function myimstat(filename)
%MYIMSTAT  Basic image statistics.
%
%MYIMSTAT(FILENAME) computes basic image statistics (minimum, maximum,
%mean, standard deviation) and stores the results in a matfile.
%
% Thorsten Hansen 2008-04-18

% extract name w/o extension  
[pathstr name ext versn] = fileparts(filename);
matfilename = [name '-mystat.mat'];

% load matfile if it exists, else compute statistics and store in matfile
if exist(matfilename)
  disp(['Load data from file ''' matfilename '''.'])
  load(matfilename)
else
  if exist(filename)
    I = imread(filename);
    I = im2double(I);
    Iv = I(:); % flatten to compute global min, max etc.
    
    min_I  = min(Iv);
    max_I  = max(Iv);
    mean_I = mean(Iv);
    std_I = std(Iv);
    
    save(matfilename, 'min_I', 'max_I', 'mean_I',  'std_I')
    disp(['Data written to ''' matfilename '''.'])
  else
    error(['Filename ''' filename ''' does not exist.'])
  end
end

% display results
disp(['Mean: ' num2str(mean_I) '+/-' num2str(std_I) '; ' ...
      'min: ' num2str(min_I) ', max: ' num2str(max_I)])