US 12,169,255 B2
Time-of-flight measurement with background light correction
Javier Miguel Sánchez, Zurich (CH); and Miguel Bruno Vaello Paños, Zurich (CH)
Assigned to ams Sensors Singapore Pte. Ltd., Singapore (SG)
Appl. No. 17/276,657
Filed by ams Sensors Singapore Pte. Ltd., Singapore (SG)
PCT Filed Sep. 13, 2019, PCT No. PCT/SG2019/050459
§ 371(c)(1), (2) Date Mar. 16, 2021,
PCT Pub. No. WO2020/060484, PCT Pub. Date Mar. 26, 2020.
Claims priority of provisional application 62/734,592, filed on Sep. 21, 2018.
Prior Publication US 2021/0270946 A1, Sep. 2, 2021
Int. Cl. G01S 7/48 (2006.01); G01S 7/4915 (2020.01); G01S 7/497 (2006.01)
CPC G01S 7/497 (2013.01) [G01S 7/4915 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method comprising:
obtaining a first light measurement using a photodetector of a sensor module, the first light measurement corresponding, at least in part, to ambient light in an environment of the sensor module;
generating modulated light using light source of the sensor module;
obtaining a second light measurement using the photodetector of the sensor module, the second light measurement corresponding, at least in part, to modulated light reflected from an object toward the photodetector; and
estimating, using an electronic control device, a distance between the sensor module and the object based on the first measurement, the second light measurement, and the modulated light;
wherein estimating the distance between the sensor module and the object comprises:
determining a first phase vector corresponding to the first light measurement,
determining a second phase vector corresponding to the second light measurement,
determining a third phase vector corresponding to the modulated light,
subtracting the first phase vector from the second phase vector to obtain a fourth phase vector,
determining a difference in phase between the fourth phase vector and the third phase vector, and
estimating the distance between the sensor module and the object based on the difference in phase between the fourth phase vector and the third phase vector, wherein the distance between the sensor module and the object is approximately proportional of the difference in phase between the fourth phase vector and the third phase vector.