4.2.2 Crosstalk calibration procedure
Crosstalk calibration should be conducted in a dark environment, with no IR contribution.
Place a 17 % reflectance chart at the crosstalk calibration distance (xcd), then call the
VL53l1X_CalibrateXtalk(dev, xcd, &xtalk) to perform the calibration. It may take a few seconds.
To characterize the xcd, refer to Section 4.2.3 Crosstalk calibration distance characterization.
4.2.3 Crosstalk calibration distance characterization
The crosstalk calibration distance needs to be characterized as it depends on the system environment which
mainly includes:
• The cover glass material and optical properties
• The air gap value i.e. the distance between the sensor and the cover glass
Do a full sweep with the target from near to far, noting the resulting measurement. You will get a plot similar to
Figure 6). At some point, the actual value and the measured value start to diverge. This is the crosstalk calibration
distance.
The figure below shows the crosstalk effect on the ranging curve. From a given distance, the effect of crosstalk is
predominant, and the sensor starts to under range.
Figure 6. VL53L1X crosstalk calibration distance definition
The crosstalk calibration distance corresponds to the maximum ranging distance achievable by the sensor when
the cover glass is present.
The ranging curve with crosstalk corrected is the ranging result when crosstalk compensation is applied i.e. when
crosstalk calibration is completed or after crosstalk calibration compensation is applied.
4.2.4 Getting crosstalk calibration data
The function VL53L1_GetXtalk () returns the current crosstalk value programmed in the sensor. Zero means there
is no crosstalk compensation. The unit is cps (counts per second).
UM2510
Crosstalk calibration
UM2510 - Rev 1
page 11/26
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