Searching With Post Video Motion Detection (Post VM)

The post video motion detection allows searching recordings for changes in one or more image areas of a camera. This is done with the help of “motion windows.”

Creating motion windows

1. Open the context menu of the plug in by right-clicking on . Select Post Video Motion detection. The dialog for setting up the post VM settings opens (see Program Call).

Fig. 71: Creating motion windows

2. Click on in the image area on the right-hand side of the settings dialog. A new window with a predefined video motion window opens.
3. You can execute the following commands:
   • Modify the size of the video motion window: By moving the sides or the corners of the window.
   • Create additional video motion windows: Draw a new window with the mouse.
   • Duplicate a video motion window: Click on .
   • Delete a video motion window: Click on .
   • Deactivate a video motion window: Click on .
To close the editor window, click on in the top right corner of the window.

Setting the trigger conditions

The Post VM window provides options for setting different parameters that influence the motion detection results.

Fig. 72: Setting the trigger conditions

• Trigger level: (White bar in diagram)
  Controls the trigger threshold of the video motion windows. Move the bar to the bottom to recognize a movement if only a few pixels change from one image to the next. Move the bar to the top to recognize a movement only if many pixels change.
• Sensitivity:
  This setting controls how large the change of each pixel in a video motion window must be to count as movement. Together with a low threshold value, this setting can be used to fine-tune video motion detection. If you move the slider to the right, the detection sensitivity increases, i.e., even smaller changes will trigger the detection.
• Correct Changes in Illumination:
  Activate this option to avoid false alarms, such as when lighting conditions change rapidly (for example, from sun to a cloudy sky).
• Deadtime:
  This sets the amount of time after the last detected post video motion event, during which pixel changes in a video motion window are ignored.
• Median Value:
  Enter a long duration (2.0 sec., for example) to improve the detection of slow movements.
  Note: Setting a value that is too high can lead to smears in the preview window.
• Color Filter:
  Select a color to limit the motion detection to a specific range or colors. The Post VM event will trigger if this color changes during post video motion detection.

Searching for changes in Video Motion Windows

Once you have defined the video motion windows and have set the trigger conditions, you can search the recordings for changes in the video motion windows. Use the playback buttons in the command bar at the bottom.
It is best to use the Backward/Forward playback buttons when searching continuous recordings. For searching in event images, use the Previous/Next image buttons. If MxMC detects a change within a video motion window, the frame of that window turns red and the search stops.