Segmentation and compression techniques for 3D animation models based on motion trajectory in the spherical coordinate system In recent days, applications using 3D animation models are increasing. Since the 3D animation model contains a huge amount of information, data compression is needed for efficient storage or transmission. Although there have been various proposals for 3D model coding, most works have considered only static connectivity and geometry information. Only a few studies have been presented for 3D animation models. This paper presents a coding scheme for 3D animation models using a new 3D segmentation algorithm. For an accurate segmentation, we take advantage of temporal coherence in the generic animated 3D model. After the motion vector of each vertex is mapped onto the surface of the unit sphere in the spherical coordinate system, we partition the surface of the sphere equally to have the same area. We then reconstruct inbetween 3D models using the reconstructed key frame and an affine motion model for each segmented unit.

IntraFrame Compression of Point Cloud Geometry using Boolean Decomposition Point clouds are one of the most promising technologies for 3D content representation. Point clouds are a set of points described by their geometry information and additional attributes, of which colour is the most typical. When transmitting a point cloud, both geometry, colour and temporal information need to be transmitted, thus making compression efficiency key in exploiting this technology. In this paper, we propose a lossless intra coder of the geometry information of voxelized point clouds. Instead of using the popular octree approach, we use wellknown techniques for coding of bilevel images, as well as a novel boolean decomposition method to further exploit the redundancy within the geometry. Results show that the proposed method outperforms other recent coders on the sequences tested.