Maximizing Perimeter Surveillance with “Slew to Cue” Capability

Video surveillance command centers typically consist of a large number of cameras providing video to a security guard, whose job it is to view them, assess situations and coordinate a response.  Studies show that an individual can effectively view a bank of video monitors for an average of only 20 minutes. This presents a significant workload issue. However, today’s video analytics software can help operators detect and react to intrusion situations.

Slew to Cue - Automatic Steering of Camera to an intrusion

Any type of security alarm needs visual verification. Enabling a PTZ camera to automatically “slew-to-cue” to the position of a sensor alarm can help reduce the workload of security personnel.


When a potential threat is identified, a series of operations are set in place to determine if
the threat warrants action. In most cases, the first action requires the security guard to orient them self to the location of the potential threat. This is often very difficult when dealing with a large number of monitors displaying imagery from different cameras at different locations and view angles.

Once the location is resolved, action can be taken to address the potential threat. The guard will most likely call a mobile team which can reach the potential threat and intervene. Simultaneously, the guard in the command center must continuously relay the threat’s location.

As the intruder continues to move, the entire problem is made more difficult as the command center operator must control the cameras via joystick and continue to provide status information.  This becomes increasingly more complex as the intruder transfers from one camera’s field of view to another. Additionally, valuable time is often lost in reacquiring the target on the new camera.


A more effective and strategic solution combines location aware security sensors (ground-based radars, fixed cameras, access control systems, intelligent fence or proximity sensors) along with pan and tilt cameras (visible and thermal) and video analytics software technology to help automate some of these critical actions the security guard must undertake.

Slew to Cue” is one such technology.   Slew to Cue allows a pan-tilt-zoom (PTZ) camera to be automatically steered to the exact latitude, longitude and elevation of an alarm, provided by itself or another sensor, and provides the security person instant gratification with a video clip.  This is also referred to as “slew to target.”

As a result, the guard can now focus his attention on relaying the pertinent information to all necessary individuals. In addition to detecting moving objects and automatically slewing the camera to the target of interest, the camera will also track the object as it moves across the area. If the tracked object moves out of the field of view of one camera, it can be picked up automatically by another camera and hands-free tracking will continue, offering the operator real time assessment of the target.

Slew to Cue is also useful in deterrent type situations where a physical response may take a considerable amount of time.  In these situations, a PTZ camera equipped with a co-mounted illuminant or acoustic deterrent devices can also track the target and issue deterrent sounds or lights to attempt to drive away the intruder.  This is particularly beneficial for remote facilities or substations where a response can take 30 to 60 minutes.


Scan to Target - Automatically steering a camera to a intruder

Long or undulating perimeters, installation anomalies, sensor accuracies and PTZ precision can result in camera pointing errors, whereby, when the camera is steered to the point of intrusion, there appears to be nothing there. “Scan to Target” can be used to attempt to compensate for these types of pointing errors and help locate the target.

A complementary technology is “Scan to Target.”  Scan to Target is a useful capability when detecting at long ranges or detecting fast moving targets, where margins of accuracy can compound.    Security systems include many inherent sources of location accuracy errors.  These might include the accuracy of the cameras PTZ mechanism, a camera’s position drift, installation variances, accuracy in the detecting sensor’s reporting position or that fact that the target is moving quickly.  The result: when the camera is steered to the point of intrusion, the target is not present in the camera’s field of view.

“Scan to Target” was introduced to address this issue.  This feature is designed to engage when the camera is slewed to a location but no target is found.  In this case, the Scan to Target algorithm is invoked and will cause the camera to intelligently scan the area where the alarm was reported in an attempt to acquire the target.  If the target is found, the PTZ camera will then automatically invoke automatic following.  At any point in the process, the operator may take manual control of the camera.


With Slew to Cue and Scan to Target functionality, security solutions can be optimized to ensure that potential threats are not missed.  The command and control center is simplified, providing automatic detection and assessment and allowing the operator to focus on making an appropriate response. These are effective tools in perimeter surveillance allowing for the most efficient and effective use of valuable security assets.

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