Video Motion Detection – Triage for IP Video Recording

January 7, 2011 by Nathan Miloszewski

Responding to disasters or emergency medical situations requires triage — the process of determining the priority of treating patients based on the severity of their condition.

Video motion detection employs a similar process in that it prioritizes only the important events and area’s of a camera’s view that you specify to be included or excluded for motion detection.

By prioritizing video recordings, video motion detection (VMD) saves on storage space and bandwidth by not having to record everything making searching for occurences easier as well.

Internal and External Video Motion Detection

Video motion detection function in similar ways for both internal and external implementations in that they will:

  • Save on bandwidth
  • Save on storage
  • Activate external devices (open/close doors,  sound alarms, turn lights on/off) when motion is detected

External VMD

“External” VMD is a function in IP camera software for cameras that don’t have this feature built-in.  The video management software program analyzes video sent from the cameras, analyzes the activity, and then triggers any alerts that you have programmed.

The drawback to relying on IP camera software for motion detection is the drain on your hardware platform’s resources – running a VMD function is CPU intensive.

Internal VMD

“Internal” VMD is when the IP cameras or video servers have video motion detection capabilites built-in and can analyze and process the activity “at the edge,” that is, in the device itself thus saving your recording devices from having to work as hard.

For example, a camera like the Axis P1311 Fixed IP Camera has built-in video motion detection, audio detection, and detection of camera tampering attempts.  And the ACTi ACD-2000Q is a 4-channel video server with video motion detection and alarm responses.

Where / How to use VMD?

“Security Info Watch has a great article, “Thinking About Motion Detection?”, by Kenneth  Gentile that outlines how and what VMD features can benefit your IP surveillance application.

First he outlines the features of VMD that you should understand:

  • Intruder Identification
  • Environmental Compensation (recognize and ignore wind blown debris, etc.)
  • Counting
  • Directional Identification (trigger alarms for movement in unauthorized directions)
  • Item Recognition
  • Subject Tracking
  • Multiple Subject Tracking

Next he talks about understanding what you want achieve from your surveillance system.

Identify what can move:

  • Vehicles
  • Routine personnel entry/exit
  • Packages

Then establish what “items of interest” you have that are “typically stationary and should not be moved” such as:

  • Intruders / unauthorized access
  • Leaks / mechanical failures
  • Smoke, fire, flame

VMD Past, Present, Future

For background on the history of video motion detection in surveillance systems I suggest reading “Digital Video Motion Detection” by Charlie Pierce.  It’s interesting to see that while this technology has been around for 25-30 years in analog/CCTV systems, there were many hurdles to overcome.

Namely, false alarms were very prevelant.  Recognizing all the bugs that had to be worked out gives me an appreciation and better understanding of how today’s advanced VMD functions work.

More importantly, the advanced algorithms at play here allow you to be creative and imaginative in what you ask of your IP surveillance system.


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