This way you get less
specific and perhaps less valid data. This means that the research should be designed in a
way that clear user tasks (to be executed during the tests) are derived from the research
questions. Use a goal-oriented approach for the tasks, this way the participants are less
distracted and you will get more useful data.
3. Always perform multiple pilot tests, to filter out the flaws of your study design.
4. Think, before starting the experiment, about using concurrent- or retrospective Think Aloud
Protocol. Think about using Think Aloud Protocol or not, it has its advantages to use concurrent
TAP, because you can code your data easier later on in your research.
5. Make note of participants that have experience and do not have experience in/with what you are
testing (Virgin eyes). You can establish the participant’s backgrounds by using questionnaires.
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3. Preparations before a data collection day It is recommended to make a test recording before going into the field for data collection. This manual
is made for the use of the Tobii Glasses Controller Software on tablets. You can also use a laptop for
this that can run the Tobii Glasses Controller Software.
3.1. Charging batteries and preparing memory cards 1. Check the Recording Unit batteries, when the batteries are at 4.2V they are full, all other voltages
need to be charged, if depleted charge the batteries with the battery charging device.
The Recording Unit can also be charged, with a battery inserted in it via USB Charging. This,
however, is not the recommended way to charge the batteries. The Recording Unit can get really
warm and this is not good for the Recording Unit.
2. Check the tablet battery, if depleted charge the tablet using the charging cable delivered with the
tablet.
3. Backup any old data on SD memory cards if necessary and empty the card.
4. Insert empty memory card in Recording Unit.
5. Make sure you bring all necessary parts and components and make sure they are packaged and
transported with care.
3.2. Check for Windows updates on the tablet
1. Turn on the tablet.
2. Connect the tablet to a Wifi network (eg. Eduroam). Use your own m/[email protected] and
password to connect to Eduroam.
3. Tap on the Windows icon in the bottom left of the screen.
4. In the pop-up start menu, select settings on the left side. The Settings screen opens up.
5. In the Settings screen, click on Update & Security.
6. In the Windows Update section, tap Check for Updates. Update Windows 10 if necessary.
7. Restart the tablet, when it finished updating. This is not necessary if there were no updates to be
installed.
3.3. Check for updates on the controller software and the firmware of the
glasses 1. Connect the tablet to a Wifi network (eg. Eduroam).
2. Connect the tablet to the Recording Unit with an Ethernet cable.
3. Open the TobiiPro Glasses Controller software on the tablet.
4. When an update is available, there will be a red exclamation mark on the settings icon at the
top center of the screen. If there is no exclamation mark, the software and firmware are up to date.
Always update the software and firmware when seeing the exclamation mark.
5. When updates are available, tap on the settings icon in the top center of the screen.
6. Click on the update button in the pop-up screen. Wait until the update is finished.
7. Close the TobiiPro Glasses Controller software by using the x mark in the top right corner.
When prompted, tap Yes.
8. Open the TobiiPro Glasses Controller software.
9. Tap the settings icon in the lower left corner of the screen to check if the newest update was
correctly installed.
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4. Data collection It is recommended making a test recording at the start of a new data collection day.
4.1. Preparing for recording 1. Use the supplied microfiber cloth to clean the Head Unit. Make sure to clean all optical parts such as
the eye tracking sensors and IR illuminators for best performance. (See 1.1. for locations) 2. Connect the Head Unit to the Recording Unit using the HDMI cable. Press the power button on the
recording unit for 3 seconds to turn the Head Unit on.
3. Turn on the tablet.
4. Start Tobii Glasses Controller Software on the tablet.
5. Open an existing study or create a new one.
6. Connect the Recording Unit and tablet (via Ethernet cable or Wifi).
7. To connect the glasses to the tablet using Wifi, tap on the wifi icon in the bottom right of the
tablet screen. A list of available networks will appear. (It may take up to two minutes before a newly
started recording unit appears in the list of available networks.) 8. If the tablet is already connected to another network, make sure to disconnect it from this network
first. You may otherwise experience that the tablet is not reconnecting automatically to the
recording unit after losing connection to it.
