Plane-based calibration of cameras with zoom variation

Plane-Based calibration algorithms have been widely adopted for the purpose of camera calibration task. These algorithms have the advantage of robustness compared to self-calibration and flexibility compared to traditional algorithms which require a 3D calibration pattern. While the common assumption is that the intrinsic parameters during the calibration process are fixed, limited consideration has been given to the general case when some intrinsic parameters maybe varying, others maybe fixed or known. We first discuss these general cases for camera calibration. Using a counting argument we enumerate all cases where plane-based calibration may be utilized and list the number of images required for each of these cases. Then we extend the plane-based framework to the problem of cameras with zoom variation, which is the most common case. The approach presented and may be extended to incorporate additional varying parameters described in the general framework. The algorithm is tested using both synthetically generated images and actual images captured using a digital camera. The results indicate that the method performs very well and inherits the advantage of robustness and flexibility from plane-based calibration algorithms.