This paper proposes methods for designing, tracking and coding hierarchical two-dimensional (2-D) content-based mesh representations. The design procedure consists of constructing a fine-to-coarse hierarchy of Delauna...
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This paper proposes methods for designing, tracking and coding hierarchical two-dimensional (2-D) content-based mesh representations. The design procedure consists of constructing a fine-to-coarse hierarchy of Delaunay meshes, using image- and shape-based criteria for mesh geometry simplification. hierarchical tracking employs a coarse-to-fine strategy with mesh-based motion vector optimization, We introduce new techniques to maintain the initial mesh hierarchy and topology during tracking by imposing certain constraints at each stage of the procedure, The hierarchical compression technique is based on a nearest neighbor ordering of mesh node points. This ordering serves to identify the mesh boundary nodes as well as establish spatial predictors for differential coding of node coordinates and motion vectors, The proposed hierarchicalmesh representation, which has applications in object-based video manipulation, indexing, and compression, provides improved tracking performance (compared to a nonhierarchical representation) and allows progressive (scalable) transmission of the object geometry (including shape) and motion information, as well as variable level-of-detail rendering, Experimental results are presented to compare the tracking and compression performance of hierarchical versus nonhierarchicalmesh representations and to demonstrate the tradeoff between image quality and mesh bit rate for 2-D mesh-based video object rendering.
There is no normative segmentation method in the emerging MPEG-4 standard. In this paper, we propose mesh-based segmentation method for object-based video which fuses mesh-based motion, and color information using reg...
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ISBN:
(纸本)0780362985
There is no normative segmentation method in the emerging MPEG-4 standard. In this paper, we propose mesh-based segmentation method for object-based video which fuses mesh-based motion, and color information using region approaches instead of pixel-based ones suitable for MPEG4. A 2D Delaunay triangulated dynamic content-based mesh is initially designed on the first frame of the sequence with an optimal number of nodes. Nodes motion values and motion values of their neighbors are used to form a test region of triangles for the determination of the boundary of the video object. The formed test region is then remeshed and whole mesh is updated. Color information of the neighboring triangles on one step layers provides us a refinement of the boundary of the video object. Inside of refined boundary is optimally meshed and a search mechanism is used through layers. The mesh based system can handle multiple video objects and the related results are given. The proposed 2D mesh based segmentation, occlusion detection and representation method suitable for progressive transmission can be applied in object-based video coding, storage and manipulation.
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