Draw multiple regions on an image- imfreehand

Question

I\'d like to manually draw multiple regions on an image to create a binary mask of the drawn regions (ground truth).

I attached the code to do it using imfreehand th

Answer 1

You can loop until you get an empty mask - this will indicate that the user finished drawing all masks.
Let sz be the desired size of the output mask, then

totMask = false( sz ); % accumulate all single object masks to this one
h = imfreehand( gca ); setColor(h,'red');
position = wait( h );
BW = createMask( h );
while sum(BW(:)) > 10 % less than 10 pixels is considered empty mask
      totMask = totMask | BW; % add mask to global mask
      % you might want to consider removing the old imfreehand object:
      delete( h ); % try the effect of this line if it helps you or not.

      % ask user for another mask
      h = imfreehand( gca ); setColor(h,'red');
      position = wait( h );
      BW = createMask( h );
end
% show the resulting mask
figure; imshow( totMask ); title('multi-object mask');