- To disconnect from your current network: tap Current connection and then tap Disconnect.
9. Tap the Wifi network that has the same name as the serial number of your recording unit (TG02X-
XXX...). You will find the serial number on the sticker on the back of the recording unit.
10. Tap Connect. If prompted for a password, type TobiiGlasses into the field and tap Next. It may take
up to two minutes before Tobii Glasses Controller Software establishes a connection to the recording
unit. On the Tobii Glasses Controller Software Dashboard, the Glasses Control panel will display
“Ready” whenever there is a connection between the software and the recording unit. On the
Recording Unit, the Connection Status LED emits a constant green light.
The connection will be lost when either the tablet or the Recording Unit is turned off, or if the distance
between the tablet and the recording unit is too great. The recommended distance is around 5 meters.
When there is no connection between Tobii Glasses Controller Software and the recording unit, the
Control panel screen in the controller software on the tablet will display “Disconnected”.
When the Tobii Glasses Controller Software says it has ‘found’ a pair of Tobii Glasses 2, make sure it is
connected, most of the time this is not the case.
4.2. Making recordings 1. Check battery and memory levels in the Tobii Glasses Controller Software, use the Dashboard tab at
the top of the controller software. With full batteries at 4.2V you can experiment for 1h45mins. 2. Fit the Glasses onto the participant. (See 5.1.) 3. Start a new recording by using by creating a new one. This process
includes calibrating the participant and verifying the accuracy though the Live Viewer before starting
the actual recording (See 5.3.). When correctly calibrated, click the record button in the bottom
right of the Live Viewer screen. 4. If connected by Ethernet cable, disconnect the cable after the start of the recording 5. Ask the participant to perform the tasks. If in any way, you lose the connection from the tablet to
the Glasses in the Live Viewer, it will still record the data on the Recording Unit’s SD card.
6. When the data collection is complete, connect the Recording Unit to the tablet if it has been
disconnected, either using the Ethernet cable or Wifi.
7. Stop the recording on the Dashboard tab or through the Live Viewer tab.
8. Remove the Glasses from the participant.
Always press record when starting the experiment, this is easy to forget. When calibrating the Tobii Glasses 2, the calibration symbol needs to be at a distance of approximately 1 meter. The HDMI cable that runs from the Glasses to the Recording Unit is 1 meter long. You can use this to easily calibrate at the right distance, without bringing extra tools.
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4.3. How to fit the Tobii Glasses 2 Eye Tracker onto a test participant To be able to collect accurate eye tracking data Tobii Glasses 2 must be calibrated individually for each
participant. Before the calibration process the participant must be wearing the Head Unit correctly so
that the Tobii Glasses 2 cameras can accurately track the participants eyes.
1. Make sure all optical parts on the Head Unit such as eye
tracking sensors, and IR illuminators are clean and not
scratched or damaged in any way. 2. Make sure that participant characteristics match the
requirements of the Glasses 2 Eye Tracker. 3. Make sure that Tobii Glasses Controller Software is
running on the tablet. 4. Make sure the Recording Unit is turned on.
5. Make sure there is a connection between Tobii Glasses Controller Software and the Recording Unit either over
Wifi or Ethernet on the Dashboard tab in the Tobii
Glasses Controller Software. 6. Gently fit the Head Unit onto the participant as shown in
the illustration. 7. Make sure the Glasses fit comfortably and securely.
8. To ensure the Head Unit is stably and securely positioned on the
participant’s head and nose, exchange the Nose Pad for another
Nose Pad in a different size or shape if necessary. (To change the
Nose Pad, see instructions in section 5.2. below) 9. It is recommended that you use the Head Strap to secure
the Head Unit on the participant’s head. This will reduce
the risk of the Head Unit falling down and your data will be more
reliable. 10. Make sure the HDMI cable runs through the Cable
Guide, and then behind the participant. Secure the cable
onto the participants clothing this
can be done by using the cable cord clip. 11. Ask the participant to gently attach the Recording Unit to the
belt or clothing somewhere along the waistband of the
trousers/skirt, preferably along the participant’s right
side of the back. The button on the Recording Unit is very
sensitive, placing it on the back of the participant negates the
possibility of accidentally pressing it and losing all data from the recordings.
