Realization of lossless-to-lossy image coding compatible with JPEG standard by direct-lifting of DCT-IDCT
A discrete cosine transform (DCT) can be easily implemented in software and hardware for the JPEG and MPEG formats. Recently, some integer DCTs (IntDCTs) for lossless-to-lossy image coding have been proposed, but they do not satisfy enough compatibility with JPEG standard. This paper proposes a realization of lossless-to-lossy image coding which has higher compatibility with it than the conventional IntDCTs. Our IntDCT is implemented by direct-lifting of DCT and inverse DCT (IDCT) and has high performance in lossless image coding compared with any IntDCT while keeping high compatibility with JPEG standard. Finally, our method is validated by its application to lossless-to-lossy image coding.