Object-Based Image Compression With Simultaneous Spatial and SNR Scalability Support for Multicasting Over Heterogeneous Networks

This paper proposes an image compression algorithm for texture coding of arbitrarily shaped image objects which supports spatial and SNR scalability features simultaneously. The proposed algorithm, is based on the Set Partitioning in Hierarchical Trees (SPIHT) algorithm and called Fully Scalable ObjectBased SPIHT (FSOB-SPIHT). It adds spatial scalability features to the SPIHT bitstream through the introduction of multiple resolution dependent lists for the sorting stage of the algorithm. It keeps important features of the original SPIHT coder such as compression efficiency, and full SNR (rate) scalability. The idea of bitstream transcoding without decoding, to obtain different bitstreams for various spatial resolutions and bit rates all from a single bitstream, is completely supported by the algorithm. Therefore the proposed algorithm efficiently facilitates multicasting visual information over heterogeneous networks.