Embedded Zerotree Coding Based On Discrete Cosine Transform

In modern communications, such as High-Definition TV, Video telephone, conference TV, how to reduce the needed data and occupied frequency band effectively is an important problem we must solve. In this situation, image occupies large amount of data, so it is a key technique to represent the image as lossless as possible by using data as few as possible, this is called image compression. The effective image compression is essential for the implementation of image communication.The target of image compression is to reduce date that represents an image as much as possible on condition that better image quality is maintained. We can get high compression ratio if consider the relativities of the neighboring pixels and the neighboring rows and the vision characteristic of human eyes in coding process. ISO has drawn up several image compressing and coding standards to suit the fast speed of the development, which make the implement of the standard more and more difficult. Image compression technology go through research for decades explore, already there are many kinds of methods at present. There are many compression methods of still picture, for example, DPCM, Vector Quantization, Block Transform Coding, Fractal Coding, ANN Coding and Wavelet Transform Coding etc. Among these Transform coding has become the standard paradigm in image (e.g., JPEG) and video coding (e.g., MPEG-2 and H.263).Discrete Cosine Transform (DCT) coding, as a kind of Block Transform Coding, is the most used and mature one. The discrete cosine transform (DCT) possess nice decorrelation and energy compaction properties and has maturet entropy coding and decoding algorithm and mature fast algorithm. DCT lossy compression rate is not the prime, but is widely used because of its high compression coding efficiency and it can be realized with hardware simply and quickly. Embedded image coding using zerotrees of wavelet coefficients (EWZ) is an effective compression technique, which is important in all digital image compression method. Embedded zerotree wavelet code (EZW) is one of the quite famous wavelet encoders, which was proposed by J.M.Shapiro in 1993. At present, it is considered as one of the most advanced image compression code methods. The advantage of the EZW method mainly depends on utilizing the direction zerotree structure effectively, causing the massive trees structure zero coefficients only to use a zerotree root to indicate, which has obtained the high compression coding efficiency. But realize zerotree coding based on Disrcrete Wavelet Transform (e.g., EWZ and SPIHT) need multiplying and adding operation of a large amount of data. It's Algorithm is complexity and no fast algorithm at all, and boundary extend is necessary. In this paper, we summarize the compression technology of the static picture at first, discuss the fundamentals of wavelet transform and the basic idea of embedded image coding using zerotrees of wavelet coefficients(EWZ).And review the history in which the picture compress the technical development. Refocus the Discrete Cosine Transform (DCT) and it's application on image compression. At the same time, recommend the Discrete Cosine Transform (DCT) with 1-Dimensional DCT, 2-Dimensional DCT and DCT fast algorithm.By introduce the embedded zerotrees of wavelet coefficients, fetch out the fundamental conception and theory of embedded coding and zerotrees coding. In the course of analyzing and comparing to Discrete Cosine Transform (DCT) and zerotree frame class based on Discrete Wavelet Transform. Have a ides of combine the Discrete Cosine Transform and the zerotrees of wavelet coefficients effectively in image compression. An efficient image coding scheme-Embedded Zerotree coding based on discrete cosine transform (EZC-DCT) is proposed. The core idea of Embedded Zerotree Coding based on Discrete Cosine Transform (EZC-DCT) is adjust the image coefficient by clustering handled, which have been transformed by block DCT ,to pyramidal distributing first. Then output all the image coefficient by zerotree frame class coding During the...