Modelling and Compensating Internal Light Scattering in Time of Flight Range Cameras

Time of flight range cameras simultaneously gather object distances for all pixels of a focal plane array by evaluating the round-trip time of an emitted signal. While ranging precisions typically amount to some centimetres, accuracies may be worse by an order of magnitude. Scattering is one of the sources of systematic errors, caused by the spreading of portions of the incident light over the sensor due to multiple reflections between the sensor, lens and optical filter. The present contribution analyses this phenomenon with respect to various capture parameters, with the objective of achieving a better understanding and a validation of assumptions. Subsequently, the authors derive both image space invariant and variant models for scattering, apply them to test scenes, and compare the results to each other and to those of existing methods.