Extracting the screen of a calculator from an image

Hi,

I have the following images:

http://i46.tinypic.com/28cd4dl.jpg

http://i40.tinypic.com/6qad7q.png

Now I am trying to do a program to extract the calculator screen only from the whole image. The above two are just sample images. I thought of using bwboundaries() function but can't implement it. Can anybody help with a generalized algorithm???

[Image Analyst]

For bwboundaries() you need a binary image, so first you'd have to have already segmented out the display. I thought you solved this a month ago when you were posting on it. No? Are you starting all over, from scratch?

[Soumyadip]

Actually I had exams, so could not devote much time to this. Yeah, I converted the image to binary but how to segment the display? That's the whole objective of this question. The B matrix in B = bwboundaries(BW) returns the row and column coordinates of all the boundary pixels. How to understand which one means the screen boundaries? It would also help if you suggest any other method to extract the screen..

Thanks in advance