www.pudn.com > EWT.rar > LocalMaxMin.m, change:2015-07-21,size:2113b

```function bound = LocalMaxMin(f,N,fm)

%===================================================================
% function bound = LocalMaxMin(f,N,fm)
%
% This function segments f into a maximum of N supports by detecting
% the lowest local minima between the N largest local maxima. If the
% input fm is provided then the local maxima are computed on f and
% the local minima on fm otherwise both are computed on f (this is
% useful if you want to compute the maxima on a regularized version
% of your signal while detecting the "true" minima).
%
% Note: the detected boundaries are given in term of indices
%
% Inputs:
%   -f: the function to segment
%   -N: maximal number of bands
%
% Optional input:
%   -fm: function on which the local minima will be computed
%
% Outputs:
%   -bound: list of detected boundaries
%
% Author: Jerome Gilles
% Institution: UCLA - Department of Mathematics
% Year: 2013
% Version: 2.0
%===================================================================

locmax=zeros(size(f));

if nargin>2
f2=fm;
else
f2=f;
end

locmin=max(f2)*ones(size(f2));
% We detect the local maxima and minina
for i=2:length(f)-1
if ((f(i-1)<f(i)) && (f(i)>f(i+1)))
locmax(i)=f(i);
end

if ((f2(i-1)>f2(i)) && (f2(i)<f2(i+1)))
locmin(i)=f2(i);
end
end

% We keep the N-th highest maxima and their index
if N~=-1
N=N-1;
[lmax,Imax]=sort(locmax,1,'descend');
if length(lmax)>N
Imax=sort(Imax(1:N));
else
Imax=sort(Imax);
N=length(lmax);
end

% We detect the lowest minima between two consecutive maxima
bound=zeros(1,N);
for i=1:N
if i==1
a=1;
else
a=Imax(i-1);
end
[lmin,ind]=sort(locmin(a:Imax(i)));
tmp=lmin(1);
n=1;
if n<length(lmin)
n=2;
while ((n<=length(lmin)) && (tmp==lmin(n)))
n=n+1;
end
end
bound(i)=a+ind(ceil(n/2))-2;
end
else
k=1;
for i=1:length(locmin)
if locmin(i)<max(f2)
bound(k) = i-1;
k=k+1;
end
end
end
```