%從MATLAB命令行加載并顯示圖像
load wbarb;
image(X);
colormap(map);
colorbar;
%================================
%轉換成為灰度級索引圖像
%對圖像進行單尺度分解
[cA1,cH1,cV1,cD1]=dwt2(X,'bior3.7');
%================================
%從分解系數中提取近似和細節
[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);
%================================
%顯示近似和細節
colormap(map);
subplot(2,2,1);
image(wcodemat(A1,192));
title('近似A1');
subplot(2,2,2);
image(wcodemat(H1,192));
title('水平細節H1');
subplot(2,2,3);
image(wcodemat(V1,192));
title('垂直細節V1');
subplot(2,2,4);
image(wcodemat(D1,192));
title('對角細節D1');
%================================
%對圖像進行多尺度分解
[C,S]=wavedec2(X,2,'bior3.7');
%================================
%提取分解后的近似和細節系數
cA2=appcoef2(C,S,'bior3.7',2);
[cH2,cV2,cD2]=detcoef2('all',C,S,2);
[cH1,cV1,cD1]=detcoef2('all',C,S,2);
================================
%從系數C重構第二層近似
A2=wrcoef2('a',C,S,'bior3.7',2);
%================================
%從系數C重構第一、二層細節
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);
%================================
%顯示多尺度分解的結果
colormap(map);
subplot(2,4,1);
image(wcodemat(A1,192));
title('近似A1');
subplot(2,4,2);
image(wcodemat(H1,192));
title('水平細節H1');
subplot(2,4,3);
image(wcodemat(V1,192));
title('垂直細節V1');
subplot(2,4,4);
image(wcodemat(D1,192));
title('對角細節D1');
subplot(2,4,5);
image(wcodemat(A2,192));
title('近似A2');
subplot(2,4,6);
image(wcodemat(H2,192));
title('水平細節H2');
subplot(2,4,7);
image(wcodemat(V2,192));
title('垂直細節V2');
subplot(2,4,8);
image(wcodemat(D2,192));
title('對角細節D2');
%================================
%從多尺度分解后的系數重構原始圖像并顯示結果
X0=waverec2(C,S,'bior3.7');
image(X0);
colormap(map);
colorbar;