INTEGRATED RANGE CAMERA CALIBRATION USING IMAGE SEQUENCES FROM HAND-HELD OPERATION

This article concentrates on the integrated self-calibration of both the interior orientation and the distance measurement system of a time-of-flight range camera that employs amplitude-modulated, continuous-wave, near-infrared light (photonic mixer device PMD). In contrast to other approaches that conduct specialized experiments for the investigation of individual, potential distortion factors, in the presented approach all calculations are based on the same data set being captured under near-real-world conditions, guided by hand and without auxiliary devices serving as high-order reference. Flat, circular targets stuck on a planar whiteboard and with known positions are automatically tracked throughout the amplitude layer of long image sequences. These image observations are introduced into a bundle block adjustment, which on the one hand results in the determination of the camera’s interior orientation and its temporal variation. On the other hand, the reconstructed exterior orientations and the known planarity of the imaged board allow for the derivation of reference values of the actual distance observations. These deviations are checked on relations with the reference distance itself, the observed signal amplitude, the integration time, the angle of incidence, and with both the position in the field of view and in object space. Eased by the automatic reconstruction of the camera’s trajectory and attitude, several thousand frames are processed, leading to comprehensive statistics.