Video Compression for Very Low Bit-Rate Communications Using Fractal and Wavelet Techniques

In this paper, we propose a very low bit-rate video compression algorithm that is based on fractal coding in the wavelet domain. Fractal compression techniques utilise local selfsimilarities present in images, to form images of properly transformed parts of itself. The recent discovery of the link between fractal compression and wavelets, have improved the performance of fractal coders. The self-similarity property of fractal techniques lends itself well to video coding since there are high spatial and temporal correlation between video frames. In the proposed scheme, each frame is decomposed using the pyramidal multiresolution wavelet transform. Thereafter a motion detection operation is used in which the subtrees are partitioned into motion and non-motion subtrees. The nonmotion subtrees are easily coded by a binary decision, whereas the moving ones are coded using the fractal variable tree size coding scheme and the wavelet SPIHT (Set Partitioning in Hierarchical Trees) Algorithm. All intra-frame compression is performed using the wavelet SPIHT coder. Simulation results show that the proposed scheme has improved performance over the H.263 compression standard, hence making it suitable for low bit rate video.