Ring light not bright enough in camera feed

Hey all-
Last week we bought a red 60mm ring light from superbrightleds.com. We wired it up, and before we mounted it to the robot we looked through the center hole and found that the targets were lighting up a bright blood red. Yet when we mounted it around the camera (the lens is looking through the center of the ring, just as our eyes were) and we look at the camera feed, the targets are only barley tinted red.

Has anyone else had this problem with any other colors? Is there a fix? Im thinking about buying a second (Green? Blue?) light for lenape this weekend. Quick replies would be awesome. Thanks!

EDIT: 12v directly out of the PD board

I haven’t seen anybody use red lights. Possibly for that reason.most teams use green. We are using blue LED’s. And they are perfect. But they are the LED strips from super brought LEDs. I would go with green our blue.

Our team chose to use IR LEDs and put a filter over the camera lens to only allow IR light… it seems to work quite well…
You might try this… it isn’t too difficult… you just need an IR source.
We use an IR source meant to be used with a security system…and the filter is a camera filter…taped over the camera lens…

it seems to work quite well… the reflective tape really pops out…

If you play with the settings of the camera (especially lowering the exposure) you can probably get the image to stand out much more. However, as stated before, I believe that on superbrightleds.com it stated that the green rings had the greatest luminosity.

What we use is three Green Rings of 3 different sizes in a ring around our camera. But then we set adjust the exposure and WAY over expose our camera image. ALL we get is super green tape rectangles.


How do you lower the camera exposure? Is it in the vision processing vi? camera settings in the browser?
Were using labview, I noticed (I have the classmate here) that our hue wheel is pointing at green. Does this effect the non processed image? If I set it to red would it appear brighter/better?

EDIT: Found it, but I’m not quite sure what it should be set to

While the human eye can see red OK (remember the old submarine movies switching to red light before surfacing) the camera is a little different. The camera has a greater sensitivity to green since the human eye has the greatest in that spectrum as well. There is a paper from Axis that describes how color cameras generally have twice as many green sensors as either blue or red.

At the Sacramento regional, there were several teams successfully using red lights.
Have you had an opportunity to set the camera’s White Balance for the lighting environment you are in? If left to auto, the camera will actually adjust it’s self to a point where the red light is almost white. In White Balance auto mode, the camera constantly tries to adjust it’s self to present a color balanced image. If there is a large amount of one color, ie. your red targets, it will push the White Balance toward the blue end of the spectrum, thus reducing the color saturation on the red end.

To parrot the advice given here. I’d first calibrate the exposure using the following procedure. Set the exposure to auto, point the camera at a bright light – flashlight or overhead light. Wait a few seconds for the camera to change its exposure. Set the exposure to Hold.

Next, you should change the white balance from auto to one of the ones built in. Play with the indoor and outdoor ones to see which results in the most saturated red color.

I typically do this in vision assistant. Feel free to post photos and it may be easier to diagnose.

Greg McKaskle

My understanding was that exposure is set in the begin.vi, I don’t know how you can just switch the settings while the camera is running. Also, you mentioned changing the white balance from auto to something like indoor. Again, when I look in the begin.vi, those settings (indoor, auto, ect) are plugged into the exposure.vi, I do not see anything about white balance.

Is there a simple way to set this up? Is that what vision assistant does, give me settings to use in the program for the camera?

Exposure time, exposure time, exposure time. Set it to 1/120s or shorter. This is the single biggest “trick” there is to make the retroreflective targets pop out from the background.

Im going to put a screencap of the begin.vi up in a moment with all the camera settings.

Until then, If I used a green ring light, will it work…better? I have one ordered and on the way. Is the camera already set up, and if I pop the light on it will show up nice and bright?

Found the white balance and exposure settings, but still unsure how I could set those while the code is running

Our purple LED (which we wanted to use just for cool points) was too dim, and there was nothing we could do about it. We switched to green, and it was so bright that it would over-saturate.

We set the exposure using the method Greg McKaskle suggested – we shined an eWatt bulb at it from six inches away, set the exposure to ‘hold’, and then worked from there – the previously washed-out squares popped nice and green.

But did you run the code, THEN shine the light and set to hold? Or did you set it to hold then shine the light & run the code?

Im trying to understand how this is done, because I dont see a way you can change that setting while the code is running. Unless I’m completely missing something here. Is this done in labview? The camera settings in the browser?

EDIT: Further research found me this: http://thinktank.wpi.edu/resources/196/Axis206Camera_Green_Lamp_Imaging.pdf
I should be good from here, thanks everyone. I wont be able to try it until we unbag on friday. I’ll try this with the red first, and if it doesn’t work and the green one is here in time, I’ll switch over.

Bingo! Change the setting for the Exposure to “Hold Current” in Begin.VI to avoid messing up your settings after you have performed the procedure Patrick described (which you could do programatically from LabVIEW, but is much easier with the browser).

Thanks, I set both exposure and white balance to “Hold Current” In the begin.vi. I’ll have to wait till friday to actually change camera settings on the camera itself.

Sorry my explanation wasn’t more detailed. The camera has flash storage. If you don’t want the program to control something in Begin, just delete it and the camera settings will be used. You can use the browser or vision assistant to view and change settings.

Greg McKaskle

I believe we opened the camera settings in a browser window and did it there.

There is a Camera Performance Example that can be used to set and hold the white balance.
Just add a “Set WB” .vi after the while loop and before the CLOSE.vi, and configure it to “Hold current”. Make sure you hold a plain white object (piece of paper works well) in front of the camera for ~15 seconds while running the vi. Make sure the object fills the video frame and reflects the light from the environment into the camera. Then make sure you exit by pressing the “Stop” button on the front panel. This will “Hold” the current white balance in the Flash Ram in the camera.
Then just set the White Balance in the Begin.vi to “Hold current”. This will cause the camera to use the calibrated white balance value from then on, or until you change it at the next competition you attend.

I’m curious what people’s images look like with the very bright LEDs and messing with exposure times.

We used 6 blue LEDs, and did not change any camera settings, and got good results.