By default, the LPR channel recognizes license plates of all vehicles passing the camera FOV: moving toward the camera and away from the camera. The module can be set to recognize and save the license plates of vehicles moving in certain direction: from the camera, to the camera, any. The following results can appear as an outcome of the vehicle movement direction recognition: From the camera, To the camera, Undefined.

If traffic direction is set, then by default, if the direction of vehicle movement does not coincide with the specified value, the Entered the oncoming lane alarm event is created. This event can be disabled. If vehicle movement direction is undefined, the Entered the oncoming lane alarm event is not created.

To select the direction of traffic for license plate recognition, do the following:

1. Go to the settings panel of the LPR channel object, corresponding to the activated module (see Activating the software module used for identifying the plates).
   
2. From the Direction calculation drop-down list (1), select the mode of determining the vehicle's movement direction:
   • by LP position—the direction is determined by the position of the upper part of the license plate. If the upper part of the license plate at the start of tracking is lower than the upper part of the license plate at the end of tracking, then the direction is defined as "from the camera", otherwise—"to the camera".
   • by LP area—the direction is determined by the license plate area. If the license plate area at the start of tracking is larger than the license plate area at the end of tracking, then the direction is defined as "from the camera", otherwise—"To the camera".

   • by SDK—the direction is determined by the SDK. Currently, the following license plate recognition modules support this mode: RR, VT, AUTO-Uragan, IV.

     If the direction of movement is detected incorrectly or the license plate recognition stops, it is recommended to select the by LP area mode.

3. From the Direction drop-down list (2), select the traffic direction relative to the camera in which it is necessary to recognize the license plates.

   For the RIDR IV and CIDR IV modules, the direction of carriages in the camera view is selected from left to right or from right to left.

4. Set the Undefined checkbox (3) to display the direction as Undefined in the Vehicle Tracer module, if it is impossible to determine the vehicle direction.

5. If the from the camera or to the camera value is selected in the Direction drop-down list, the Record violation checkbox becomes available (4). By default this checkbox is set. That means that if the direction of vehicle movement doesn't coincide with the specified value, the Entering an oncoming lane alarm event is created. If this event must not be created, clear the checkbox.

   The following variations are possible depending on the selected traffic direction: if the to the camera direction is selected and the Record violation checkbox is set, the recognition is performed in both directions; if the movement is from the camera, the alarm event is created; if the from the camera direction is selected and the Record violation checkbox is set, the recognition is performed in both directions; if the movement is towards the camera, the alarm event is created; if the to the camera direction is selected and the Record violation checkbox is not set, the recognition is performed only in direction to the camera; if the from the camera direction is selected and the Record violation checkbox is not set, the recognition is performed only in the direction from the camera.

6. If you want the LPR channel to record the direction of vehicle movement as Entrance to the territory, set the Entrance checkbox (5).
   

   This setting is taken into account in WEB Report System PSIM when working with AUTO reports (see WEB Report System PSIM. User Guide).

7. Click the Apply button (6) to save the settings.

The traffic movement direction is now selected.