function [x, y, v] = peak(inp,threshold,blocksize,max_peaks)
% PEAK
%    count peaks in an image
%
%    [x, y, v] = peak(inp, threshold, blocksize,max_peaks)
% INPUTS:
%    inp        input image
%    threshold  threshold value for peaks
%    blocksize  square region of width 2*blocksize+1 around peak
%    max_peaks  maximum number of peaks to seek
% OUTPUTS:
%    x     row index of peak
%    y     col index of peak
%    v     value at peak

%	Written by: John Loomis

s = size(inp);

if nargin<4
   max_peaks = 20;
end
if nargin<3
   blocksize = 5;
end
if nargin<2
   threshold = 0.05;
end

np = 0;
fprintf('image size: %d x %d\n',s(1),s(2));
fprintf('block size: %d\n', blocksize);
fprintf('threshold: %g\n',threshold);
fprintf('max # peaks: %d\n',max_peaks);


while np < max_peaks

    [col_val, row_idx] = max(inp);
    [val, col] = max(col_val);
    row = row_idx(col);
    if val<threshold
        break;
    end

    % erase region of peak
    ra = max(row-blocksize,1);
    rb = min(row+blocksize,s(1));
    ca = max(col-blocksize,1);
    cb = min(col+blocksize,s(2));

    inp(ra:rb,ca:cb) = 0;

    % save results
    np = np + 1;
    x(np) = row;
    y(np) = col;
    v(np) = val;


    if (np==1)
        fprintf('%4s\t%8s\t%4s\t%4s\n','peak','value','row','col');
    end
    fprintf('%4d\t%8.6f\t%4d\t%4d\n',np,val,row,col);
end

if (np==0)
   disp('no peaks found exceeding threshold')
end

Published with MATLAB® 7.6