Precise calibration of dynamic geometric parameters cameras for aerial mapping

Abstract

Calibration is crucial for mapping cameras. Traditional calibration methods assume the geometric parameters are unchanged during the imaging process. However, aerial mapping cameras perform earth observation during a moving process. Owing to the forward flying of airplane, the exterior orientation parameters are changed during the exposure process. This leads to problems if directly applying the traditional methods to aerial mapping cameras. This paper presents a set of working time sequence and a new high-precision calibration method for aerial mapping cameras. We prove that the aerial mapping on a moving platform can be transformed into a mapping on a stationary platform by using the proposed method. Specifically, three steps are given to perform as follows. First, a proper distance is selected to decide a spot for the detector. We fix the detector at the selected spot and calibrate intrinsic parameters by exploiting traditional calibration methods. Second, the working time sequence of camera imaging is designed. The camera starts to expose an image and the exterior orientation parameters are obtained when the detector is driven to move to the calibrated spot. Third, a distortion model is proposed to correct distortions. We show that the dynamic measurement is identical to static measurement by using the proposed method. Experiments based on both simulated and real data are provided to show the effectiveness of the method.