[badpun]

3d computer vision is very cool. You basically take a bunch of pictures of a scene, or a video shot by camera, and do a 3d reconstruction of such scene. The math behind it is tricky. If you manage to code even the basic reconstruction algorithm, you'll grow immensely in math, and math-related coding along the way (assuming no previous background). On the other hand, the job market for such skills is very limited. This is not a good career track, unless one is willing to relocate to Silicon Valley.