Full Court Target Detection

[Twistedtruth360]

Do I have to use a network camera with the led lighting or can we use something.

[Greg McKaskle]

The Asix camera is well integrated into WPILib, but nothing requires that you use any of it. Perhaps the question to ask yourself is, do you have a better idea? If so, investigate it, here or elsewhere.

Greg McKaskle

[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.

The way I look at it, the spread of the light determines how many people it impacts. The brightness of the light determines how much it affects the people with the light in their eyes. The teams I'm familiar with that did this last year shined it on the floor, wall, ceiling, and everything in between. I'm not saying it was a bad strategy, but the lights were far far brighter than the LEDs.

Heres another way of looking at this. The retroreflective material is graded by how much more light it reflects than white paint. I believe the material used is at least 300x brighter. That means it only takes 1/300th the intensity of light when used properly.

Greg McKaskle

[Bpk9p4]

Just a warning for other teams. The axis 206 camera has an IR filter. We attempted to remove the filter today and found it not to be possible.

[twiggzee]

Originally Posted by Greg McKaskle

I've seen teams nest the LED rings one inside the other which will increase the brightness.

I don't know if other teams are experiencing this as well but it seems to me that the retro-reflective tape in this year's game doesn't seem to reflect as bright as the one last year with the same green led ring light. has anybody tried adding another LED ring as Greg suggests here? did it improve brightness / vision results?

[faust1706]

1706's program for computer vision is able to function at well over 80 feet. Without the illuminators and just using the build in ir light on the kinect, it reaches a little under 60. last year we got to over 100 feet.

[Johnny_5]

Originally Posted by faust1706

1706's program for computer vision is able to function at well over 80 feet. Without the illuminators and just using the build in ir light on the kinect, it reaches a little under 60. last year we got to over 100 feet.

How are you doing this? What are the lighting conditions in your testing environment?

[Bryscus]

SPAM is able to track the retro reflective goals using just two ring lights - we originally tried just the smaller one and it wasn't quite bright enough. We overexpose the image to darken it a bit so that in bright conditions the green light doesn't saturate. If this were to happen, a color shift would occur and make thresholding with HSL not work. We shine a bright light into the camera and hold the settings for both white balance and exposure. We are able to detect full court without any problems. Last year we did the same thing and we could work outside, in fluorescent lights, tungsten, at events, etc. and we never retuned. Hope this helps!

- Bryce

[faust1706]

We do it in every condition. it doesnt matter. To test, we did every hallway at the high school, the gyms, and put up stage lights, still works, unless the stage lights are pointed at the kinect, then it blinds us. That is why the program doesnt work well outside when sunny. I used OpenCV's libraries with a Microsoft Kinect. This year, my mentor suggested saturating the targets with more IR light to help, and we tested it and it does make a huge difference. I hated using axis cameras. They were cheap and the fps was garbage. For the kinect, it is 30 fps if it only captures an rgb image, with my program, it runs a little under 27. I would invest in different hardware. 1706 will be attending the St louis Regional and the Terra Houte (pardon my spelling) regionals. If you are there, I'd love to explain it for you. I wrote a paper about last year's vision program for state symposium, and am going to ISWEEEP in Houston for a week to compete at internationals. I have a part of it posted as a doc on here. Feel free to take a look. (Cant give away all my secrets, sorry, the teacher that sponsers robotics wants me to patent it)

[apalrd]

I don't know what Axis camera you are using, but I had no issues running at 30fps. We chose to run at 20 last year to avoid any buffered TCP issues, and it seemed to work fine.

The Axis camera is also very light and very easy to use.

[faust1706]

please refer to 1706 at the st louis regional. solutions accurate to the quarter of an inch.

[Greg McKaskle]

One man's garbage is another man's treasure ...

But seriously, both the Kinect and Axis are quality products intended for rather different purposes. It sounds like you've converted your Kinect into a rather big IR camera and splotchy IR emitter.

I think using it on the robot is an awesome project, but there is no need to trumpet so loudly, especially if you aren't willing to teach others how it is done.

Greg McKaskle

[Coach Norm]

Originally Posted by Greg McKaskle

One man's garbage is another man's treasure ...

I think using it on the robot is an awesome project, but there is no need to trumpet so loudly, especially if you aren't willing to teach others how it is done.

Greg McKaskle

Well said Greg.

[faust1706]

I've posted a paper on here describing my methods from last year's program. I help team's in the pit all the time, answer questions they have and give advice.

[Greg McKaskle]

I downloaded and reviewed the paper, and I applaud you for publishing it. I do have a number of questions it didn't answer.

I didn't see a description of which image feature was used to estimate the distance. The accuracy of the distance measurement will depend largely on the resolution of the camera and the pixel size of that feature. One quarter inch accuracy seems to be a tall order even at twenty feet. Interpolation of other image features can be used once you can make assumptions about a feature, but that wasn't mentioned.

Also, couldn't the approaches in the paper be applied to other cameras? It doesn't seem like IR is a requirement for the approach either?

Good job taking on the challenge and good luck in the competition.

Greg McKaskle