thrown object detection white paper

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USING LASER TECHNOLOGY TO DETECT OBJECTS/PASSPORTS BEING THROWN OVER CONTROLLED AREAS IN AIRPORTS By Nicholas Gouloussis, NSquare, CEO and Richard Hobson, Technical Manager, Optex Application paper:

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Page 1: Thrown Object Detection White Paper

USING LASER TECHNOLOGY TO DETECT OBJECTS/PASSPORTS BEING THROWN OVER CONTROLLED AREAS IN AIRPORTS By Nicholas Gouloussis, NSquare, CEO and Richard Hobson, Technical Manager, Optex

Application paper:

Page 2: Thrown Object Detection White Paper

Detecting ‘thrown passports’ in airports

Airports are some of the most challenging environments for delivering effective security solutions, both because of their size, and the sheer volume of passengers who pass through their terminal buildings every day. One specific area that is the most challenging of all is passport control, where the opportunity to pass personal documentation between passengers over walls to effect illegal entry is very real, and a constant headache for border enforcement agencies.

International airports are obliged to have controls in place to ensure documents are not exchanged, usually either by using ‘structural’ barriers to physically prevent passports being passed across, or by deploying electronic systems that detect objects that are being thrown.

Trial and error with video-based detection only

At one international airport in Greece, the authorities decided to tackle the issue first by exploring the video analytics capabilities of its existing video management system and high definition (HD) cameras with built-in video analytics.

The system design was based on a theoretical concept used for event detection and alarm in sterile zones, but in practice the results were little short of disastrous. Capture rates were virtually nil, and the system was plagued by numerous false alarms caused primarily by people going about their legitimate business.

Trial and success using laser detection technology

A second trial was therefore implemented, but this time using a REDSCAN laser detection system from Optex (with a special firmware version provided for the project) and two, 5-Megapixel cameras to prove the concept. REDSCAN is a laser scan detector that can detect a moving object’s size, speed and distance and process that information with a unique algorithm, resulting in high-reliability detection with minimal false alarms.

In this particular installation, the laser scanner was placed at the same height as the wall aperture, scanning the critical area inside the passport control hall where a passport being thrown into or from the hall had to be detected.

Since a REDSCAN with this customized ‘airport’ firmware can detect an object travelling at high speed, the distance between where the REDSCAN was located and the key area of detection was critical to catching a ‘flying’ object. The Laser scanner uses X and Y coordinates with great precision, which can enable a camera, connected to the REDSCAN either directly or through a compatible VMS operation, to ‘look’ straight (point straight) at the object being detected. Using high definition or multi-megapixel imagers and a digital zoom allows the person throwing the object to also be identified.

A second scanner was sited in the secure area, thereby strengthening the system’s ability to ‘capture’ any objects being thrown. Experimenting with the scanner placement and set up ultimately enabled a 100% detection rate to be achieved.

Key factors for success

So why did the REDSCAN application succeed where the ‘traditional’ video analytics-based approach appear to fail so spectacularly? There are several reasons.

Firstly, REDSCAN is a laser system, and therefore not affected by harsh lights, glare or reflection. It also works

“Experimenting with the

laser scanner placement

and set-up ultimately

enabled a 100% detection

rate to be achieved.”

Page 3: Thrown Object Detection White Paper

in total darkness. As such it is not impacted by numerous false alarms caused by the environment in which it is installed. Secondly, the firmware feature of the REDSCAN allows scenes to be masked. It can therefore effectively ‘ignore’ areas that may be prone to triggering false alarms.

A further factor in its success is its flexibility in installation, and specifically that it is capable of being installed both on a ceiling and on a wall (ie both vertically and horizontally) to further improve the chances of an object being detected. It can be configured to provide detection within areas where the calibration of cameras, to enable video analytics, would not be possible.

When using video analytics the quantitative success rate of the system relies heavily on good design and proper camera calibration. The required camera mounting heights and fields of view are unlikely to be achieved by using existing surveillance cameras. Similarly, the use of video analytics is seriously restricted by lighting conditions, reflective backgrounds, glass surfaces and other limitations such as overcrowded areas.

Above all though, the main technical limitation of this technology in this case was the minimum object size and the maximum object speed that the analytics could detect.

The system initially deployed could theoretically only detect objects of a size larger than 3% of the camera’s field of

view. By utilising a typical 20-meter wide field of view, the minimum object size translates to 45 centimeters, which is considerably larger than a typical passport. Moreover, objects that move at a speed high enough to travel along the field of view in less than 2 seconds, are not reliably detected. A thrown object can easily achieve a minimum of 30 meters/second speed which is more than twice the maximum detectable speed for general video analytics applications.

In terms of how it integrates and interacts with the camera, the REDSCAN’s X and Y coordinates allow the camera to point directly where it is needed (i.e. to where an object has been detected). In simple terms it ‘talks’ to the camera, telling it where to point to capture an event and the person responsible. It also automatically triggers the event to be recorded, such that the video can subsequently be used for successful prosecution.

In this particular project, the ideal scenario to provide the best solution would have been to install a number of 5 MP panoramic cameras just above the passport control booths to provide a continuous monitoring and recording of the entire control area. ‘Dewarping’ the video feeds from these cameras provide a PTZ-like functionality to specific areas but at the same time providing continuous recording for the whole area.

This article has been written by: Nicholas Gouloussis and Richard Hobson

For more information about the laser detection solution and the REDSCAN series, please visit www.optex-europe.com.

Nicholas Gouloussis is the owner and CEO of N Square, a leading system integrator in Greece, and specialized in security system design for critical infrastructure and large scale projects.

Richard Hobson is the Technical Manager for OPTEX, the leading sensor manufacturer in EMEA, and is supporting the special project team in the region.

“REDSCAN can be configured

to provide detection

within areas where calibration

of cameras, to enable

video analytics, would

not be possible.”

The REDSCAN provides X and Y coordinates for any object detected in the defined area (red dots).

Page 4: Thrown Object Detection White Paper

OPTEX (EUROPE) LTD, EMEA Headquarters

European/UK office Tel: +44 (0)1628 631 000

Middle East/Dubai branch Tel:+971 (0)4 501 53 94

Email: [email protected]

www.optex-europe.com

N SQUARE

Tel: +30 210 2527000 | skype: n2square

Email: [email protected]

www.nsquare.gr