4.4. How to change the Nose Pad
1. To remove the existing nose pad from the Head Unit:
Gently squeeze the tips of the nose pad towards each
other and then gently pull the Nose pad straight away
from its mounting. 2. To mount a new nose pad: Gently squeeze the tips of
the nose pad towards each other and then gently push
the nose pad straight onto its mounting until it locks in
place.
The white dotted nose pad is for broader noses, the black dotted nosepad for slimmer noses.
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4.5. The Track Status
The Track Status or Adjustments tool is designed as a guide to help you position the Tobii Glasses 2 on
a participant correctly. The button is located in the bottom left of the Live Viewer screen of the Tobii
Glasses Controller Software. Below is a table of the most common scenarios, what they mean and
possible solutions to any problems. These are only shown on the live viewer screen and there is one for
each eye.
No eyes detected — The glasses cannot detect
eyes with any of the Eye Tracking Cameras.
Move the Head Unit closer to the participants’
eyes or change the Nose Pad.
Pupils detected, but not in range — The glasses
can detect pupils, but they are too far away
from the cameras. Move the Head Unit closer to
the participants’ eyes or change the Nose Pad. Pupils detected, bad distance and on the limit of
the field of view of the eye cameras — The
glasses can detect the participants’ pupils,
however they are only just within the field of
view of the Head Units’ eye tracking cameras
and are too far away. Move the Head Unit
closer to the participants’ eyes or change the
Nose Pad.
Pupils detected, OK distance and within the field
of view of the eye cameras — The glasses can
detect the participants’ pupils, they are on the
outer rim of the recommended field of view for
the Head Units’ eye tracking cameras.
Recording should be possible with this status.
However, it is recommend that you try and
achieve a better status if possible. You can
achieve a better track status by moving the
Head Unit closer to the participants’ eyes or by
changing the Nose Pad.
Pupils detected, good distance and within the
field of view of the eye cameras — The glasses
can detect the participants’ pupils within the
preferred field of view of the Head Units eye
tracking cameras. This is the best status
achievable with the glasses and should give
you the best tracking.
4.6. Checking the recording 1. Check recorded data by replaying the video from the Recording List. The Glasses need to be
connected to check the recorded data on the tablet.
4.7. Turning the Glasses off
1. This is not necessary if you continue with other participants in the same study. (Start with 4.2.2.)
2. On the Recording Unit, press and hold the power button until the LEDs stop flashing
4.8. After data collection 1. Back up all recorded data from the SD memory card to a computer or an external storage drive. 2. Charge the Recording Unit batteries with the battery charging device.
3. Charge the tablet battery using the charging cable delivered with the tablet.
4. Place all the components to their right places in the carry case as depicted in section 1.3.
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6. Analysis of the recordings with Tobii Glasses Analysis Software To perform any analysis beyond simple replay of a recording, you need to import your recordings into
Tobii Glasses Analysis Software.
6.1. Basic Operations
Tobii Pro Glasses Analyzer organizes and stores data in projects, which makes it easy to keep track of
recordings and participants. Each project can contain numerous recordings, participants, snapshots,
mapped data and events, etc. The projects are managed from the Applications menu.
To open the Applications menu:
• Click the icon at the top left of the Tobii Pro Glasses Analyzer window.
6.2. Creating a new project
To create a new project:
1. If the Applications menu is not already open, click the icon at the top left of the Tobii Pro Glasses
Analyzer window to open the Applications menu.
2. Click Create new project in Applications menu.
3. Enter a name for the project in the Project name field.
4. To change the default location of the project files, click Browse and choose a new folder. The default
location is [user]\Documents\Tobii Pro Glasses Analyzer\
5. Click Create to create the new project. An empty Project Dashboard will open.
6.3. Opening an existing project
To open an existing project:
1. If the Applications menu is not already open, click the icon at the top left of the Tobii Pro Glasses
Analyzer window to open the Applications menu.
