常用去噪之均值滤波

 均值滤波是用像素点邻域的均值代替该像素点，通过将各个像素点做平均平滑滤波，平滑效果与滤波窗口有关，窗口越大，平滑效果越强，但细节和边缘也越加模糊。

matlab实现

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1. %均值滤波 test
   
2. A = imread('E:\test\Lenna.jpg');
   
3. B = imnoise(A,'gaussian');
   
4. 
   
5. figure;subplot(221),imshow(A);title('原图')
   
6. subplot(222),imshow(B);title('高斯噪声图')
   
7. 
   
8. C = m_average_filter(B,5);
   
9. subplot(223),imshow(uint8(C));title('均值滤波后')
   
10. 
    
11. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
12. 
    
13. % Purpose: do averge filter
    
14. % Author: pottor
    
15. % Date: 2017/5/10
    
16. 
    
17. function out = m_average_filter(in,w)
    
18. 
    
19. if( mod(w,2)==0 )
    
20.     error( 'w must be odd' );
    
21. end
    
22. 
    
23. out = in;
    
24. hw = floor(w/2);
    
25. 
    
26. F = ones(w,w)/(w*w);
    
27. 
    
28. if size(in,3) == 1
    
29.     [m,n] = size(in);
    
30.     for i = 1:m
    
31.         for j = 1:n
    
32.             iMin = max(i-hw,1);
    
33.             iMax = min(i+hw,m);
    
34.             jMin = max(j-hw,1);
    
35.             jMax = min(j+hw,n);
    
36.             
    
37.             I = in(iMin:iMax,jMin:jMax);
    
38.             out(i,j) = sum(sum(double(I).*F((iMin:iMax)-i+hw+1,(jMin:jMax)-j+hw+1)));
    
39.         end
    
40.     end
    
41. else
    
42.     r = in(:,:,1);
    
43.     g = in(:,:,2);
    
44.     b = in(:,:,3);
    
45.     [m,n] = size(r);
    
46.     for i = 1:m
    
47.         for j = 1:n
    
48.             iMin = max(i-hw,1);
    
49.             iMax = min(i+hw,m);
    
50.             jMin = max(j-hw,1);
    
51.             jMax = min(j+hw,n);
    
52.             
    
53.             Ir = r(iMin:iMax,jMin:jMax);
    
54.             Ig = g(iMin:iMax,jMin:jMax);
    
55.             Ib = b(iMin:iMax,jMin:jMax);
    
56. 
    
57.             out(i,j,1) = sum(sum(double(Ir).*F((iMin:iMax)-i+hw+1,(jMin:jMax)-j+hw+1)));
    
58.             out(i,j,2) = sum(sum(double(Ig).*F((iMin:iMax)-i+hw+1,(jMin:jMax)-j+hw+1)));
    
59.             out(i,j,3) = sum(sum(double(Ib).*F((iMin:iMax)-i+hw+1,(jMin:jMax)-j+hw+1)));
    
60.         end
    
61.     end
    
62. end

滤波效果