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About the dead time of VL53L8CH

Licx
Associate III

I woulke to know the dead time of VL53L8CH to know the max value of one bin, but there is no information in the datasheet. Besides, currently I am using  the example in VL53LMZ_MassMarket_ULD of cubeide to get the histogram, I want to know if the number of the bin represent the number of the photons or does it need to multiply with some special scale value?

2 REPLIES 2
Licx
Associate III

Because I found that the number of some bins is smaller than 1 so I think if there is any scale value to get the real number of photons.

RogerM
ST Employee

Hi,
Histogram bin values are not simple photon counts. There has been normalization applied to the raw data (the "N" in "C.N.H. data"). The normalization is compensating for particular aspects of how the ToF ranging engine optimizes the capture process.
In addition to the normalization there are two addition functions then applied to the data.
(1) Ambient level removal(subtraction).
(2) Optical cross-talk signal removal.
Negative values you may see in histogram bin values are the result of these two processes being applied to data that is in inherently noisy. Also, depending on the accuracy of the xtalk (cross-talk) data this may push the histogram bin values to become negative in the xtalk region of the histogram.
Histogram values are not clipped at zero to preserve the noise distribution.
Hope this helps.