function Z=wavelet2(x)
debug=0;
x=x(1:60000);
t=1:60000;
n=1:60000;
fs=1000;
show=0;
N=length(x);
if debug
figure(1);
plot(t,x);
grid;
xlabel('时间(ms)','fontsize',8);
ylabel('幅值��v)','fontsize',8);
title('原始信号','fontsize',8);
end
%低通去除基线漂移
k = .7;
% cut-off value
fc=0.8/fs;
alpha = (1-k*cos(2*pi*fc)-sqrt(2*k*(1-cos(2*pi*fc))-k^2*sin(2*pi*fc)^2))/(1-k);
y = zeros(size(x));
for i = 1:size(x,1) %可以去掉
y(i,:) = filtfilt(1-alpha,[1 -alpha],x(i,:));
end
x1=x-y;
%figure(2)
%plot(x1);
%grid;
%xlabel('时间/ms');
%ylabel('幅值/mv');
%title('去除基线漂移后的信号');
%axis tight;
%figure(3)
%plot(x1-x);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%小波去噪%%%%%%%%%%%%%%%%%%%%
%小波分解%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
[c,l]=wavedec(x1,5,'db5');
%小波分解
if(show)
%a6=wrcoef('a',c,l,'db6',6);
a5=wrcoef('a',c,l,'db5',5);
%a4=wrcoef('a',c,l,'db6',5);
%d6=wrcoef('d',c,l,'db6',6);
d5=wrcoef('d',c,l,'db5',5);
d4=wrcoef('d',c,l,'db5',4);
d3=wrcoef('d',c,l,'db5',3);
d2=wrcoef('d',c,l,'db5',2);
d1=wrcoef('d',c,l,'db5',1);
%显示各层信号
figure(4)
subplot(3,2,1)
plot((1:N)/fs,a5,'LineWidth',1);
%plot((1:N)/fs,a6,'LineWidth',1);
grid;
ylabel('a5');
%ylabel('a6');
subplot(3,2,2);
plot((1:N)/fs,d5,'LineWidth',1);
grid;
ylabel('d5');
%plot((1:N)/fs,d6,'LineWidth',1);
%grid;
%ylabel('d6');
subplot(3,2,3);
%plot((1:N)/fs,d5,'LineWidth',1);
%grid; ylabel('d5');
%xlabel('时间 t/s');
%subplot(3,2,4);
plot((1:N)/fs,d4,'LineWidth',1);
grid; ylabel('d4');
xlabel('时间 t/s');
subplot(3,2,4);
plot((1:N)/fs,d3,'LineWidth',1);
grid; ylabel('d3');
subplot(3,2,5);
plot((1:N)/fs,d2,'LineWidth',1);
grid; ylabel('d2');
subplot(3,2,6);
plot((1:N)/fs,d1,'LineWidth',1);
grid; ylabel('d1');
xlabel('时间/s');
grid;
%信号重构
figure(5)
y=a5+d5;
%y=a6+d6;
plot((1:N)/fs,y,'LineWidth',1);
grid; xlabel('时间 t/s');
ylabel('电压 A/uV');
title('降噪后的信号');
diffence=x-y;
%重构误差
figure(6);
plot(diffence);
grid;
title('小波重构误差');
%%%%%%%%%%%%%%%%%%%多尺度分解提取低频和高频系数%%%%%%%%%%%%%%%%%%%%%%%
%提取高频系数
ca1=appcoef(c,l,'db5',1);
ca2=appcoef(c,l,'db5',2);
ca3=appcoef(c,l,'db5',3);
ca4=appcoef(c,l,'db5',4);
ca5=appcoef(c,l,'db5',5);
%ca6=appcoef(c,l,'db6',6);
figure(7); title('低频系数');
subplot(5,1,1);
plot(ca1);
grid;
title('尺度1的低频系数');
subplot(5,1,2);
plot(ca2);
grid;
title('尺度2的低频系数');
subplot(5,1,3);
plot(ca3);
grid;
title('尺度3的低频系数');
subplot(5,1,4);
plot(ca4);
grid;
title('尺度4的低频系数');
subplot(5,1,5);
plot(ca5);
grid;
title('尺度5的低频系数');
%subplot(6,1,6);
%plot(ca6);
%grid;
%title('尺度6的低频系数');
%提取高频系数
cd1=detcoef(c,l,1);
cd2=detcoef(c,l,2);
cd3=detcoef(c,l,3);
cd4=detcoef(c,l,4);
cd5=detcoef(c,l,5);
%cd6=detcoef(c,l,6);
figure(8);
title('高频系数');
subplot(5,1,1);
plot(cd1);
grid;
title('尺度1的高频系数');
subplot(5,1,2);
plot(cd2);
grid;
title('尺度2的高频系数');
subplot(5,1,3);
plot(cd3);
grid;
title('尺度3的高频系数');
subplot(5,1,4);
plot(cd4);
grid;
title('尺度4的高频系数');
subplot(5,1,5);
plot(cd5);
grid;
title('尺度5的高频系数');
%subplot(6,1,6);
%plot(cd6);
%grid;
%title('尺度6的高频系数');
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%小波压缩%%%%%%%%%%%%%%%%%%%%%%%%%
alpha=1.5;
sorh='h';
[thr,nkeep]=wdcbm(c,l,alpha);
[xc,cxc,lxc,perf0,perfl2]=wdencmp('lvd',c,l,'db5',5,thr,sorh);
%figure(9);
%subplot(2,1,1);
%plot(x);
%grid;
%title('原始信号')
%subplot(2,1,2);
% plot(xc);
%grid;
%title('压缩后信号');
%figure(10);
%plot(xc-x1);
%figure(11);
%plot(xc,'r');hold on,plot(x1);
%figure(12);
% plot(xc,'r');
Z=xc;