Image coding using adaptive wavelet packet and zerotree structure

In this paper, we propose an image compression method associating a wavelet packet and a zerotree coding scheme. The wavelet packet is employed to reduce the correlation of the image pixels. To encode the coefficients, we apply the zerotree structure which can reduce the correlation across the decomposed component images. In this case, the decomposition criterion for each decomposition level is computed by simplified local zerotree structure. If a target bit rate or distortion is given, we can obtain the most suitable decompositions using the least computational operation. In the simulation, it is shown that the proposed method has a better coding efficiency than the JPEG case of about 3 dB and the octave decomposition case of about 1 dB in PSNR at 0.4 bpp with the standard image "Barbara".