Critical Motion Sequences for the Self-Calibration of Camerasand Stereo Systems with Variable Focal Length
Peter F. Sturm · 1999
. We consider the self-calibration problem for a moving camera whose intrinsic parameters are known, except the focal length, which may vary freely across different views. The conditions under which the determination of the focal length's values for an image sequence is not possible, are derived. These depend only on the camera's motions. We give a complete catalogue of the so-called critical motion sequences. This is then used to derive the critical motion sequences for stereo systems with variable focal lengths. 1 Introduction One of the major goals of computer vision is the recovery of spatial information about the environment. Classical approaches assume that the cameras are calibrated beforehand, but a great interest in uncalibrated vision and on-line calibration has arisen during the last decade. A key result is that even with completely uncalibrated cameras, spatial information -- projective structure -- can be obtained: the scene can be reconstructed up to an unknown project...