1. ` 1 Department of Electrical Engineering, Stanford University Anne Aaron, Prashant Ramanathan and Bernd Girod Wyner-Ziv Coding of Light Fields for Random Access

2. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 2 Overview  Light fields  Predictive coding and random access  Wyner-Ziv coding for light fields  Simulation results

3. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 3 What is a Light Field? A 4-D data set for image-based rendering,typically parameterized as a 2-D set of images. [Levoy and Hanrahan, 1996] [Gortler et al., 1996]

4. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 4 Light Field Coding using Prediction geometry model image 1 image 2 level 0 level 1 level 2 hierarchical prediction desired image decoded images [Magnor and Girod, 2000] [Ramanathan et al., 2002][Chang et al., 2003]

5. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 5 Rendering a Single Novel View Garfield light field How do we perform better than intracoding?

6. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 6 Wyner-Ziv Coding Lossy compression with decoder side information Encoder Decoder Statistically dependent [Wyner and Ziv, 1976]

7. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 7 Wyner-Ziv image Key image Better rate-distortion performance than intracoding [Zhu, Aaron, Girod, 2003] Similar work by [Jagmohan, Sehgal, Ahuja, 2003] At the decoder, side information for decoding Wyner-Ziv image is rendered from available key images Wyner-Ziv Coding of Light Fields

8. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 8 Wyner-Ziv DCT Light Field Codec WZ image W Rendering Reconstruction Key image K Shape-adaptive Intracoding Shape- adaptive decoding DCT For each transform band k K’ YkYk XkXk Xk’Xk’ IDCT Decoded WZ image level Quantizer DCT Turbo Encoder Turbo Decoder Extract bit- planes qkqk bit-plane 1 bit-plane 2 bit-plane M k … qk’qk’ Side information Shape processing

9. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 9 R-D Performance for WZ images Garfield light field 288 images each at 144x192 pixels Hemispherical camera setting with 8 rows and 32 columns Half of the images are WZ images

10. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 10 Rendering a Single Novel View Garfield light field data set R-D Performance averaged over 20 novel views. Each novel view is rendered from closest 4 images. 25% 2 dB

11. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 11 Sample Rendered View Intracoding 1.5 bpop, 33.8 dB OriginalWyner-Ziv coding 1.4 bpop, 36.2 dB

12. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 12 Summary  Wyner-Ziv coding of light field images for random access and compression efficiency  Up to 2 dB PSNR improvement over intracoding for rendering novel views  Single representation of data set multiple representation solution [Ramanathan and Girod, MMSP 2004]

13. Aaron, Ramanathan, Girod: Wyner-Ziv coding of light fields for random access 13 Sample Rendered View Intracoding 1.6 bpop, 33.7 dB OriginalWyner-Ziv coding 1.9 bpop, 36.6 dB