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arXiv · 2507.09386

Free-running vs. Synchronous: Single-Photon Lidar for High-flux 3D Imaging

Ruangrawee Kitichotkul·Shashwath Bharadwaj·Joshua Rapp·Yanting Ma·Alexander Mehta·Vivek K Goyal
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Abstract

Conventional wisdom suggests that single-photon lidar (SPL) should operate in low-light conditions to minimize dead-time effects. Many methods have been developed to mitigate these effects in synchronous SPL systems. However, solutions for free-running SPL remain limited despite the advantage of reduced histogram distortion from dead times. To improve the accuracy of free-running SPL, we propose a computationally efficient joint maximum likelihood estimator of the signal flux, the background flux, and the depth using only histograms, along with a complementary regularization framework that incorporates a learned point cloud score model as a prior. Simulations and experiments demonstrate that free-running SPL yields lower estimation errors than its synchronous counterpart under identical conditions, with our regularization further improving accuracy.

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Ruangrawee Kitichotkul, Shashwath Bharadwaj, Joshua Rapp, Yanting Ma, Alexander Mehta, Vivek K Goyal. 2025-07-12. Free-running vs. Synchronous: Single-Photon Lidar for High-flux 3D Imaging. https://arxiv.org/abs/2507.09386

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