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Optical Engineering

New method for overcoming ill-conditioning in vanishing-point-based camera calibration
Author(s): Xiaochen He; Nelson Hon Ching Yung
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Paper Abstract

A common problem in vanishing-point-based camera calibration methods is that they are ill-conditioned when the parallel lines for calibration in the world coordinates also appear to be parallel or near-parallel in the image coordinates. Then the camera parameters are not calculable or incur substantial error because one of the vanishing points approaches infinity. We propose a new method that overcomes the ill-conditioning. Using lane markings on a road to form a rectangular calibration pattern with two vanishing points, we first derive a set of equations based on one vanishing point without assuming any extrinsic parameters being known a priori. Because only one vanishing point can approach infinity at any one time, ill-conditioning can be avoided completely by selecting the vanishing point that does not suffer from it. This enables us to produce a set of extrinsic camera parameters that maps the world and image coordinates accurately. Simulation and real image tests show that the proposed method conquers ill-conditioning successfully and is insensitive to pixel offset on the calibration pattern.

Paper Details

Date Published: 1 March 2007
PDF: 12 pages
Opt. Eng. 46(3) 037202 doi: 10.1117/1.2714991
Published in: Optical Engineering Volume 46, Issue 3
Show Author Affiliations
Xiaochen He, The Univ. of Hong Kong (Hong Kong China)
Nelson Hon Ching Yung, The Univ. of Hong Kong (Hong Kong China)

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