Practical Calibration Method for Aerial Mapping Camera Based on Multiple Pinhole Collimator

Calibration of aerial mapping camera has an important influence on the applications of earth observation. However, the traditional aerial mapping cameras calibrations depend on large-scale calibration target or collimated light, moreover, it is difficult to build the large-scale calibration targets and the collimated light method requires an accurate turntable and a high-precision goniometer, which is a kind of expensive instrument. To solve this problem, this paper proposes a novel high-precision calibration method which is not restricted by the rigorous conditions, such as small aperture, unevenly energy distribution and expensive equipment. Specifically, a collimator and an elaborately designed multiple pinhole mask are firstly used to generate the collimated light of a large aperture with known directions to simulate the calibration targets at infinity. Then, the camera takes pictures for the aperture of the multiple pinhole collimator at multiple angles to ensure that the image points cover the entire detector. Thirdly, the final calibrated results are obtained by solving the data acquired from multiple angles. Finally, the proposed method is verified by Monte-Carlo simulation and real experimental data, whose results indicate that our method can reach the same accuracy performance as the existing methods at lower cost and faster speed, and thus is practical for engineering application.