2. Click Open project in the Applications menu. A list of recent projects is displayed.
3. If the project that you would like to open is in the Recent project list, double click the name of the
project and the project will open.
4. If the project that you would like to open is not in the Recent projects list, click the Browse button.
5. Locate and select the project you would like to open in the Windows File Manager. Click Open and
the project will open.
6.4. Importing data from Tobii Pro Glasses 2
To import Tobii Pro Glasses 2 data:
1. Insert the SD memory card used during recording into the SD card slot on your computer. 2. In the Application Menu in Tobii Pro Glasses Analyzer, create a new or existing project, see 6.1.1 or
6.1.2.
3. In the Project Dashboard Menu, click Import and then Glasses Recording. A Glasses Data Import
dialog box opens.
4. In the Glasses Data Import dialog box, locate and select the Tobii Pro Glasses 2 data file (named:
*.ttgp) on the SD memory card that you want to import. 5. Click Open to import the data.
6. Here you can select per file, which recording you want to import into the Analyzer software.
If a problem occurs when importing the recordings and the Analyzer says that the files are corrupted, restart the computer with the SD card still in the computer. This was, what I found to be, the only way to import the recordings into the Analyzer without getting the corrupted error.
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7. Replaying recordings and recording settings
During replay of a recording, gaze data is first processed by the fixation filters in the software and then superimposed on the recorded scene camera video. All replay takes place in replay tabs; each open tab corresponds to a specific recording. Multiple replay tabs can be opened simultaneously, but only one can be active and replayed at any time. To open a Replay tab: In the Recordings List, double-click the recording you want to replay and a Replay tab will open. Alternatively: In the Recordings list, right-click the recording you want to replay, and then select “Open in Background tab” in the context menu. The tab will open, but the Recordings List will still be visible. To skim through or jump to a location in the video replay: Click and drag the track slider below the video display area. To step frame by frame in a recording: Click the arrows at either side of the Play button to step forward or backward frame by frame in the video.
7.1. Gaze data settings
During replay of a recording, gaze data is first processed and classified by the fixation filter and then superimposed on the recorded scene camera video. The eye movement classification algorithm (the fixation filter) and the appearance of the visualized gaze data can be customized to fit the needs of the researcher/analyst. The fixation filter processes and classifies the recorded gaze data samples into fixations and other eye movements. For details on how they work and what effects they have on your data, see “Tobii Pro Glasses Analyzer: User’s manual” section: Appendix B Fixation Filters, how they work and what effects they have, page 31. When the I-VT fixation filter is enabled the classified eye movements (fixation, saccade, UnknownEyeMovement) are visualized below the timeline in the replay view. Fixations are visualized as a yellow thick line, saccades are visualized as a thin gray line and unknown eye movements are visualized as a striped thick gray line. All settings are available in the Tools panel to the right of the video display area. To Change Fixation Filter: 1. Make sure the correct Replay tab is active. 2. In the Tools panel on the right, locate: Gaze Data > Settings > Gaze Filter. 3. Open the Fixation Filter drop down menu by clicking the down arrow to the right of the currently active filter. 4. In the drop down menu, select the filter of your choice. The available options are:
a. Tobii I-VT (Fixation) b. Tobii I-VT (Attention) c. Raw d. Create new Raw filter (for custom settings) e. Create new I-VT filter (for custom settings)
5. The new filter is now applied during replay.
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8. Specific methods for analysis
In this section, different methods of analysis are worked out for qualitative and quantitative research.
8.1. Qualitative Analysis
8.1.1. Observing behavior and Logging Events (Coding)
Tools for logging interesting and important events in the recordings are included in the software.
These Custom Events, for example “Participant picks up item 1”, can also be exported together with
all the other data collected during a recording. The logged events appear on the timeline and in the
Events List in the Tools panel on the right. To manually log events, you must first define a Custom
Events scheme, that contains the events you want to log and define which keyboard keys you want to
use for logging the events.
