MATLAB 2维小波变换经典程序

%  FWT_DB.M;

%  此示意程序用DWT实现二维小波变换

%  编程时间2004-4-10，编程人沙威

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clear;clc;

T=256;       %  图像维数

SUB_T=T/2;   %  子图维数

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%  1.调原始图像矩阵

load wbarb;  %  下载图像

f=X;         %  原始图像

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%  2.进行二维小波分解

l=wfilters('db10','l');    %  db10（消失矩为10)低通分解滤波器冲击响应（长度为20）

L=T-length(l);

l_zeros=[l,zeros(1,L)];    %  矩阵行数与输入图像一致，为2的整数幂

h=wfilters('db10','h');    %  db10（消失矩为10)高通分解滤波器冲击响应（长度为20）

h_zeros=[h,zeros(1,L)];    %  矩阵行数与输入图像一致，为2的整数幂

for i=1:T;   %  列变换

    row(1:SUB_T,i)=dyaddown( ifft( fft(l_zeros).*fft(f(:,i)') ) ).';    %  圆周卷积<->FFT

    row(SUB_T+1:T,i)=dyaddown( ifft( fft(h_zeros).*fft(f(:,i)') ) ).';  %  圆周卷积<->FFT

end;

for j=1:T;   %  行变换

    line(j,1:SUB_T)=dyaddown( ifft( fft(l_zeros).*fft(row(j,:)) ) );    %  圆周卷积<->FFT

    line(j,SUB_T+1:T)=dyaddown( ifft( fft(h_zeros).*fft(row(j,:)) ) );  %  圆周卷积<->FFT

end;

decompose_pic=line;  %  分解矩阵