1. Representing Animation by Principal Components EUROGRAPHICS 2000 Speaker: Alvin Date: 4/18/2005

2. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components2 Outline Introduction Framework Results Conclusions

3. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components3 Introduction Progressive animation compression with spatial and temporal. Level-of-detail High compression ratios. Allow mapping animations onto other objects.

4. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components4 Keyframe Animation Separate geometry from animation

5. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components5 Normalization Translate their center of mass to origin. Minimize the square distance of corresponding vertices regard to the first frame.

6. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components6 Normalization The geometry is described mainly by B 0 The animation is described by T i and a i This representation is easy to adopt compression and LOD.

7. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components7 PCA Singular Value Decomposition Costly (N vertex * N key-frames ) 2 –Solution: Simplify the base shapes Do not consider every key-frame

8. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components8 Results Chicken Crossing –400 frames –3030 vertices

9. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components9 Results

10. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components10 Results

11. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components11 Evaluation Form 論文簡報部份 – 完整性介紹 (4) – 系統性介紹 (4) – 表達能力 (3) – 投影片製作 (3) 論文審閱部分 – 瞭解論文內容 (4) – 結果正確性與完整性 (4) – 原創性與重要性 (4) – 讀後啟發與應用： This representation of animation compare to key-frame can achieve high compression ratios but is weakly support by various tools or API. So automatically key-frame extraction is still valuable and practical.

12. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components12 Conclusions Representing animation based on principal components of key-frame geometries. It can compress the base shape again. The hierarchy could be used for LOD. It might break long animation into pieces. The necessary operations are supported in MPEG4.

13. Alvin/GAME Lab./CSIE/NDHU Representing Animation by Principal Components13 Appendix Compute a mesh of 15000 vertices need 1GB to store covariance matrix. “ Compression of soft-body animation sequence ” in 2003 exploit LPC to enhance this paper.