example7_4.m

Matlab6.5小波分析与应用

%给定一个原始图像
load geometry;
nbcol=size(map,1);
colormap(pink(nbcol));
figure(1);
image(wcodemat(X,nbcol));
title('原始图像');
%================================
%设置延拓模式为补零方式，对图像应用小波sym4进行3层分解，然后重构第3层近似
lev=3;
wname='sym4';
dwtmode('zpd'); 
[c,s]=wavedec2(X,lev,wname);
a=wrcoef2('a',c,s,wname,lev);
figure(2);
image(wcodemat(a,nbcol));
%================================
%改变延拓模式为对称延拓且同样应用小波sym4将原始图像分解到第3层，之后重构第3层近似
dwtmode('sym');
[c,s]=wavedec2(X,lev,wname);
aa=wrcoef2('a',c,s,wname,lev);
figure(3);
image(wcodemat(aa,nbcol));
%================================
%设置平滑填补的延拓模式，应用小波sym4对原始图像进行3层分解，然后重构第3层近似
dwtmode('spd');
[c,s]=wavedec2(X,lev,wname);
aaa=wrcoef2('a',c,s,wname,lev);
figure(4);
image(wcodemat(aaa,nbcol));