%裝載并顯示原始圖象
A=imread('C:\Documents and Settings\luom\My Documents\study\新建文件夾\江華榮（基于小波變換的弱信號提取）\程序\源程序\e.jpg');
subplot(2,2,1);
image(A);
%colormap(map);
%colorbar;
title('原始圖象');
axis square;
%=============================================
%轉換為索引圖
A=double(A);
Xrgb=0.2990*A(:,:,1)+0.5870*A(:,:,2)+0.1140*A(:,:,3);
Nbcolors=255;
X=wcodemat(Xrgb,Nbcolors);
map=pink(Nbcolors);
subplot(2,2,1);
image(X);
colormap(map);
%colorbar;
title('原始圖象');
axis square;
%=============================================
%加噪并顯示圖象
init=2055615866;
rand('seed',init);
XX=X+50*randn(size(X));
subplot(2,2,2);
image(XX);
colormap(map);
title('含噪圖象');
axis square;
%===============================================
%對圖象消噪
%用sym4小波函數對XX進行2層分解
[c,l]=wavedec2(XX,2,'sym4');
%實現低通濾波消噪
a1=wrcoef2('a',c,l,'sym4',1);
%再次實現低通濾波消噪
a2=wrcoef2('a',c,l,'sym4');
%==============================================
%顯示消噪后的結果
subplot(2,2,3);
image(a1);
colormap(map);
title('第一次消噪圖象');
axis square;
subplot(2,2,4);
image(a2);
colormap(map);
title('第二次消噪圖象');
axis square;