  Time-of-flight (ToF) cameras calculate depth maps by reconstructing phase
shifts of amplitude-modulated signals. For broad illumination or transparent
objects, reflections from multiple scene points can illuminate a given pixel,
giving rise to an erroneous depth map. We report here a sparsity regularized
solution that separates K-interfering components using multiple modulation
frequency measurements. The method maps ToF imaging to the general framework of
spectral estimation theory and has applications in improving depth profiles and
exploiting multiple scattering.
