US 12,228,684 B2
Rangefinder, rangefinding system, and rangefinding method
Kensei Jo, Kanagawa (JP); Tomoya Takeda, Kanagawa (JP); and Nana Matsumoto, Kanagawa (JP)
Assigned to SONY SEMICONDUCTOR SOLUTIONS CORPORATION, Kanagawa (JP)
Appl. No. 17/250,517
Filed by SONY SEMICONDUCTOR SOLUTIONS CORPORATION, Kanagawa (JP)
PCT Filed Jul. 10, 2019, PCT No. PCT/JP2019/027353
§ 371(c)(1), (2) Date Jan. 31, 2021,
PCT Pub. No. WO2020/031603, PCT Pub. Date Feb. 13, 2020.
Claims priority of application No. 2018-148529 (JP), filed on Aug. 7, 2018.
Prior Publication US 2021/0293939 A1, Sep. 23, 2021
Int. Cl. G01S 7/4865 (2020.01); G01S 17/46 (2006.01); G01S 17/89 (2020.01)
CPC G01S 7/4865 (2013.01) [G01S 17/46 (2013.01); G01S 17/89 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A rangefinder, comprising:
a time-of-flight (ToF) sensor configured to receive light reflected from a surface of an object, wherein the reflected light is output from each of a plurality of light sources included in a light source unit;
a sensor clock configured to control an image capture timing of the ToF sensor, wherein
the sensor clock is a clock specific to the rangefinder,
the light source unit has a light source-light emission timing controlled by a light source unit clock, and
the sensor clock is different from the light source unit clock; and
a distance calculation unit configured to:
analyze an output of the ToF sensor;
calculate a distance between the rangefinder and the object based on two distance calculation formulas, wherein
the two distance calculation formulas calculate a distance from at least two light sources of the plurality of light sources included in the light source unit to the rangefinder,
the two distance calculation formulas are based on first data related to the distance between the rangefinder and the object, second data related to a distance between the object and each light source of the plurality of light sources included in the light source unit, and an offset C that corresponds to a rangefinding error, and
the rangefinding error occurs based on a difference in phase between the sensor clock and the light source unit clock;
create one difference calculation formula to calculate a difference of a first distance calculation formula and a second distance calculation formula of the two distance calculation formulas;
create a linear equation based on a line that connects the rangefinder and the object; and
solve the difference calculation formula and the linear equation as a first simultaneous equation.