Efficient computation of vanishing points

Man-made environments possess a lot of regularities which simplify otherwise difficult pose estimation and visual reconstruction tasks. The constraints arising front parallel and orthogonal lines and planes can be efficiently exploited at various stages of vision processing pipeline. In this paper we propose an approach for estimation of vanishing points by exploiting the constraints of structured man-made environments, where the majority of lines is aligned with the principal orthogonal directions of the world coordinate frame. We combine efficient image processing techniques used in the line detection and initialization stage with simultaneous grouping and estimation of vanishing directions using expectation maximization (EM) algorithm. Since we assume an uncalibrated camera the estimated vanishing points can be used towards partial camera calibration and estimation of the relative orientation of the camera with respect to the scene. The presented approach is computationally efficient and has been verified extensively by experiments.