cl; img=imread('3.17.tif'); imgn=imnoise(img,'salt & pepper',0.02); [m n]=size(img); %h=fspecial('average',[3 3]);    %   3*3的均值滤波 %imgn1=imfilter(imgn,h,'replicate'); %imgn=medfilt2(imgn,[3 3]);     %    3*3的中值滤波 %%%%自己编写3*3均值滤波 %{
    tem=0; for i=2:1:m-1     for j=2:1:n-1             for p=i-1:1:i+1             for q=j-1:1:j+1                 tem=tem+double(imgn(p,q));             end         end         tem=tem/9;         imgn(i,j)=tem;         tem=0;     end end %} %%%%自己编写3*3中值滤波 %{
    s=zeros(1,9); for i=2:1:m-1     for j=2:1:n-1             he=1;         for p=i-1:1:i+1             for q=j-1:1:j+1                            s(he)=imgn(p,q);                 he=he+1;                           end         end         s=sort(s);         imgn(i,j)=s(5);     end end %} imshow(imgn)