Getting stuck into an open source image processing/computer vision project
I believe it would if you intend to practice your knowledge, rather than go into academia.

I suggest you look into the code base of opencv, simplecv, and scikit-image, as suggested. Once you become comfortable with using them, you can submit patches for bugs and new algorithms.

Nevertheless, you will also need to understand what you are doing at a theoretical level, so get some books too. There are also courses online, such as this and that.

Good luck!