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MSAMB.1
Associate III
July 21, 2020
Question

Hello,in ST's documentation on tofs it is mentioned that ToF sensors provide us with precise answers regardless of the color of the target but I do not understand why we have several different results with gray white targets or black, can someone exp

  • July 21, 2020
  • 1 reply
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1 reply

John E KVAM
ST Employee
July 21, 2020

Sure - Color doesn't matter, but reflectivity does. The biggest variation in accuracy is going from a very reflective (white) target to a very dull (black) one.

We need enough photons to get an good answer. if the target is particularly small, dull or far away, we might be able to get an answer, but it might not be as accurate as you might like. Conversly, a bright, large, near target also has issues. The photons might reflect multiple times before being detected. This leads to 'over ranging' in the very near targets.

This issue is why the accuracy specifications in the datasheet are set where they are.

The marketing department writes stuff like "provides precise answers". The engineering department puts the accuracy numbers in the datasheet.