My team hasn't had experience with the ODROID but we have used an
Intel NUC (Next Unit of Computing). It offered us a huge boost in image processing and allowed us to do a lot with our OpenCV application. The NUC is rated at 1.70 GHz so its slower than an overclocked ODROID. I think that should be plenty fine for what you want to do with your image processing. The downside to the NUC is that it becomes a really expensive part of the control system so if you're tight on money, it certainly isn't a good choice.
Since you wrote your program in standard C++, the only part you will need to change is the threading/socket model.
Alex Brinister