High resolution TCSPC imaging of diffuse light with a one-dimensional SPAD array scanning system

TL;DR

This paper introduces a high-resolution, time-resolved TCSPC imaging system using a line-scan CMOS SPAD array, capable of locating objects in scattering media by leveraging early photon detection.

Contribution

The work presents a novel line-scanning TCSPC imaging system with a CMOS SPAD array for high-resolution imaging and object localization in scattering environments.

Findings

Successfully constructed a 0.26 Mpixel TCSPC image using line-scan architecture.

Demonstrated improved object localization by imaging early arriving photons.

Achieved effective imaging of point sources in highly scattering media.

Abstract

We report a time-resolved single photon counting (TCSPC) imaging system based on a line-scanning architecture. The system benefits from the high fill-factor, active area, and large dimension of an advanced CMOS single photon avalanche diode (SPAD) array line-sensor. A two-dimensional image is constructed using a moving mirror to scan the line-sensor field-of-view (FOV) across the target, to enable the efficient acquisition of a two-dimensional 0.26 Mpixel TCSPC image. We demonstrate the capabilities of the system for TCSPC imaging and locating objects obscured in scattering media - specifically to locate a series of discrete point sources of light along an optical fibre submerged in a highly scattering solution. We demonstrate that by selectively imaging using early arriving photons which have undergone less scattering than later arriving photons, our TCSPC imaging system is able to locate the position of discrete point sources of light than a non-time-resolved imaging system.