1. 3/23/2005 © Dr. Zachary Wartell 1 “Just Enough Reality: Comfortable 3-D Viewing via Microstereopsis” Mel Seigel and Shojiro Nagata IEEE TCSVT, Vol 10., No. 3, April 2000, 387-397. Presentation: Revision 1.0 Copywrite Zachary Wartell University of North Carolina at Charlotte 2006

2. 3/23/2005 © Dr. Zachary Wartell 2 Image Collection camera-to-scene distance: {132,48,30} cm (w/ lens focal length {50,20,12.5}mm) camera positions [-20,+20] mm from center-line at 1-mm intervals (41 positions total) 640 x 480 res. {132,48,30} cm [-20,+20] mm

3. 3/23/2005 © Dr. Zachary Wartell 3 Center-of-interest Correction Cross Lens Axis (CLA) Parallel Axis –image shift (display) –CCD shift (camera)

4. 3/23/2005 © Dr. Zachary Wartell 4 Center-of-interest – Crossed Lens Axis (CLA) CCD R “direct mapping” screen L

5. 3/23/2005 © Dr. Zachary Wartell 5 COI: Parallel Camera – Image Shift CCD R L “direct mapping” image shift screen R L R L image shift+ clipping

6. 3/23/2005 © Dr. Zachary Wartell 6 COI: Parallel Camera – CCD Shift CCD screen R L “direct Mapping”

7. 3/23/2005 © Dr. Zachary Wartell 7 CCD Shift: Multi-Axis Shift CCD screen R L “direct mapping” CCD shift in X and Y x y

8. 3/23/2005 © Dr. Zachary Wartell 8 CCD Shift: X-Axis Shift + Inverted Telephoto CCD screen R L “direct mapping”

9. 3/23/2005 © Dr. Zachary Wartell 9 Depth-Pair Ordering Experiment 80 pairs of stereo pictures –1 st 40: one picture has no stereo –2 nd 40: both have stereo –within each 40: 5 sequences of 8 pairs, each sequence has mean m.e.s. in {4.5,3.5,2.5,1.5,0.5} mm sub’s indicates whether left, right, or neither stereo image has more ‘3D-ness’ than the other use wide-angle set of images (D=30cm)

10. 3/23/2005 © Dr. Zachary Wartell 10 left picture m.e.s. [0,10]mm right picture m.e.s. [0,10]mm 0% 100% Results

11. 3/23/2005 © Dr. Zachary Wartell 11 Results informally, 10 mm m.e.s. fusion time is effectively 0 microstereopsis gives depth order information, but not absolutely correct depth: “delivers ‘just enough reality’ for computer graphics, video news and entertainment, and enough for most eye-hand coordinated tasks, including teleoperation of mobile robots” -Question: Is this an overstatement? For which tasks? at smallest m.e.s., sub’s w/out stereo glasses ‘perceive’ only a slight blurring that is not distracting

12. 3/23/2005 © Dr. Zachary Wartell 12 Hypothesis on Future Displays with microstereopsis, “it should be possible to stimulate binocular stereopsis even in presence of substantial crosstalk” suggests stereo displays presenting microstereopic applications may allow for lots of crosstalk –might support new display technology

13. 3/23/2005 © Dr. Zachary Wartell 13 Crosstalk Experiment (Anecdotal) 3 sub’s modify LCD shutter-glasses to control cross-talk increase cross-talk until stereo animation with 20mm m.e.s. yields diplopia reduce m.e.s. to 2mm at 2mm, sub’s report perception of depth and no perception of ghosting

14. 3/23/2005 © Dr. Zachary Wartell 14 Zoneless Autostereoscopic Display assuming microstereopsis applications, crosstalk may not be problem, so what kind of new displays are possible? brighter to right eye brighter to left eye right eye image left eye image 60 Hz

15. 3/23/2005 © Dr. Zachary Wartell 15 Microstereopsis Summary for m.e.s. of 1-3 mm (out of 60-65mm) –disparity stimulate binocular stereopsis –cross-talk perceived as blur (depth-of-field) rather than ghosting non-veridical adjustment of image-shift alters balance between negative & positive screen parallax which in microstereopsis condition appears to transfer blur to foreground or background problem: capturing left/right eye simultaneously using microstereopsis’s range of m.e.s. will require custom camera’s

16. 3/23/2005 © Dr. Zachary Wartell 16 Future Work more formal user studies investigate new display technology

17. 3/23/2005 © Dr. Zachary Wartell 17 Comments & Questions? What does this mean to VR? –VR doesn’t require any extra work to get basic “center-of-interest” correction—it is automatic; just use proper asymmetric view frustums as needed. –experiment shows very small m.e.s. (1-3mm) can still yield binocular stereopsis. How much does this help in real tasks? undoubtedly task dependent (see prior work, etc.) What was viewer distance to display in exp. #1? –If view frustum not equivalent to CCD frustum, displayed 3D image will be distorted. Could distortion exaggerate depth making stereopsis at 1- 3mm m.e.s. discernable when it might not be under other distortions?

18. 3/23/2005 © Dr. Zachary Wartell 18 COI: Parallel Camera – CCD Shift CCD screen R L image shift+ clipping

19. 3/23/2005 © Dr. Zachary Wartell 19

20. 3/23/2005 © Dr. Zachary Wartell 20 COI: Parallel Camera – Image Shift CCD L R “naïve stretch” L R correct! screen

21. 3/23/2005 © Dr. Zachary Wartell 21