wavn.m

小波去噪的分解与重构示例

s1=load('open.txt');
plot(s1),title('原始信号'),grid on;
title('原始信号');

%小波分解
[c,l]=wavedec(s1,4,'db4');
[cd1,cd2,cd3,cd4]=detcoef(c,l,[1 2 3 4]);
ca4=appcoef(c,l,'db4',4);
a4=wrcoef('a',c,l,'db4',4);
a3=wrcoef('a',c,l,'db4',3);
a2=wrcoef('a',c,l,'db4',2);
a1=wrcoef('a',c,l,'db4',1);
d4=wrcoef('d',c,l,'db4',4);
d3=wrcoef('d',c,l,'db4',3);
d2=wrcoef('d',c,l,'db4',2);
d1=wrcoef('d',c,l,'db4',1);
%不需要的系数置零
 caa4=zeros(size(ca4));

%消噪后信号重构，并画图
cl=[caa4',cd4',cd3',cd2',cd1'] ;  
s2=waverec(cl,l,'db4');
figure(2);
plot(s2);title('消噪后重构信号');grid on;