Define a Custom Events logging scheme: 1. Make sure a Replay tab is active. 2. Locate Events in the Tools panel on the right. 3. Click the New Event Type button at the top right of the panel. The New event dialog box opens. 4. Enter the name/description of the event in the New Event dialog box. 5. Click the drop down menu in the New Event dialog box and select the keyboard key, or combination of keys that you would like to use for logging this event. It may be easy to have opposite actions defined as e.g. P-key and CTRL + P-keys 6. Click OK. Edit an existing Custom Event: 1. Locate Events in the Tools panel on the right. 2. Place the mouse cursor over the custom event you want to edit; icons appear on the right. 3. Click the edit icon. An Edit Custom Event dialog box opens. 4. Edit the name or description in the Custom Event dialog box. 5. Click the drop down menu in the New Event dialog box and select the keyboard key, or combination of keys that you would like to use for logging this event. 6. Click OK. Delete a Custom Event from the Custom Events Scheme: 1. Locate Events in the Tools panel on the right. 2. Place the mouse cursor over the Custom Event you want to delete; icons appear on the right. 3. Click the Delete icon. A Delete Custom Event dialog box opens. 4. Click Delete event to confirm. To manually log events, you must first define a Custom Events scheme that contains the events you want to log (see the section above). Manually log an event: 1. Make sure the correct Replay tab is active. 2. Make sure you have defined the Custom Events that you would like to log. 3. While replaying or pausing a recording press the shortcut key on your keyboard associated to the event you want to log. Alternatively click the Log icon that appears when placing the mouse cursor over an event type in the Custom Events list on the right.
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8.1.2. Managing snapshots and mapping eye gaze
Wearable eye tracking devices such as Tobii Pro Glasses 2 produce eye gaze data mapped to a
coordinate system relative to the wearable eye tracker and the recorded video, not to static objects of
interest in the environment around the participant wearing the eye tracker. For most
statistical/numerical analysis to be meaningful, the collected eye tracking data needs to be mapped
on to objects of interest and into a new coordinate system with its origin fixed in the environment
around the participant. TobiiPro Glasses Analyzer addresses this challenge by allowing the user to map
eye gaze data onto still images (snapshots) of environments and objects of interest in two different
ways; either semi-automatically or fully automatically with the Real-World Mapping function. Real World
Mapping is Tobii Pro’s software technology for automatic mapping of gaze data from Glasses 2
onto a snapshot (such as a landmark). In Tobii Pro Glasses Analyzer users will use the feature
Automatic gaze mapping to map gaze onto a snapshot. With the result, the user can complete or
override with manual coding and aggregate data from multiple participants. The snapshots images are
typically created by the data collector or the researcher by using a standard digital camera, for details
see “Tobii Pro Glasses Analyzer: User’s manual” section: Appendix G Snapshot Considerations When
Using Real-World Mapping.
Snapshots created from multiple images do not work flawlessly with Real-World Mapping at the
moment. To make the manual mapping process efficient, Tobii Pro Glasses Analyzer lets you map
entire fixations on a snapshot with just one click, rather than mapping each data point individually. If
you have chosen to map data when the Raw Data fixation filter option enabled, the data will be mapped
gaze point by gaze point. Gaze data from a recording can be mapped on one or several snapshots.
8.1.2.1. Importing snapshots
Snapshots are still images of environments, areas or objects of interest relevant for the study.
Snapshots are typically created by the data collector or researcher by using a standard digital camera.
Requirements for snapshot images:
• Less than 25 megapixels • PNG or JPG file format
Snapshots created from multiple images that are stitched together into one image are allowed as long
as the final snapshot file matches the snapshot requirements above. Stitched images are images that
are put together from a series of images covering a greater area than the camera was capable of
covering in just one shot. Snapshots (still images) can be imported either from the Dashboard menu, or
from the Tools panel within a Replay tab.
