A few years ago, when Patrick was a student on FRC11, and doing hard core collection of frames from
Video4Linux directly into his own Java code on my Dell Mini 9's with Microsoft USB cameras we discovered an annoying issue that basically abstracts away your ability to control the exposure (auto white balance) via the exposed registers on Linux (Ubuntu 9 Karmic at the time) with the Microsoft USB cameras we had and the newer models are not much different. Keeping in mind you have Linux on the RoboRIO but it is not Ubuntu.
We contacted the package maintainer who was part of the V4L project, which OpenCV draws from and GRIP depends on, but between us we weren't able to expose whatever
Microsoft had done with the
OmniVision CMOS sensor in the core of their camera. I've been a long time user of OmniVision products which are at the core of some of the best webcams (more than 10 years) and it's clearly something particular with the way this was used or the sensor was configured. I tried to pull in some friends from Microsoft but was not successful. A little transparency would have long ago solved this issue.
We were able get this to work from V4L directly into Java and OpenCV with Logitech cameras. Logitech has been pretty forthcoming with the Linux community for a long time (considering how many Logitech 3 button mice I used to buy for X-terminals where the middle button was a tricky matter).
This issue, by the way, is the reason I provided FRC11 the Logitech C920 USB cameras and why I recommended to several people on ChiefDelphi the Logitech cameras.
Take those same Microsoft branded cameras and put them on a Windows laptop and you'll see the issue is much less a problem. The Windows drivers do something to the camera configuration that expands the response. I did consider, at one time, reversing the camera communications with my logic analyzer but, to be honest, the camera is too cheap to waste that kind of energy.
Normally I don't expose this kind of interaction but this topic has been respectful so please continue to be polite so I don't regret pointing out the likely problem.