OpenCV, the open-source computer vision library originally sponsored by Intel and now by Willow Garage, has been adding functionality at an amazing pace for the past 18 months or so. Much of the new functionality plugs holes that are particularly interesting for robotics, e.g. the new stereo pipeline, or adressing developer usabillity (e.g. the C++ and Python APIs). When you follow OpenCV's twitter account, you can also see that they have been paying a lot of attention to testing and other engineering improvements.

A couple of people here in the applied informatics group already use the new version and I can only recommend it all other interested people, students or researchers alike. To see what is there, check out the much improved documentation for OpenCV w/ C++, OpenCV w/ C and OpenCV w/ Python. Also, if you want to get a glimpse of what the OpenCV guys are up to in the future, check out their meeting notes and the OpenCV Monthly is a great way to stay informed about what has actually been done.