Calibrating an active omnidirectional vision system

This paper describes a straightforward process for calibrating an active vision system containing both pinhole perspective and omnidirectional cameras. The perspective cameras can be easily calibrated using standard methods. Unfortunately, these methods are not suitable for omnidirectional cameras. Methods that rely on iterative least squares optimization, using a set of known image-world correspondences, are adopted for omnidirectional cameras. To ensure unbiased estimation of camera parameters, an omnidirectional calibration rig is employed so that nearly the entire field of view contains known calibration points. Measurement uncertainties collected from each stage of calibration are then combined to estimate the overall system uncertainty. This calibration process is evaluated experimentally by estimating the location of known points using triangulation, where the results achieved are comparable with the estimated system uncertainties.