Development of a Stereoscopic Projection System

DEVELOPMENT OF A STEREOSCOPIC PROJECTION SYSTEM

Thesis Proposal

V 2..2

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INTRODUCTION TO 3D PROJECTION SYSTEMS

3D APPLICATIONS Medical Scientific Engineering Education Entertainment Military Advertising

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INTRODUCTION TO 3D PROJECTION SYSTEMS

BUDGET FOR THE EXAMPLE SYSTEMS

System Type Price (Bath)

Volumetric 3D Display Volumetric 4,800,000

42-3D6W01 42" Wow Autostereoscopic 59,600

i-visor FX601 HMD 55,920

Duality X3(+ Cyviz Xpo 1024x768)

Polarizing 1,232,800

Mirage S+2K Shutter Glass 2,387,800

InFocus DepthQ NuVision + 2 pairs of 60GX glasses

Shutter Glass 254,800 3

From www.inition.co.uk

PROJECT PREFACE If you want a Stereoscopic System,

But you have small budget. What is our alternative?

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PROJECT PREFACE

PROBLEM Commercial 3D stereoscopic systems are too

expensive for average users because they require a customized projector.

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245,800 Bath!!!40,000 Bath , OK!!

If we can adapt a common projector to project 3D stereopsis without modifying them,the cost of the system can be reduced.

40,000 Bath , OK!!

PROJECT PREFACE

IDEA

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The objective of this project is to develop a shutter-glass based stereoscopic upgrade kit for an off-the-shelf DLP projector.

40,000 Bath , OK!!

PROJECT PREFACE

OBJECTIVE

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Stereoscopic

Volumetric

Autostereoscopic

Stereoscopic

3D Display

TYPE OF DISPLAYS

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VOLUMETRIC

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PRINCIPLE OF STEREOSCOPIC Invented By Charles Wheatstone in 1838. Stereopsis is depth perception from binocular

visions through exploitation of parallax. Use two correspondence images to create an

illusion of depth.

Stereoscopic

Volumetric

Autostereoscopic

Stereoscopic

3D Display

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AUTOSTEREOSCOPIC Lenticular lens Sweeping light source

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STEREOSCOPIC

Stereoscopic Display Technology•HMD (Head Mounted Display)•2-Color Anaglyph•AnaChrome•ChromaDepth•Polarizing Glass•Shutter Glass

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STEREOSCOPIC

HMD HMD (Head Mounted Display) Disadvantage

Low Resolution Heavy ,Inconvenient Expensive ($1399-$145,000)

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2-Color anaglyph Use two of color filters. Advantage

Simple Disadvantage

Color Distortion

Anachrome is an Anaglyph Variant Anaglyph only in the border of object,

and preserve the color in the center object. This technique can reduce color distortion.

STEREOSCOPIC

2-COLOR ANAGLYPH

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STEREOSCOPIC

CHROMADEPTH Use prism. Advantage

Can be viewed without glasses.

Disadvantage Colorless

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STEREOSCOPIC

POLARIZING GLASS Advantage

Polarized eyeglasses are cheap. Disadvantage

Not feasible to use with LCD projector. Viewers need to keep their head level

to prevent left and right channels bleedover the opposite channel.

Need a polarization preserving screen.

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STEREOSCOPIC

SHUTTER GLASS Create 3D Stereoscopic illusion

by Switching projected picture for left and right eyes continuously.

The appeared image and shutter glasses have to be synchronize.

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Shutter Glass Mechanical

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จุดโฟก�ส

ฉากฉายภาพ

Shutter

Left Eye Right Eye

STEREOSCOPIC

SHUTTER GLASS

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3D SYSTEMS COMPARISON TABLE

ColorDistortion

Cost

HMD No (But Low Res)

Medium

Anaglyph Medium Cheap

AnaChrome Low Cheap

ChromaDepth High Cheap

Polarizing No Expensive(2 Projector)

Shutter Glass No Medium(1 Projector)

TRACKING SYSTEM

•Raw Data

•Position & Orientation Post Recognition

•Measurement Data Fusion

•Projection Matrix Calculation20

TRACKING SYSTEM

Tracker System

•Mechanical Tracker•Ultrasonic•Electromagnetic•Optical•Laser•Marker•Face Recognition

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TRACKING SYSTEM Position Tracker System

Mechanical Tracker Ultrasonic Electromagnetic Optical

Laser Marker Face Recognition

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CONCEPT OF THE PROPOSED SYSTEM

CONCLUSION

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•Commercial Stereoscopic is Expensive.•Commercial stereoscpic uses special custom made projector.

