A cross line detector is a VMDA detector that triggers when the trajectory of an object that is in the camera coverage and crosses a virtual line.

To configure a cross line detector, do the following:

1. Go to the settings panel for a VMDA detection object.
   
2. Select a line type (straight or polyline) the crossing of which leads to a detector triggering. Only one line can be added. The first line will be deleted if there is an attempt to add a second one. 
   
   1. If a detector is to trigger while crossing a straight line, click the Add line button (1).
   2. If a detector is to trigger while crossing a polyline, click the Add polyline button (2).
3. In the Video preview field ( 4), set the end point of the line, by clicking left mouse button, which crossing leads to a detector triggering.
   

4. Make necessary operations with a line. Line operations are shown in the table.

   Operation	Result
   Left mouse click in the video surveillance window	Creation of a line’s end point
   Hover to an end point and holding the left button pressed move the mouse	Shift of a line’s end point
   Hover to an end point and click the right mouse button	A line’s deletion

   
   

5. To select object type for which the detector will be enabled, click the  symbol. Available object types are:

   1.  Any object. Detector triggers when the line is crossed by any object
   2.  Man. Detector triggers when the line is crossed by a man

   3.  Vehicle. Detector triggers when the line is crossed by a vehicle

      Detection of the following object types can be configured using scripts and registry keys: human, group of humans (with a possibility to count number of people in a group), car, noise, object carried into the area, object carried out of the area, other. See also CAM_VMDA_DETECTOR section of the Programming Guide.

      
      

6. By clicking the left mouse button upon one of the grey arrows, set the object’s direction across the line by which the detector will trigger. The arrow will be colored white.

   Approximate speed of detected objects is displayed close to arrow. It is possible to change value of speed by changing arrow length moving arrowhead with pressed left mouse button. The detection tool alarm triggers when an object crosses the line in the selected direction with a speed that is less than shown near the arrow. The detection tool alarm is not registered when the object crosses the line if the speed is greater than shown. At minimal and maximal value of speed the "?" sign will display and fact of cross line regardless of speed will be detected.

   Arrow has minimal length while adding.

   
   

   It is necessary to set at least one object’s direction across the line.

   
   

   If both directions are set, the detector will trigger at line crossing by an object in any direction.

   
   

7. If the alarm is to be generated when the detector triggers, set the Generate alarm on camera checkbox (5).
8. To save the changes, click the Apply button (6).

A cross line detector is now configured.