A Nearly Lossless Subband Compression Algorithm
一种准无损压缩图象子带编码算法

It is well known that there are a lot of noise data in many digital images. In generally speaking, the embedded noise data in an image are not only harmful to view the image, but also there is less correlation among noise data and original image data. So the noise data are hard to be compressed by general compression methods based on predictive or schotistic coding. Therefore a new method to achieve nearly lossless compression of an image is proposed in this paper. In the first step in the proposed method the noise data in an image are eliminated based on a noise model, and then the resulted image is as better as the original one for the usages. In the second step, the image is encoded by using a region adaptive subband compression algorithm without loss any data. Obviously, after decoding, the reconstruction image is a nearly lossless image without harmful to the usages. Coding time of the proposed algorithm is affordable thanks to fast convergence of the algorithm. Coding could always be performed in real time. The experimental result shows that the compression scheme provides impressive performance such as high signal to ratio and high compression ratio. According to the theory of the algorithm, the noise elimination algorithm based on noise model can also be extended to the other compression algorithms such as DCT, DPCM, JPEG, SPIHT and MPEG.