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User Issues in 3D TV & Cinema

User Issues in 3D TV & Cinema. Martin S. Banks Vision Science Program UC Berkeley. Issues in 3D TV & Cinema. Technical Issues Developing content Sufficient resolution over time: temporal aliasing Sufficient separation between two eyes’ images: “ghosting” User Issues

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User Issues in 3D TV & Cinema

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  1. User Issues in 3D TV & Cinema Martin S. Banks Vision Science Program UC Berkeley

  2. Issues in 3D TV & Cinema • Technical Issues • Developing content • Sufficient resolution over time: temporal aliasing • Sufficient separation between two eyes’ images: “ghosting” • User Issues • Perceptual distortions due to incorrect viewing position • Flicker & motion judder due to temporal sampling • Maintaining depth across scene cuts • Window violations • Residual ghosting • Visual discomfort due to vergence-accommodation conflict • Appropriate blur relative to other depth signals • Conflict between visually-induced motion & vestibular signals

  3. Issues in 3D TV & Cinema • Technical Issues • Developing content • Sufficient resolution over time: temporal aliasing • Sufficient separation between two eyes’ images: “ghosting” • User Issues • Perceptual distortions due to incorrect viewing position • Flicker & motion judder due to temporal sampling • Maintaining depth across scene cuts • Window violations • Residual ghosting • Visual discomfort due to vergence-accommodation conflict • Appropriate blur relative to other depth signals • Conflict between visually-induced motion & vestibular signals

  4. Issues in 3D TV & Cinema • Technical Issues • Developing content • Sufficient resolution over time: temporal aliasing • Sufficient separation between two eyes’ images: “ghosting” • User Issues • Perceptual distortions due to incorrect viewing position • Flicker & motion judder due to temporal sampling • Maintaining depth across scene cuts • Window violations • Residual ghosting • Visual discomfort due to vergence-accommodation conflict • Appropriate blur relative to other depth signals • Conflict between visually-induced motion & vestibular signals

  5. Vergence & Accommodation: Natural Viewing Vergence distance Focal distance

  6. Vergence & Accommodation: Natural Viewing 6 4.5 Vergence distance Focal distance Focal Distance (diopters) 3 1.5 0 1.5 3 4.5 6 0 Vergence Distance (diopters)

  7. Vergence & Accommodation: Natural Viewing zone of clear single binocular vision 6 4.5 Vergence distance Focal distance Focal Distance (diopters) 3 1.5 0 1.5 3 4.5 6 0 Vergence Distance (diopters)

  8. Vergence & Accommodation: Natural Viewing zone of clear single binocular vision 6 Percival's zone of comfort 4.5 Vergence distance Focal distance Focal Distance (diopters) 3 1.5 0 1.5 3 4.5 6 0 Vergence Distance (diopters)

  9. Vergence & Accommodation: Stereo Display Vergence distance Focal distance

  10. Vergence & Accommodation: Stereo Display zone of clear single binocular vision 6 Percival's zone of comfort 4.5 Vergence distance Focal Distance (diopters) Focal distance 3 1.5 0 1.5 3 4.5 6 0 Vergence Distance (diopters)

  11. Displays with Nearly Correct Focus Cues • Two multi-focal displays we’ve developed: • Fixed-viewpoint, volumetric display with mirror system & 3 focal planes (Akeley, Watt, Girshick, & Banks, SIGGRAPH,2004). • Fixed-viewpoint, volumetric display with switchable lens & 4 focal planes (Love, Hoffman, Kirby, Hands, Gao, & Banks,Optics Express, 2009)

  12. Multi-focal Display Akeley, Watt, Girshick & Banks (2004), SIGGRAPH.

  13. Multi-focal Display Akeley, Watt, Girshick & Banks (2004), SIGGRAPH.

  14. Multi-focal Display Akeley, Watt, Girshick & Banks (2004), SIGGRAPH.

  15. Depth-weighted Blending • Depth-weighted blending along lines of sight • Weights dependent on dioptric distances to planes Akeley, Watt, Girshick, & Banks (2004), SIGGRAPH.

  16. Do V-A Conflicts Cause Fatigue/Discomfort?

  17. Do V-A Conflicts Cause Fatigue/Discomfort? • 600-ms stimulus at near or far vergence-specified distance • Appeared at each focal distance Hoffman, Girshick, Akeley, & Banks (2008), Journal of Vision

  18. Do V-A Conflicts Cause Fatigue/Discomfort? 9 cues-consistent cues-inconsistent 7 Severity of Symptom 5 3 ** ** ** ** 1 How do your eyes feel? How clear is your vision? How tired are your eyes? How does your head feel? How tired or sore are your neck & back? **= p < 0.01 (Wilcoxen test) Hoffman, Girshick, Akeley, & Banks (2008), Journal of Vision

  19. Do V-A Conflicts Cause Fatigue/Discomfort? cues-inconsistent much worse than consistent no difference cues-consistent much worse than inconsistent * ** ** ** Which session was more fatiguing? Which session did you prefer? Which session irritated your eyes more? Which session gave you more headache? ** = p < 0.01 (Wilcoxen test) Hoffman, Girshick, Akeley, & Banks (2008), Journal of Vision

  20. Discomfort & 3D Cinema

  21. Discomfort & 3D Cinema

  22. Discomfort & 3D Cinema

  23. Discomfort & 3D Cinema

  24. Discomfort & 3D Cinema & TV

  25. Issues in 3D TV & Cinema • Technical Issues • Developing content • Sufficient resolution over time: temporal aliasing • Sufficient separation between two eyes’ images: “ghosting” • User Issues • Perceptual distortions due to incorrect viewing position • Flicker & motion judder due to temporal sampling • Maintaining depth across scene cuts • Window violations • Residual ghosting • Visual discomfort due to vergence-accommodation conflict • Appropriate blur relative to other depth signals • Conflict between visually-induced motion & vestibular signals

  26. Viewing Pictures • Almost never view pictures from correct position. • Retinal image thus specifies different scene than depicted. • Do people compensate, and if so, how?

