clear all; close all;clc;img=imread(‘lena.jpg‘);imshow(img,[]);[h w]=size(img);imgn=zeros(h,w);n=12;nw=floor(w/n)*n;nh=floor(h/n)*n;for y=1:n:nh    for x=1:n:nw        imgn(y:y+n-1,x:x+n-1)=mean(mean(img(y:y+n-1,x:x+n-1)));           end    imgn(y:y+n-1,nw+1:w)=mean(mean(img(y:y+n-1,nw+1:w)));   %处理最后一列    imgn(y,1:w)=128; endfor x=1:n:nw    imgn(nh+1:h,x:x+n-1)=mean(mean(img(nh+1:h,x:x+n-1)));   %处理最后一行    imgn(1:h,x)=128;    endimgn(nh+1:h,nw+1:w)=mean(mean(img(nh+1:h,nw+1:w)));     %处理最后一个角imgn(1:h,nw)=128;imgn(1:h,w)=128;imgn(nh,1:w)=128;imgn(h,1:w)=128;figure;imshow(imgn,[])