exam10_16.m

《小波分析理论与Matlab7实现例程》一书里面各章节的源码

clc;
clear;
load noisbloc
s= noisbloc;
ls=length(s);
plot(s);
[swa,swd] = swt(s,1,'db4');
subplot(2,1,1);plot(swa);title('低频系数')
subplot(2,1,2);plot(swd);title('高频系数')
A0 = iswt(swa,swd,'db4');
err=norm(s-A0)
figure(2)
subplot(3,1,1);plot(s);title('原始信号')
subplot(3,1,2);plot(A0);title('重构信号')
subplot(3,1,3);plot(s-A0);title('误差信号')

nulcfs = zeros(size(swa));
A1 = iswt(swa,nulcfs,'db4');
D1 = iswt(nulcfs,swd,'db4');
figure(3)
subplot(2,1,1), plot(A1); 
title('重构低频A1');
subplot(2,1,2), plot(D1); 
title('重构高频D1');

[swa,swd] = swt(s,3,'db4');
kp = 0;
for i = 1:3
subplot(3,2,kp+1), plot(swa(i,:));
title(['低频系数：level ',num2str(i)])
subplot(3,2,kp+2), plot(swd(i,:));
title(['高频系数：level ',num2str(i)])
kp = kp + 2;
end

mzero = zeros(size(swd));
A = mzero;
A(3,:) = iswt(swa,mzero,'db4');
D = mzero;
for i = 1:3
swcfs = mzero;
swcfs(i,:) = swd(i,:);
D(i,:) = iswt(mzero,swcfs,'db4');
end
A(2,:) = A(3,:) + D(3,:);
A(1,:) = A(2,:) + D(2,:);
kp = 0;
figure(4)
for i = 1:3
subplot(3,2,kp+1), plot(A(i,:));
title(['低频信号：level ',num2str(i)])
subplot(3,2,kp+2), plot(D(i,:));
title(['低频信号：level ',num2str(i)])
kp = kp + 2;
end