Web Cam in MATLAB

Refer to this web page:
http://madan.wordpress.com/2007/03/23/image-capture-using-webcam-in-matlab/ . This web showing how we can use our web cam or any camera installed in our PC to work in MATLAB. I have tried this and found out the frame captured is not sharp enough when it is being display as an image. Need further understanding...

Besides the link given above, in order to know the basic in image processing, MATLAB help as per link http://www.mathworks.com/access/helpdesk/help/toolbox/images/ is also useful as a start.