To import a snapshot from the Dashboard Menu:
1. In the Dashboard Menu, click Import > Snapshots, the import dialog will open. 2. Locate the image file (*.png or *.jpg) on your computer that you want to use as snapshot and click
Open. An import progress bar appears. 3. Once the snapshot image has been imported, click OK.
To import a snapshot from the Tools Panel in a replay tab: 1. Locate the Gaze Data Tool in the Tools panel on the right.
2. Select the Snapshots tab.
3. To the right of the text “Snapshot images”, click the”+” icon. The Import snapshot dialog box
opens.
4. Locate the image file (*.png or *.jpg) on your computer you want to use as a snapshot and click
Open. An import progress bar appears.
5. Once the snapshot image has been imported, click OK.
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8.1.2.2. Mapping data onto a snapshot
Mapping data onto a snapshot manually
1. If not already enabled, click the Snapshots switch just below the video replay to enable mapping.
2. Locate the Gaze Data Tool in the Tools panel on the right.
3. Select the Snapshots tab. 4. Select/Deselect the Automatically step to next fixation checkbox. Selecting the Automatically step to
next fixation checkbox will cause the paused replay to automatically jump to the next fixation/raw data
point on the time line, as the previous one is already mapped. This eliminates the need to use arrow
keys to step forward manually on the time line. 5. In the grid/list of snapshot images, select the snapshot onto which you want to map data. The
Snapshot appears next to the recorded scene camera video. At any time during mapping of data, you
can switch back and forth between different snapshots without losing mapped data. 6. While skimming through the recording replay, locate and pause the video at the start of the section
that you want to map onto the selected snapshot. 7. To map data onto the snapshot, first locate the gaze data point (circle superimposed on the video) in
the recorded video. Click once in the corresponding location on the snapshot image as precisely as
possible. 8. Continue this process until all data has been mapped onto the active snapshot. As data points are
mapped onto the snapshot, the snapshot time line will indicate at which times data points have been
mapped. 9. Make sure to replay the recording straight through to verify that data has been mapped correctly
onto the snapshot.
Mapping data onto a snapshot automatically with Real-World Mapping
1. If not already enabled, click the Snapshots switch just below the video replay to enable mapping.
2. In the grid/list of snapshot images, select the snapshot onto which you want to map data. The
Snapshot appears next to the recorded scene camera video.
3. Select the interval you want to map automatically on the time line. This can be done by placing the
yellow bars found on the timeline to the time you want to map. 4. Right-click on the chosen interval, or click the ellipsis “(...)” located directly over the time line, and
choose “Run automatic mapping”. If needed, you can zoom in the time line to make the interval
selection easier. The interval is now placed in the processing queue and Real-World Mapping starts the
automatic mapping. 5. Now you can choose to create another mapping task by repeating steps 4 to 6 and place it in the
processing queue, or if you don’t have any more pending tasks, continue to step 8. 6. You can check the jobs placed in queue by clicking the number on the top right end of the window. 7. When the automatic mapping is completed, a diagram is shown on the time line with the confidence
results for every frame. This diagram shows how Real-World Mapping classifies each point of the
automatic mapping. A high bar indicates that Real-World Mapping thinks the mapping has a high
confidence; a lower bar means that Real-World Mapping could not determine the mapping with
confidence — it could be a good mapping as well as a bad one. 8. (Optional) You now have the possibility to complete the analyzed confidence results by manually
coding/correcting them. • Go to the areas on the time line with low confidence intervals and check whether the gaze
points on the snap shot correspond with the gaze points in the recorded movie. There is no way to add or delete vertices on an existing Area of Interest (AOI) at present. Tobii
is constantly improving the performance of Real World Mapping • For each point you can now choose to either remove the point, by pressing Delete or by right-
clicking on the point in the image and choose Delete, correct the point by manually place it
where it should be, just like you do in manual mapping described earlier, or leave the point as
it is. • The manually coded frames are marked in with a solid green color without a graph. In the
snapshot image, the automatically generated mapping is marked with a green circle, and the
manually coded mapping is marked with a red circle. Over-ridden, automatically mapped,
points are marked with a grey circle.
