[Greg McKaskle]

That calibration process sounds like it works, but you may want to check the setting on the camera. If you choose a fixed white balance, you should see the hue change less. The light returned to the camera should largely be due to the LED ring, and they should be pretty stable. But auto-adapting white balance code running on the code is constantly trying to identify and adjust for lighting that it not quite white. For image processing, consistent is better than pretty, so set it to something like Fixed Fluorescent one. You may also want to do this to exposure so that saturation doesn't change so wildly.

Greg McKaskle