小波去噪声，二为.m

小波变换的matlab程序

load wgatlin;
subplot(2,2,1),image(X);
colormap(map);
title('原始图像');
axis square;
init=2055615866;
rand('seed',init);
XX=X+12*(randn(size(X)));
subplot(2,2,2),image(XX);
colormap(map);
title('含噪声图像');
axis square;
[c,l]=wavedec2(XX,2,'sym4');
a1=wrcoef2('a',c,l,'sym4',1);
a2=wrcoef2('a',c,l,'sym4',2);
subplot(2,2,3),image(a1);
colormap(map);
title('第一次去噪声图像');
axis square;
subplot(2,2,4),image(a2);
colormap(map);
title('第二次去噪声图像');
axis square;