f12_3.m

来自「《Matlab时频分析技术及其应用》电子书。」· M 代码 · 共 32 行

%读信号
load noisbloc
x = noisbloc;
%3层小波包分解
t = wpdec(x,3,'sym4');
%%显示树结构
plot(t);

%设置全局阈值.
t1 = t;
sorh = 'h';
thr = wthrmngr('wp1ddenoGBL','penalhi',t);
cfs = read(t,'data');
cfs = wthresh(cfs,sorh,thr);
t1  = write(t1,'data',cfs);
plot(t1)

%对每个节点分别设置阈值. 
t2 = t;
sorh = 's';
thr(1) = wthrmngr('wp1ddenoGBL','penalhi',t);
thr(2) = wthrmngr('wp1ddenoGBL','sqtwologswn',t);
tn  = leaves(t);
for k=1:length(tn)
  node = tn(k);
  cfs = read(t,'data',node);
  numthr = rem(node,2)+1;
  cfs = wthresh(cfs,sorh,thr(numthr));
  t2 = write(t2,'data',node,cfs);
end
plot(t2)