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• Keep repeating this procedure until you are satisfied.
9. View the result in gaze replay
8.1.2.3. Visualizing eye tracking data
In the Visualizations tool in Tobii Pro Glasses Analyzer, data can be visualized using heat maps and
gaze plots. Heat maps can be of great value when creating reports, papers or presentations as they
help you summarize large quantities of data in an intuitive way. Heat maps are created on top of
snapshots. A heat map uses different colors to illustrate the number of fixations participants made
within certain areas of the snapshot or for how long they fixated within that area. Red usually indicates
the highest number of fixations or the longest time, and green the least, with varying levels in
between.
Gaze plots can be used to illustrate the gaze pattern of a single test participant throughout the entire
eye tracking session, or of several participants in a short time interval. The visualisations are very hard
to create when dealing with constantly changing environments, it is not recommended to make
visualisations when experimenting in- or outdoors with a changing environment.
Creating heat maps and gaze plots
To create a heat map:
To be able to create heat maps on snapshots, at least one snapshot in the project has to have gaze
data mapped onto it.
1. Select Visualizations in the Dashboard Menu. A Visualizations tab opens.
2. In the Visualization Type and Settings tool, select heat map.
3. In the Tools panel on the right, in the Analysis Sets tool, select the snapshot (Analysis Set) that you
want to use as the base of your visualization.
4. In the Tools panel on the right, in the Data Selection tool, select/deselect the recordings and/or
intervals that you want to visualize in the heat map. To see the intervals included click the arrows to
the left of the recording checkboxes, to expand the view. An interval is a subset of mapped data
associated to a specific recording. These subsets are generated automatically when there is a gap of
data for at least 5 seconds in the mapped data.
5. In the Tools panel, in the heat map settings tool, in the Type dropdown menu, select the calculation
basis for the heat map
• Absolute count — calculated by the number of fixations (or gaze data samples if using raw
data).
• Absolute duration — calculated by the duration of fixations (or gaze data samples if using
raw data).
• Relative count — calculated by the number of fixations relative to the total number of
fixations made by the participants in the Analysis set (or gaze data samples instead of fixations
if using raw data).
• Relative duration — calculated by the duration of the fixations relative to the sum of all
fixation durations mapped in the Analysis set on the snapshot (or gaze data samples instead of
fixations if using raw data).
6. The heat map is now drawn on top of the snapshot image.
To generate a gaze plot: The gaze plot visualization shows the sequence and position of fixations (dots) on a snapshot image.
The size of the dots indicates the fixation duration and the numbers in the dots represent the order of
the fixations. Gaze plots can be used to illustrate the gaze pattern of a single test participant
throughout the entire eye tracking session, or of several participants in a short time interval.
1. Select Visualizations in the Dashboard Menu. The Visualizations tab will open. 2. In the Visualization Type and Settings tool, select gaze plot. 3. In the Tools panel on the right, in the Analysis Sets tool, select or import the snapshot (Analysis Set) that you want to use as the base of your visualization.
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4. In the Tools panel on the right, in the Data Selection tool, select/deselect the recordings and/or intervals that you want to visualize in the gaze plot. To see the intervals included click the arrows to the left of the recording checkboxes, to expand the view. An interval is a subset of mapped data associated to a specific recording. These subsets are generated automatically when there is a gap of at least 5 seconds in the mapped data. 5. The gaze plot is now drawn on top of the snapshot image. Heat maps and gaze plots can be saved as image files to be incorporated later into reports.
Available image file formats are *.png and *.jpg.
