source: proiecte/pmake3d/make3d_original/Make3dSingleImageStanford_version0.1/third_party/local_ext_mod/lmin.m @ 37

function [lmval,indd]=lmin(xx,filt)
%LMIN   function [lmval,indd]=lmin(x,filt)
%       Find local minima in vector X, where LMVAL is the output
%       vector with minima values, INDD is the corresponding indeces 
%       FILT is the number of passes of the small running average filter
%       in order to get rid of small peaks.  Default value FILT =0 (no
%       filtering). FILT in the range from 1 to 3 is usially sufficient to 
%       remove most of a small peaks
%       Examples:
%       xx=0:0.01:35; y=sin(xx) + cos(xx ./3); 
%       plot(xx,y); grid; hold on;
%       [a b]=lmin(y,2)
%        plot(xx(a),y(a),'r+')
%       see also LMAX, MAX, MIN
        
%
%**************************************************|
%       Serge Koptenko, Guigne International Ltd., |
%       phone (709)895-3819, fax (709)895-3822     |
%--------------06/03/97----------------------------|

x=xx;
len_x = length(x);
        fltr=[1 1 1]/3;
  if nargin <2, filt=0; 
        else
x1=x(1); x2=x(len_x); 

        for jj=1:filt,
        c=conv(fltr,x);
        x=c(2:len_x+1);
        x(1)=x1;  
        x(len_x)=x2; 
        end
  end

lmval=[];
indd=[];
i=2;            % start at second data point in time series

    while i < len_x-1,
        if x(i) < x(i-1)
           if x(i) < x(i+1)     % definite min
lmval =[lmval x(i)];
indd = [ indd i];

           elseif x(i)==x(i+1)&x(i)==x(i+2)     % 'long' flat spot
%lmval =[lmval x(i)];   %1   comment these two lines for strict case 
%indd = [ indd i];      %2 when only  definite min included
i = i + 2;              % skip 2 points

           elseif x(i)==x(i+1)  % 'short' flat spot
%lmval =[lmval x(i)];   %1   comment these two lines for strict case
%indd = [ indd i];      %2 when only  definite min included
i = i + 1;              % skip one point
           end
        end
        i = i + 1;
    end

if filt>0 & ~isempty(indd),
        if (indd(1)<= 3)|(indd(length(indd))+2>length(xx)), 
           rng=1;       %check if index too close to the edge
        else rng=2;
        end

           for ii=1:length(indd), 
                [val(ii) iind(ii)] = min(xx(indd(ii) -rng:indd(ii) +rng));
                iind(ii)=indd(ii) + iind(ii)  -rng-1;
           end
  indd=iind; lmval=val;
else
end