MATLAB2维小波变换经典程序

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%  FWT_DB.M;

%  此示意程序用DWT实现二维小波变换

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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

%  图像分为四块

lt_pic=decompose_pic(1:SUB_T,1:SUB_T);      %  在矩阵左上方为低频分量–fi(x)*fi(y)

rt_pic=decompose_pic(1:SUB_T,SUB_T+1:T);    %  矩阵右上为–fi(x)*psi(y)

lb_pic=decompose_pic(SUB_T+1:T,1:SUB_T);    %  矩阵左下为–psi(x)*fi(y)

rb_pic=decompose_pic(SUB_T+1:T,SUB_T+1:T);  %  右下方为高频分量–psi(x)*psi(y)

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%  3.分解结果显示

figure(1);

colormap(map);

subplot(2,1,1);

image(f);  %  原始图像

title(‘original pic’);

subplot(2,1,2);

image(abs(decompose_pic));  %  分解后图像

title(‘decomposed pic’);

figure(2);

colormap(map);

subplot(2,2,1);

image(abs(lt_pic));  %  左上方为低频分量–fi(x)*fi(y)

title(‘\Phi(x)*\Phi(y)’);

subplot(2,2,2);

image(abs(rt_pic));  %  矩阵右上为–fi(x)*psi(y)

title(‘\Phi(x)*\Psi(y)’);

subplot(2,2,3);

image(abs(lb_pic));  %  矩阵左下为–psi(x)*fi(y)

title(‘\Psi(x)*\Phi(y)’);

subplot(2,2,4);

image(abs(rb_pic));  %  右下方为高频分量–psi(x)*psi(y)

title(‘\Psi(x)*\Psi(y)’);

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%  5.重构源图像及结果显示

% construct_pic=decompose_matrix’*decompose_pic*decompose_matrix;

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l_re=l_zeros(end:-1:1);   %  重构低通滤波

l_r=circshift(l_re’,1)’;  %  位置调整

h_re=h_zeros(end:-1:1);   %  重构高通滤波

h_r=circshift(h_re’,1)’;  %  位置调整

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

top_pic=[lt_pic,rt_pic];  %  图像上半部分

t=0;

for i=1:T;  %  行插值低频

if (mod(i,2)==0)

topll(i,:)=top_pic(t,:); %  偶数行保持

else

t=t+1;

topll(i,:)=zeros(1,T);   %  奇数行为零

end

end;

for i=1:T;  %  列变换

topcl_re(:,i)=ifft( fft(l_r).*fft(topll(:,i)’) )’;  %  圆周卷积<->FFT

end;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

bottom_pic=[lb_pic,rb_pic];  %  图像下半部分

t=0;

for i=1:T;  %  行插值高频

if (mod(i,2)==0)

bottomlh(i,:)=bottom_pic(t,:);  %  偶数行保持

else

bottomlh(i,:)=zeros(1,T);       %  奇数行为零

t=t+1;

end

end;

for i=1:T; %  列变换

bottomch_re(:,i)=ifft( fft(h_r).*fft(bottomlh(:,i)’) )’;  %  圆周卷积<->FFT

end;

construct1=bottomch_re+topcl_re;  %  列变换重构完毕

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left_pic=construct1(:,1:SUB_T);   %  图像左半部分

t=0;

for i=1:T;  %  列插值低频

if (mod(i,2)==0)

leftll(:,i)=left_pic(:,t); %  偶数列保持

else

t=t+1;

leftll(:,i)=zeros(T,1);    %  奇数列为零

end

end;

for i=1:T;  %  行变换

leftcl_re(i,:)=ifft( fft(l_r).*fft(leftll(i,:)) );  %  圆周卷积<->FFT

end;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

right_pic=construct1(:,SUB_T+1:T);  %  图像右半部分

t=0;

for i=1:T;  %  列插值高频

if (mod(i,2)==0)

rightlh(:,i)=right_pic(:,t);  %  偶数列保持

else

rightlh(:,i)=zeros(T,1);      %  奇数列为零

t=t+1;

end

end;

for i=1:T; %  行变换

rightch_re(i,:)=ifft( fft(h_r).*fft(rightlh(i,:)) );  %  圆周卷积<->FFT

end;

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construct_pic=rightch_re+leftcl_re;  %  重建全部图像