To save a heat map:
1. Right-click within the heat map area. A context menu appears with the option to “Save to File...”
2. In the Context menu, select Save to File... A Windows File Manager dialog box opens.
3. In the file manager dialog box, locate the folder you want to save the file in.
4. In the File name field, enter a file name for your image.
5. In the Save as Type dropdown menu, select desired file type (*.png or *.jpg). (For images with
transparent backgrounds, the file type must be *.png to maintain the transparency)
6. Click Save to save the image.
8.2. Quantitative Analysis
8.2.1. Metrics (Areas Of Interest)
Areas of Interest (AOIs) enable numerical/statistical analysis based on regions or objects of interest in
your snapshot images. AOIs are drawn around objects in your snapshot that you would like to analyze
further in third party software such as SPSS, Matlab or Excel. AOIs can be of any shape. Once an AOI
has been drawn onto a snapshot, and there is data mapped onto the snapshot, the data export output
file will include data on whether the participant’s gaze point is inside or outside the AOI.
To draw AOIs on a Snapshot:
1. Select AOI editor in the main menu and an AOI editor tab will open. You can have multiple AOI editor
tabs open simultaneously, one for each snapshot.
2. To draw an AOI, do one of the following: • To draw polygons: Select the Polygon tool and click where you want the AOI to start and then
click wherever you want to add vertices. Close the shape by clicking on the first vertex. • To draw rectangles or ellipses: Select the Draw rectangle or Draw ellipse tool on the top, click
and drag until the shape is the size you want. To make the shape a perfect square or circle,
press and hold SHIFT while you drag to draw.
To name an AOI, do one of the following:
• In the list of AOIs, double click the previous AOI name and enter the new name. • In the AOI shape, double click the name label and enter the new name.
To change the shape of an existing AOI:
1. Make sure the AOI you want to edit is visible
2. On the toolbar, select the Select/Move Vertices tool.
3. Drag the vertices to transform the AOI.
To change the size of an existing AOI:
1. Make sure the AOI you want to resize is visible.
2. On the toolbar, select the Select/Move AOI tool.
3. Click the AOI that you want to resize. A rectangle with sizing handles in the corners appears around
the selected AOI.
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4. To increase or decrease the size, click and drag one of the sizing handles. To maintain the object's
proportions, press and hold SHIFT while you drag the sizing handle. The size of a selected AOI can also
be adjusted by modifying the width (W:) and height (H:) values in the property fields on the toolbar.
To move an existing AOI:
1. Make sure the AOI you want to move is visible.
2. On the toolbar, select the Select/Move AOI tool.
3. Click the AOI that you want to move. A rectangle appears around the selected AOI.
4. Drag the AOI to its new location. To constrain an AOI so that it moves only horizontally or vertically,
press and hold SHIFT while you drag the object. The position of a selected AOI can also be adjusted by
modifying the X: and Y: values in the property fields on the toolbar.
To export an image of the AOIs on the snapshot:
1. Right click on the snapshot and the context menu opens.
2. Click Export Image in the context menu. A Save As dialog box opens.
3. In the Save As dialog box, locate an appropriate folder, enter a file name and click Save.
Export metrics
1. Select the Metrics tab in the Dashboard Menu. A Metrics Export tab opens.
2. Select the metrics you want to include in the exported Excel file.
3. Click the Export button on the top right. A Windows File Manager dialog box opens.
4. In the file manager dialog box, locate the folder you want to save the file in.
5. In the File name field, enter a file name for your file.
6. Click Save to save the export file (named *.xlsx).
8.2.2. Eye tracking data
From the Data Export tab you can export all the raw data collected by the eye tracker as well as all data
generated by the user, such as events that have been logged in the recordings. Exports from Data
Export are saved in a tab-separated values file (.tsv) and follows the Unicode standard.
With these data sets you can e.g. quantify the logged events and identify outlying participants in
the data. When you select Recording Timestamp and Event, you can see precisely when a certain
event took place in the experiment.
To export data:
1. Select Data Export in the Dashboard Menu. A Data Export tab opens.
2. Select the data types you want to include in the .tsv file.
3. Click the Export button on the top right. A Windows File Manager dialog box opens.
4. In the file manager dialog box, locate the folder you want to save the file in.
5. In the File name field, enter a file name for your file.
6. Click Save to save the export file (named *.tsv).
