The New Detectives

New detection tools increase border control, customs officers' capabilities to find contraband

• By Dana Strawser, Troy Techau
• Apr 01, 2010

Customs and border officials are an important component of national security, protecting the nation from the entry of illegal, dangerous or biologically disruptive goods. Until now, customs officials have had to rely on traditional screening technologies that are ill-suited for the customs mission and have produced mixed results. Now, advanced imaging technology in the form of millimeter wave imagers and other devices are emerging as the newest tools in a customs officer's toolkit.

Smugglers often hide items such as currency, narcotics and even live animals on their bodies to evade law enforcement. And these evasive tactics will continue to increase as efforts against laundering become more effective. Analysts not only warn that international smuggling is a method used by terrorist elements to move funds, but also caution that smuggling provides the funding for the terrorism itself.

A Unique Challenge

In November 2009, the World Customs Organization and the Department of Homeland Security announced the success of Operation Atlas, a multinational effort that yielded seizures of more than $3.5 million of narcotics over a five-day period. The announcement coincided with the WCO's first-ever Technology and Innovation Summit, which highlighted several advanced screening technologies to the assembled customs delegates. Live demonstrations of Brijot Imaging Systems' MobileScan millimeter wave screening technology aptly demonstrated that currency and narcotics could be detected in real time using advanced imaging technology.

The WCO recognizes that the use of advanced imaging technology will be critical to the future success of customs organizations worldwide. As new tools and techniques become available, sharing techniques and information regarding the application of emerging capabilities to the customs application is of paramount importance.

Customs officials, tasked with detecting and deterring smuggling, face unique challenges to support commerce with rapid, uncomplicated screening procedures. Long lines, vast screening checkpoints and 100-percent screening is not an economically or politically feasible option for most customs organizations.

Current screening technologies, such as walkthrough metal detectors, cannot detect items without metallic content, leaving a substantial gap in the effectiveness of screening technologies. Advanced imaging technology already in use in some nations provides the capability to quickly locate items hidden on the body, without violating individual privacy or slowing travelers.

The Up-and-Comers

Multiple new technologies hold great promise for the customs screening application. Millimeter wave imagers—essentially a technology that can see objects hidden on the human body—are perhaps the most significant advanced detection technology to emerge in the past few years.

Millimeter wave imaging devices can be divided into two classes: active and passive. Each class of technology has relative strengths and unique characteristics that tailor their application to various situations. In general, active millimeter wave devices generate energy that is projected onto the body and refl ected back into sensors, while passive millimeter wave imagers simply collect the energy naturally emitted by the human body. In both types of devices, objects hidden on the body appear differently than the human body and are visible to the screener.

Active millimeter wave systems operate by sending waves of energy onto the human body, which reflect back to the system's sensors. Typically, human skin and hidden objects reflect differing amounts of energy, yielding a detailed image of the body on the operator's screen. These systems can locate small objects, such as coins, or other objects in pockets or underneath clothing, as the clothing itself is normally transparent to the imaging system.

Privacy advocates have declared these naked images as unacceptable in most uses; however, opinions tend to vary by culture and as our perceptions of world security change in relation to terrorist events. Generally, active millimeter wave systems are large and placed in fixed locations such as airport security screening checkpoints. As an emitter of energy onto the human body, active systems usually require regulatory approval for health and human safety in each nation where they are deployed.

Passive millimeter wave systems do not emit energy and receive energy naturally emitted by the human body. In a real-time, high-throughput screening environment, passive millimeter wave imagers are typically employed to find larger objects such as currency, narcotics or bombs. Passive devices usually do not require regulatory approval as needed for human imaging, and the operator's image does not display an image of the body with enough resolution to distinguish anatomical details. Without the need for high-powered sources to emit millimeter wave energy onto the body, some passive millimeter wave devices can be operated on battery power. This characteristic, along with small form factors, makes mobile operations with a passive sensor an easy way to move within a customs venue.

