New Models for Scattering Bias Compensation in Time-of-Flight Range Camera Self-Calibration

Abstract

The geometric calibration of time-of-flight range cameras is a necessary quality assurance measure performed to estimate the interior orientation parameters. Self-calibration from a network of range imagery of an array of signalized targets arranged in one or two planes can be used for this purpose. The latter configuration requires the addition of a parametric model for internal light scattering biases in the range observations to the background plane due to the presence of the foreground plane. In a previous study of MESA Imaging SwissRanger range cameras, such a model was developed and shown to be effective. A new parametric model is proposed here because the scattering error behavior is camera model dependent. The new model was tested on two pmdtechnologies range cameras, the CamCube 3.0 and CamBoard nano, and its effectiveness was demonstrated both graphically and statistically. The improvement gained in the root-mean square of the self-calibration range residuals of 22 and 32%, respectively, indicates the model’s ability to compensate for the scattering error. A reduction in correlation between the camera position and rangefinder offset of up to 10% was achieved, which is consistent with previous findings. In addition, a systematic approach for designing the optimal separation between the foreground and background planes is presented.