Hi,
I understand that you want to define a dynamic rectangular region of interest and enhance the contrast of the region inside the rectangular area only.
For contrast enhancement, several techniques can be used, as shown here. In the following code, imadjust is used.
I = imread('cameraman.tif');
himg = imshow(I);
roi = drawrectangle('LineWidth',2,'Color','red');
addlistener(roi,'MovingROI',@(src,evt)allevents(I, himg, src, evt));
function allevents(Img, himg, src,evt)
evname = evt.EventName;
switch(evname)
case{'MovingROI'}
rectPos = evt.CurrentPosition();
croppedImage = imcrop(Img, rectPos);
enhancedImage = imadjust(croppedImage);
newImg = Img;
newImg(rectPos(2)+(0:rectPos(4)), rectPos(1)+(0:rectPos(3))) = enhancedImage;
himg.CData = newImg;
end
end
