4.9 Target order
The VL53L8CX can measure several targets per zone. Thanks to the histogram processing, the host is able to
choose the order of reported targets. There are two options:
• Closest: The closest target is the first reported
• Strongest: The strongest target is the first reported
The target order can be changed using function vl53l8cx_set_target_order(). The default order is Strongest.
The example in the following figure represents the detection of two targets. One at 100 mm with a low reflectance,
and one at 700 mm with a high reflectance.
Figure 12. Example of histogram with 2 targets
4.10 Multiple targets per zone
The VL53L8CX can measure up to four targets per zone. The user can configure the number of targets returned
by the sensor.
Note: The minimum distance between two targets to be detected is 600 mm.
The selection is not possible from the driver; it has to be done in the ‘platform.h’ file. The macro
VL53L8CX_NB_ TARGET_PER_ZONE needs to be set to a value between 1 and 4. The target order described
in Section 4.9 Target order directly impacts the order of detected target. By default, the sensor only outputs a
maximum of one target per zone.
Note: An increased number of targets per zone increases the required RAM size.
4.11
Xtalk margin
The Xtalk margin is an additional feature only available using the plugin Xtalk. The .c and .f files
'vl53l8cx_plugin_xtalk' need to be used.
The margin is used to change the detection threshold when a cover glass is present on the top of the sensor. The
threshold can be increased to ensure that the cover glass is never detected, after setting Xtalk calibration data.
For example, the user can run a Xtalk calibration on one single device, and re-use the same calibration data for
all other devices. The Xtalk margin can be used to tune the Xtalk correction. The figure below represents the Xtalk
margin.
Figure 13. Xtalk margin
UM3109
Target order
UM3109 - Rev 1
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