1. Introduction
Not knowing what is happening to your property when you are away is worrisome and discomforting. Yet, knowing that something has happened, but not exactly what, can be just as frustrating, sometimes even worse. Network video surveillance offers versatile perimeter protection that allows you to find out what’s going on around your premises and why, and thereby enabling resourceful and cost effective protection of your assets.

2. Traditional measures for perimeter protection
Safeguarding against trespassing, theft and vandalism has long been a part of daily business life. An increasing number of enterprises are also experiencing a growing need for continuous security operations to counter what they perceive as a rising global threat level.

To that end, they invest in various perimeter protection measures, such as short-distance radar, lasers, ground sensors, motion sensors or motion-sensitive fence wires. All these technologies perform well, and can, under many circumstances, capably detect an intrusion and set off an alarm.

However, all of these systems have an obvious and significant limitation: they cannot distinguish between real and false alarms. So for every alert, someone – i.e. in-house security personnel or a security company providing the corresponding services – has to decide whether or not a patrol should be dispatched to the area. Not until an inspection is carried out can it be confirmed if there has been an actual breach of the perimeter, and if this breach is a threat that needs to be dealt with, or whether it was caused by something harmless, e.g. an animal or malfunctioning equipment.

Such procedures tend to be rather time-consuming and will – especially if the false alarms are frequent – eventually lead to more lax or even dropped security checks. Consequently, the whole operation runs the risk of becoming very expensive without providing any peace of mind.

3. Network video for a clear picture and strong decision support
With network video cameras, on the other hand, it is possible to build an intelligent and reliable surveillance system for perimeter protection. A vast range of products from the leading supplier makes such IP-based systems very versatile and high performing, especially in di cult lighting environments and in varying and demanding weather conditions. Clear and crisp images facilitate detection and identification of objects, people and incidents, thus making it easier to separate true alarms from false alarms and other incidents that don’t require any measures to be taken. Automated solutions and advanced video analytics software can further reduce the need for monitoring staff.

3.1 Detect - verify - act: How it works
Basically, the main objective for perimeter protection is to detect a threat or an intrusion at the earliest possible stage. However, areas where valuable assets sometimes are kept, for instance rail yards, bus depots, car parks or harbors can pose a significant challenge for security managers. The sheer size of these places can be a problem. Lighting conditions can also be troublesome, especially during nighttime if there is little or no electric lighting available.

3.2 First line of defense - thermal network cameras
Modern thermal network cameras are very sensitive and accurate. They are unrivaled when it comes to detection, making them ideal in a first line of defense. Once a suspicious event has been detected, the thermal camera can be configured so that it automatically directs a PTZ (pan/tilt/zoom) camera to the right place.

The PTZ camera can be further used for tracking a perpetrator or any suspicious activity. Tracking can be done in several different ways, from manual maneuvering by joystick to auto tracking relying on intelligent video analytics. Working in parallel, these two camera types form an unbeatable combination.

As opposed to day/night cameras, which use the near-infra red spectrum of light, thermal cameras do not require any light at all to operate. Instead, these cameras are able to detect a person or an object by visualizing the thermal radiation they emit. This capacity makes the cameras highly functional in complete darkness as well as in fog, snow and other challenging conditions.

Less apparent is their usefulness in broad daylight. Thermal cameras are also very e cient when it comes to discovering people or objects that are obscured by complex backgrounds or who hide in deep shadows. Another advantage is that they cannot be interfered by bright lights or laser pointers.

 3.3 On top with PTZ domes and fixed cameras
With thermal network cameras, operators can detect suspicious activity around the clock. However, after detection must follow verification before any decision on further actions can be taken.

As soon as a threat has been identified a horn speaker can be used to deter or delay an intrusion by sending out warnings or messages. Floodlights, sirens and similar components can also be used for deterrence.

PTZ cameras are very adaptable and can enable an operator to get on top of a situation very quickly. After an alert, he can pan and tilt the camera by remote control and get an overview of the area in question. From there it is easy to zoom in on details. State of the art network cameras deliver sharp images with very high resolution enabling facial identification or license plate recognition even at very long distances.

There are many situations where surveillance video with color is an important factor for successful identification. Special low-light technology that reduces noise and maintains colors even in very dark conditions is therefore a useful capability that greatly enhances the user’s possibility to effectively recognize and identify people, vehicles and incidents.

