Calibrating the Sharp virtual loop - SharpOS 11.8

Sharp Administrator Guide 11.8

SharpOS 11.8

If your fixed Sharp 11.X system uses the Continuous with virtual loop reading mode, and you notice that the number of NOPLATE reads is not accurate, you can calibrate the system in the Sharp Portal.

What you should know

  • Calibration is necessary so that the system can determine the expected vehicle direction and speed.
  • For best results when using the virtual loop feature, ensure that the detection area is well illuminated. If there is not enough light for reliable operation, the virtual loop is temporarily disabled until lighting conditions improve.
  • For the calibration to finish quickly, choose a time when vehicles are expected to be traveling in the appropriate direction in the designated area.
  • When you select the Continuous with virtual loop reading mode and save your selection, the system automatically starts the initial calibration.
  • You cannot use the virtual loop as a trigger for gate control.
  • It is not recommended to use Virtual loop in conjunction with the Optimize for static image background feature when vehicles travel faster than 50 km/h (30 MPH).
  • During calibration, the system continues to send plate reads to Security Center.
  • During calibration, NOPLATE reads and other objects passing in front of the camera are ignored and do not affect the calibration.
  • Calibration is complete when the system has successfully read ten license plates. For best results, vehicles that pass the camera during calibration should behave as normal traffic (similar speed and direction).


  1. In the Sharp Portal, select the Configuration tab.
  2. In the Plate read section, click the Calibrate button located beside the Reading mode drop-down list.
    NOTE: The Calibrate button is only available if the Continuous with virtual loop reading mode is selected.
  3. Click Save.
    The system calibrates the virtual loop based on the speed and direction of the first ten vehicles that pass in front of the camera. There is no feedback to indicate that the calibration is complete.

After you finish

Monitor the plate reads in Security Center to ensure that vehicle license plates are read (when plates are visible), that NOPLATE reads are generated (when plates are not visible), and that vehicles are not ignored because they fall outside of the vehicle speed and direction expected by the system.