1. Building an Autostereoscopic Display CS448A – Digital Photography and Image-Based Rendering Billy Chen

2. Original Goals dynamic, real-time display convenient 3D display for the home (3D desktops) autostereoscopic light field viewer

3. Display design choices Display TypeResolutionAdvantageDisadvantage CRT/LCD72-115 dpicheap, everywherelow resolution, challenging calibration Projector~150 dpieasier to control pixel depth, adjustable angular resolution projector distortion Big Bertha211.66 dpihigher resolutionexpensive, need special hardware to drive it Printer300 dpihigh resolutionstatic images

4. Physical Setup

5. Overview of display process Render ` Calibration

6. The calibration problem +

7. Calibration affine transformation correction (mostly scale) projective transformation correction

8. Calibration solution 1 OpenGL program displays a moiré pattern can calibrate up to affine transformations most effective for finding correct size

9. Calibration solution 2 p h p Finding the homography without getting projector parameters A B A’ B’

10. xy1xy1 cx’ cy’ c Calibration solution 2 M = M p cp’ Let M i = i’th row of M (1) M 1 p = cx’ (2) M 2 p = cy’ (3) M 3 p = c y’ (M 1 p) - x’(M 2 p) = 0 M 1 p - x’(M 3 p) = 0 xy’ yy’ y’ -xx’ -yx’ -x’ 0 0 0 M 11 M 12 M 13 M 21...... = 0 8x9 9x1 A= Take SVD(A) and look at matrix

11. Calibration solution 2

12. Rendering sampling the light field computing lenslet distances cropping and compositing

13. Rendering: Sampling a light field Isaksen et al., Siggraph 2000

14. Getting “floating” images Halle, Kropp. SPIE ‘97

15. Sampling a light field

16. Rendering: computing the FOV

17. Rendering: compositing and cropping images subsample crop composite

18. Implementation Details Fresnel hex array #300; 0.12 in. focal length, 0.12 in. thickness,.09 in. diameter default size for a lenslet image: 26x31 pixels (for 300 dpi displays) calibrate scale is.49 (sanity check: 300 dpi / 150 dpi) OpenGL unit == 1 pixel (300 dpi) SEE WEBPAGE!

19. Results compared to original goals real-time display is hard, must handle the bandwidth spatial resolution too small for 3D desktops light fields have problems with much depth complexity, but NEED depth for effective autostereoscopic displays

20. Future Work reflective display auto-calibration hardware accelerated light field sampling overloading pixels per direction: perspective views, displacing display pixels from focal plane use a light field of captured data

21. Acknowledgements calibration: Vaibhav Vaish light field generator: Georg Petschnigg hardware accelerated approach: Ren Ng bootstrap: Sean Anderson