Time of flight calculation with inter-bin delta estimation

A lidar transceiver comprising:

• a transmitter configured to transmit light pulses;
• a receiver configured to receive reflected photons from the light pulses transmitted by the transmitter;
• and
• processing circuitry connected to the transmitter and receiver, the processing circuitry configured to:
• i) start an acquisition time period by causing the transmitter to transmit a light pulse;
• ii) for a plurality of successive time portions in the acquisition time period, if a photon is received:
• iia) record a time at which the photon is received;
• iib) update a histogram to record a cumulative count of photons received by the receiver during the time portion;
• iic) calculate a time difference between the time at which the photon is received relative to a reference point of the time portion;
• iid) update a cumulative total of the calculated time difference for the time portion;
• iii) repeat steps i) to iid) for a succession of N transmitted light pulses;
• iv) identify a peak in a time portion of the histogram;
• and
• v) estimate a time of flight from the cumulative total of the calculated time difference for the time portion of the histogram containing the identified peak.

A lidar transceiver comprising:

• sensor circuitry comprising:
• a transmitter configured to transmit light pulses;
• a receiver including a single photon avalanche diode (SPAD) configured to receive reflected photons from the light pulses transmitted by the transmitter;
• and
• processing circuitry connected to the sensor circuitry, the processing circuitry configured to:
• i) start an acquisition time period by causing the transmitter to transmit a light pulse;
• ii) for a plurality of successive time portions in the acquisition time period, if a photon is received:
• iia) record a time at which the photon is received;
• iib) update a histogram to record a cumulative count of photons received by the receiver during the time portion;
• iic) calculate a time difference between the time at which the photon is received relative to a reference point of the time portion;
• iid) update a cumulative total of the calculated time difference for the time portion;
• iii) repeat steps i) to iid) for a succession of N transmitted light pulses;
• iv) identify a peak in a time portion of the histogram;
• and
• v) estimate a time of flight from the cumulative total of the calculated time difference for the time portion of the histogram containing the identified peak.