Some advanced technologies also can automatically analyze and locate objects on a person's image. This capability can reduce operator training, increase the probability of detection and reduce false alarms. This detection assistance helps an imaging systems operator focus on areas where there is a potential for hidden items. The military and loss prevention community have used this capability to trigger external devices when a detection event occurs, such as initiating an automated lockdown, as well as notifying security authorities.

Factors normally considered when evaluating various millimeter wave technologies include detection capability, privacy, throughput, convenience, portability and operational cost. Customs agencies should look for advanced technologies that fit the unique requirements of the customs model.

Detection capability. Normally expressed as probability of detection (Pd) and false alarm rate, these figures express a technology's capability to detect a given test item under controlled conditions and how often the technology will indicate a detection event when there isn't actually an item present.

Privacy. Often a subjective factor that varies from culture to culture, the amount of privacy and dignity afforded to the traveling public is a critical factor in the implementation of advanced imaging technologies.

Throughput. Usually expressed as a theoretical rate per hour of how many people can be screened if all factors perform as expected. Actual throughput rates are usually lower as a result of human factors, such as a subject who doesn't understand screening instructions.

Convenience. A critical factor for customs applications, as customs officials most often are not willing or permitted to impose the strict protocols typically found in post-9/11 aviation security screening. That type of screening typically requires full divestiture of coats, jackets and items in pockets and even removal of shoes. Many customs agencies desire screening technology that can expediently screen travelers as they transit the customs area. In this usage, the advanced screening technology serves to assist in the selection of travelers with suspicious hidden objects for secondary screening, minimizing the need for customs officials to resort to controversial and inconsistent tactics such as profiling or random screening.

Portability. To maximize the ability to place technology at the most effective location, customs agencies typically desire advanced imaging systems that are portable and can be relocated as needed.

Operational cost. In addition to the expense of acquiring and maintaining advanced imaging technology, customs agencies can minimize operational costs if minimal training is required.

Integration and Sensor Fusion

As the adoption of advanced imaging technologies becomes more widespread, the detection industry will continue to offer additional capabilities to customs officials.

The fusion of multiple sensors into integrated sensor suites will increase detection capability and automated detection and simplify the application of disparate technologies to the contraband detection task. For example, the simple integration of a metal detector and advanced imaging technology could yield valuable information about a hidden object, helping to determine its location and composition. Integration of imaging sensors at infrared and other frequencies, as well as the integration of devices such as laser spectrometers, also is a topic of discussion in scientific circles. Spectrometers show promise in yielding information on the specific composition of a hidden object, which would be useful to a customs official scanning a traveler for contraband items.

Increasingly, the output from those advanced sensors also will be integrated into command and control suites that improve coordination and alignment of limited customs resources to the most critical tasks. The military term "common operating picture" is often used to describe the aggregation and assimilation of disparate sensor information onto integrated displays, providing operators unparalleled situational awareness and intelligence analysis capabilities. Current screening technologies tend to be operated in isolation, but visionary companies and government agencies are developing initial requirements to guide development of this critical capability for security management.

Some work in both of these areas has already begun. DHS has initiated the Standoff Explosives Detection Technology Demonstration Program, a multi-year research and development effort to accelerate the development of integrated systems, concepts of employment and deployment scenarios to improve public safety and increase law enforcement's detection capabilities. The program has begun evaluating the applicability of video analytics, command and control software and various detection technologies.

Customs agencies are not likely to have significant research and development budgets, and most product development will likely occur as manufacturers and governments invest precious funding in pursuit of technology suited for the aviation security checkpoint market. While the SOTDP program and the efforts of the World Customs Organization are laudable, it is critical that customs officials clearly define and articulate the unique requirements of the customs application to government and the private sector if suitable products are to be developed over the next few years.

Another advancement on the development horizon is imaging sensors with greater detection capabilities and ranges. These next-generation sensors will enable screening for hidden bombs and contraband at signifi- cantly longer ranges.

The forward-looking customs agencies already engaged with today's technology stand to gain the most from these advances. The lessons learned and operational experiences gained through the use of available advanced imaging technology will serve as a foundation for agencies to spring ahead and rapidly implement new technology as soon as it becomes available.