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Distance measuring method and distance measuring system

  • US 9,778,361 B2
  • Filed: 07/01/2015
  • Issued: 10/03/2017
  • Est. Priority Date: 01/31/2013
  • Status: Active Grant
First Claim
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1. In a time-of-flight (TOF) distance measuring system including a light source for emitting light, a sensor for operating in synchronization with the light source to convert received reflected light into an electrical signal and accumulate the electrical signal, and a calculation device, a method for measuring a distance to an object comprising:

  • emitting light to the object during a predetermined emission period using the light source;

    accumulating signal amounts during a plurality of signal accumulation periods different from each other in at least one of a start time and an end time in the sensor; and

    calculating the distance to the object based on the signal amounts accumulated in the plurality of signal accumulation periods using the calculation device,whereina first signal accumulation period that is at least one of the plurality of signal accumulation periods is set so that a first accumulated signal amount that is a signal amount accumulated during the first signal accumulation period varies depending on the distance to the object,emission intensity of the light source during the emission period is changed so that the first accumulated signal amount and the distance to the object have a nonlinear relationship within a distance measurement range, andthe emission intensity of the light source is higher during an initial portion of the emission period than during the other portion of the emission period so that the proportion of a change in the distance to the object to a change in the first accumulated signal amount is smaller in the vicinity of an upper limit of the distance measurement range than in the other portion of the distance measurement range.

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