Re: LED Ring Colour
 

Blue worked very well for us last year, as did green. We preferred to aim manually though i.e. use the camera as a viewfinder. In LabView we put crosshairs over the camera feed which was incredible helpful

The green ring light is working great for us!!!!'

Re: LED Ring Colour
 

We used a custom created ring of blue LEDs (on a custom PCB) in 2011. It worked great.

We used green last year, two sets of rings, sort of in a Venn-Diagram fashion, with the lens of the camera in the middle, which helped to get the light as close as possible to the lens. It worked well too, but we ran into a lot of problems with it at our second regional (North Carolina) due to all the sunlight shining directly in to the camera.

YMMV.

Re: LED Ring Colour
 

Consider that vision processing is not just about color. In a number of Michigan districts, bright LCD signs were almost directly behind the goals cycling through different colors and shapes, and it confounded all except the best vision systems. Several Michigan teams who were deadly at districts struggled at Worlds because of the LCD signs around the arena.

Remember that geomtry is equally if not more important. Length, width, aspect ratios, min and max sizes, and angles between the centroids of the objects you detect will all help you throw out bad targets and keep the good ones.

Re: LED Ring Colour
 

I came here to say the same thing.

This was a problem for a lot of teams at champs. The sponsor boards around the arena would cause trouble when they were the color of team's tracking lights.

I'm thinking white (or at least high intensity white) could fix that issue. Hard to say without prototyping, though!

Re: LED Ring Colour
 

we used two green led rings in 2012. green seems to be a good idea because there are not many neon green colored objects on the field. :]

Re: LED Ring Colour
 

To add to the discussion, please note that video is made up of about 60% green light, with blue being the least amount, about 11%. The sensitivity of the human eye is centered on green so video pickups mimic the human eye. Green would then give you the greatest sensitivity at the video pickup. That is why most chroma keys work best with green. (hence the name 'green screen')