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%  结果显示

figure(3);

colormap(map);

subplot(2,1,1);

image(f);  %  源图像显示

title(‘original pic’);

subplot(2,1,2);

image(abs(construct_pic));   %  重构源图像显示

title(‘reconstructed pic’);

error=abs(construct_pic-f);  %  重构图形与原始图像误值

figure(4);

mesh(error);  %  误差三维图像

title(‘absolute error display’);

clear

clc

%在噪声环境下语音信号的增强

%语音信号为读入的声音文件

%噪声为正态随机噪声

sound=wavread(‘c12345.wav’);

count1=length(sound);

noise=0.05*randn(1,count1);

for i=1:count1

signal(i)=sound(i);

end

for i=1:count1

y(i)=signal(i)+noise(i);

end

%在小波基’db3’下进行一维离散小波变换

[coefs1,coefs2]=dwt(y,’db3′); %[低频 高频]

count2=length(coefs1);

count3=length(coefs2);

energy1=sum((abs(coefs1)).^2);

energy2=sum((abs(coefs2)).^2);

energy3=energy1+energy2;

for i=1:count2

recoefs1(i)=coefs1(i)/energy3;

end

for i=1:count3

recoefs2(i)=coefs2(i)/energy3;

end

%低频系数进行语音信号清浊音的判别

zhen=160;

count4=fix(count2/zhen);

for i=1:count4

n=160*(i-1)+1:160+160*(i-1);

s=sound(n);

w=hamming(160);

sw=s.*w;

a=aryule(sw,10);

sw=filter(a,1,sw);

sw=sw/sum(sw);

r=xcorr(sw,’biased’);

corr=max(r);

%为清音(unvoice)时,输出为1;为浊音(voice)时,输出为0

if corr>=0.8

output1(i)=0;

elseif corr<=0.1

output1(i)=1;

end

end

for i=1:count4

n=160*(i-1)+1:160+160*(i-1);

if output1(i)==1

switch abs(recoefs1(i))

case abs(recoefs1(i))<=0.002

recoefs1(i)=0;

case abs(recoefs1(i))>0.002 & abs(recoefs1(i))<=0.003

recoefs1(i)=sgn(recoefs1(i))*(0.003*abs(recoefs1(i))-0.000003)/0.002;

otherwise recoefs1(i)=recoefs1(i);

end

elseif output1(i)==0

recoefs1(i)=recoefs1(i);

end

end

%对高频系数进行语音信号清浊音的判别

count5=fix(count3/zhen);

for i=1:count5

n=160*(i-1)+1:160+160*(i-1);

s=sound(n);

w=hamming(160);

sw=s.*w;

a=aryule(sw,10);

sw=filter(a,1,sw);

sw=sw/sum(sw);

r=xcorr(sw,’biased’);

corr=max(r);

%为清音(unvoice)时,输出为1;为浊音(voice)时,输出为0

if corr>=0.8

output2(i)=0;

elseif corr<=0.1

output2(i)=1;

end

end

for i=1:count5

n=160*(i-1)+1:160+160*(i-1);

if output2(i)==1

switch abs(recoefs2(i))

case abs(recoefs2(i))<=0.002

recoefs2(i)=0;

case abs(recoefs2(i))>0.002 & abs(recoefs2(i))<=0.003

recoefs2(i)=sgn(recoefs2(i))*(0.003*abs(recoefs2(i))-0.000003)/0.002;

otherwise recoefs2(i)=recoefs2(i);

end

elseif output2(i)==0

recoefs2(i)=recoefs2(i);

end

end

%在小波基’db3’下进行一维离散小波反变换

output3=idwt(recoefs1, recoefs2,’db3′);

%对输出信号抽样点值进行归一化处理

maxdata=max(output3);

output4=output3/maxdata;

%读出带噪语音信号,存为’101.wav’

wavwrite(y,5500,16,’c101′);

%读出处理后语音信号,存为’102.wav’

wavwrite(output4,5500,16,’c102′);

function [I_W , S] = func_DWT(I, level, Lo_D, Hi_D);

%通过这个函数将I进行小波分解,并将分解后的一维向量转换为矩阵形式

% Matlab implementation of SPIHT (without Arithmatic coding stage)

% Wavelet decomposition

% input:    I : input image

%           level : wavelet decomposition level

%           Lo_D : low-pass decomposition filter

%           Hi_D : high-pass decomposition filter

% output:   I_W : decomposed image vector

%           S : corresponding bookkeeping matrix

% please refer wavedec2 function to see more

[C,S] = func_Mywavedec2(I,level,Lo_D,Hi_D);

