In this paper, we propose a new image codec, which called embedded zerotree wavelet coefficients envelop coding
(EZWCEC). The coefficients envelop is characterized by describing the global tendency of the significant wavelet
coefficients. Based on the empirical analysis and experimental results, our EZWCEC algorithm restores the trend of the
significant wavelet coefficients and estimates the magnitude of some insignificant coefficients on the decoder. Unlike
other zerotree coding algorithms such as Said and Pearlman's SPIHT using three lists, EZWCEC only uses two lists
during encoding and decoding. So the memory requirement for the hardware implementation is reduced significantly.
Although PSNR values for EZWCEC are lower than SPIHT's and JPEG2000's, our experiment results have shown that
EZWCEC can dramatically improve the visual quality of reconstructed at low bit rates (e.g., below 0.1bpp).