Multi-threshold fractal image compression of medical images based on regions of interest

摘要

Image compression based on regions of interest (ROI) means to compress interesting regions in an image with high quality, and to compress uninteresting regions with relatively low quality. Based on this idea, a multi-threshold fractal image-coding algorithm based on regions of interest is proposed in this paper. It uses different error threshold for different regions, and puts both near-lossless coding in the ROI and lossy coding in the UROI (uninteresting regions) under the same fractal frame. Quadtree partition algorithm is employed to compresses the regions of interest near-losslessly and the other regions roughly. By using this algorithm, good decoding image quality of the regions of interest can be obtained while maintaining high compression ratio. Image coding time is also shortened greatly. Simulation results for some medical images have shown the effectiveness of the proposed method. As compared to other known method, the proposed method is very attractive both in computation and in storage.