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Video Cameras
(Chapter 2   Video Surveillance, Continued)

To monitor or not to monitor

Each year, a great number of camera systems are bought in the United States with the objective of assigning a security person to constantly monitor the scenes from the video cameras in real time. The objective of such installations is that some sort of response may then be dispatched immediately and an undesirable incident prevented or stopped, basically using the live person watching the monitor as a detector. This is quite often an unrealistic approach to security, particularly in school applications.

Exhibit 2.05Experiments were run at Sandia National Laboratories 20 years ago for the U.S. Department of Energy to test the effectiveness of an individual whose task was to sit in front of a video monitor(s) for several hours a day and watch for particular events. These studies demonstrated that such a task, even when assigned to a person who is dedicated and well-intentioned, will not support an effective security system. After only 20 minutes of watching and evaluating monitor screens, the attention of most individuals has degenerated to well below acceptable levels. Monitoring video screens is both boring and mesmerizing. There is no intellectually engaging stimuli, such as when watching a television program. This is particularly true if a staff member is asked to watch multiple monitors, with scenes of teenagers milling about in various hallways, in an attempt to watch for security incidents (exhibit 2.5).

A practical security application of real-time viewing of a video monitor might be the intent to actively allow or disallow individuals to enter a particular locked door. In this case, the security person at or near the video monitors receives an alarm or other announcement that a person desires entry into that facility or area. The security person would then focus his or her attention directly on the screen and make a decision (according to procedures) as to whether to release the remote lock on a door to allow the person access.

Most schools have a security staff, whether it be an assistant principal assigned security as one of his or her duties, a few security aides equipped with two-way radios, or an impressive number of sworn police officers. Few schools, however, find themselves with surplus security-staff time. Because of the ineffectiveness of people monitoring video scenes in real time, it would seem to be a very poor use of school security staff. One possible exception is when a certain incident is expected at a school during a finite time period. For example, if cars in a parking lot are frequently broken into during the noon hour, security staff may want to actively monitor their cameras' outputs during this period so that they may immediately assess an incident in progress and apprehend the suspect. This would be particularly appropriate if the suspect is not known and not a member of the school.

The use of cameras and a real-time display unit without the benefit of a recorder is not recommended. It is true that a video camera and monitor alone are much cheaper than a complete video system with recording and multiplexing capabilities. However, the hard evidence made available in the form of a video recording can more than make up for the cost of a recording system. Ease of prosecution and the likely prevention of future incidents by this individual are additional benefits.

 



Research Report:   The Appropriate and Effective Use of Security Technologies in U.S. Schools