Backward compatible JPEG lossy-to-lossless compression of medical data

This paper presents a two-layered lossy-to-lossless still image coding system for medical images. The proposed system is compliant with widely used JPEG standard, in the sense that the base layer of the system is compressed by a conventional JPEG encoder. The enhancement layer includes extra information of the difference between the original medical image and a JPEG compressed version. It is compressed losslessly and its bitstream is embedded in the base layer codestream. Performance evaluations of single-layer and two-layer lossless compression are both carried out on a set of medical images. Single-layer lossless compression results show that JPEG 2000 delivers similar performance as JPEG-LS, and that both outperform JPEG XR and PNG. The experimental results of two-layer lossless compression demonstrate that the proposed system outperforms an earlier proposed JPEG based coding system with residual coding, and yields similar results as JPEG 2000 and JPEG-LS standard while providing quality scalability and backward compatibility to JPEG.