Correctional facilities have a long history of hardening their perimeters to keep people from leaving the property. Yet an increasingly serious problem many prisons face is the introduction of contraband coming from the outside. Given the size of correctional perimeters, it can been difficult to stop individuals from approaching a fence from the exterior and throwing packages that contain pre-paid cell phones, drugs, weapons and other contraband. Now, technology in the form of smart outdoor sensors can provide an effective solution to what has been a difficult problem by providing area coverage outside the fence line. 

Prisons face a number of challenges in securing their perimeters against contraband, beginning with the sheer size of the perimeters that must be secured, with much of the fence length vulnerable to objects coming in from outside. These facilities often border public spaces, so they require an early warning system and a level of detection that goes far beyond casual detection. A fence that borders public land offers an opportunity for any member of the general public to approach. Therefore, prisons need a way to extend that perimeter by creating some sort of buffer zone that doesn’t require purchasing additional land or installing additional fences.

At present, the perimeter of a prison is generally secured using physical barriers, which can be walls or fences with concrete beneath them to prevent anyone from tunneling in or out. Fences are typically 10 or 12 feet high with barbed wire or razor ribbon along the top to discourage anyone from climbing over. There are often layers of protection that may include electrified fences, microwave detection systems, motion sensors and video surveillance cameras used in combination to create a sterile zone between the inner and outer perimeters.

While this multi-pronged approach to perimeter security is effective for preventing escapes, the existing technology is not as effective for detecting outsiders approaching the fence. Motion sensors and visible light cameras used for detection can generate a high number of false alarms because of environmental conditions like precipitation, wind, darkness and reflected light. In a security situation where every alarm must be investigated, excessive nuisance alerts outside the fence caused by the environment cannot be tolerated because they will have the effect of decrease vigilance to future alarms. Surveillance cameras are good at recording an event for later analysis, but a guard watching monitors will almost never “catch” an event in progress. Given the critical need for a quick response, systems at correctional facilities must send accurate alarms that detect intruders outside the fence in real time, every time.

Most prisons are owned and operated by states, municipalities and other public entities, so they are often dealing with limited funds. Since it’s too expensive to hire more guards to increase vigilance on the perimeter, prisons are seeking ways to leverage technology to lower costs while maintaining the appropriate balance of people and technologies. To help prisons accomplish this goal and find that balance, consider these best practices when selecting a perimeter detection solution:

Smart Thermal Sensors

Automated solutions can be used to monitor the perimeter and sterile zones and can also provide the necessary buffer zone outside the perimeter. This eliminates the need for people to monitor those areas, freeing them to perform other critical security tasks. When an incident is detected, the automated solution notifies prison staff, who can then investigate.

The key to the success of an automated solution is to ensure accurate detection without nuisance alerts. When combined with video analytics, “smart” thermal cameras, which sense heat, are the perfect “people detector” and are highly accurate for automation detection. This is the reason smart thermal cameras have become the solution of choice for critical asset security like refineries, airports and bridges where intruders must be detected at all times and under all conditions.

While some prison perimeters are well-lit, many are not, leaving them particularly vulnerable to activities that occur at night, which are ideal for thermal solutions. However, today’s systems have come a long way from the “night vision” solutions of the past. By using a high degree of image processing, they detect accurately 24 hours a day, in darkness, bright sun and harsh environmental conditions. The same image processing is also used to virtually eliminate false detection alarms caused by small animals, weather and other anomalies. These cameras can also decrease the cost of a perimeter protection solution and increase security responsiveness by combining detection and visual verification into a single system.

GPS-based Analytics

Some smart thermal cameras incorporate GPS-based video analytics, enabling very accurate determination of location, target size, bearing and speed. This offers a number of benefits. For one, knowing an object’s actual size lets the smart camera ignore smaller objects, like animals and blowing trash, while still detecting human-sized intruders, aiding the camera’s accuracy. GPS target information can be used to project the precise location of an alarm onto a site map of the area, providing real-time situational awareness about an event as it unfolds. GPS-based analytics also let you create geospatial “From To Zones” which only trigger alarms only when a person is walking towards a facility on the outside of the fence. This can be instrumental in stopping contraband activities at the source of the problem. GPS analytics can also be used to steer PTZ cameras to zoom and follow a target automatically, helping to identify the source of an event and make a fast and precise response.

Detection Range

A longer and wider field of view is an ideal means for extending security beyond the fence to create a perimeter buffer zone for early detection. Smart thermal solutions can detect areas well over an acre, increasing the time guards have to respond while decreasing the number of cameras needed, reducing costs. Wide-area solutions are also effective for monitoring sterile zones, providing rooftop security and for roadside applications to detect loitering vehicles.

Good decisions depend on timely information, and the impact of an unfolding event is directly proportional to a security department's ability to intercept it quickly. Prison perimeters perform the dual task of keeping inmates inside the fence while preventing outsiders from delivering contraband items into the facility. When designing and selecting a perimeter security solution for prisons, keeping these best practices in mind will ensure the accurate, reliable detection necessary to address the many requirements these facilities have and maintain the highest level of security from both the inside and the outside.