sample_images_all.m

function images = sample_images_all(dataname)

switch lower(dataname),
case 'olshausen',
    fpath = '../natural_imgs';
    flist = dir(sprintf('%s/*.tif', fpath));
end

images = [];
% for imidx = 1:min(length(flist), 100)
%     fprintf('[%d]', imidx);
%     fname = sprintf('%s/%s', fpath, flist(imidx).name);
%     im = imread(fname);
% 
%      if size(im,3)>1
%          im2 = double(rgb2gray(im));
%      else
%         im2 = double(im);
%      end
%     
%     
%     [r,c] = size(im2);  %# Get the image dimensions
% if c > r                   %# Pad rows
%   im2 = imcrop(im2,[(c-r)/2 0 r-1 r]);
% elseif r > c               %# Pad columns
%   im2 = imcrop(im2,[0 (r-c)/2 c c-1]);
% end
% 
% im2=imresize(im2,[512 512],'bicubic');
% 
% %     ratio = min([512/size(im,1), 512/size(im,2), 1]);
% %     if ratio<1
% %         im2 = imresize(im2, [round(ratio*size(im,1)), round(ratio*size(im,2))], 'bicubic');
% %     end
% 
%     im2 = tirbm_whiten_olshausen2(im2);
%     % im2 = tirbm_whiten_olshausen1_contrastnorm(im2, 32, true, 0.6);
%     % im2 = preprocess_image(im2, 'whiten'); % whiten the image before resizing
%     im2 = im2-mean(mean(im2));
%     im2 = im2/sqrt(mean(mean(im2.^2)));
%     imdata = im2;
%     imdata = sqrt(0.1)*imdata; % just for some trick??
%     images{length(images)+1} = imdata;
% 
%     if 0
%         imagesc(imdata), axis off equal, colormap gray
%     end
% end
for imidx = 1:min(length(flist), 200)
    fprintf('[%d]', imidx);
    fname = sprintf('%s/%s', fpath, flist(imidx).name);
    im = imread(fname);

    if size(im,3)>1
        im2 = double(rgb2gray(im));
    else
        im2 = double(im);
    end
    ratio = min([512/size(im,1), 512/size(im,2), 1]);
    if ratio<1
        im2 = imresize(im2, [round(ratio*size(im,1)), round(ratio*size(im,2))], 'bicubic');
    end

    im2 = tirbm_whiten_olshausen2(im2);
    % im2 = tirbm_whiten_olshausen1_contrastnorm(im2, 32, true, 0.6);
    % im2 = preprocess_image(im2, 'whiten'); % whiten the image before resizing
    im2 = im2-mean(mean(im2));
    im2 = im2/sqrt(mean(mean(im2.^2)));
    imdata = im2;
    imdata = sqrt(0.1)*imdata; % just for some trick??
    images{length(images)+1} = imdata;

    if 0
        imagesc(imdata), axis off equal, colormap gray
    end
end
fprintf('\n');


end