This (http://www.amazon.com/Introductory-Techniques-3-D-Computer-V...) is the best book on Computer Vision I 've come across. I first encountered it when trawling Stanford courses for good problem sets and research projects. Sebastian Thrun used to teach a class with this book (http://robots.stanford.edu/cs223b04/). It is fairly expensive and fairly mathematical but it is worth every cent you pay for it (imho).

Good Luck !