Motion Detection with Sophisticated Video Security Systems

 

 

At one time, a computer was only needed by NASA or science fiction movies.  Now a computer is nearly as common as a television.  Likewise, video security systems have been combined with computer technology to provide intelligent monitors outside of the high-profile environments.

 

We all have noted the security cameras at the airport and bank.  The newest generation of video security equipment is taking advantage of technology that was developed for high definition television and satellite TV: digital video. Once the signal is in digital format, it can easily be combined with computer technology to produce capabilities that seem at home in a Hollywood production.

 

 

Motion Detection Variable Sensitivity

 

Modern motion detection systems are much more sophisticated than the motion sensors we know from burglar alarms.  A video motion detector can be configured with variable sensitivity over the area.   This allows us to realize some interesting possibilities.

 

Motion detection video surveillance systems save imagery only when triggered, providing a time stamped record of events as they occur without recording inactivity between events.  Before the capabilities of motion detection, video cassette recorders would run continuously, and hours and hours of video would have to be viewed to find a specific event.  

 

With this technology, each image received by the camera is processed by software and compared to the previous image. If the system detects changes that exceed the threshold (a parameter set by the user), the system implements the predefined action.  The action could be simply that the video is saved, and/or a cell-phone text message or email is sent, or a relay is activated to turn on lights or an alarm.

 

 

Motion Detection Setup for Video Security Systems

 

Areas of the image can be set as insensitive by excluding certain portions of the screen.  For example, motion of specific objects that must be protected in an environment where other movement should be ignored can be performed (a painting surrounded by visitors in a museum).  Another example is the monitoring of a parking lot surrounded by trees; the area of the image that encompasses the trees could be set off-limits, so that only vehicles and pedestrians activate the motion detection.  It should be noted that outdoor monitoring is inherently more prone to false alarms than indoor monitoring.  For example lightning in a thunderstorm will almost always cause the detection of motion.   

 

 

During setup, the image is separated into grids (grid patterns of 100-500 zones are common).  Setup is simple.  A static image is displayed with a grid overlay.  A mouse is used to select areas, and only the highlighted boxes are active.  Each grid can be set with the appropriate sensitivity.

 

Time limits can be set so that the motion detection is not active until defined periods, and these periods can be different for each day of the week.  This feature could be used for the monitor of a warehouse that is busy during the day, but is idle at night.

 

Because of advances in technology, systems that once seemed appropriate only for Mission Impossible movies can be implemented by a small business or homeowner.  Someday, these systems will be as commonplace as the old-fashioned burglar alarm is today.   Today, the “smash and grab” burglary is most common.  Police estimate that the average home burglar is inside the house less than 2 minutes.  He knows that with this method, he is unlikely to get caught.  With a video record of his appearance, however, the bet is different. 

 

The perception is that the United States has a worse crime problem than other countries.  It is not true.  The overall crime rate in the United States is lower than in Britain and about the same as in Canada.  That does not mean that we don't have a problem.  Statistics show that a home burglary occurs in the U.S. every 15 seconds.  A car is stolen every 25 seconds.  Overall, a property crime occurs in the U.S. every 3 seconds (10 million each year).  Each person must decide for themselves how best to react to the threat.

 

 

Motion Detection Video Security Design Worksheet

 

 

B.V. Technology Website

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