Your final project should be roughly the same scope and difficulty as Project 2 (the augmented reality game). Please look over the course syllabus for the next couple of weeks, and skim the textbook and papers from the website to get ideas for what you might want to do.
I will likely approve almost any computer-vision related topic (but I might reserve the right to try to negotiate you down to something more tractable).
Here is a sampling of final project ideas from past years of the E27 course:
Ben Lipton and Phil Koonce implemented a HDR imaging system to capable of re-exposing photos in postprocessing to reveal greater detail and color depth.
Alex Burka and Becca Roelofs created an interactive augmented reality game using the Kinect sensor.
David D'Annunzio and Andreas Bastian implemented a head-tracking display which allows the user to interactively view content from different viewpoints based on their location.
Thomas Drew and Noah Weinthal implemented an interactive gesture-based painting program with the Kinect sensor.
Katherine Bertaugh and David Saltzman implemented structure from motion using an affine (weak) perspective model.