Hey there!
OpenCV is a better and more stable option. Since it's already late in build season, you may not have time to write new code. You should be able to directly port your GRIP code into OpenCV. It will take some time to port but is definitely doable since OpenCV is the backbones for GRIP. Now if you want some code to sample or look at. I would recommend taking a look at Fauge7's TowerTracker. Our team has been able to run it on a Pi. It is Java though and so you have to install the JDK and make it your default JDK in order to install the library properly. Or you can check out Team 2053's TowerTracker C++ port, which is a direct port of Fauge7's code but instead in the faster and more documented, C++.
If you need any help, feel free to PM
