Combination of spatially-modulated ToF and structured light for MPI-free depth estimation

Multi-path Interference (MPI) is one of the major sources of error in Time-of-Flight (ToF) camera depth measurements. A possible solution for its removal is based on the separation of direct and global light through the projection of multiple sinusoidal patterns. In this work we extend this approach by applying a Structured Light (SL) technique on the same projected patterns. This allows to compute two depth maps with a single ToF acquisition, one with the Time-of-Flight principle and the other with the Structured Light principle. The two depth fields are finally combined using a Maximum-Likelihood approach in order to obtain an accurate depth estimation free from MPI error artifacts. Experimental results demonstrate that the proposed method has very good MPI correction properties with state-of-the-art performances.