I am the programmer for team 4983, and I have been working on getting vision processing to work for our team since last year. I seem to be having trouble just getting the GRIP software to pick up the reflection from our LED ring light.
Included in the kickoff release of WPILib are some photos we took with a USB camera and LED ring. Also in the ZIP file is an example GRIP pipeline. I would compare the images you see and your pipeline to the sample images and pipeline.
I think something that will make the vision problem more manageable is to turn down the exposure setting on the camera. Your original image should look more like the samples - where the only thing that is not black is the retro reflective tape and maybe some direct light sources.