DEPLOYMENT OF CONSTRAINED DELAUNAY MESH IN VOP SHAPE AND TEXTURE CODING

Son Minh Tran - Lajos Konyha - Balázs Enyedi - Kálmán Fazekas - Ján Turán

   The work presents an alternative method for encoding shape-information of video objects, which is a new requirement in the recent revolution of video codec scheme: compressing and transmitting object-based video streams. The proposed method takes the advantage of the latest development in the video encoding - motion compensation on the base of mesh presentation of frame - to complete its target. The so-called constrained Delaunay mesh is deployed to represent video objects, which are detected from a previous video object detector. This special mesh structure in one hand constructs the base for successive motion compensation taking root on mesh-vertices. In another hand, the virtue of its constrained property opens a possibility to encode the shape of video object implicitly, through the bounding polygon of the mesh. Hence, this lossy presentation of the shape-information reduces the amount of transmitted information. We discuss the trade-off between the precision of shape approximation and necessary bandwidth. We integrate the shape encoder into a mesh-based video codec scheme. The simulating results of quality and bitrate are encouraging.

Keywords: shape coding, Delaunay mesh, VOP, MPEG-4

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