program_11_14.m

这是基于MATLAB系统上开发的,应用于小波分析方面,很有用的程序模块,书名为"MATLAB在小波分析中的应用"

% 装载图像信号
load belmont2;
% 完成图像的单层次小波分解
[swa,swh,swv,swd] = swt2(X,1,'db1');
% 显示低频和高频系数
map = pink(size(map,1));
figure(1)
colormap(map)
nbcol = size(map,1)
subplot(2,2,1), image(wcodemat(swa,nbcol));
title('低频系数swa')
subplot(2,2,2), image(wcodemat(swh,nbcol));
title('水平方向高频系数swh')
subplot(2,2,3), image(wcodemat(swv,nbcol));
title('垂直方向高频系数swv')
subplot(2,2,4), image(wcodemat(swd,nbcol));
title('对角方向高频系数swd')
% 通过平稳小波逆变换重构图像
A0 = iswt2(swa,swh,swv,swd,'db1');
nulcfs = zeros(size(swa));
% 由分解系数重构第一层的低频和高频部分
A1 = iswt2(swa,nulcfs,nulcfs,nulcfs,'db1');
H1 = iswt2(nulcfs,swh,nulcfs,nulcfs,'db1');
V1 = iswt2(nulcfs,nulcfs,swv,nulcfs,'db1');
D1 = iswt2(nulcfs,nulcfs,nulcfs,swd,'db1');
% 显示第一层的分解结果，包括显示低频和高频部分
figure(2)
colormap(map)
subplot(2,2,1), image(wcodemat(A1,nbcol));
title('低频 A1')
subplot(2,2,2), image(wcodemat(H1,nbcol));
title('水平高频H1')
subplot(2,2,3), image(wcodemat(V1,nbcol));
title('垂直高频V1')
subplot(2,2,4), image(wcodemat(D1,nbcol));
title('对角高频D1')
% 图像的多层二维离散平稳小波分解
[swa,swh,swv,swd] = swt2(X,3,'db1');
% 显示多层二维离散平稳小波分解结果
figure(3)
colormap(map)
kp = 0;
for i = 1:3
subplot(3,4,kp+1), image(wcodemat(swa(:,:,i),nbcol));
title(['低频系数：level ',num2str(i)])
subplot(3,4,kp+2), image(wcodemat(swh(:,:,i),nbcol));
title(['水平高频系数：level ',num2str(i)])
subplot(3,4,kp+3), image(wcodemat(swv(:,:,i),nbcol));
title(['垂直高频系数：level ',num2str(i)])
subplot(3,4,kp+4), image(wcodemat(swd(:,:,i),nbcol));
title(['对角高频系数：level ',num2str(i)])
kp = kp + 4;
end
%  重构低频分量
mzeroh = zeros(size(swh));
mzerov = zeros(size(swv));
mzerod = zeros(size(swd));
 
A = iswt2(swa,mzeroh,mzerov,mzerod,'db1');  %  重构低频
 
%  重构H,V,D高频分量
mzeroa = zeros(size(swa));
H = iswt2(mzeroa,swh,mzerov,mzerod,'db1');  %  重构H分量
V = iswt2(mzeroa,mzeroh,swv,mzerod,'db1');  %  重构V分量
D = iswt2(mzeroa,mzeroh,mzerov,swd,'db1');  %  重构D分量
 
norm(H+V+D+A-X)  %  误差
 
%  显示结果
figure(4)
colormap(map)
subplot(2,2,1), image(wcodemat(A,nbcol));
title('低频：level ')
subplot(2,2,2), image(wcodemat(H,nbcol));
title('水平高频：level ')
subplot(2,2,3), image(wcodemat(V,nbcol));
title('垂直高频：level ')
subplot(2,2,4), image(wcodemat(D,nbcol));
title('对角高频：level ')