paper: Team 341 Vision System Code

[Jared Russell]

http://www.chiefdelphi.com/forums/sh...82&postcount=5

I posted some detailed explanation about the "magic numbers" in our code in the post above.

[fovea1959]

What is best practice for setting the Camera up? Do it in the Dashboard code, or do it in the robot code?

Originally Posted by Jared341

Changing the default camera settings is the most important thing you can do in order to obtain reliable tracking and stay underneath the bandwidth cap.

In particular, there are six settings to pay attention to:

1) Resolution. The smaller you go, the less bandwidth you use but the fewer pixels you will have on the target. If you make all of the other changes here, you should be able to stay at 640x480.

2) Frames per second. "Unlimited" results in a 25 to 30 fps rate under ideal circumstances. Depending on how you use the camera in a control loop, this may be overkill. Experiment with different caps.

3) White balance. You do NOT want automatic white balance enabled! Failing to do so makes your code more susceptible to being thrown off by background lighting in the arena. All of our Axis cameras have a white balance "hold" setting - use it.

4) Exposure time/priority. You want a very dark image, except for the illuminated regions of the reflective tape. Set the exposure time to something very short. Put the camera in a bright scene (e.g. hold up a white frisbee a foot or two in front of the lens) and then do a "hold" on exposure priority. Experiment with different settings. You want virtually all black except for a very bright reflection off of the tape. This is for two purposes: 1) it makes vision processing much easier (fewer false detections), 2) it conserves bandwidth, since dark areas of the image are very compact after JPEG compression. The camera doesn't know what you are looking for, so it will try to send you the entire scene as well as it can. But if it can't see the "background" very well, you are "tricking" the camera into only giving you the part you need!

5) Compression. As the WPI whitepaper says, this makes a huge difference in bandwidth. Use a minimum of 30, but you may be able to get away with more (we are using 50 this year). Experiment with it.

6) Brightness. You can do a lot of fine tuning of the darkness of the image with the brightness slider.

[Jared Russell]

Originally Posted by fovea1959

What is best practice for setting the Camera up? Do it in the Dashboard code, or do it in the robot code?

Neither.

With a laptop (such as the driver station) that is on the same network as the camera, open a web browser and navigate to the camera's IP address (which is set using the Axis Camera utility). From this web interface, you can tinker with all of the settings I mentioned and more, then save them so they are permanent (well, unless you press the reset switch on the camera).