Flexible camera calibration using not-measured imperfect target

A constrained optimization process is proposed for camera calibration with an imperfect and not-measured calibration target. The proposed method uses the geometry of the calibration target in an optimization process with constraints based on the pattern design statistically. As a result, the camera can be calibrated in the absolute scale without taking any measurement of the imperfect calibration target. It is verified through simulation and experiment that the reprojection errors by using the proposed method are obviously smaller than those of the traditional calibration approach by trusting an imperfect target. The slightly higher measurement precision is also exemplified through an experimental calibration of a stereo vision system. (C) 2013 Optical Society of America