The Algorithm Research Of Image Denoising Based On Wavelet Transform And Median Filter

In the digital information age,the transmission of information is no longer just through the text,and the image information occupies the mainstream.In the process of storage or transmission,the image information will be disturbed by a variety of noise,if the image information that contains noise is carried out directly for subsequent image processing work,it can not get better processing results.In order to extract more useful information from the noisy image and meet the needs of subsequent higher-level processing,it is necessary to denoise before the subsequent processing.This thesis mainly studies how to use wavelet transform and median filter to filter the image with Gauss noise and impulse noise.This research contents consist of the following aspects:First,the research background and significance of image denoising,the current situation of image denoising at home and abroad,the classification of image noise,the quality evaluation method after image denoising and the commonly used image denoising method and several improved median filtering method is introduced in detail.Second,based on the extremum median filtering and the adaptive median filtering,an extreme value adaptive median filter algorithm based on impulse noise detection is proposed.The basic principle and steps of the algorithm are introduced,and the simulation experiment is carried out using the proposed algorithm,the results show that the algorithm not only has better image denoising effect,but also better protect the image detail.Then,the principle and method of wavelet image denoising are introduced in detail,and the wavelet threshold denoising method is analyzed emphatically.At the same time,the key problems such as threshold function and threshold selection in wavelet threshold denoising method are discussed in detail,and a novel threshold function and threshold are proposed for denoising.The simulation results show that the algorithm has a good denoising effect.Finally,aiming at the advantages of denoising,including median filtering and wavelet filtering in removing impulsive noise and Gaussian noise,an improved denoising method combining the improved median filter and wavelet threshold denoising method is proposed.The Experimental simulation shows that this method is better than the single filter effect,and more practical and effective.