US 12,449,515 B2
Time of flight calculation with inter-bin delta estimation
Maxim Kulesh, Hamburg (DE); Sebastián André Fatjó Carvajal, Leuven (BE); and Mark Steigemann, Ebstorf (DE)
Assigned to NXP B.V., Eindhoven (NL)
Filed by NXP B.V., Eindhoven (NL)
Filed on Oct. 21, 2021, as Appl. No. 17/451,685.
Claims priority of application No. 20214530 (EP), filed on Dec. 16, 2020.
Prior Publication US 2022/0187430 A1, Jun. 16, 2022
Int. Cl. G01S 7/4865 (2020.01); G01S 7/48 (2006.01); G01S 7/4863 (2020.01)
CPC G01S 7/4865 (2013.01) [G01S 7/4808 (2013.01); G01S 7/4863 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of calculating time of flight of a lidar signal, the method comprising:
i) transmitting a light pulse to start an acquisition time period having a plurality of successive time portions;
ii) for each successive time portion, if a photon is received:
iia) recording a time at which the photon is received;
iib) updating a histogram to record a cumulative count of photons received during the time portion by subtracting a measure of noise from the cumulative count of photons received during the time portion;
iic) calculating a time difference between the time at which the photon is received relative to a reference point of the time portion, wherein the reference point is greater than zero;
iid) updating a cumulative total of the calculated time difference for the time portion;
iii) repeating steps i) to iid) for a succession of N transmitted light pulses;
iv) identifying a peak in a time portion of the histogram; and
v) estimating a time of flight from the cumulative total of the calculated time difference for the time portion of the histogram containing the identified peak.