Wavelet Zerotree Coding Is Applied Research In Image Compression And Its Denoising

Image compression coding plays a very important role in the multimedia communication technology.Various compression standards,such as JPEG2000 and MPEG-4, have appeared.Wavelet transform technology is used both in JPEG2000 and MPEG-4.In this paper,firstly,I mainly discuss the problem about wavelet zerotree in image coding and two improved algorithms are proposed.Secondly,we compress image combined with deleting noise by wavelet zerotree algorithm.Lastly,several compessing methods based on wavelet zerotree idea are compared and summarized.Firstly,all kinds of image compressing methods and image coding standards are reviewed. Furthermore I introduce the elementary wavelet theory. Secondly,two classical wavelet image coding algorithm based wavelet zerotree idea are introduced and two improved algorithms are proposed.The first algorithm is that we combine runlength coding and zerotree coding in which LL band coefficients are coded lonely with DPCM.The second algorithm is the zerotree algorithm with vector quantization is combined with LL band coefficients alone coding with DPCM.The simulating results show they can get better performance both in PSNR and subjective quality.Thirdly, we make research on how to compress image combined with deleting noise by zerotree algorithm.First we use soft-threshold method to denoise image with noise,and then the first improved zerotree algorithm is used to compress image.Simulating results show that the subjective quality of the decoded image is good.Lastly,we compare,analyse and summarize all kinds of compressing methods based on wavelet zerotree idea.