Computational and Optical techniques for single photon sensors
Advisor: Prof. Mohit Gupta

Optimal flux and attenuation for single photon sensors (Under Review, manuscript available on request):
Single photon avalanche diodes (SPAD) are depth sensors that are highly photonefficient and have high timing resolution. However they suffer from nonlinear distortions under high flux conditions, due to their peculiar image formation model. We model the problem of depth recovery as statistical parameter estimation, and derive an optimal flux criterion using a notion of statistical efficiency. This leads to an attenuationbased solution that dramatically improves performance.

Asynchronous shifting for single photon sensors (In progress):
LiDAR (light based depth ranging) systems typically use a synchronous acquisition scheme, where the laser and sensor operate in phase at the same frequency. While this is inconsequential for standard sensors, we show that for single photon sensors, asynchronization eliminates nonlinear distortions and reduces depth error. Using a firstorder analysis of the random measurement sequence of a SPAD, we derive the optimal shift in frequency that achieves the lowest error.