•We can reduce cost if we can use a common off the shelf projector.

•There are synchronization Problem when integrating common projector to stereoscopic system.•Because, The shutter glass and appeared picture isn’t sync.

•We can fix this problem by building synchronization kit.

CONCEPT OF THE PROPOSED SYSTEM

SYNCHRONIZATION PROBLEM

The problem is , When we use common projector in projecting 3D

stereoscopic signal, the projected picture isn’t synchronized with the shutter glasses.

Cause of problems The mechanism of DLP Projector Micromirror and its operation. Color Wheel

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External BoxExternal Box

Shutter Glass

DisplayDisplay

Shutter Glass Sync

CONCEPT OF THE PROPOSED SYSTEM

CAUSE OF PROBLEM, DLP TECHNOLOGY

DLP (Digital Lighting Processor) DMD (Digital Micromirror Device) MEMS (Micro Electro-Mechanism)

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Shutter Glass Sync

CONCEPT OF THE PROPOSED SYSTEM

SOLUTION The cause of the problem

The interval in digital lighting processor causes the appeared frame on the screen delayed. Ghosting Effect Frame Dropped Rainbow Effect, Especially on DLP Projector.

Solution Change synchronization source from graphic card output

signal to the marker on appeared picture on the screen.

Graphic Card

External BoxExternal Box

Shutter Glass

DisplayDisplay

Sync

DongleShutter Glass Sync

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PROPOSED SYSTEM

Com : ComputerMIB : Marker Insertion BoxProj : ProjectorTcam :Tracker CameraODD : Opto Detection DeviceShtCnt : Shutter glasses Control

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PROPOSED SYSTEM

COMPONENT DETAILS Components that have to be developed. MIB : Marker Insertion Box

Insert the marker in projected picture. There is switch on the box for reset, If the pictures from left and right

eyes were swapped.

ODD : Opto Detector Device Detect the appearance of the synchronization marker on screen,

And transmit signal to the shutter glasses control box if there were a marker appeared.

Easy to attached on Left-top of the screen.28

PROPOSED SYSTEM

COMPONENT DETAILS ShtCnt : Shutter glasses Control

Synchronize shutter glasses timing to the picture by detecting signal from ODD.

Can slice timing from synchronization signal by using digital PLL.

Tcam : Tracker Camera Track viewer head position by the shutter glasses attached camera. Locate head position by looking at the implanted LED marker on the

screen. Can be fused with angular acceleration sensor.

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PROPOSED SYSTEM

BUY OR BUILD

Proposed 3D Display

System

Computer with Stereoscopic

Renderer

DLP Projector

Shutter Glasses

Shutter Glass

Controller

Opto Detection

DeviceMarker

Insertion BoxTracking System

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Developed ComponentsOff the Shelf

PROPOSED SYSTEM

BUDGET COMPARISON

Proposed System

(55,400 Bath)

Customized System

(654,800 Bath)

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* Tracker :InterSense IS-1200 VisTracker* Computer and Software are omited

PROPOSED SYSTEM

IMPLEMENTATION PLAN

Proposed 3D Display System

Display Synchronization

Marker Insertion Box

Opto Detection

Device

Shutter Glass

Controller

TrackerIR TrackerHardware

Tracking Software

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• The inserted marker will be appear on top-left of the screen.

PROPOSED SYSTEM

MIB : FUNCTION Synchronization System

Marker Insertion Box Opto Detector Device(ODD) Shutter Glass Controller

ODD

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PROPOSED SYSTEM

MIB : IMPLEMENTATION

Synchronization System Marker Insertion Box Opto Detector Device(ODD) Shutter Glass Controller

Counting Circuit Horizontal

Compare-Horizontal Compare-Vertical

Counting Circuit Vertical

FPGA

Comparator (b)

Switch (a)

Pixel Clock GeneratorPixel Clock Generator VSyncVSync HSyncHSync

To ProjectorTo Projector

MarkerMarker

VGA SourceVGA

Source Switch

(c)

(d) 34

PROPOSED SYSTEM

ODD

Synchronization System Frame Marker Insertion Opto Detector Device(ODD) Shutter Glass Controller

Shutter Glass Controller

35Computer

(WinSGL Scheme)

PROPOSED SYSTEM

ODD : WINSGL Synchronization System

Fix Frame-Dropped Problem.

