Research On Median Filter Denoising Algorithm Used In Image Processing

When the image signal is generated and transmitted during the operation,it is often interfered by various types of noise,hindering the visual effect that it can present.Therefore,it is necessary to select a suitable scheme to reduce the negative effects of noise,that is,to achieve the corresponding filtering operation,which is also a key pre-processing link.As a nonlinear filter,median filter can not only suppress the noise well,but also protect the details of the signal.Therefore,median filtering technology has always been a hot topic in image processing research.In this paper,two kinds of optimal median filtering algorithms are proposed to deal with the filtering problems related to impulse noise.The main work achieved in this paper is as follows:Firstly,Based on the shortcomings of adaptive median filtering algorithm during noise detection and filtering,an adaptive median filtering algorithm based on impulse noise detection correlation is proposed.The differences in this algorithm are:First of all,according to the presence of signal points in the noise detection window will automatically vary with the size of the window,and in the case of the analysis of the correlation between adjacent pixels,Can accurately determine the signal point and its noise point;Then,according to the dependence of direction,the edge-preserving filtering method is used to reconstruct the gray value of the pixels affected by noise.Simulation results show that the proposed algorithm can effectively remove noise and preserve image features,and the PSNR parameters obtained are higher than the existing median filtering algorithms.Secondly,In order to detect and filter the noise effects more accurately,this paper presents a new switching median filtering algorithm based on differential block based on the analysis of the problems expressed by the switching median filtering algorithm.Considering the contradiction between detail protection and noise filtering,the corresponding pixel regions in the filter window are firstly divided into corresponding image blocks.Then,according to the number relation of the noise block and the pixel part of the signal block,the noise point is defined.Finally,an effective filter window is selected according to the noise density of its neighborhood,and the median value of the signal block in the window is regarded as the filter output value.The experimental results show that the proposed algorithm can effectively filter the noise in the image and retain the relevant texture information in the image to a greater extent,and the visual effect is better.Finally,the main work of this paper is summarized,and the future research direction is put forward.