用Matlab使用wdencmp进行去燥

clc;
clear;
%加载信号
load leleccum;
%采样点
s=leleccum(300:2000);
%画出原始信号
subplot(2,2,1);plot(s);title('原始信号');grid on;axis tight;
%% 用sym4小波对原始信号进行5层小波分解并提取系数
[c,l]=wavedec(s,5,'sym4');
ca5=appcoef(c,l,'sym4',5);
cd5=detcoef(c,l,5);
cd4=detcoef(c,l,4);
cd3=detcoef(c,l,3);
cd2=detcoef(c,l,2);
cd1=detcoef(c,l,1);
%对信号进行强制性去噪处理：将每层的高频系数置零
cdd5=zeros(1,length(cd5));
cdd4=zeros(1,length(cd4));
cdd3=zeros(1,length(cd3));
cdd2=zeros(1,length(cd2));
cdd1=zeros(1,length(cd1));
c1=[ca5 cdd5 cdd4 cdd3 cdd2 cdd1];
s1=waverec(c1,l,'sym4');
subplot(2,2,2);plot(s1);title('强制去噪后信号');grid on;axis tight;
%% 用默认阈值对信号进行去噪
% 用ddencmp函数获得信号的默认阈值
[THR,SORH,KEEPAPP]=ddencmp('den','wv',s);
s2 =wdencmp('gbl' ,s,'sym4',5,THR,SORH,KEEPAPP);
subplot(2,2,3);plot(s2);title('ddencmp/wdencmp默认阈值去噪后信号');grid on;axis tight;
%% 用多层软阈值去噪，利用wthresh函数产生阈值
thr=thselect(s,'rigrsure');
softd5=wthresh(cd5,'s',thr);
softd4=wthresh(cd4,'s',thr);
softd3=wthresh(cd3,'s',thr);
softd2=wthresh(cd2,'s',thr);
softd1=wthresh(cd1,'s',thr);
c2=[ca5 softd5 softd4 softd3 softd2 softd1];
s3=waverec(c2,l,'sym4');
subplot(2,2,4);plot(s3);title('多层软阈值去噪后信号');grid on;axis tight;