  27. Stimuli Vishwanath, Girshick, & Banks (2005), Nature Neuroscience.

  28. Experimental Task CRT Stimulus: simulated 3D ovoid with variable aspect ratio. Task: adjust ovoid until appears spherical. Vary monitor slant Smto assess compensation for oblique viewing positions. Spatial calibration procedure. If compensate, will set ovoid to sphere on screen (ellipse on retina). Sm Observation Point Vishwanath, Girshick, & Banks (2005), Nature Neuroscience.

  29. Predictions No compensation: set ovoid to make image on retina circular: retinal coordinates screen coordinates Observation Point Center of Projection

  30. Predictions Compensation: Set ovoid to make image on screen circular: retinal coordinates screen coordinates Observation Point Center of Projection

  31. Aspect Ratio (screen coords) Sm Predictions invariance predictions 1.4 1.2 1 -40 -20 0 20 40 Viewing Angle Sm (deg)

  32. Sm Predictions invariance predictions retinal predictions 1.4 Aspect Ratio (screen coords) 1.2 1 -40 -20 0 20 40 Viewing Angle Sm (deg)

  33. Results monoc-aperture JLL 1.4 invariance predicts retinal predicts Aspect Ratio (screen coords) 1.2 1 -40 -20 0 20 40 Viewing Angle (deg) Vishwanath, Girshick, & Banks (2005), Nature Neuroscience.

  34. Results Results monoc-aperture JLL 1.4 binoc-no aperture invariance predicts retinal predicts Aspect Ratio (screen coords) 1.2 1 0 20 40 -40 -20 Viewing Angle (deg) Vishwanath, Girshick, & Banks (2005), Nature Neuroscience.

  35. Compensation for Incorrect Viewing Position • Pictures not useful unless percepts are robust to changes in viewing position. • People compensate for oblique viewing position when viewing 2d pictures. • Two theories of compensation: pictorial & surface. Data clearly favor surface compensation. • Two versions of surface method: global & local. Data clearly favor local slant.

  36. 2D Pictures vs 3D Pictures 2D • Two eyes presented same image • Binocular disparities specify orientation & distance of picture surface; hence useful for compensation

  37. 2D Pictures vs 3D Pictures 2D 3D • Two eyes presented same image • Binocular disparities specify orientation & distance of picture surface; hence useful for compensation • Two eyes presented same image • Binocular disparities specify orientation & distance of picture surface; hence useful for compensation • Two eyes presented different images • Binocular disparities specify orientation & distance of picture surface and layout of picture contents; hence not useful for compensation

  38. Stereo (3D) Pictures • For most applications, viewers will not be at correct position. • Retinal disparities thus specify a different layout than depicted. • Do people compensate? • Is correct seating position for a 3D movie more important than for 2D movie?

  39. Stereo Picture Geometry display surface stereo projectors

  40. Stereo Picture Geometry display surface depicted hinge stereo projectors

  41. Stereo Picture Geometry display surface depicted hinge stereo projectors

  42. Stereo Picture Geometry disparity-specified hinge display surface depicted hinge stereo projectors

  43. Stereo Picture Geometry disparity-specified hinge display surface depicted hinge perceived dihedral angle? stereo projectors

  44. Predictions 35° 17.5° 0° -35° -17.5° 120 Invariance: Hinge settings are 90° for all viewing angles and base slants 90 Hinge Setting (deg) 60 Retinal disparity: Hinge settings vary significantly with viewing angle & base slant 30 0 0 25 45 Viewing Angle (deg)

  45. Results non-stereo pictures 120 90 60 Hinge Setting (deg) 30 45 0 25 Viewing Angle (deg)

  46. Results non-stereo pictures stereo pictures 120 120 90 90 60 60 Hinge Setting (deg) 30 30 45 45 0 0 25 25 Viewing Angle (deg)

  47. Results non-stereo pictures stereo pictures 120 120 90 90 60 60 Hinge Setting (deg) 30 30 45 45 0 0 25 25 Viewing Angle (deg)

  48. Summary • User issues in 3D cinema & TV • Vergence-accommodation conflicts cause visual fatigue & discomfort • Can be handled by attending to viewer’s distance from screen & range of disparities presented relative to screen • Perceptual distortions due to incorrect viewing position • Compensation is good with non-stereo pictures • Compensation is significantly poorer with stereo pictures suggesting that viewer position could be more important

  49. Acknowledgments • Kurt Akeley (Microsoft) • Simon Watt (Univ. of Wales, Bangor) • AhnaGirshick (NYU) • David Hoffman (UC Berkeley) • Robin Held (UC Berkeley) • Funding from NIH, NSF, & Sharp Labs

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