I wasn't the lead on our RPi Vision project, I'll have him come in and help you when he gets back from his vacation, but I recommend you look at our GitHub as a place to start. We implemented a vision system on our RPi 2 with a PiCam using Network Tables for variable communication to the RoboRIO.
https://github.com/GarnetSquadron4901
https://github.com/GarnetSquadron490...ion-processing