About Calibration order between Crosstalk calibration and Offset calibration

GHuan.2 · ‎2022-11-05

According to api Manuals, for VL53L0CX and VL53L1CX, Offset calibration should be performed before Crosstalk calibration, but for newer ToF sensors, such as VL53L3CX or VL53L1CB, it's said Crosstalk calibration should take place before Offset calibration. Are alll these guides correct? Or order guide in earlier api manuals should be revised to be consistent with newer products?

John E KVAM · ‎2022-11-05

It's a tricky problem - the offset affects the crosstalk measurement and the crosstalk affects the offset measurement.

The reason one uses a reasonably near, highly reflective target to do offset cal. is so the (hopefully few) photons from the crosstalk will be completely overwhelmed by the zillions coming from the target as they are averaged together.

That prevents the crosstalk from affecting the offset much. So that's a good arguement for doing offset first.

For the histogram based sensors - the VL53L3CX, the VL53L1CB, the VL53L4CX and the VL53L5CX, one can do crosstalk without a target. All the crosstalk is in the first few bins of the histogram and with no signal one can simply record the shape and ampliture of those bins. So clearly for those chips - do the crosstalk first.

So the change was not from older to newer - but from Standard rangeing to Histogram based ranging.

john

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John E KVAM · ‎2022-11-05

It's a tricky problem - the offset affects the crosstalk measurement and the crosstalk affects the offset measurement.

The reason one uses a reasonably near, highly reflective target to do offset cal. is so the (hopefully few) photons from the crosstalk will be completely overwhelmed by the zillions coming from the target as they are averaged together.

That prevents the crosstalk from affecting the offset much. So that's a good arguement for doing offset first.

For the histogram based sensors - the VL53L3CX, the VL53L1CB, the VL53L4CX and the VL53L5CX, one can do crosstalk without a target. All the crosstalk is in the first few bins of the histogram and with no signal one can simply record the shape and ampliture of those bins. So clearly for those chips - do the crosstalk first.

So the change was not from older to newer - but from Standard rangeing to Histogram based ranging.

john

Our community relies on fruitful exchanges and good quality content. You can thank and reward helpful and positive contributions by marking them as 'Accept as Solution'. When marking a solution, make sure it answers your original question or issue that you raised.

ST Employees that act as moderators have the right to accept the solution, judging by their expertise. This helps other community members identify useful discussions and refrain from raising the same question. If you notice any false behavior or abuse of the action, do not hesitate to 'Report Inappropriate Content'

GHuan.2 · ‎2022-11-05

Thanks a million for your quick and professional answer, John, especially at the weekend. Now it's clear, We'll follow api manuals to do sensors calibrations. Have a nice weekend.