We run our vision code on a Raspberry Pi 2, which is an ARM v7 processor with a 40-pin GPIO header, an ethernet port, and four USB ports.
We use mjpg_streamer to stream from one of two LifeCam-3000 USB cameras, each ringed with green LEDs. We use GRIP to autonomously process the images from these cameras and output the contours of retroreflective tape to the networktables.