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-   -   Blue or Red colored LEDs causing problems? (http://www.chiefdelphi.com/forums/showthread.php?t=104476)

mega900997 11-03-2012 19:16

Blue or Red colored LEDs causing problems?
 
Hello. I was wondering since we are using a red LED, will it affect our vision tracking on the field since parts of the field are red. And if it does, what do you propose on how to fix it?

fb39ca4 11-03-2012 19:52

Re: Blue or Red colored LEDs causing problems?
 
Use a green LED?

mega900997 11-03-2012 20:01

Re: Blue or Red colored LEDs causing problems?
 
Lol, I wanted to know if there was any problem with tracking. I wanted to know if we had to switch out our LED or leave it.

om23 11-03-2012 20:51

Re: Blue or Red colored LEDs causing problems?
 
yeah my team's using green LEDs for camera tracking.
you can also change the contrast

Al Skierkiewicz 11-03-2012 21:12

Re: Blue or Red colored LEDs causing problems?
 
Quote:

Originally Posted by mega900997 (Post 1142357)
Hello. I was wondering since we are using a red LED, will it affect our vision tracking on the field since parts of the field are red. And if it does, what do you propose on how to fix it?

Tejas,
The red parts of the field are on the floor or a few inches above it. Compared with the height of the retro rectangles, a little judicial aiming of the camera high will eliminate that.

mega900997 11-03-2012 22:29

Re: Blue or Red colored LEDs causing problems?
 
True, true. Just wanted to make sure so that we wouldn't have any problems on the field with vision. Thanks guys and Good Luck at your Regionals :D

R1ffSurf3r 11-03-2012 22:44

Re: Blue or Red colored LEDs causing problems?
 
with a blue light we didnt notice much interference with the field elements. however, our turret was really itching to target a glowing advertisement instead

billbo911 12-03-2012 01:51

Re: Blue or Red colored LEDs causing problems?
 
If you used the Rectangular Target Tracking example for the basis of your tracking code, then you shouldn't have too much to worry about. Part of the code allows you to decide how close a target must be to rectangular before it is accepted as a target. Careful calibration should filter out just about everything except the targets above the hoops.

blackflame2996 12-03-2012 23:55

Re: Blue or Red colored LEDs causing problems?
 
We use red LED's, but because of the nature of the retro-reflective tape and that of the Axis cameras, the rectangle returns as pure white. to process this, we use a gray scale image and identify the rectangle by the intensity of the light. This is an effective and efficient means of target identification.

aldenm 13-03-2012 00:23

Re: Blue or Red colored LEDs causing problems?
 
I think that your problem may have to do with field lighting interference. My team has had problems with lighting interference from the field lights. We are using green LEDs. Some people posted on my thread and recommended infrared LEDs, since the field lighting probably won't interfere with the IR light.

Al Skierkiewicz 13-03-2012 08:28

Re: Blue or Red colored LEDs causing problems?
 
You guys know that due to the nature of the retro reflective tape, only light coming from your robot or directly in front of or behind your robot or the target is actually reflected back to your camera? The reason green LEDs work so well is human vision is more sensitive in the green spectrum so the camera is more sensitive in that area to mimick human vision.
If you are receiving a white image of the target, it is possible you are receiving so much light from the tape that the camera is actually white clipping the video. White clip prevents output video from exceeding a certain value and so additional light causes all three colors to "clip" off the top and return a monochrome signal above that level. The result is a zero chroma signal during that interval.


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