detect own marker
I want do detect marked spots in the picture of a video recording. Which kind of mark lends itself to find it again as definitely and quickly as possible? Which way is the best for finding these marks or rather the coordinates of the marked spot?
As it can seen in the picture above I already tried three different ways. In all attempts I looked for the center of the marker (intersection at the cross, center of the circle or center of the chessboard). The idea of the first attempt was to calculate the intersection of straight lines. But there are lots of straight lines in such a picture, as for example the ones belonging to the lego brick (which isn't determined to always lay this nicely right in the middle of the four spots). The idea of the two later attempts is based upon calibration. Here I tried to make the spots modeled on the spot-search of calibration with a chessboard or circles.
Unfortunately these attempts weren't as successful as I had expected. Which is why I hope for hints from you as experienced openCV-users.
Thanks a lot.
PS. In case it is of interest: The four spots always demonstrate the corners of a rectangle.
I would try to detect them using template matching: http://docs.opencv.org/doc/tutorials/imgproc/histograms/template_matching/template_matching.html