Abstract
Many camera calibration methods for a non-metric digital camera have been proposed. Most of them adopt polynomials of image coordinates composed of terms representing the correction to the principal distance, the offsets of the principal point, the radial lens distortion, and the decentering lens distortion of the target camera as the image distortion model in the calibration. However, few reports on selection of unknown parameters of the image distortion model in the calibration evaluate an estimated distribution of image distortion directly. Therefore, we conducted a numerical simulation on selection of unknown parameters of the ordinary image distortion model widely used for camera calibration. Evaluation of calibration results was performed by differences of image distortions calculated at all pixels on the image between the obtained image distortion model and the setup one. The simulation results indicate that an image distortion model without the terms representing the decentering lens distortion of the target camera in the calibration cannot necessarily provide a reliable distribution of the image distortion. The authors propose selecting all parameters of the widely used image distortion model as unknowns in the camera calibration.
