The audit process consists of comparing the presence and movement of people counted by human “ground truth collectors” (i.e. auditors) to the numbers calculated by the BlueZoo cloud service. Dividing the difference between the counted and calculated values, divided by the larger value delivers an accuracy percentage.
LARGER-VALUE – SMALLER VALUE
ACCURACY = —----------------------------------------------------
Auditing a calibration (of calculated *visits*) requires that the sensor location first be calibrated. Once it’s calibrated, collect ground truth again and compare the ground truth results to the calculated values returned by the sensors. Today, the process is as follows:
- Identify the detection zone for the ground truth collectors: one option is to mark the floor with blue tape to indicate the detection zone for a single sensor location. Ground truth collectors will count people present in the zone (snapshot ground truth), or who transition into and out of the zone (threshold ground truth).
- Calibrate the sensor: How to calibrate your sensor?
- Once the sensor location is calibrated, and typically weeks or months later, you can audit this result. Use the BlueZoo Foot Traffic Analytics mobile app to once again collect and report Ground Truth data for the detection zone. You must choose a collection time that starts and ends on a quarter-hour boundary. The ground truth record collected will be visible in the BlueZoo dashboard for that sensor location.
- Knowing the number of completed visits (i.e. the count of people exiting the inner detection zone), use the BlueZoo dashboard to report the number of completed visits calculated by BlueZoo. Compare the calculated value (of outgoing visitors) with the counted value (of visitors exiting) using the formula at the top to get “Accuracy %”.
The BlueZoo Foot Traffic Analytics 2023 mobile app will simplify this exercise by including Audit capabilities. The mobile app will calculate and display accuracy based on new ground truth:
- Confirm that the sensor location is calibrated.
- Collect GT data for an audit: collect either a snapshot count or a count of visits for a full 15-minute period.
- Once collected, the mobile app will compare the GT data to the value calculated by the BlueZoo cloud for that sensor location and return an accuracy percentage.
- This ground truth collected can also be used as input data for a new calibration job.
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