A Clustering Based Denoising Technique for Range Images of Time of Flight Cameras

A relatively new technique for measuring the 3D structure of visual scenes is provided by time of flight (TOF) cameras. Reflections of modulated light waves are recorded by a parallel pixel array structure. The time series at each pixel of the resulting image stream is used to estimate travelling time and thus range information. This measuring technique results in pixel dependent noise levels with variances changing over several orders of magnitude dependent on the illumination and material parameters. This makes application of traditional (global) denoising techniques suboptimal. Using free additional information from the camera and a clustering procedure we can get information about which pixels belong to the same object, and what their noise level is, which allows for locally adapted smoothing. To illustrate the success of this method, we compare it with raw camera output and a traditional method for edge preserving smoothing, anisotropic diffusion. We show that this mathematical technique works without individual adaptations on two camera systems with highly different noise characteristics.