João Fradinho Oliveira*

1. Animating Scanned Human Models João Fradinho Oliveira* Bernard Buxton* Dongliang Zhang** Bernhard Spanlang* * Department of Computer Science, University College London ** CAD/CAM Center Hong Kong University of Science & Technology

2. Overview Background 1 - Feature extraction/segmentation 2 - Building the skeleton 3 - LOD to reduce computation 4 - Mapping skin to skeleton/surface growing 5 - Motion capture DEMO & Acknowledgements Conclusion

3. Overview Background 1 - Feature extraction/segmentation 2 - Building the skeleton 3 - LOD to reduce computation 4 - Mapping skin to skeleton/surface growing 5 - Motion capture DEMO & Acknowledgements Conclusion

4. Background Control skeleton Medial axis, Convex Hull Library • Standard layered approach Control skeleton + skin e.g.[Sun W et al.] Layered Animation of Captured Data, Animation and Simulation’99 • Control skeleton has BVH hierarchy • Motivation to create skeleton automatically

5. 1 - Feature extraction/segmentation [Dekker et al.] Building Symbolic Information for 3D Human Body Modelling Range Data Proceedings of the 2nd International Conference on 3-D Digital Imaging and modelling, IEEE Computer Society Octree/horizontal slices

6. 1 - Feature extraction/segmentation Slice approach (binning, changes in Depth) Projected contour approach /local maxima 2 levels/phases of feature extraction 6 groups of centroids

7. 2 - Building the skeleton centroids + landmarks centroids closest centroids to landmarks skeleton

8. 3 - LOD to reduce computation 135 099 triangles ---------------------------- 4999 triangles 67595 vertices -------------------------------- 2535 vertices

9. 4 – Mapping skin to skeleton/surface growing A - Select triangle closest to endpoints of skeleton B - Select connected triangles that are behind separation planes • Use skeleton + bisector planes, for skin mapping • Volume queries, user placement of separation planes

10. 4 – Mapping skin to skeleton/surface growing

11. 4 – Mapping skin to skeleton/surface growing Bi-sector separation plane Landmark constrained separation plane

12. 4 – Mapping skin to skeleton/surface growing STEP 1 – select connected triangles after plane & below small vertical offset of landmark e.g. smallest edge length of model /will also work with a zero offset in all models

13. 4 – Mapping skin to skeleton/surface growing STEP 2 – select connected triangles above the vertical offset of the landmark & behind the landmark constrained plane

14. 4 – Mapping skin to skeleton/surface growing mapped skin result

15. 4 – Mapping skin to skeleton/surface growing Rigid transformation vs Soft transformation W = u Mapping parameters/ vertex attributes

16. 4 – Mapping skin to skeleton/surface growing Two-link structure Multi-link structure More on deformation constraints: [Weber J.] Run-Time Skin deformation, Game Developers Conference 2000

17. 5 - Motion capture DEMO & Acknowledgements • Hamamatsu Photonics UK • Prof. Mel Slater, EPSRC grant GR/M46082/01 (UK) • Fundacao Calouste Gulbenkian (Portugal) • Ministerio da Ciencia e Tecnologia (Portugal), JNICT/PRAXIS XXI