S(:,3) = S(:,1).*S(:,2);        % dim of detail coef nmatrices 求低频和每个尺度中高频的元素个数

%st=S(1,3)+S(2,3)*3+S(3,3)*3;%%%%对前两层加密

%C(1:st)=0;

L = length(S); %a求S的列数

I_W = zeros(S(L,1),S(L,2));%设一个与原图像大小相同的全零矩阵

% approx part

I_W( 1:S(1,1) , 1:S(1,2) ) = reshape(C(1:S(1,3)),S(1,1:2)); %将LL层从C中还原为S(1,1)*S(1,2)的矩阵

for k = 2 : L-1   %将C向量中还原出HL,HH,LH 矩阵

rows = [sum(S(1:k-1,1))+1:sum(S(1:k,1))];

columns = [sum(S(1:k-1,2))+1:sum(S(1:k,2))];

% horizontal part

c_start = S(1,3) + 3*sum(S(2:k-1,3)) + 1;

c_stop = S(1,3) + 3*sum(S(2:k-1,3)) + S(k,3);

I_W( 1:S(k,1) , columns ) = reshape( C(c_start:c_stop) , S(k,1:2) );

% vertical part

c_start = S(1,3) + 3*sum(S(2:k-1,3)) + S(k,3) + 1;

c_stop = S(1,3) + 3*sum(S(2:k-1,3)) + 2*S(k,3);

I_W( rows , 1:S(k,2) ) = reshape( C(c_start:c_stop) , S(k,1:2) );

% diagonal part

c_start = S(1,3) + 3*sum(S(2:k-1,3)) + 2*S(k,3) + 1;

c_stop = S(1,3) + 3*sum(S(2:k,3));

I_W( rows , columns ) = reshape( C(c_start:c_stop) , S(k,1:2) );

end


%%%%%%%mallat algorithm%%%%% clc; clear;tic; %%%%original signal%%%% f=100;%%frequence ts=1/800;%%抽样间隔 N=1:100;%%点数 s=sin(2*ts*pi*f.*N);%%源信号 figure(1) plot(s);%%%源信号s title(‘原信号’); grid on; %%%%小波滤波器%%%% ld=wfilters(‘db1′,’l’);%%低通 hd=wfilters(‘db1′,’h’);%%高通 figure(2) stem(ld,’r’);%%%低通 grid on; figure(3) stem(hd,’b’)%%%高通 grid on; %%%%% tem=conv(s,ld);%%低通和原信号卷积 ca1=dyaddown(tem);%%抽样 figure(4) plot(ca1); grid on; tem=conv(s,hd);%%高通和原信号卷积 cb1=dyaddown(tem);%%抽样 figure(5) plot(cb1); grid on; %%%%%%%% %[ca3,cb3]=dwt(s,’db1′);%%小波变换 %%%%%%%% [lr,hr]=wfilters(‘db1′,’r’);%%重构滤波器 figure(6) stem(lr); figure(7) stem(hr); tem=dyadup(cb1);%%插值 tem=conv(tem,hr);%%卷积 d1=wkeep(tem,100);%%去掉两头的分量 %%%%%%%%% tem=dyadup(ca1);%%插值 tem=conv(tem,lr);%%卷积 a1=wkeep(tem,100);%%去掉两头的分量 a=a1+d1;%%%重构原信号 %%%%%%%%% %a3=idwt(ca3,cb3,’db1′,100);%%%小波逆变换 %%%%%%%%% figure(8) plot(a,’.b’); hold on; plot(s,’r’); grid on; title(‘重构信号和原信号的比较’);toc; %figure(9) %plot(a3,’.b’); %hold on; %plot(s,’r’); %grid on; %title(‘重构信号和原信号的比较’);


(这一段比较纠结,有时间研究下)




通用函数


Allnodes   计算树结点


appcoef   提取一维小波变换低频系数


appcoef2   提取二维小波分解低频系数


bestlevt   计算完整最佳小波包树


besttree   计算最佳(优)树


*biorfilt   双正交样条小波滤波器组


biorwavf   双正交样条小波滤波器


*centfrq  求小波中心频率


cgauwavf   Complex Gaussian小波


cmorwavf   coiflets小波滤波器


cwt   一维连续小波变换


dbaux   Daubechies小波滤波器计算


dbwavf   Daubechies小波滤波器


dbwavf(W)    W=’dbN’   N=1,2,3,…,50


ddencmp   获取默认值阈值(软或硬)熵标准


depo2ind   将深度-位置结点形式转化成索引结点形式


detcoef   提取一维小波变换高频系数


detcoef2   提取二维小波分解高频系数


disp   显示文本或矩阵


drawtree   画小波包分解树(GUI)


