Brightness on 2016 vision samples

[Greg McKaskle]

There are many ways to set up the camera and get images, but I'll list the elements using the WPILib terminology.

The retroreflective tape is such a strong reflector that you can think of it as an amplifier of the ring light. The material will return either 300 or 600 times as much light as bright white paint. I no longer remember the spec for the material being used. It is so bright that it can overwhelm the camera's sensor and auto settings and you will actually get an image with a white target and an LED colored fringe. This is called sensor bloom. Fancier camera sensors will postpone the blooming, but sufficiently bright light is a challenge.

The good news is that you can use this to your advantage. If you lower the exposure time and/or lower the brightness of the image, the background will darken and the tape will turn from white to the LED color. This also helps with processing performance, by the way, because many of the color conversion and processing algorithms will then be dealing with lots of dark pixels which they can quickly dismiss.

So FIRST did this on purpose. You can too by setting the brightness and/or the exposure settings. You may also want to turn off the auto white balance and choose something that will stay predictable.

Greg McKaskle