util_img2mat.m

Standard model object recognition matlab code

function util_img2mat (img_dir, target_dir, varargin)

% FUNCTION util_img2mat (img_dir, target_dir, varargin)
%
% Convert (and resize) the images into mat files, with the naming
% convention of 'r_i00x.mat', so that main_model program can
% process them.  The extra arguements are:
%   varargin{1} = stimulus size (eg. [256 128])
%                 default: the first image size.
%   varargin{2} = image format (eg. 'pgm')
%                 default: 'pgm'.
% For example, running
%   util_img2mat('Raw','Test',[256 256],'jpg');
% will take all jpg images in Raw/*.jpg, and resize them in
% 256x256, and save in Test/r_i00x.mat formats. 
% If the images need to be normalized (mean subtraction, etc),
% uncomment the commands within the code.
%
% 05/25/06: Created.
% 07/17/06: Added normalization part (commented).

if ~exist(img_dir,'dir')
  error (['No image directory named: ' img_dir]);
else
  % Get extra arguements: image format and image size.
  if length (varargin) > 1
    img_format = varargin{2};
  else 
    img_format = 'pgm';
  end

  D = dir([img_dir '/*' img_format]);

  if length (varargin) > 0
    stim_size = varargin{1};
  else
    stim_size = size(imread([img_dir '/' D(1).name]));
  end

  % is everything okay with the target directory?
  if ~exist(target_dir, 'dir')
    mkdir(target_dir);
  elseif length(dir([target_dir '/*.mat'])) > 0
    error('Target directory not empty');
  end


  fid = fopen([target_dir '/file_list.txt'], 'w');
  for i = 1:length(D)
    stim_fn  = [img_dir '/' D(i).name];
    disp(stim_fn);  
    % We write file_list.txt in the target directory.
    fprintf(fid, '%s\n', stim_fn);
    
    stim_img = imread(stim_fn);
    stim_img = double(stim_img)/255;
    stim_img = imresize(stim_img, stim_size);

    % Make the stimulus mean-zero and [0 1].
    %stim_img = (stim_img-mean(mean(stim_img)));
    %max_val  = max(max(stim_img));
    %min_val  = min(min(stim_img));
    %stim_img = (stim_img-min_val)/(max_val-min_val);

    r        = stim_img;

    % build file name
    max_num_zero   = length(num2str(length(D)));
    save_file_name = repmat('0', [1 max_num_zero-length(num2str(i))]);
    save_file_name = ['r_i' save_file_name num2str(i)];
    save_file_name = [target_dir '/' save_file_name];
    save(save_file_name, 'r');
  end
  %save ([target_dir '/stim_size.mat'], 'stim_size');
  fclose(fid);
end

% Now examine all the files.
%util_view_img_files(target_dir);