Keeping an EYE on things

Jost Schmidt explains how Germany’s ATC provider, DFS Deutsche Flugsicherung GmbH (DFS) is using automated video analysis for its security needs.

Important national infrastructure installations deserve high-quality security defences. (All images DFS)

Jörg Rodens, a member of the Physical Security Management team of DFS Deutsche Flugsicherung GmbH (DFS) in Langen, Germany, is calm and relaxed.  It’s perhaps not the expected demeanour of a security manager in an important organisation.  There’s the fear of a loophole missed in the security system or failure to recognise a new ploy by a terrorist.  Mr Rodens spends all day ensuring that this does not happen.
 
Pillars of security
Air traffic control, with its towers and control centres, is clearly a key element in flight safety and management, so protecting its staff and buildings are of paramount importance.  The level of resources invested in air traffic control is influenced by the importance of the individual business premises for air traffic.
The first pillar of DFS’ security concept includes flexible physical barriers as well as personal and organisational measures that prevent intruders from accessing the premises.
The company’s second important pillar is video surveillance.  It ensures that security staff at each control centre are immediately able to spot any abnormal behaviour that may concern or affect them.  They are assisted in their work by video content analysis software provided by Securiton.
 
Retrospect
Securiton manufactures its IPS VideoManager software but it does not build cameras.  In addition to its software, it routinely plans and sets up systems for high-security installations such as power stations.
Rodens admits to being somewhat sceptical about video content analysis back in 2005.  Now he is more than happy with it, saying: “The system is extremely reliable and really helps us establish a high standard of security.  The false alarm rate is low.”
IPS VideoManager primarily performs two tasks for DFS’ facilities: movement recognition and ‘people tracking’.  The software allows freely-definable limits to be set for the field of vision of each camera.  If these limits are exceeded, the software triggers a visual and audible alarm in the control centre.  Employees can then verify what’s happening on site from the comfort of their chair and, in certain instances, zoom in digitally.  The software relieves operators of the laborious task of watching giant walls of monitors.
 
Content analysis
One of the major challenges facing the planning and setup of a video system with content analysis is the careful planning of danger zones.  If an alarm threshold is defined as being 6ft (2m) in front of the wall of a house, for example, the system triggers a signal if anything crosses the virtual line.  IPS VideoManager safely distinguishes between small animals and humans: the minimum size from which object movements are to be detected can be freely defined.  Cats or dogs can therefore be easily distinguished from people.  Frank Betsch, Sales Manager at Securiton explains: “In practice, the key is to find the best parameters for each individual camera and modify them if need be.  This can be done quickly, is generally only rarely needed and so is economical.”  He adds: “In an interior room that is off limits to people, the software can register even the smallest change – and this is how the ‘Smoke Detection’ module of the IPS VideoManager works.”
DFS has now installed the software in three of its control centres.  The security service also makes great use of another feature: the system can distinguish between permitted and prohibited directional movements.  It can be programmed so that if, for example, someone crosses a line in a certain direction (perhaps leaving a building), the system will ignore it.  However, a movement in the opposite direction, when someone enters the premises, is spotted instantly and reported.
“This software feature allows any number of zones to be defined within a given area and for movements to be reported on a time-controlled basis too,” says Rodens.  Access to the cafeteria is permitted all day long, for example, while every movement in front of the building at night is recorded.
 

German air traffic control is gradually converting and upgrading its systems.

People tracking

DFS also conducts ‘people tracking’ in certain open-air areas.  In this situation, objects or people recorded by a camera because they are entering a prohibited zone are automatically transferred if they reach the capture range of another camera.  “Of course, this only works if the zones being monitored by the cameras overlap,” says Mr Betsch.  In this case, a person is zoomed into the centre of the picture.  The camera then follows all of their movements with a digital or mechanical pan.
 
Focusing with the click of a mouse
Should worrying activity occur on air traffic control territory, the security service can call another security assistant into action.  All of the cameras are marked on a digital location map and their capture ranges are plotted in colour.  A quick turn of the camera, with the click of a mouse, is all it takes for the security service to orientate the camera’s range of vision towards the action.  It means potential dangers can be displayed on a monitor at high resolution from several perspectives with a long overview or close-ups.  Rodens sees video analysis as a quantum leap in the world of video technology: “It forms a supporting pillar of our security architecture.”
Betsch says he is now able to look back on a great number of installations of the software in Germany, other parts of Europe and overseas.  The IPS VideoManager has become established over a period of many years, especially in German prisons.  “People are already talking about the ‘IPS standard’ in judicial circles,” says Betsch.  “More than 50 penal institutions in Germany now use the system.  There hasn’t been a single break-out attempt in recent years that hasn’t been spotted.”
He therefore regards content analysis as an important extension of existing video surveillance systems.  “There’s no point in overloading people in control centres with more and more output from more and more cameras.  The sense of security can be deceptive, since a lot of what’s going on can easily be overlooked.”
Betsch is clear that only images from modern digital systems with content analysis software can be analysed.  Analogue legacy systems, however, can be upgraded with encoders.  German air traffic control is also gradually converting its systems.  “A camera’s service life is ten years at the most.  We are gradually switching over to modern, digital technology and saving ourselves from a major investment backlog,” says Rodens.
 
Rare false alarms
Rodens and Betsch believe that content analysis is now well equipped even for difficult tasks.  Variable weather conditions once presented a major challenge for automated security systems.  Sudden changes from sunshine to rain, fog, reflections from puddles and glass panes were once tricky stuff for algorithms.  Now, the software can handle these situations. “We’re extremely satisfied,” says Jörg Rodens.