Research On Threshold Image Denoising Based On Dyadic Wavelet Transform

In real life,the existence of noise is still a problem can not be ignored.In recent years,with the continuous development of science and theory of wavelet characteristics further fill in image denoising by wavelet becomes more and more advantages,it has gradually become one of the important research contents of image processing.In the field of orthogonal wavelet transform,most of the research work is done,but the next sampling makes the image position deviation caused by the image transform to the wavelet domain.This paper has constructed dyadic wavelet filter and orthogonal wavelet convolution type high-order vanishing moment at the same time a threshold function and effect of image denoising is proposed,and the PSNR data to image after denoising and after comparison and analysis.Finally,the simulation results show that this method is an effective method for image denoising.The main research contents are as follows:(1)This paper introduces the research background and significance of this topic,and the development and status quo of wavelet threshold denoising,the structure and arrangement of the article,the innovation of the article.(2)The basic theory of wavelet transform,a simple description of the definition of continuous,discrete wavelet transform and related theorems to some key theory introduction and two into wavelet correlation,finally introduces two fast algorithms:Mallat algorithm and a? trous algorithm,highlighting the differences between the two algorithms to a certain extent.(3)On the basis of analyzing the advantages and disadvantages of soft and hard threshold function,a kind of threshold function with adjustable parameters is constructed;(4)Orthogonal wavelet transform is not shift invariant,the denoised images to Gibbs phenomenon and can not meet the characteristics of human visual requirements.In order to suppress this phenomenon,the introduction of the dyadic wavelet transform with translational invariance,has put forward dyadic wavelet filter high order vanishing moments and based on the experimental results,put forward a a denoising method of wavelet transform has put forward two into dyadic wavelet filter high order vanishing moments.The threshold based on the simulation results show that this method both in peak signal-to-noise ratio or the visual effects and wavelet hard threshold,soft threshold denoising method is significantly improved and improved method an efficient image denoising.