An Optimised Vanishing Point Detector

In this paper we use line segments from a Hough transform algorithm to locate vanishing points in an image. The line parameters have already been determined to high accuracy, and the purpose of this paper is to present a scheme for locating the vanishing points from the line intersections which takes full advantage of this accuracy. We present a natural generalisation of the usual accumulator method which incorporates statistical hypothesis testing to account for the effects of noise and errors in line segment parameters. Using this smooth voting kernel in the accumulation process, we have developed an optimisation scheme as a post-process to remove sampling errors in the vanishing point accumulator. We demonstrate the improvement in the results using synthetic imagery for which ground truth is known. We then demonstrate the algorithm on two images of outdoor scenes. The first is a road scene for which we determine vanishing points for a building in the street, and the second is an infra-red image of a runway as seen from an approaching aircraft.