Fig. 1. Waveform distortion among the pulse laser, photon, and corrected waveforms.

Fig. 2. Comparison with Xu et al.’s method. (a) Correlation distance versus the intensity; (b) time cost versus the width of the time bin.

Fig. 3. Description of the photon counting system. (a) Schematic diagram: the components are a semiconductor laser source, a GM-APD detector, a TCSPC system, and the optical system. The optical system contains a beam splitter (BS), PIN fast photodiode, optical attenuation system (OAS), beam expansion (BE), telescope, bandpass filter (BPF), and fiber coupling receiver (FCR); (b) photograph of the experiment system.

Fig. 4. Photon waveform, which is the statistical histogram from multiple cumulative detections of TCSPC and corrected waveform when (a) N_s=0.04 and (b) N_s=0.6. The blue line and the green line are the fitting curves of the photon waveform and the correction waveform, respectively.

Fig. 5. Correlation distance versus the average number of photons.

Fig. 6. Photon waveforms and correction waveforms of depth targets with (a) N_s=0.02 and (b) N_s=0.5 at K_l=1.4.

Fig. 7. Photon waveforms and correction waveforms of depth targets with (a) N_s=0.04 and (b) N_s=0.27 at K_l=0.93.

Table 1. Comparison of Correction Effects with Different Echo Photon Numbers