Capture Image Size

Hi 

For a while i have been trying to get the captured camera frame and do some cropping and OCR on it. I managed to build up all the required systems to acieheve that goal. But the problem was , when i cropped the image according to the target image on the camera screen there was a problem with the height, the width was fitting perfectly for the target but the height was always bigger than excepted. 

And finally i found out that the frame that is captured from the camera with he method described  in this link, is capturing bigger area than the camera shows on the app. The width is the same, but the height is bigger. So when i want to do the cropping according to the calculated  target points on the camera, it takes a taller image.

Is there a way to change that captured frame to cath exactly the same frame as its seen on the screen of the app while the camera is open?

Thanks