Object-based analysis-synthesis coding based on the source model of moving rigid 3D objects

摘要

The topic of investigation was object-based analysis-synthesis coding (OBASC) using the source model of ‘moving rigid 3D objects’ for the encoding of moving images at very low data rates. According to the coding concept, each moving object of an image is described and encoded by three parameter sets defining its motion, shape and surface color. The parameter sets of each object are obtained by image analysis. They are coded using an object-dependent parameter coding. Using the coded parameter sets, an image can be synthesized by model-based image synthesis. In comparison to block-based hybrid coding, OBASC requires the additional transmission of shape parameters. The transmission of shape information avoids the mosquito and block artifacts of a block-based coder. Furthermore, important areas such as facial areas can be reconstructed with a significant image quality improvement. OBASC based on the source models of ‘moving flexible 2D objects’ and of ‘moving rigid 3D objects’ gives almost identical image quality for the same data rate. Therefore the use of more advanced source models like flexible 3D objects or 3D face models is expected to further improve image quality.