Layered DCT still image compression
Motivated by Shapiro's (1993) embedded zerotree wavelet (EZW) coding and Taubman and Zakhor's (1994) layered zero coding (LZC), we propose a layered discrete cosine transform (DCT) image compression scheme, which generates an embedded bit stream for DCT coefficients according to their importance. The new method allows progressive image transmission and simplifies the rate-control problem. In addition to these functionalities, it provides a substantial rate-distortion improvement over the JPEG standard when the bit rates become low. For example, we observe a bit rate reduction with respect to the JPEG Huffman and arithmetic coders by about 60% and 20%, respectively, for a bit rate around 0.1 b/p.