First, you should find out what's your interest.

Then, you can search in this book: (Richard Szeliski - Computer Vision: Algorithms and Applications). You can see general topics in its contents.

And you can visit (Computer Vision and Image Understanding) that is a journal in Elsevier. There are some parts in this page contain (Most Downloaded Articles, Recent Articles and ...). So it will help you to choose a good area.

There are a lot of journals about computer vision in Elsevier. you can see them, too.

http://www.google.fr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCkQFjAB&url=http%3A%2F%2Fszeliski.org%2FBook%2Fdrafts%2FSzeliskiBook_20100903_draft.pdf&ei=mNrNVInLNobwaM--gOgK&usg=AFQjCNHqTsYAnDVhorFlGhVe5gNq1KxPuw&bvm=bv.85076809,d.d2s

http://www.journals.elsevier.com/computer-vision-and-image-understanding/

I would advise you to think about multispectral imaging. It's really interesting and promising topic

Take a look at gesture recognition, for a undergraduate project a small gesture vocabulary (2-3 gestures will be sufficient)

Take a look at following papers:

Yee Yong Pang, Nor Azman Ismail, and Phuah Leong Siang Gilbert. A real time vision-based hand gesture interaction. In Proceedings of Fourth Asia International Conference on Mathematical/Analytical Modelling and Computer Simulation, pages 237–242, 2010.

Gihan Shin and Junchul Chun. Vision-based multimodal human computer interfacebased on parallel tracking of eye and hand motion. In Proceedings of International Conference on Convergence Information Technology, pages 2443–2448, 2007.