Novel Methods Of Static And Sequence Medical Image Coding

With the maturity of the wavelet and fractal theory in recent years, image coding schemes based on these two theories have become the research focus. At the same time, medical imaging techniques have achieved tremendous advances, which provide various kinds of new image types that effectively increase the accuracy of the diagnosing of human diseases. Under this trend, the main research efforts are on putting forward new medical image coding schemes for telemedicine based on wavelet and fractal theories, which specially fit in with clinical requirements. The main contributions of my work are as follows:1) Proposing a novel Wavelet Image Coding scheme based on Predictive Quadtree-Split. This method hybridizes the intra-band and inter-band coding. Wavelet coefficients in same band are partitioned into many blocks, and the blocks split according to quadtree with the moving of bitplane. This kind of dynamic block spirting can overcome some shortcomings brought by fixed block size. At the same time, the algorithm introduces a predictive coding procedure to truncate the block and make the block's shape fit in with the actual image. A context based arithmetic coder is adopted in entropy coding, and four different sets of models are designed for the arithmetic coder which could be adjust adaptively according to different kinds of medical images.2) Presenting a fast fraction coding scheme for fast sequence medical image coding based on the principle of OFC(Optimal Fuzzy Clustering). The algorithm makes use of LBG method to initialize the searching space, then fuzzy clustering algorithm is applied to give a soft classification of the searching space. Global searching is replaced by searching in the resulting classes and fractal coding is focused on the most effective local area, thus the new algorithm significantly reduce the matching times and coding complexity. Simulation resultsshow the computation time is reduced by 5 times compared with the traditional sequence image fractal coding schemes at the same PSNR level.