test.asv

小波去噪的分解与重构示例

%阀值wthresh，软阀值或者硬阀值
%upcoef重构小波系数
%appcoef多分辩小波分解
%waverec多分辩小波重构
%detcoef小波细节系数
clear;
s=load('open2.txt');
%分解,用db1其它的需要进行信号延拓
[ca1,cd1]=dwt(s,'db1');
[ca2,cd2]=dwt(ca1,'db1');
[ca3,cd3]=dwt(ca2,'db1');

figure;plot(s);
figure;plot(ca1);
figure;plot(ca2);
figure;plot(ca3);
figure;plot(cd1);
figure;plot(cd2);
figure;plot(cd3);
%Sof thresholding,sqtwolog option
cd3=wthresh(cd3,'s',thselect(s,'sqtwolog'));
cd2=wthresh(cd2,'s',thselect(s,'sqtwolog'));
cd1=wthresh(cd1,'s',thselect(s,'sqtwolog'));
%重构
ca2=idwt(ca3,cd3,'db1');
ca1=idwt(ca2,cd2,'db1');
ns=idwt(ca1,cd1,'db1');

% subplot(4,2,1);plot(s);ylabel('原始序列');
% subplot(4,2,2);plot(ca1);ylabel('一层低频信号');
% subplot(4,2,3);plot(ca2);ylabel('二层低频信号');
% subplot(4,2,4);plot(ca3);ylabel('三层低频信号');
% 
% subplot(4,2,5);plot(ns);ylabel('信号重构') 
% subplot(4,2,6);plot(cd1);ylabel('一层高频信号');
% subplot(4,2,7);plot(cd2);ylabel('二层高频信号');
% subplot(4,2,8);plot(cd3);ylabel('三层高频信号');
figure;plot(ns);