Lossless image compression using the discrete cosine transform

In this paper, a new method to achieve lossless compression of two-dimensional images based on the discrete cosine transform (DCT) is proposed. This method quantizes the high-energy DCT coefficients in each block, finds an inverse DCT from only these quantized coefficients, and forms an error residual sequence to be coded. The number of coefficients used in this scheme is determined by using a performance metric for compression. Furthermore, a simple differencing scheme is performed on the coefficients that exploits correlation between high energy DCT coefficients in neighboring blocks of an image, The resulting sequence is compressed by using an entropy coder, and simulations show the results to be comparable to the different modes of the lossless JPEG standard. (C) 1997 Academic Press.