%Sigma 西格玛平滑滤波clc;clear *;F=rgb2gray(imread('img\girl.jpg')); figure,imshow(F); title('originImage');F=imnoise(F,'salt & pepper',0.01); %Add salt noisefigure,imshow(F); title('saltNoise');F=double(F); [row,col]=size(F);for i=3:row-2 %use templet 5X5for j=3:col-2Templet=[F(i-2,j-2) F(i-2,j-1) F(i-2,j) F(i-2,j+1) F(i-2,j+2)F(i-1,j-2) F(i-1,j-1) F(i-1,j) F(i-1,j+1) F(i-1,j+2)F(i,j-2) F(i,j-1) F(i,j) F(i,j+1) F(i,j+2)F(i+1,j-2) F(i+1,j-1) F(i+1,j) F(i+1,j+1) F(i+1,j+2)F(i+2,j-2) F(i+2,j-1) F(i+2,j) F(i+2,j+1) F(i+2,j+2)];Trows = reshape(Templet,5*5,1); %将模板转换成1列theta=std2(Trows);delta=2*theta;count_1=0;count_0=0;for m=1:5for n=1:5A=Templet(m,n)-delta;B=Templet(m,n)+delta;if A<=Templet(3,3)<=BSigma(m,n)=1;count_1=count_1+1;elseSigma(m,n)=0;count_0=count_0+1;endendendK=3;N=2;Sum=0;Num=0;if count_1>=Kfor m=1:5for n=1:5Sum=Sum+Sigma(m,n)*Templet(m,n);Num=Num+Sigma(m,n);endendF(i,j)=Sum/Num;elseF(i,j)=mean(Trows);endendendfigure,imshow(uint8(F)); title('Sigma');