Is it possible to read in an input image, add an overlay and then output the result so that it is exactly the same size in MATLAB 7.6 (R2008a)?

I was looking through the documentation on how to perform this but was unable to find an example or a straightforward procedure.

Answer 1

[MathWorks Support Team]

A description of how to perform an operation like this does not exist in the documentation. Although it is a common operation, performing it is non-trivial. Here is a method on how to do this using figures and PRINT.

function plotimage ()

      im = imread ('input.jpg'); % read input file

      fig = figure;

      [x y colors]=size(im);   %get position data

      set (gcf, 'PaperUnits', 'normalized');

      set (gcf, 'PaperPosition', [0 0 1 1]);

      set (gcf, 'PaperSize', [1 1]);

      set (gcf, 'PaperPositionMode', 'auto');

      warning ('off', 'Images:initSize:adjustingMag');

       imshow (im, 'Border', 'tight', 'InitialMagnification', 100);

      set (gcf, 'units','pixels');

      set (gcf, 'position', [1 1 y x]);

      hold on;

      plot (100, 100, 'g+');

      print ('-djpeg', 'output.jpg', '-r0');

      close (fig);

end

Below is a much simpler method of performing the same operation using IMWRITE and IMREAD.

function plotimage_imwrite ()

im = imread ('input.jpg');  %read input file

fig = figure;

%Note that IMSHOW is part of IPT.

imshow (im, 'Border', 'tight', 'InitialMagnification', 100);  

hold on;

plot (1:10:100, 1:10:100, 'g+');

F = getframe (gcf); % capture frame

imwrite (F.cdata,'output.jpg','jpg','Quality',100); % write image to file

close (fig);

end