1. Projector with Radiometric Screen Compensation Shree K. Nayar, Harish Peri Michael Grossberg, Peter Belhumeur Support: National Science Foundation Computer Science Columbia University Procams Workshop ICCV 2003, Nice, France

3. Projecting on Any Surface ?

5. Textured Screen Camera Computer Projector Projector-Camera System

6. Geometric Calibration Projector InputCamera Output Maximum Error: 0.6 pixels, RMS Error: 0.18 pixels

7. Display Device Projector Screen I D P E x i x d x s Camera Capture Device B M C L x b x m Projector-Camera Pipeline: Radiometry What Display Image (I) will produce a Desired Captured Image (M) ?

8. Radiometric Model (for each pixel) Display Device Projector Screen I D P E Camera Capture Device B M C L display reponseprojector reponse capture reponsecamera reponse projector channel screencamera channel camera irradianceprojector brightness color mixing matrix

9. Finding the Model Parameters (at each pixel) Display Device Projector Screen I D P E Camera Capture Device B M C L camera irradianceprojector brightness color mixing matrix display image color projector color composite response camera irradianceprojector brightness modified color mixing matrix (known)

10. Finding the Color Mixing Matrix camera irradianceprojector brightness modified color mixing matrix (known) arbitrary imageonly change in red only change in green only change in blue

11. Color Mixing: V Matrices

12. Radiometric Calibration: Color Projector InputCamera Output desired projector output compensated display image composite response

13. Texture of Screen Color Experiment Uncompensation outputs (flat gray inputs: 100, 150, 200 gray levels) Compensation images (flat gray inputs: 100, 150, 200 gray levels) Compensated outputs (flat gray inputs: 100, 150, 200 gray levels) Compensation Accuracy 50,50,50 100,100,100 150,150,150 200,200,200 25,26,26 66,70,71 75,98,95 50,99,90 2,3,7 6,8,14 19,15,21 39,29,25 24.1,24.2,24.5 58.9,57.2,64.9 49.0,44.5,69.1 27.7,47.5,42.7 0.6, 0.8, 1.7 1.6, 1.9, 5.4 4.8, 3.1, 5.8 12.7,4.0,10.7 Projected Brightness Max. ErrorRMS Error Without Comp. With Comp. (R, G, B) Without Comp. With Comp.

14. Original (desired) image (I)Uncompensated output (M) Face Image on Checkerboard Screen Compensated output (M) ~ Compensation image ( I ) ~

15. Face Video on Brick Texture Normal ProjectorProjector With Compensation

16. Scene Video on Brick Texture Normal ProjectorProjector With Compensation

17. Face Video on Butterfly Poster Normal ProjectorProjector With Compensation

18. Summary Off-Line Method for Radiometric Calibration On-Line Algorithm for Screen Compensation Refinement using Continuous Feedback Radiometric Model for Projector-Camera System