An embedded DCT approach to progressive image compression

Motivated by Shapiro´s (see IEEE Trans. on Signal Processing, vol.41, no.12, p. 3445-62, 1993) embedded zerotree wavelet coding (EZW) and Taubman and Zakhor´s (see IEEE Trans. on Image Processing, vol.3, no.3, p.572-88, 1994) layered zero coding (LZC), we propose a layered 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 bpp