MATLAB代码：

clear

% load  wbarb;

[X,map] = imread('lena256gray.png');

X=double(X);

whos

figure(1); % Display the image

imshow (X,map); axis on; colorbar;

title('原始图像','FontSize',12,'FontName','隶书','color','b');

% Perform a single-level wavelet decomposition

[cA1,cH1,cV1,cD1] = dwt2(X,'bior3.7');

% Construct and display approximations and details from the coefficients

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);

% Display the results of the level 1 decomposition, type

figure(2); % colormap(map);

subplot(2,2,1);  imshow(wcodemat(A1,192),map); axis on;

xlabel('图(a) 近似系数A1','FontSize',12,'FontName','隶书','color','b');

subplot(2,2,2); imshow (wcodemat(H1,192),map); axis on;

xlabel('图(a) 水平细节系数H1','FontSize',12,'FontName','隶书','color','b');

subplot(2,2,3); imshow (wcodemat(V1,192),map); axis on;

xlabel('图(a) 垂直细节细节V1','FontSize',12,'FontName','隶书','color','b');

subplot(2,2,4); imshow (wcodemat(D1,192),map); axis on;

xlabel('图(a) 对角细节系数D1','FontSize',12,'FontName','隶书','color','b');

% Regenerate an image by single-level Inverse Wavelet Transform.

Xsyn = idwt2(cA1,cH1,cV1,cD1,'bior3.7');

figure(3); % colormap(map);

imshow(Xsyn,map); axis on; colorbar;

title('重构图像','FontSize',12,'FontName','隶书','color','b');

% Perform a multilevel wavelet decomposition.

[C,S] = wavedec2(X,2,'bior3.7');

% Extract approximation and detail coefficients

% Extract the level 2 approximation coefficients from C

cA2 = appcoef2(C,S,'bior3.7',2);

% Extract the first- and second-level detail coefficients from C

cH2 = detcoef2('h',C,S,2);

cV2 = detcoef2('v',C,S,2);

cD2 = detcoef2('d',C,S,2);

cH1 = detcoef2('h',C,S,1);

cV1 = detcoef2('v',C,S,1);

cD1 = detcoef2('d',C,S,1);

% Reconstruct the Level 2 approximation and the Level 1 and 2 details.

% Reconstruct the level 2 approximation from C

A2 = wrcoef2('a',C,S,'bior3.7',2);

% Reconstruct the level 1 and 2 details from C

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);

% Display the results of the level 2 decomposition, type

figure (4);

subplot(2,4,1);imshow(wcodemat(A1,192),map);

xlabel('近似系数A1','FontSize',12,'FontName','隶书','color','b');

subplot(2,4,2);imshow(wcodemat(H1,192),map);

xlabel('水平细节H1','FontSize',12,'FontName','隶书','color','b');

subplot(2,4,3);imshow(wcodemat(V1,192),map);

xlabel('垂直细节V1','FontSize',12,'FontName','隶书','color','b');

subplot(2,4,4);imshow(wcodemat(D1,192),map);

xlabel('对角细节D1','FontSize',12,'FontName','隶书','color','b');

subplot(2,4,5);imshow(wcodemat(A2,192),map);

xlabel('近似系数A2','FontSize',12,'FontName','隶书','color','b');

subplot(2,4,6);imshow(wcodemat(H2,192),map);

xlabel('水平细节H2','FontSize',12,'FontName','隶书','color','b');

subplot(2,4,7);imshow(wcodemat(V2,192),map);

xlabel('垂直细节V2','FontSize',12,'FontName','隶书','color','b');

subplot(2,4,8);imshow(wcodemat(D2,192),map);

xlabel('对角细节D2','FontSize',12,'FontName','隶书','color','b');

% Reconstruct the original image from the multilevel decomposition.

X0 = waverec2(C,S,'bior3.7');

figure(5); % colormap(map);

imshow(X0,map); axis on; colorbar;

title('重构图像2','FontSize',12,'FontName','隶书','color','b');

%%*********************************************************************

效果图：