Progressive windowed JPEG coder for efficient image transmission

Applications involving transmission of color images through low bandwidth telecommunication media involve a trade-off between image quality and decoding complexity. In this paper we investigate techniques that locally optimize the output quality of foreground objects in the decoded image, while obtaining significant gain by coarser coding of information of low interest areas of the image. High compression/quality ratios are achieved by introducing high-quality windows, as well as by using progressive coding principles in image filtering, and enhanced run length encoding techniques. The system described is currently fully operational and serving telemedicine image communication applications for remote diagnosis.