Multi-Layer ToF: Comparison of different multipath resolve methods for indirect 3D time-of-flight

Multipath Interferences (MPI) represent a significant source of error for many 3D indirect time-of-flight (iToF) applications. Several approaches for separating the individual signal paths in case of MPI are described in literature. However, a direct comparison of these approaches is not possible due to the different parameters used in these measurements. In this article, three approaches for MPI separation are compared using the same measurement and simulation data. Besides the known procedures based on the Prony method and the Orthogonal Matching Pursuit (OMP) algorithm, the Particle Swarm Optimization (PSO) algorithm is applied to this problem. For real measurement data, the OMP algorithm has achieved the most reliable results and reduced the mean absolute distance error up to 96% for the tested measurement setups. However, the OMP algorithm limits the minimal distance between two objects with the setup used to approximately 2.7 m. This limitation cannot be significantly reduced even with a considerably higher modulation bandwidth.