A setup is considered good if the sensor detects only the floor in the two FoVs. Consequently, the verticality of the
FoV is ensured. However, the tracking area must not be too narrow. In situations where the verticality cannot be
fully ensured, or when the FoVs are narrow, it is advised to alternatively enable N*M SPADs as follows:
•
N to be within the interval [4, 8] as described above and enabled SPADs should be centered
•
M to be within the interval [8, 16] and the SPADs to remain centered for a narrow but non vertical setup. If
the verticality of the FoV cannot be ensured, the SPADs do not have to be centered.
Floor detection reliability can be checked by running a trimming procedure to adjust the width of the back and
front FoVs, by enabling the relevant SPADs. Analysis of the extracted histograms can help in detecting the SPADs
belonging to the parts of the FoVs that do not range on the floor and should never be enabled. Note that the
smaller the number of lines of SPADs used for this trimming, the larger the number of histogram values that have
to be computed.
The figure below shows a trimming procedure example in which a significant number of distances have been
extracted by ranging with the SPADs enabled within the red rectangle (10 SPADs lines). The red rectangle can be
moved by one line or more between each test.
Figure 11.
Trimming procedure
UM2600
Ranging on the floor to determine the threshold
UM2600
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Rev 2
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