Recent years have seen significant growth in the use of a variety of video devices for outdoor surveillance and threat detection. This can be attributed to a growing realization that proactive security measures are an important part of a complete security plan, compared to only using reactive or forensic measures. This desire is complemented with the improved capabilities of today’s technologies, such as remote transmission over IP, monitoring, intelligent video analytics and the imagers that can provide useable information, day and night.
Getting usable video imagery outdoors often means you have to overcome any number of challenges. These can include shadows, reflections, sun glare, inclement weather, and of course lack of light during nighttime hours.
To this last imaging challenge, historically, IR (infrared) illumination has been used to provide light that is not visible to the naked eye, but that day/night cameras are sensitive to. But now more and more people are using thermal imagers to overcome many of the imaging challenges that can plague effective video surveillance. The costs of thermal imaging have been dropping steadily, enabling a viable return on investment feasible for applications beyond traditional critical infrastructure uses and including applications as diverse as auto auctions, storage yards, construction sites, car dealerships and gated communities.
Whether you’re looking at an IR illuminated solution, a thermal imaging solution, or a combination of the two, there are a number of factors to consider if you’re going to deploy these technologies effectively. Knowing the needs of your customer and designing the installation plan to fit their needs are critical. In order to do this, you need some baseline questions answered. Here are some of the questions to ask right up front.
1. What are the main objectives of surveillance at the customer’s site?
Is the customer looking for detection, assessment/classification or identification capability or some combination of those three basic functions? This is critical as it will determine which types of imagers— or what mix of imagers—are most able to provide a comprehensive solution, as well as the fields of view, resolution, and placement of the imagers. If the customer determines that detection and general assessment is the most important function, you should be looking at thermal imagers as they maximize detection capabilities by providing greater contrast on what’s important as well as less noise and clutter, regardless of the lighting conditions. However, thermal cameras don’t provide identification capabilities like facial features or color information.
2. What is the customer trying to prevent and what are the expected costs/consequences should a breach in security happen?
This falls in line with the client’s budget expectations and the general level of security they will need at the site. They need to consider the cost of any loss of materials stolen and the potential for loss of life. What will it cost to fix the issues created and just as importantly, what will the resulting losses in revenue be from a stoppage in operations? Damage to the client’s reputation may be a consideration as well.
3. How and where will this information be processed or used? Will it be recorded for after the fact forensic and/or evidence?
Many customers will have onsite personnel to monitor their surveillance system, while others may have a centralized security operations center, and still others may look to a third party central station that has the capability of remote video monitoring. If the video will be saved for evidentiary purposes, remember that thermal will not provide details necessary for identification in a court of law.
4. Are there other systems they are trying to augment? What are they and are they operational?
This could include legacy detection technologies that incur high false alarm rates and/or no visual assessment. Sometimes the customer wants to replace the system completely; other times the goal is to provide an additional layer of video security to enable more accurate alarming. The ultimate goal is to end up with a solution that is simple yet reliable. This means that the system is not missing real events, but it also cannot generate so many false alarms that it creates “The boy that cried wolf” syndrome. There are many cases where systems have been all-out turned off because of this.
5. Will the customer be actively controlling the cameras?
This question relates to whether it is better to use fixed imagers that provide a constant vigil on areas of importance, or if pan/tilt systems can provide added value. Many installations incorporate a combination of fixed and pan/tilt systems so they can have the unblinking eye on certain areas, while using pan/tilt cameras to assess alarms or scan larger areas.
6. What is the available infrastructure?
This question is important in any security project, however outdoor surveillance poses additional challenges because quite often the imagers are placed in remote areas that lack good sources of power or communication. The costs of installation are often greater because of these added challenges. These factors can greatly affect the design’s end result.
Answering these questions will get you started on the right foot when designing your installation, but you also need to consider the strengths and weaknesses of different imaging technologies.
IR illuminated cameras can provide identification levels of information, but only when used conservatively. It is common to expect too much in terms of capability. The chances of gaining an identifiable image outdoors at any distance is very slim, especially at night. Using IR illumination for identification is typically only recommended for use in areas where the ingress/egress is well defined, such as gates or doorways. These are locations in which cameras and illuminators can be strategically placed to optimize illumination.
Great care should also be taken to avoid uneven illumination and overtaxing the camera’s distance capabilities, as illumination levels degrade quickly with distance. An IR illuminator is just like a flashlight. Objects outside the cone of illumination are often less noticeable than if there was no illumination at all and there are many ways in which the effective distance can be cut down. Overall, the customer’s expectations should be set correctly regarding the chances of achieving identification.
For the most reliable detection and classification, the use of thermal imagers with good video analytics is a potent combination. If the infrastructure allows, the most straight forward and effective approach is to place imagers toe to toe along the perimeter of concern. This allows a virtual thermal fence in which objects crossing into the area will be detected, and in some analytics, classified for even lower false alarm rates. When infrastructure is limited, the imager placements may be limited to the buildings or other structures on the site. This will increase the number of imagers necessary to cover an area or perimeter as they are now looking out toward the perimeter.
Combining a thorough understanding of the imaging technologies you’ll be deploying with the answers to these six foundational questions should provide you with the information and confidence you need to design the best installation for your clients.
