High-resolution depth profiling using a range-gated CMOS SPAD quanta image sensor

Ren Ximing, P Connolly, Abderrahim Halimi, Yoann Altmann, Stephen McLaughlin, Istvan Gyongy, Robert Henderson, Gerald Buller

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

A CMOS single-photon avalanche diode (SPAD) quanta image sensor is used to
reconstruct depth and intensity profiles when operating in a range-gated mode used in conjunction with pulsed laser illumination. By designing the CMOS SPAD array to acquire photons within a pre-determined temporal gate, the need for timing circuitry was avoided and it was therefore possible to have an enhanced fill factor (61% in this case) and a frame rate (100,000 frames
per second) that is more difficult to achieve in a SPAD array which uses time-correlated single photon counting. When coupled with appropriate image reconstruction algorithms, millimeter resolution depth profiles were achieved by iterating through a sequence of temporal delay steps in synchronization with laser illumination pulses. For photon data with high signal-to-noise
ratios, depth images with millimeter scale depth uncertainty can be estimated using a standard cross-correlation approach. To enhance the estimation of depth and intensity images in the sparse photon regime, we used a bespoke clustering-based image restoration strategy, taking into
account the binomial statistics of the photon data and non-local spatial correlations within the scene. For sparse photon data with total exposure times of 75 ms or less, the bespoke algorithm can reconstruct depth images with millimeter scale depth uncertainty at a stand-off distance of approximately 2 meters. We demonstrate a new approach to single-photon depth and intensity
profiling using different target scenes, taking full advantage of the high fill-factor, high frame rate and large array format of this range-gated CMOS SPAD array.
Original languageEnglish
Pages (from-to)5541-5557
Number of pages17
JournalOptics Express
Issue number5
Publication statusPublished - 5 Mar 2018


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