OpenCV parallel lines cull

Question

I have an algorithm that simply goes through a number of corners and finds those which are parallel. My problem is, as shown below, that I sometimes get false positive results.

To eliminate this I was going to check if both points fell onto a single hough line but this would be quite computationally intensive and I was wondering if anyone had any simpler ideas.

Thanks.

Answer 1

Ok based on the comments, this should be fix-able. When you detect a pair of parallel lines, get the equation of the line using the two corners that you've used to construct it. This line may be of the form y = mx + c. Then for every y coordinate between the two points, compute the x coordinate. This gives you a set of all the pixels that the line segment covers. Go through these pixels, and check if the intensity at every pixel is closer to black than white. If a majority of the pixels in the set are black-ish, then it's a line. If not, it's probably a non-line.