1. What’s on page 13-25? Tom Butkiewicz

4. Refresh Rates Flicker from shutter systems Halve refresh rates 2 eyed 120Hz != 1 eyed 60Hz Phosphors 2 Polarized Monitors + Half Silvered Monitor

5. Brightness Filter glasses –remove frequencies –dim images Shutter glasses –Brightness halved over time –Never 100% clear (shutter and polarized)

7. Example Hypothetical stereoscopic display Standard CRT LCD shutter glasses

8. Spatial resolution –Res = 1280 x 1024 –Shutter cut vertical in half –Res = 1280 x 512 Angular resolution –“comfortable viewing distance” = 18 inches –Screen size = 33” x 26” –Φ = 1.9 min x 3.8 min = 1.9’ x 3.8’ Pixel Pitch –Pitch = (33cm/1280) = (26cm/1024) =.025cm/pixel

9. Field of view –FOV = 40° x 32° Depth resolution –(0.00025 x 0.46) / (0.65 – 0.00025) = 0.0018m Refresh rate: –120Hz refresh rate = 60Hz per eye Brightness: –LCD shutter transmits 30% of light –Screen seen 50% of the time –Overall: brightness = 15%

10. Interactive Stereoscopic Display Autostereoscopic displays: –Advantages: No viewing aids required Multiple 3D views of the scene Interactive systems can achieve this viewpoint-dependence –Head Tracking (HMDs and HTDs)

12. Example Same system as before –Add head tracking Interactive Motion parallax Head / Boom system

13. Same typical monitor –1280x1024 Special optics –90° field of view for each eye –Partially overlapping –FOV = 135° x 90° –Φ = 90° / 1280 = 4.2’ = 0.0012 radians –Coarse resolution Easily change optics to suit different tasks –FOV vs Angular Resolution

14. Depth resolution –Must calculate the pitch for infinite-focus screen at 46cm: Pitch = 0.0012 x 46cm = 0.056 cm –D = (0.00056 x 0.46) / (0.065 – 0.00056) = 0.0040 m

15. Lenticular Screen Array of cylindrical lenses –Generates autostereo image –Directs 2D images into viewing subzones –Viewer puts one eye in each subzone

17. Lenticular Screen Horizontal resolution -> one pixel per lenticule Vertical resolution -> same as back screen N subzones created by N pixels behind each lenticule

18. Side-Lobes are duplicate sub-zones off to the side of the main centered viewing zone. Moving out of viewing zone into side-lobes causes pseudoscopic 3D image (right left)

19. Limitations High horizontal resolution required Pixel size limits number of views Imperfections in lenses focusing abilities –Reduces the directivity –Emerging rays not parallel Need to have back screen perfectly aligned with lenticules –Hard because CRTs not flat

20. Can be used with multiple projectors Diffusing screen High horizontal resolution and large number of views possible High bandwidth costs

21. Integral photography Similar to lenticular imaging Small spherical lenses instead of vertical cylinders Up and down in addition to left and right Requires more resolution or 2D array of projectors

22. Example Horizontal resolution –Res of each view = screen width / lenticle width = horizontal res of back screen / number of views Horizontal angular resolution = lenticule width / D screen

23. Depth Resolution Finite size of horizontal imaging elements Limits resolvable depth levels

25. Depth Resolution Subzones may overlap –Due to imperfect direction from lenses –Can degrade depth resolution –Since image space quantized depth res not degrade until blur angle approaches the angle of the viewing subzones

26. Depth resolution –To avoid loss of resolution: –αc is the spread due to min electron beam width / focal length of lenticules –αd = 2 asin λ(wavelenght) / pitch

31. Brightness + Color Lenticular screens offer comparatively good brightness to other methods such as parallax barriers. Directs only a fraction of the screen, but collects light from a larger area. Color can be problem because of CRT phosphor layouts.

32. Example Similar to Hamasaki’s using Braun tube –Allows accurate registration of vertical pixel strips –8 views –256 x 256 each –1 mm lenticules –Focal length 2.25 mm –Horizontal pitch.125 mm –Min electron beam size 0.07 mm –Subzones 35 – 40 mm wide at 750 mm distance