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Calibration

MSAMB.1
Associate III

Hello I am new in the field of Tof sensors I would like to know how you proceed to carry out your calibrations? are there any software manipulations to perform? I read in a conversation in which you spoke about function and variable Xtalk .. If so, please tell me which files to modify .. Thank you

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Accepted Solutions
John E KVAM
ST Employee

Calibration is the most often asked question. There are funtions in the API that you can call.

You didn't say which ToF sensor you have, but all follow the same basic rules.

Please note all our parts have a datasheet and a user manual. The calibration procedure is in the user manual.

The 4 different ToF sensors vary slightly, but the basics are below.

Refspad() is the easiest. Just call it with no near target.

This function has to be called after the VL53L1_DataInit() and VL53L1_StaticInit() functions are called.

The crosstalk calibration is a a touch more difficult. If you have a coverglass you need to do this. The photons that return immidately from the coverglass is a constant. The photons from your target is variable. To determine which is which, place a light gray target at a distance where there the sensor under reports the distance by 10 or 20 percent. (This takes some trial and error on your part). Then call the crosstalk function. On the VL53L1X the function is: VL53L1_PerformXTalkCalibration());

This function will range many times and compare the reported answer to the distance you entered.

The last calibration you need is Offset. During the soldering process the chip changes just a little bit. But with the speed of light a little bit adds up to a lot. Place a paper-white target at 10 -14 centimenters aways and call the VL53L1_PerformOffsetCalibration() function. This will compare the returned range with the known range you entered. The delta is your offset.

Call a get_calibration function() which will return all the calibration data. Store this in your host. After every boot call the Put_calibration function.

And there you have it.

  • john


If this or any post solves your issue, please mark them as 'Accept as Solution' It really helps. And if you notice anything wrong do not hesitate to 'Report Inappropriate Content'. Someone will review it.

View solution in original post

2 REPLIES 2
John E KVAM
ST Employee

Calibration is the most often asked question. There are funtions in the API that you can call.

You didn't say which ToF sensor you have, but all follow the same basic rules.

Please note all our parts have a datasheet and a user manual. The calibration procedure is in the user manual.

The 4 different ToF sensors vary slightly, but the basics are below.

Refspad() is the easiest. Just call it with no near target.

This function has to be called after the VL53L1_DataInit() and VL53L1_StaticInit() functions are called.

The crosstalk calibration is a a touch more difficult. If you have a coverglass you need to do this. The photons that return immidately from the coverglass is a constant. The photons from your target is variable. To determine which is which, place a light gray target at a distance where there the sensor under reports the distance by 10 or 20 percent. (This takes some trial and error on your part). Then call the crosstalk function. On the VL53L1X the function is: VL53L1_PerformXTalkCalibration());

This function will range many times and compare the reported answer to the distance you entered.

The last calibration you need is Offset. During the soldering process the chip changes just a little bit. But with the speed of light a little bit adds up to a lot. Place a paper-white target at 10 -14 centimenters aways and call the VL53L1_PerformOffsetCalibration() function. This will compare the returned range with the known range you entered. The delta is your offset.

Call a get_calibration function() which will return all the calibration data. Store this in your host. After every boot call the Put_calibration function.

And there you have it.

  • john


If this or any post solves your issue, please mark them as 'Accept as Solution' It really helps. And if you notice anything wrong do not hesitate to 'Report Inappropriate Content'. Someone will review it.
MSAMB.1
Associate III

Thanks for your answer ! I have the VL6180 and the VL53L0X and I want to make calibration of these both sensor