Full Court Target Detection

[dvanvoorst]

So far in testing our infrared, we only need to run it through an HSI Threshold filter and we get a nearly perfect result. If our target is near the side of the image, and we're fairly close, then we get a poorer image that results in some small particles - so we may add a filter for that, or just ignore those in code.
Our infrared light is currently mounted immediately next to the camera. We are still testing things though....

[Bpk9p4]

what type of camera are yo using? Did you remove the IR filter from the camera if it has one?

[dvanvoorst]

We are using the Axis M1011 camera. For testing we just taped an infrared filter in front of the lens. The filter is one intended for use on a regular 35mm camera lens. We haven't done any special camera settings (yet).

[Greg McKaskle]

The axis cameras do have IR filters, but at least for the 206 it was on the lens, not the sensor. I suspect that the M1011 is the same, but can't be certain.

If you choose to use IR, you may want to consider setting the camera to monochrome and if it returns an RGB image, simply take one of the planes such as red. This should reduce time needed to process.

Last year I took some movies of the field using a Kinect and there seemed to be lots of IR coming from the lights above and to each side of the field. This light would bounce off tape stripes, plastic, and of course other robots. I'm not saying whether IR is or isn't a good choice.

One of the issues is that you can't see IR. Just because you don't see it doesn't mean it isn't there.

Greg McKaskle

[dvanvoorst]

Hi Greg,
What do you mean by the Axis cameras already having an IR filter? Is that a physical filter? A software filter? I wasn't aware of any particular IR capabilties - but I have minimal experience so far.
We just put an IR filter in front of the camera - and that worked well, but if the camera has a way to do that itself, that would be convenient.
Dale

[Alan Anderson]

Originally Posted by dvanvoorst

What do you mean by the Axis cameras already having an IR filter? Is that a physical filter?

It has a physical filter to block IR light.

[Greg McKaskle]

As Alan said, the IR filter is a physical coating or lens element on the interior portion of the M206 lens.

I learned this when I replaced the lens to change focal length. My color saturation was horrible after that. The new lens was for a monochrome sensor and had no filter.

The camera sensors, a CMOS sensor in this case, is sensitive to the visible spectrum and down into IR. If you do not block IR, the IR light will wash out the image and you will lose color saturation. So camera manufacturers add this to capture the portion of light you typically care about in photography. Alternately, you could block visible light and allow IR through and make it an IR camera. If you have both filters in place, you've made a camera that senses very little.

Greg McKaskle

[Bpk9p4]

you are saying the IR filter is in the removable lens for the axis 206? Where did you get a replacement lens for the axis 206 that did not have an IR filter?

[Greg McKaskle]

From here

http://www.edmundoptics.com/imaging/...lated-products

The factory lens in the Axis 206 camera is a 4mm.

Greg McKaskle

[Bpk9p4]

thanks you for posting this. Would you recommend using this lens on an axis 206?

[Greg McKaskle]

I'm not sure I understand the question. They are good quality lenses and I have used them on the 206. If you remove the lens you will find that the threads are pretty loose. I applied a bit of teflon tape to keep the lens from twisting due to vibration on the robot.

I'm not convinced that IR is a better solution than visible light, and I think it will be harder to debug if/when it doesn't work. If you try out IR, do it methodically, and perhaps have a backup plan -- a visible-light LED ring and lens to swap back to.

Greg McKaskle

[Bpk9p4]

i agree that IR might not be the best way to go. Are only problem with RGB light is currently we can not get full court detection without having a very strong light and running the risk of violating the rules

[Greg McKaskle]

If you get the LEDs close to the lens I think you'll find that they won't be nearly as bright as the folks with the photon cannons. Please post images and I'll do what I can to help analyze them.

Greg McKaskle

[Bpk9p4]

thanks a lot for your help. i will try to get some screen shots this weekend

[Bryscus]

Originally Posted by Greg McKaskle

If you get the LEDs close to the lens I think you'll find that they won't be nearly as bright as the folks with the photon cannons. Please post images and I'll do what I can to help analyze them.

Greg McKaskle

The difference is that for camera tracking you typically want a somewhat wider spread light which is more likely to bother people (unless of course you're shooting from far enough away to allow you to limit the spread). Using a highly directional photon cannon pointed up shouldn't bother many opposing drivers. Its just the people up in nosebleed seats that will get blasted.

- Bryce