dtree   构造DTREE类


dwt   单尺度一维离散小波变换


dwt2   单尺度二维离散小波变换


dwtmode   离散小波变换拓展模式


*dyaddown   二元取样


*dyadup   二元插值


entrupd   更新小波包的熵值


fbspwavf   B样条小波


gauswavf   Gaussian小波


get   获取对象属性值


idwt   单尺度一维离散小波逆变换


idwt2   单尺度二维离散小波逆变换


ind2depo   将索引结点形式转化成深度—位置结点形式


*intwave   积分小波数


isnode   判断结点是否存在


istnode   判断结点是否是终结点并返回排列值


iswt   一维逆SWT(Stationary Wavelet Transform)变换


iswt2   二维逆SWT变换


leaves     Determine terminal nodes


mexihat   墨西哥帽小波


meyer   Meyer小波


meyeraux   Meyer小波辅助函数


morlet   Morlet小波


nodease   计算上溯结点


nodedesc   计算下溯结点(子结点)


nodejoin   重组结点


nodepar   寻找父结点


nodesplt   分割(分解)结点


noleaves     Determine nonterminal nodes


ntnode     Number of terminal nodes


ntree     Constructor for the class NTREE


*orthfilt   正交小波滤波器组


plot   绘制向量或矩阵的图形


*qmf   镜像二次滤波器


rbiowavf     Reverse biorthogonal spline wavelet filters


read   读取二进制数据


readtree   读取小波包分解树


*scal2frq     Scale to frequency set


shanwavf     Shannon wavelets


swt   一维SWT(Stationary Wavelet Transform)变换


swt2   二维SWT变换


symaux     Symlet wavelet filter computation.


symwavf   Symlets小波滤波器


thselect   信号消噪的阈值选择


thodes     References treedpth   求树的深度


treeord   求树结构的叉数


upcoef   一维小波分解系数的直接重构


upcoef2   二维小波分解系数的直接重构


upwlev   单尺度一维小波分解的重构


upwlev2   单尺度二维小波分解的重构


wavedec   单尺度一维小波分解


wavedec2   多尺度二维小波分解


wavedemo   小波工具箱函数demo


*wavefun   小波函数和尺度函数


*wavefun2   二维小波函数和尺度函数


wavemenu   小波工具箱函数menu图形界面调用函数


*wavemngr   小波管理函数


waverec   多尺度一维小波重构


waverec2   多尺度二维小波重构


wbmpen     Penalized threshold for wavelet 1-D or 2-D de-noising


wcodemat   对矩阵进行量化编码


wdcbm     Thresholds for wavelet 1-D using Birge-Massart strategy


wdcbm2    Thresholds for wavelet 2-D using Birge-Massart strategy


wden   用小波进行一维信号的消噪或压缩


wdencmp    De-noising or compression using wavelets


wentropy   计算小波包的熵


wextend    Extend a vector or a matrix


*wfilters   小波滤波器


wkeep   提取向量或矩阵中的一部分


*wmaxlev   计算小波分解的最大尺度


wnoise   产生含噪声的测试函数数据


wnoisest   估计一维小波的系数的标准偏差


wp2wtree   从小波包树中提取小波树


wpcoef   计算小波包系数


wpcutree   剪切小波包分解树


wpdec   一维小波包的分解


wpdec2   二维小波包的分解


wpdencmp   用小波包进行信号的消噪或压缩


wpfun   小波包函数


wpjoin    重组小波包


wprcoef   小波包分解系数的重构


wprec   一维小波包分解的重构


wprec2   二维小波包分解的重构


wpsplt   分割(分解)小波包


wpthcoef   进行小波包分解系数的阈值处理


wptree     显示小波包树结构


wpviewcf     Plot the colored wavelet packet coefficients.


wrcoef   对一维小波系数进行单支重构


wrcoef2   对二维小波系数进行单支重构


wrev   向量逆序


write   向缓冲区内存写进数据


wtbo     Constructor for the class WTBO


wthcoef   一维信号的小波系数阈值处理


wthcoef2   二维信号的小波系数阈值处理


wthresh   进行软阈值或硬阈值处理


wthrmngr   阈值设置管理


wtreemgr   管理树结构