Wheels Up

• By Bob Banerjee
• Sep 01, 2009

Major airports typically have more than 1,000 cameras installed at and around their buildings and runways. Their security personnel often monitor facility perimeters with CCTV cameras as well, but these devices may be inadequate in truly keeping a close eye on potential risks.

Video Content Analysis Focuses Attention
With camera counts that can amount to more than 50 times the number of surveillance monitors used by personnel to oversee airport security, there are too many video streams for each to be watched effectively. Here, video content analysis can serve as an important assistive technology as it helps surveillance system operators focus their attention to possible risks. This technology is especially useful for areas where there is generally limited activity, but where the potential for serious risk remains, like perimeters.

VCA can detect a number of behaviors that would indicate a person is attempting to cross an airport’s perimeter at an illegal entry point. A function called tripwire, which sets an invisible line, for example, along a fence. When the camera detects a person or object crosses that line, it issues an alarm and brings up video of the scene on an operator’s screen.

Loitering is another behavior that is important to detect at airport perimeters. VCA can be configured to issue an alert if a person or vehicle enters an area and does not leave after a specified time. When programmed for loitering, the technology serves as an early warning system to alert security personnel that someone with mal intentions may be trying to enter the airport at a restricted area. With advanced warning, security personnel can dispatch someone to the area before the perimeter breach occurs.

By tracking the way objects behave, VCA serves as a sensor that can distinguish between small animals, people and vehicles, thus reducing false alarms and alerting personnel to only serious concerns. This capability is an immense improvement over more traditional motion detection that struggles with accuracy in outdoor applications with varying weather and wind vibration.

Illumination Enhances Detection Capabilities
While some airports may already be using day/night cameras at outdoor locations, added illumination is critical for night vision at perimeters. These areas often have only widely dispersed, high-intensity lamps that create overexposed “hotspots” against a backdrop of darkness in surveillance images. Adequate illumination is essential to acquiring images that allow security personnel to monitor an area, observe activity at the location, and identify specific actions, objects or people.

There are several options for adding illumination to perimeter locations. White light illuminators add visible light to a dark scene, allowing security personnel to detect the color of an intruder’s clothing or of a suspicious vehicle. Visible lighting also can help serve as a deterrent by alerting intruders that surveillance technology is in use.

Infrared or thermal illuminators allow cameras to “see” in the dark without visible lighting. Thermal illuminators are useful for identifying potential risks at long distances, but they provide very little image detail. Infrared lighting produces nighttime surveillance video that more closely resembles crisp, monochrome images captured during the day. They also consume less power and eliminate the light pollution that occurs with visible lighting at an airport perimeter.

Combining active infrared illumination with VCA provides effective and automated video surveillance day and night -- better equipping airport security personnel to watch over and secure their entire perimeters in even the darkest conditions. Some cameras even offer integrated infrared or stand-alone infrared illuminators that can be placed near existing cameras.

With either option, airport security directors should look for illuminators that eliminate hotspots and underexposure by lighting both the foreground and background of an entire scene. More advanced than conventional illuminators, these products allow for improved situational awareness 24 hours a day.

Encoders Solve Wireless Connectivity Challenges
Surveillance cameras at outlying areas of an airport facility are often connected wirelessly rather than a wired local area network. However, with a wireless connection, airport security personnel may have concerns about bandwidth for video transmission back to the central security office, and they inherently run the risk of temporary video outages as a wireless network is usually not as reliable as a wired LAN. Airport security directors who face this challenge may want to explore encoders that provide a built-in back-up plan for network outages to help to improve bandwidth management.

Encoders that offer embedded VCA functionality help to reduce the amount of video that is sent over the wireless network from perimeter locations. These encoders process video at the network’s edge and can be configured to send only alarm video to airport security personnel.

Video can be sent over the network for viewing and recording at any resolution and frame rate that satisfies security personnel’s requirements, as the analysis has already been completed using the high-quality raw video. In this scenario, embedded VCA offers better bandwidth management than content analysis technology that requires a centralized server for processing. With a centralized server, all video must be transmitted over the network at a high resolution and frame rate before it can be analyzed.

Encoders that provide local storage capabilities also can record at the network’s edge during an outage. If the video recorder is equipped with a technology like Bosch’s Automatic Network Replenishment, it can automatically fill gaps in the recording with video stored by the encoder. This technology ensures uninterrupted recording even when the network is down.

There is not one silver bullet for improving security at an airport’s perimeter. Often a combination of devices and technologies produces the best surveillance results in terms of focusing attention, enhancing image quality and event detection, and improving system reliability. By exploring all the options available, airport personnel can make dramatic improvements at their perimeters, helping to bolster the overall security of the facility.