Calibration of the fast range imaging camera SwissRangerTM for the use in the surveillance of the environment

Many security & defense systems need to capture their environment in one, two or even three dimensions. Therefore adequate measurement sensors are required that provide fast, accurate and reliable 3D data. With the upcoming range imaging cameras, like the SwissRanger (TM) introduced by CSEM Switzerland, new cheap sensors with such ability and high performance are available on the market. Because of the measurement concept these sensors long for a special calibration approach. Due to the implementation of several thousand distance measurement systems as pixels, a standard photogrammetric camera calibration is not sufficient. This paper will present results of investigations on the accuracy of the range imaging camera SwissRanger. A systematic calibration method is presented which takes into consideration the different influencing parameters, like reflectivity, integration time, temperature and distance itself The analyzed parameters with respect to their impact on the distance measuring pixels and their output data were determined. The investigations were mainly done on the high precision calibration track line in the calibration laboratory at ETH Zurich, which provides a relative accuracy of several microns. In this paper it will be shown, under which circumstances the goal accuracy of the sub centimeter level can be reached. The results of this work can be very helpful for users of range imaging systems to increase their accuracy and thus the reliability of their systems. As an example, the usefulness of a range imaging camera in security systems for room surveillance is presented.