Calibration of focal length and 3D pose based on the reflectance and depth image of a planar object

The estimation of position and orientation of a Photonic Mixer Device (PMD) camera in a global reference frame is required by many measurement applications based on such systems. PMD cameras produce a depth as well as a reflectance image of low resolution compared to standard optical cameras, so that calibration of the cameras based on the reflectance image alone is difficult. We will present a novel approach for calibrating the focal length and 3D pose of a PMD camera based on the depth and reflectance image of a planar checkerboard pattern. By integrating both sources of information higher accuracies can be achieved. Furthermore, one single image is sufficient for calibrating the focal length as well as the 3D pose from a planar reference object. This is because the depth measurements are orthogonal to the lateral intensity measurements and provide direct metric information.