Geometric Calibration of the Aerial Digital Camera "ULTRACAM D"

The evaluation of the geometric function of a large-scale digital camera (ULTRACAMD) is the main subject of this paper. The concepts of geometric calibration by bundle adjustment method have been described. The additional parameters based on the specific design of the camera are determined and defined, and the BINGO group modification software has been upgraded to manage these parameters. The entire calibration process will consist of four steps. In the first step, a set of images is taken from fully-clear targets such that additional observations (with high degree of freedom) are possible. The second step is to measure the coordinates of the image. Automation and accuracy are achieved by image processing techniques utilizing a special form of fully-clear targets. The third step involves processing the semi-automatic adjustment, and the unknown parameters (focal length, principal point coordinates, distortion parameters and additional parameters) are estimated. In the fourth step, we will identify the linear and non-linear parameters. Linear parameters are used to reduce the linear effects of distortion in the camera. This will be achieved by linear transmission of measured coordinates, so that only nonlinear small effects will remain. The remaining effects are then described in a table (Look Up table). The results of a series of full calibration operations, modified parameters and the effects of these parameters were presented. Finally calibration has been confirmed and implemented.