Dead-time-based sequence coding method for single-photon lidar ranging

• Published in: Optics communications 2022-08, Vol.517, p.128260, Article 128260
• Main Authors: Li, Zhijian, Lai, Jiancheng, Wu, Zhixiang, Wang, Chunyong, Yan, Wei, Li, Zhenhua
• Format: Article
• Language: English
• Subjects: Dead time; Photon-counting; Pulse coding; Single-photon lidar
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2022.128260

Sequence coding is beneficial for reducing range ambiguity and acquisition time in single-photon lidar (SPL) ranging. In SPL data acquisition, dead time is usually regarded as an adverse condition. However, properly utilizing echo-induced dead time in sequence coding may allow it to be useful. In this study, we propose a dead-time-based sequence coding method. We set the time intervals of the subpulses to be slightly longer than the dead time, such that the detection of a subpulse can ‘block’ incoming noise detections until the arrival of the next subpulse. Starting with a sequence of three subpulses, we determined the optimal pulse-interval criteria of ‘≈ dead time + pulse width’ when the subpulses are identical in shape and intensity. A method to extract the range with few accumulations was proposed (FARE method), incorporating the maximum cross-correlation and threshold filtering. Simulation and experiment results demonstrated that our ‘optimal interval + FARE’ method is more efficient and less ambiguous than the sequence coding method without the merit of dead time, and the conventional ‘single laser pulse’ method. Our method is promising for low range ambiguity and fast ranging, and helps reduce laser energy consumption without wasting transmitting pulses. •Utilizing the dead time of SPAD as a merit other than a drawback in data acquisition.•Proposed the dead-time-based sequence coding method.•Concluded the optimal time intervals criteria: ‘ ≈Td(dead time) + Pw(pulse width)’ when the subpulses are identical.•Our method is more efficient and less ambiguous than conventional methods.