Maximum likelihood range estimation for 3D-imaging based on pseudo-noise optical modulation

Acquiring real-time 3D images poses many challenges. Many 3D-imaging systems are based on estimating the time-of-flight (TOF) of photons between an emitter and a receiver, which in turn is based on transmitting a pseudo-noise optical signal and correlation measurements. The precision of such measurements is limited by photon shot noise. In this paper, we develop a maximum-likelihood estimator for the TOF (and thus for the range) that takes into account the Poisson distribution of the detected photons. The proposed estimator is shown to give better range estimates than a standard estimator that is used in current systems. The improvement is particularly significant when the period of the pseudo-noise sequence-based modulation signal is short.