Integrated 3D Range Camera Self-Calibration

An integrated bundle adjustment has been developed to facilitate the precise definition of the geometry of time-of-flight range imaging cameras, including the estimation of range-measurement-specific correction parameters modelling linear, periodic and sensor-position-dependent effects of a distance measurement. The integrated calibration routine jointly adjusts data from both information channels (amplitude and range) and automatically estimates optimum observation weights. The method is based on the flexible principle of self-calibration. It does not require spatial object data, thus avoiding the time-consuming determination of reference distances with superior accuracy. The accuracy analyses carried out using a PMD[vision] CamCube 2.0 confirm the correctness of the proposed functional contexts, but they also exhibit challenges caused by non-parameterised range-measurement-specific errors. The level of accuracy of the observations is computed by variance component estimation and becomes in mean 1/35 pixel for an amplitude image coordinate measurement and 9.5 mm for a distance measurement. The precision of a 3D point coordinate can be set at 5 mm after calibration, compared to several centimetres before applying any correction terms. In the case of depth imaging technology, which is influenced by a variety of noise sources, this accuracy level is very promising.