Driven by the recent resurgence of 3D cinema, depth cameras and stereoscopic displays are becoming commonplace in the consumer market. Introduced last October, Microsoft Kinect has already fostered gesture-based interaction for applications well beyond the intended Xbox 360 platform. Similarly, consumer electronics manufacturers have begun selling stereoscopic displays and inexpensive stereoscopic cameras. Most commercial 3D displays continue to require cumbersome eyewear, but inexpensive, glasses-free 3D displays are imminent with the release of the Nintendo 3DS. At SIGGRAPH 2010, the Build Your Own 3D Display course demonstrated how to construct both LCD shutter glasses and glasses-free lenticular screens, providing Matlab-based code for batch encoding of 3D imagery. This follow-up course focuses more narrowly on glasses-free displays, describing in greater detail the practical aspects of real-time, OpenGL-based encoding for such multi-view, spatially multiplexed displays. The course reviews historical and perceptual aspects, emphasizing the goal of achieving disparity, motion parallax, accommodation, and convergence cues without glasses. It summarizes state-of-the-art methods and areas of active research. And it provides a step-by-step tutorial on how to construct a lenticular display. The course concludes with an extended question-and-answer session, during which prototype hardware is available for inspection.

2. Constructing Glasses-free 3D Displays

3. Multi-view Rendering using OpenGL

4. Multi-view Interlacing using GLSL

5. Designing Content for Glasses-free 3D Displays

6. Emerging Technology

8. Attenuating masks using parallax barriers [Ives, 1903]

9. Refracting lenslet arrays [Lippmann, 1908]

10. Barriers cause severe attenuation  dim displays

11. Lenslets impose fixed trade-off between spatial and angular resolutionHow to select mask/lenslet properties and generate base images?

13. Lenslets are linear array of cylindrical lenses (i.e., a lenticular sheet)Depth perception not supported when viewed “sideways”

15. Lenslets consist of a 2D array (i.e., a “fly’s eye" lens array)Requires additional views slower rendering and lower resolution Pinholes furtherreduce brightness of parallax barrier displays

19. Supports oblique projections (i.e., skewed orthographic cameras)

21. Practically, this is only achieved with custom-manufactured lenslets

24. Must define offset between lenslet array and screen (calibration error)

25. First, evaluate closest lenslet for each pixel  spatial imagesample

26. Second, evaluate offset from lenslet center  angular viewpointAntialiasing by oversampling (i.e., average samples in each pixel)

27. Interlacing Content: MATLAB Demonstration

29. Can interpret as a moiré magnifier[Hutley et al., 1994]

30. Viewing an array of images through lenslets produces magnified images

31. Relative pitch/orientation determines scaling/rotation of magnified imagesM. C. Hutley , R. Hunt , R. F. Stevens and P. Savander.The Moiré Magnifier.Pure and Applied Optics, 1994

33. Place lenticular sheet in direct contact with the screen

35. Place lenticular sheet in direct contact with the screen

38. Generate an interlaced image (one white pixel below each lens)

39. When calibration is correct, no magnified stripes will be visible (i.e., screen is white when directly in front of display, otherwise black)

41. Generate an interlaced image (one white pixel below each lens)

42. When calibration is correct, no magnified stripes will be visible(i.e., screen is white when directly in front of display, otherwise black)

44. Generate an interlaced image (one white pixel below each lens)

45. When calibration is correct, no magnified stripes will be visible(i.e., screen is white when directly in front of display, otherwise black)

47. Generate an interlaced image (one white pixel below each lens)

48. When calibration is correct, no magnified stripes will be visible(i.e., screen is white when directly in front of display, otherwise black)

50. Generate an interlaced image (one white pixel below each lens)

51. When calibration is correct, no magnified stripes will be visible(i.e., screen is white when directly in front of display, otherwise black)

53. Generate an interlaced image (one white pixel below each lens)

54. When calibration is correct, no magnified stripes will be visible(i.e., screen is white when directly in front of display, otherwise black)

56. Interlaced base images were generated for the “numbers” sequence

57. Results confirm motion parallax up to ten views with the prototype(i.e., 10 LPI lenticular sheet and 100 DPI screen  10 views)

59. Interlaced base images were generated for the “photos” sequence

60. Results confirm motion parallax up to ten views with the prototype(i.e., 10 LPI lenticular sheet and 100 DPI screen  10 views)

66. Generate an interlaced image (one “marker” pattern below each lens)

67. When calibration is correct, no magnified “markers” will be visible(i.e., screen is uniform color when directly in front of display)

69. Generate an interlaced image (one “marker” pattern below each lens)

70. When calibration is correct, no magnified “markers” will be visible(i.e., screen is uniform color when directly in front of display)

72. Results confirm motion parallax up to 8x8 views with the prototype(i.e., 0.09 inch lenslet diameter and 90 DPI screen  8x8 views)

73. Results: Light Field (Toy Humvee and Soldier) viewer moves right Sample Image viewer moves up

74. Results: Light Field (Toy Humvee and Soldier)

75. Results: Light Field (Tarot Cards and Crystal Ball) viewer moves right viewer moves right viewer moves up viewer moves up Sample Image Sample Image

76. Results: Light Field (Tarot Cards and Crystal Ball)

80. Dynamic barriers can eliminate resolution loss

82. Dynamic barriers can eliminate resolution loss

84. Dynamic barriers can eliminate resolution loss

85. Must translate faster than flicker fusion threshold (i.e., 60 Hz)While eliminating resolution loss, display is still dim

86. LCD Disassembly: Removing the Case

87. LCD Disassembly: Removing the Case

88. LCD Disassembly: Removing the Case

89. LCD Disassembly: Separating the Power Supply

90. LCD Disassembly: Separating the Power Supply

91. LCD Disassembly: Separating the Controller Board

92. LCD Disassembly: Removing the Backlight

93. LCD Disassembly: Removing the Diffusing/Polarizing Films

94. LCD Disassembly: Cleaning the Spatial Light Modulator

95. Assembled Dual-Stacked LCD Barrier Display Dual-Stacked LCD Construction Rear LCD panel and backlight (unmodified) Plastic spacer Front LCD panel (modified) Replacement linear polarizing sheet

96. Interlacing Content: MATLAB Implementation Interlaced (Rear) Image (1 of 9) Pinhole Array (Front) Image (1 of 9)

98. Each panel connected via DVI (driver ensures synchronization)

100. A sequence of nine time-shifted pinhole arrays were displayed

101. Results confirm motion parallax with 3x3 views for the prototype (effective refresh rate is 120 Hz / 9 = 13.3 Hz)

103. Construction Glasses-free 3D Displays

104. Multi-view Rendering using OpenGL

105. Multi-view Interlacing using GLSL

106. Designing Content for Glasses-free 3D Displays

107. Emerging Technology

108. Q & A and Demonstrations