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Unread 10-10-2014, 19:46
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FRC #1706 (Ratchet Rockers)
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Join Date: Apr 2012
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Re: Vision: what's state of the art in FRC?

Quote:
Originally Posted by Greg McKaskle View Post

But vision is a hungry beast and will bring any computer to its knees if you just brute force it. The "right" solution depends on where the camera is mounted, where it is pointed, lighting, lenses, and of course processing. Makes it challenging, huh.
I don't think people realize this. After the image is acquired, it is literally pure mathematics. If you aren't careful, as in don't put in a wait function, your computer will try to execute the program as fast as possible, and the program is basically in an infinite loop until you somehow close the program. (I believe the majority of teams don't gracefully exit their program after a match, but instead simply power off).

To give an example, when you have a binary image you desire, as in your targets are white (1) and everything else is black (0), you preform the operation described in this paper (http://wenku.baidu.com/view/6cb52ede...aa811dad5.html) This paper was published in 1983. There do exist other methods, but the computational cost is about the same. (See also: http://en.wikipedia.org/wiki/Edge_detection).
Basically what this step does is reduces a 640x480 (or whatever resolution image you have) matrix to a sequence of curves that allow you to do cool things, such as recursively approximate a polygon to guess how many sides it has.
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