Long Delayed - Frame Synchronization SoftGenlock

Short Delayed – Signal Synchronization Hardware GenLock (SGI / GeForce (SLI) / nVidia) Software (WinSGL)

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PROPOSED SYSTEM

SHUTTER GLASSES CONTROLLER

Synchronization System Frame Marker Insertion Opto Detector Device(ODD) Shutter Glass Controller

Implemented on Microcontroller.

PLL Increase / Decrease Time base

÷N

ODDShutter Glass

Time Base

Glass ControlSequential Circuit 37

PROPOSED SYSTEM

SHUTTER GLASSES CONTROL

LCD Technology in shutter glasses Problem in controlling Shutter Glass

Spectrum Transparency Ghosting Effect : LCD Responding

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PROPOSED SYSTEM : SHUTTER GLASSES CONTROL

LCD TECHNOLOGY IN SHUTTER GLASSES

LCD (Liquid Crystal Display) TN (Twisted Nematic) TFT (Transistor Film Transistor)

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PROPOSED SYSTEM : SHUTTER GLASSES CONTROL

LCD TECHNOLOGY IN SHUTTER GLASSES

LCD (Liquid Crystal Display) TN (Twisted Nematic) TFT (Transistor Film Transistor)

40Twist Direction

BipolarityCapacitanceDead Band

PROPOSED SYSTEM : SHUTTER GLASSES CONTROL

GHOSTING EFFECT

Slow response. LCD molecular momentum and capacitance. Can be reduced by adding an Interval between

control sequences. Proposed by Kunz ,2001

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PROPOSED SYSTEM : SHUTTER GLASSES CONTROL

IMPLEMENTATION PLAN

PLL Increase / Decrease Time base

÷N

ODDShutter Glass

Time Base

Glass ControlSequential Circuit

42Bipolar Generator

Dead Band Generator

PROPOSED SYSTEM

TRACKING SYSTEM

Synchronization System Frame Marker Insertion Dongle, Snap on screen Device Shutter Glass Controller

Head Tracker IR Marker Implanted Screen

& IR Camera Vision Base Tracking

Software

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PROPOSED SYSTEM

TRACKING SYSTEM

Vision based tracker system. Integrate angular acceleration sensor for a better respond.

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PROPOSED SYSTEM : TRACKING SYSTEM

IMPLEMENTATION

Head Tracker IR Marker Implanted Screen

& IR CameraVision Based Tracking

SoftwareLocalization based on correspondences from

the features in known environment.

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PROJECT SCHEDULE

Synchronization System•MIB Improvement•ODD & Shutter Glass Controller Development

Tracking •Building IR Marker Implanted Projector Screen•Implement of Vision Tracker Software

Paper Works•System Testing•Conclusions•Publish Paper

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CONCLUSIONS

I will Build a stereoscopic upgrading kit for DLP projectorConsisting of….

• A Marker Insertion Box• Opto Detector Device (ODD)• Shutter Glass Controller• Integration of Tracking System• IR Marker Implanted Screen• Vision Based Tracking Software• Rendering Application Example

System Capability

• Display 3D object and with corrected volume.• User will see objects at stationary position floating in the screen. 47

Thank you

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The End

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PROJECT’S SCHEDULE

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PROPOSED SYSTEM

SYNCHRONIZATION SYSTEM : WINDOWS TIMMER

What is WinSGL time base. And, How precision it is?

The WinSGL Timming retrieves from QueryPerformanceCounter Function.

The time base frequency can retrieve from QueryPerformanceFrequency Function.

Each computer has different timer resolution. For Example the timer resolution of this computer is

1/3579545 Hz = 0.279 uS51

PROPOSED SYSTEM

SYNCHRONIZATION SYSTEM : CHANGING GRAPHIC CARD SIGNAL STRUCTURE

Changing of output VGA signal timing structure may cause the monitor malfunction.

From Waschbusch, 2006 experiments.

So, The most suitable method in changing timing without distortion of picture is the changing of vertical front porch.

