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Visitor II
September 29, 2016
Question

Fielf of view of VL53LOX

  • September 29, 2016
  • 3 replies
  • 918 views
Posted on September 29, 2016 at 13:03

How the 25 degree field of view of VL53LOX TOF sensor was covered? If there any algorithm to measure the distance with in that field of view ?

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    3 replies

    ST Employee
    June 15, 2017
    Posted on June 16, 2017 at 01:03

    The distance the sensor gives is a weighted average of all the objects seen in the field of view. The 25 degree FoV is a cone where the diameter of the circle is about have the length of the distance to the sensor. Unfortunately there is no way to determine if there are multiple objects within the field.

    Visitor II
    August 7, 2017
    Posted on August 07, 2017 at 13:57

    I was searching for information about the FligthSense technology, which the VL53L0X sensor is based, on when I came across this post. Would it be possible for anyone of ST people(or anyone else) to explain how this weighting is done/performed insight the VL53L0X; Not in details just the principles. Does it calculate the arrival time of each photon its recieves within a certain intervail and then do a weighted average on them all to calculate the distance?? I've measured the distance to a floor with one of these sensors tilted at an angle towards the floor. Here the absolute distance reading does not match up with the FoV/ model om mibe but the weighted averaging might explain it. If I measure directly towards the surface my model and measurements is identical.

    ST Employee
    August 18, 2017
    Posted on August 18, 2017 at 18:12

    Google 'Sigma Delta'. You can find some good papers on how it works. But basically it ends up being a weighted average. In your example of a floor at an angle, more photons are returned by the surface nearest the sensor, so you will get an answer that is nearer than you would get from a straight average. 

    Does it calculate the arrival time of each photon its receives within a certain interval and then do a weighted average on them all to calculate the distance?? Yes. Exactly right. But objects nearer to the sensor are going to reflect more light and get counted more heavily than the same object farther away.

    Very nice experiment by the way.