example7_3.m

<小波分析理论与MATLAB 7实现>是“MATLAB应用技术”系列丛书之一

%从MATLAB命令行加载并显示图像
load wbarb;
whos
image(X);
colormap(map);
colorbar;
%================================
%转换成为灰度级索引图像
%对图像进行单尺度分解
[cA1,cH1,cV1,cD1]=dwt2(X,'bior3.7');
%================================
%从分解系数中提取近似和细节
[cA1,cH1,cV1,cD1]=dwt2(X,'bior3.7');
A1=upcoef2('a',cA1,'bior3.7',1);
H1=upcoef2('h',cH1,'bior3.7',1);
V1=upcoef2('v',cV1,'bior3.7',1);
D1=upcoef2('d',cD1,'bior3.7',1);
%================================
%显示近似和细节
colormap(map);
subplot(2,2,1);
image(wcodemat(A1,192));
title('近似A1');
subplot(2,2,2);
image(wcodemat(H1,192));
title('水平细节H1');
subplot(2,2,3);
image(wcodemat(V1,192));
title('垂直细节V1');
subplot(2,2,4);
image(wcodemat(D1,192));
title('对角细节D1');
%================================
%对图像进行多尺度分解
[C,S]=wavedec2(X,2,'bior3.7');
%================================
%提取分解后的近似和细节系数
cA2=appcoef2(C,S,'bior3.7',2);
[cH2,cV2,cD2]=detcoef2('all',C,S,2);
[cH1,cV1,cD1]=detcoef2('all',C,S,2);
%================================
%从系数C重构第二层近似
A2=wrcoef2('a',C,S,'bior3.7',2);
%================================
%从系数C重构第一、二层细节
H1=wrcoef2('h',C,S,'bior3.7',1);
V1=wrcoef2('v',C,S,'bior3.7',1);
D1=wrcoef2('d',C,S,'bior3.7',1);
H2=wrcoef2('h',C,S,'bior3.7',2);
V2=wrcoef2('v',C,S,'bior3.7',2);
D2=wrcoef2('d',C,S,'bior3.7',2);
%================================
%显示多尺度分解的结果
colormap(map);
subplot(2,4,1);
image(wcodemat(A1,192));
title('近似A1');
subplot(2,4,2);
image(wcodemat(H1,192));
title('水平细节H1');
subplot(2,4,3);
image(wcodemat(V1,192));
title('垂直细节V1');
subplot(2,4,4);
image(wcodemat(D1,192));
title('对角细节D1');
subplot(2,4,5);
image(wcodemat(A2,192));
title('近似A2');
subplot(2,4,6);
image(wcodemat(H2,192));
title('水平细节H2');
subplot(2,4,7);
image(wcodemat(V2,192));
title('垂直细节V2');
subplot(2,4,8);
image(wcodemat(D2,192));
title('对角细节D2');
%================================
%从多尺度分解后的系数重构原始图像并显示结果
X0=waverec2(C,S,'bior3.7');
image(X0);
colormap(map);
colorbar;