Fakultät für Informatik und Mathematik


Paper Description

BibTex entry

author="T. Hanning, R. Schoene",
title="Additional constraints for Zang's closed form solution of the camera calibration problem",
institution="Fakult{\"a}t f{\"u}r Informatik und Mathematik, Universit{\"a}t Passau",


A known planar model and its observation in the image of a pinhole camera are related by a planar homography. This planar homography is up to a scale factor given by the projection matrix and a rotation and translation. From a number of observations of the same model one can derive the projection matrix by two constraints introduced by the rotation part. These constraints can be transformed to a homogeneous system of linear equations. An additional constraint is needed to avoid the trivial solution. The canonic way is to determine the solution on the unit sphere. But this side condition does not reflect any correlation between the parameters. A solution of this problem may not represent a valid projection matrix. In this article we search for more meaningful restrictions for the solution. For some special but relevant cases we are able to express the problem by a quadratic constraint, which leads to a generalized Eigenvalue problem. We show the profit of the additional constraints in several experimental results.

Paper itself