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PROPOSED SYSTEM

SYNCHRONIZATION SYSTEM : CHANGING GRAPHIC CARD SIGNAL STRUCTURE

Frame Structure

Line Structure

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PROPOSED SYSTEM

3D STEREOSCOPIC RENDERING OpenGL has stereoscopic rendering capability. Programmer can select which buffer to render using

glDrawBuffer();

Stereoscopic rendering buffer alias.GL_BACK_LEFT or GL_BACK_RIGHT

There are 2 process in rendering stereoscopic on OpenGL

1. Select rendering buffer GL_BACK_LEFT or GL_BACK_RIGHTEx glDrawBuffer(GL_BACK_LEFT);

2. Change projection matrix of left or right projection.Ex gluLookAt(camera.vp.x + r.x, camera.vp.y + r.y, camera.vp.z + r.z, camera.vp.x + r.x + camera.vd.x, camera.vp.y + r.y + camera.vd.y, camera.vp.z + r.z + camera.vd.z, camera.vu.x, camera.vu.y, camera.vu.z);

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PROPOSED SYSTEM

3D STEREOSCOPIC RENDERING The Difference of Symmetric & Asymmetric Frustum rendering

In Toed-In camera which is an incorrect rendering of stereo image, Use Symmetric Frustum ,This incorrect create stress of depth perception. (Lacotte,1995)

Right Camera

Left Camera

Projective Plane

Screen

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PROPOSED SYSTEM

3D STEREOSCOPIC RENDERING A correct rendering use Asymmetric Frustum, which change

the camera axis perpendicular to screen.

Right Camera

Left Camera

Screen = Projective Plane

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PROPOSED SYSTEM

3D STEREOSCOPIC RENDERING

Parallax

Right Camera

Left Camera

Screen = Projective Plane

Negative Parallax

Right Camera

Left Camera

Screen = Projective Plane

Zero Parallax

Right Camera

Left Camera

Screen = Projective Plane

Positive Parallax

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PROPOSED SYSTEM

SYNCHRONIZATION SYSTEM : GENLOCK

Can Sync Display Signal. Using Special Hardware. Very expensive.

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PROPOSED SYSTEM

SYNCHRONIZATION SYSTEM : SOFTGENLOCK

Proposed by Schaeffer, 2000 Using LAN, Long Delay time. Able to Sync Rendering Sequence of multiple

Displays. Guarantee 100 ms Cannot Sync in Signal Level

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PROPOSED SYSTEM

SYNCHRONIZATION SYSTEM : SOFTGENLOCK

Proposed by Allard, 2002 Using LAN (Myrinet) , 50uS Guarantee. System needs Real Time OS. Cannot be used in WindowXP.

Alternative System has been proposed by Allard 2003

Using Parallel Port, 50uS Guarantee. Can be used in Non-Realtime OS.

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PROPOSED SYSTEM

SYNCHRONIZATION SYSTEM : WINSGL

Proposed by Waschbusch, 2006 Can synchronize signals from multiple

Graphic cards. Can be used in WindowsXP Using Special API Library . PowerStrip Using Software Phase Lock Loop (PLL) technique. PLL is a Proportional-Integral (PI) feedback system.

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PROPOSED SYSTEM

SYNCHRONIZATION SYSTEM : WINSGL

Mechanic of WinSGL (M. Waschbüsch,2006)62

POLARIZATION OF LIGHT

Circular Elliptical Linear 63

CONCEPT OF THE PROPOSED SYSTEM

CAUSE OF PROBLEM, DLP TECHNOLOGY

DLP (Digital Lighting Processor)

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PROPOSED SYSTEM : SHUTTER GLASSES CONTROL

LCD SPECTRUM TRANSPARENCY

The transparency in different colors are difference. Investigated By Woods ,2002

The transparencies in same spectrum on different time are difference.

Showing a Non-Linear Characteristic.

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PROPOSED SYSTEM

Com : ComputerMIB : Marker Insertion BoxProj : ProjectorTcam :Tracker CameraODD : Opto Detection DongleShtCnt : Shutter glasses Control

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PROPOSED SYSTEM

This project consists of the development of four devices which are , Marker Insertion Box Opto Detector Dongle attached on the projected screen Shutter Glasses mobile Controller. Vision- Inertia fusioned head tracking system.

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