The Research Of EZW Based On Directionlets Transform Image Coding Algorithm

Recently, with the increasing popularity of the Internet in the world and the rapid development of mobile communications, as well as the emergence of new multimedia services, image/video compression technology has been made many higher demand. Ideal image compression coding technology in addition provide traditional good compression performance and reconstruction quality, it should also provide information on quality, resolution, signal to noise ratio and other scalable coding structure, and multi-resolution coding, embedded coding and anti-transmission error, which can provide users with wireless mobile environment personalized service.Wavelet theory can be used in image processing, but the effect is not very ideal because standard wavelet transform(WT) based on only vertically and horizontally directions, it fails to provide a optimal sparse representation of feature information,such as edges and contours of a smooth image.In order to obtain better geometric feature information, such as edges or contours, this paper systematic study of the directionlets transform theory, and its application in the field of image compression, mainly in the following two aspects:(1) Effective representation method of smooth image using directionlets transform. We further studied the transformation structure of directionlets, and we study to how to construct the separable filter method.(2) The algorithm of EZW image compression makes full use of multi-resolution characteristics of standard wavelet transform(WT). Then, through coding the significant nodes and zero-root nodes, The process of compression is realised. Here, by combining directionlets and EZW, the algorithm of zero-tree coding is applied to encode.Compared with traditional EZW algorithm based on standard wavelet transform, the experimental result has been demonstrated that EZW algorithm based on directionlets transform are more superior in the fileds of PSNR and subjectivity vision.