LPR camera triggering

An application for Noptel laser sensors is vehicle detection, when a vehicle is approaching LPR camera or receding from it. The operation principle is to measure the distance to a vehicle fast and to use this distance measurement information to define the exact triggering moment.

Typical sensor installation locates five to seven meters above the road, looking forward and down at the road. When a vehicle enters the triggering area defined by the parameters, the sensor sends a trigger pulse to the camera. Depending on the installation the triggering accuracy in such cases can be as high as 5-10 cm (or one millisecond).


  • Approaching and receding vehicles
  • One or several triggering windows
  • User defined trigger pulse operation
  • Enables delayed camera triggering
  • Single lane or multilane measurement
  • Fixed or mobile installation
  • Accurate and reliable
  • Simple to maintain
  • Easy to install
  • Eye safe


The compact and small size Noptel laser sensor can be placed into the camera housing together with the camera pointing to the same direction. However, thanks to the delayed camera triggering feature the Noptel laser sensor can be pointed further on the road than the camera.

Therefore, the operating distance of the camera doesn’t restrict the operating distance of the Noptel laser sensor and the triggering window of the laser sensor can be defined to the desired distance (typically to 30 – 40 m).

Experience: Laser trigger & LPR camera