It is definitely a cool project! But I agree with others that it would be more useful on a computer, which has the added benefit of being able to use a better (or at least more suitable) camera. What could be really cool is getting this sort of overlay in a microscope view, with the system keeping track of where the microscope FOV is on the PCB. I guess that would need a second larger FOV camera to track the board, but it could be very helpful when working at higher magnifications on a relatively dense board, where it can be hard to keep your bearings.