How-tos.md

@@ -292,7 +292,8 @@ dataROI    = imfill(dataMargin,'holes');      % fill space within hexagon with '
 mask       = dataROI(1:2:end,1:2:end);        % downscale image/matrix size to 512 x 640        
 
 %%% Visualize scaled tracking mask (512 x 640) used as tracking mask:
-figure; spy(mask);                      % save 'mask' logical as 'maskHexagon' 
+figure; spy(mask);                      % visualize created mask              
+% finally save 'mask' logical as 'maskHexagon' 
 ```
 
 **Image thresholding**