US 11,982,768 B2
Systems and methods for optical distance measurement
Xiang Liu, Shenzhen (CN); Mingming Gao, Shenzhen (CN); Xiaoping Hong, Shenzhen (CN); and Di Wu, Shenzhen (CN)
Assigned to SZ DJI TECHNOLOGY CO., LTD., Shenzhen (CN)
Filed by SZ DJI TECHNOLOGY CO., LTD., Shenzhen (CN)
Filed on Jun. 18, 2019, as Appl. No. 16/445,146.
Application 16/445,146 is a continuation of application No. 15/944,729, filed on Apr. 3, 2018, granted, now 10,371,802.
Application 15/944,729 is a continuation of application No. PCT/CN2017/093688, filed on Jul. 20, 2017.
Prior Publication US 2019/0302241 A1, Oct. 3, 2019
Int. Cl. G01C 3/08 (2006.01); G01S 7/4861 (2020.01); G01S 17/10 (2020.01); H03K 5/133 (2014.01); H03K 19/0175 (2006.01); H03K 5/24 (2006.01)
CPC G01S 7/4861 (2013.01) [G01S 17/10 (2013.01); H03K 5/133 (2013.01); H03K 19/017581 (2013.01); H03K 5/24 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A system for measuring a distance to an object, the system comprising:
a light emitter configured to emit an outbound light pulse;
a light sensor configured to receive a returning light pulse reflected from the object and output an analog pulse signal representing the returning light pulse;
a field-programmable gate array (FPGA) coupled to the light sensor and configured to:
convert the analog pulse signal to a plurality of digital signal values by (1) comparing the analog pulse signal to a plurality of threshold values and (2) generating the plurality of digital signal values based on the comparison, and
generate a plurality of time measurements corresponding to the plurality of digital signal values by sampling each digital signal value, wherein a time resolution of the sampling is shorter than a clock period of the FPGA; and
a controller configured to calculate the distance to the object based on the plurality of digital signal values and the plurality of time measurements.