Based On Wavelet Transform Of Fractal Compression Method

Image is the most important carrier among the information intercommunion in people's life, and it is the biggest media containing information. As we all know, the data quantity is very large in a digital image. If the data couldn't be compressed efficiently, it will be a great obstacle to the development of communication and multimedia technologies when high transmission speed and large memory are needed in multimedia communication system. Image compression technology, as a crucial technology in the fields of communication and multimedia, is very important to information technology nowadays and future.Along with many new theorieses and new method flows out, many new image compression methods have been proposed in recent years.The fractal compression scheme is one of the focus methods. Fractal coding is a compression scheme which based on the Mandelbrot's fractal geometry theory. The key of this scheme is to find IFS of the image, and then utilize the IFS to compress the image. The genius of the fractal coding is the high redundancy degree. In other words, the image contains many self- frame of reference, which has many self- resemblanced parts. Each region can express the other one through appropriate transformation. The core of this compression scheme is Collage Theorem.Wavelet-based compression scheme has been put into practice in the areas of compression of static images and motive images as well as a key part in some international standards such as JPEG2000. The basic ideology of the wavelet-based compression scheme is multi-resolution. Analyzing the image in the different space and different frequency is the first process, then we carry coefficient coding on the sub-block. Coefficient coding is the core of wavelet-based compression scheme,and the substance of the compression is carry quantiti- compression on coefficient. One image is divided into four frequency thought wavelet-transformation. However, it is still a research hotspot that how to deal with the coefficients transformed from adigital image with wavelet in a more efficient way.This paper focuses on fractal compression coding method after image wavelet decomposition. Based on the analysis of the traditional fractal method of the wavelet field, it presents an improved compression approach that it respectively takes the method of combining the intelligent helix search method (IHSM) and the equivalent element parallelism method (EEPM) to improve the original approach. The presentation of the IHSM is trying to put the use of part of the similarities of its own of the space field image into the analysis of the wavelet field, and it has broken the traditional searching method and has better expanded the concept of the fractal method. However, the EEPM just utilizes the similarity of the sub-band after the image wavelet decomposition, by calculating and contrasting the fractal coding in low frequency block to take place of the one in high. It not only reduced the calculating time but also advanced the image compression rate so that the advantage of the image wavelet decomposition can better embodiment.The mock computer test shows that by taking the above-mentioned improved approach the subjective effect of the reconstructed image has little difference between the one via original calculating method, but the calculating efficiency and the compression rate both get great improvement Then this explains that the improved approach mentioned in this essay has got fine effect, and it makes full combination of the wavelet transformation and the advantage of the fractal coding so that it has formed an image compression approach which is effective in operation and excellent in capability.