Dynallax: Dynamic Parallax Barrier Autostereoscopic Display BY THOMAS PETERKA B.S., University of Illinois at Chicago, 1987 M.S., University of Illinois at Chicago, 2003 PH.D. DISSERTATION Submitted as partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computer Science in the Graduate College of the University of Illinois at Chicago, 2007 Chicago, Illinois This thesis is dedicated to Melinda, Chris, and Amanda, who always believed in me, and whose confidence helped me believe in myself. Graduate school would never have been possible without their love and support, and for this I will always be grateful. iii ACKNOWLEDGEMENTS I would like to express my sincere gratitude to the following individuals for their assistance and support. • Andrew Johnson of the Electronic Visualization Laboratory (EVL), University of Illinois at Chicago (UIC) for advising me during my Ph.D. studies, for serving on the dissertation committee and for providing valuable feedback and critical reviews of my writing • Dan Sandin of EVL, UIC for introducing me to autostereoscopy, for providing the opportunity to work with him in this exciting field, for serving on the dissertation committee, and for many years of dedication to the advancement of VR as both an art and a science • Jason Leigh, EVL, UIC for serving on the dissertation committee and providing guidance, support, insight, and funding for my work • Tom DeFanti, EVL, UIC, UCSD, for making time to serve on my committee, and for his ongoing support and friendship for many years at EVL • Jurgen Schulze, UCSD, for taking the time and effort to travel from San Diego to Chicago to serve on the committee and for his interest and willingness to participate TP iv TABLE OF CONTENTS CHAPTER PAGE 1. INTRODUCTION...........................................................................................................................1 1.1 Problem statement .........................................................................................................1 1.2 Features and modes ...................................................................................................1 1.3 Prototype system ...........................................................................................................3 2. BACKGROUND.............................................................................................................................4 2.1 Types of computer images.............................................................................................4 2.2 Virtual reality (VR) and AS VR....................................................................................5 2.3 Tracking overview.........................................................................................................6 2.4 Rendering multiple perspectives via the graphics rendering pipeline ...........................8 2.5 Introduction to parallax barrier AS................................................................................9 2.6 AS systems literature review .......................................................................................11 2.6.1 Spatial multiplexing.....................................................................................................12 2.6.2 Temporal – spatial multiplexing..................................................................................13 2.6.3 Volumetric and holographic displays ..........................................................................14 2.7 AS rendering algorithms..............................................................................................17 2.8 Optimizations ..............................................................................................................18 2.9 Light fields ..................................................................................................................20 3. SOLID STATE DYNAMIC PARALLAX BARRIER .................................................................22 3.1 Motivation ...................................................................................................................22 3.2 Solid state dynamic barrier..........................................................................................23 3.3 LCD technology primer...............................................................................................24 3.4 Stacked LCD construction...........................................................................................26 3.5 Features and advantages for parallax barrier AS.........................................................28 4. IMPLEMENTATION ...................................................................................................................29 4.1 System structure ..........................................................................................................29 4.1.1 Computation ................................................................................................................29 4.1.2 Display ........................................................................................................................31 4.2 Dynallax software........................................................................................................34 4.2.1 Software structure........................................................................................................35 4.2.2 Master module.............................................................................................................35 4.2.3 Slave module...............................................................................................................36 4.2.4 Controller module .......................................................................................................36 4.2.5 User interface ..............................................................................................................38 4.3 Auxiliary software components...................................................................................40 4.3.1 Window management..................................................................................................40 4.3.2 Configuration management .........................................................................................40 4.3.3 Message passing..........................................................................................................41 4.4 Calibration and test patterns........................................................................................44 v 5. RESULTS .....................................................................................................................................47 5.1 Variable parameters.....................................................................................................47 5.1.1 3D – 2D switchable display.........................................................................................48 5.1.2 Barrier period adjustment ............................................................................................49 5.1.3 Barrier duty cycle adjustment......................................................................................50 5.1.4 Barrier angle adjustment..............................................................................................51 5.2 Side effects ..................................................................................................................53 5.2.1 Physical and virtual barrier registration.......................................................................53 5.2.2 Reduced color shifts ....................................................................................................53 5.3 Sub-pixel barrier..........................................................................................................55 5.3.1 Discrete barrier model .................................................................................................56 5.3.2 Continuous barrier model............................................................................................61 5.3.3 Final algorithm ............................................................................................................62 5.4 View distance and channel separation.........................................................................68 5.4.1 The effect of view distance on channel output ............................................................68 5.4.2 View distance equations..............................................................................................72 5.4.3 Optimal view distance algorithm.................................................................................73 5.4.4 Results .........................................................................................................................76 5.5 Rapid channel steering ................................................................................................77 5.6 Two viewer mode........................................................................................................80 5.6.1 Repetition of virtual lobes ...........................................................................................81 5.6.2 General optimization algorithm...................................................................................83 5.6.3 Two viewer optimizations ...........................................................................................84 5.6.3.1 One degree of freedom direct barrier period computation .........................................85