A visual close-up also helps the security operator to further analyze the situation at hand. Is the person that caused the alarm an unwanted intruder with possible ill intent? Or is it a visitor who has come astray or is it in fact an authorized staff member?

The whereabouts of detected trespassers can be followed with a remotely operated PTZ dome or well-placed fixed cameras while an employee or a guard patrol is guided to intercept the perpetrator. Saved video of an intruder’s movements and activities can later prove valuable evidence in a trial.

 4. Scalable, flexible and cost efficient
Large surveillance systems can comprise countless sensors, cover huge areas and include a well-equipped command center with plenty of security personnel. Many of these large systems tend to be complex and involve several different technologies. Not only can this make them expensive and di cult to manage but also risk hampering both flexibility and scalability.

Furthermore, the bigger the site, the greater the information load will become, which can make it di cult to run operations smoothly and effectively. This is particularly evident when it comes to the task of distinguishing between alarms and false alarms.

Using network cameras for perimeter surveillance solves many of these difficulties. A wide range of cameras, accessories and various applications enables end-users to obtain a comprehensive and efficient video-based solution. Network video also comes with a distributed system architecture, which eliminates the need for back-end hardware and makes it flexible as well as scalable.

Detection and analysis of suspected intrusions and other critical situations might be fully or partially automated with video analytics applications.

Traditional solutions, such as microwaves, infra-red or underground sensors, leave the operator with the di cult challenge to understand the nature of the threat every time an alarm is set off. However, if the alert comes in the form of images it is much easier for the operator to recognize and categorize the type of alarm and react accordingly. There is an immediate visual understanding of the situation which not only minimizes the time it takes make a well-informed decision but also reduces the stress load, since false alarms can be easily identified and ignored.

High system accuracy – i.e. a high probability of detection in combination with a low rate of false alarms – makes guards and other operators more efficient and facilitates alarm management. Knowing with certainty which alarms are serious and require immediate action and which can be dismissed as false also render the operator greater peace of mind and better opportunities to stay focused. Network video is consequently a very cost efficient way to improve over-all security and works equally well regardless if the alarms are handled locally or remotely.

4.1 Automation - detection without eyes
Network cameras provide the high quality images needed to enable advanced features such as video motion detection, virtual fence or cross line detection. Compared to a radar or laser system that is typically installed on the inside of a fence, a network camera can be configured to sustain an alarm trigger outside the fence and thus give an earlier warning.

Large systems allow even more advanced configurations and functionalities. For example: Object filtration which reduces the number of false alarms by only reacting to objects that fulfill certain, pre- determined criteria, such as size and speed etc. Similarly, conditional alarm requires a number of rules to be fulfilled before the alarm is triggered. Another example of a useful application to minimize false alarms is masking area, which is a zone within the camera’s field of view where events don’t trigger alarms.

The most advanced application in the market even enables detection of multiple events occurring simultaneously in different places. It can analyze detected events, then dismiss non-threatening ones and notify security staff of any potentially critical situations. The bottom line is accurate detection and a minimal number of false alarms.

4.2 Automatic notification
When an alarm is triggered, a real time notification can be automatically sent to a single or multiple simultaneous users, either by e-mail or text. Using a remote viewing app, the receiver can then see a live stream from the camera or a recording of the triggering event. Based on this visual information, it is easy to go ahead and decide on the appropriate action.

IP-based systems are flexible and scalable as well as being possible to integrate with other security technologies, such as access control and motion sensors etc. Relying on open industry standards also facilitates the development of a wide variety of third party applications.

5. Conclusion
Network camera surveillance for perimeter protection enables you not only to detect a possible intruder at an early stage, but it will also help you to verify the extent and severity of a breach as well as providing essential visual information to adopt an appropriate response. Furthermore, by checking video streams, it is easy to distinguish false alarms from serious intrusions.

The versatility of network cameras, in combination with many available applications and video analytics software, makes the system flexible, scalable and cost efficient. Finally, avoiding all the work, stress and problems that are caused by misinterpreted alarms will also pay dividends – if nothing else, in the form of a greater peace of mind.

A network camera surveillance system doesn’t leave you in the dark.