3a orphan paper

8/20/2019 3A Orphan Paper

1/14

Advanced Cargo Container Scanning Technology Development

Victor Orphan, Ernie Muenchau, Jerry Gormley and Rex RichardsonScience Applications International Corporation

San Diego, California 92127

Introduction

The terrorist use of a cargo container to smuggle a nuclear weapon or radiologicalmaterial which could be used in a radiological dispersion device (RDD) is a serious

threat currently being addressed by the US and other governments. The US government

has negotiated through the Container Security Initiative (CSI) placing Customs andBorder Protection inspectors in 20 major overseas ports to help ensure that cargo

containers bound for the US do not constitute a threat. CSI and other initiatives to help

secure the supply chain, such as CT-PAT (Customs Trade Partnership against Terrorism)

are effective initial efforts to protect against terrorist use of cargo containers to launch aWMD (weapons of mass destruction) attack. However, the 7 million containers which

enter the US by sea every year present a difficult inspection challenge. Currently, only arelatively small percentage (~5-6%) of containers, those deemed “high threat” containers,are physically inspected usually using non-intrusive scanners (either gamma-ray or x-ray)

to detect contraband hidden within the cargo. Advancements in cargo container scanning

technologies are needed to further enhance the security of cargo containers withoutdisrupting the essential flow of cargo. The economic consequences of a successful WMD

attack by terrorist involving cargo containers are potentially catastrophic since an attack

could lead to a shut-down of the supply chain for an extended period. Improved containerscanning technologies hold the key to expeditiously re-starting the supply chain post-

attack.

We describe the development of an Integrated Container Inspection System (ICIS) whichcombines existing technologies (Portal VACIS, Radiation Portal Monitors and automated

container identification using OCR) into an optimized system which enhances the ability

to detect nuclear or radiological material in a cargo container. In addition, two significantenhancements to VACIS, the gamma-ray radiographic inspection system widely used for

inspecting cargo containers, are discussed: (1) a next generation gamma-ray imaging

detector which provides a factor of ~4 improvement in spatial resolution and (2)automated “empty container” detection using a Portal VACIS and automated image

analysis software.

Need for Integrated Container Inspection System (ICIS)

The primary detection technique for nuclear weapons, nuclear and other radioactive

materials is passive gamma-ray and neutron detection using large area, high efficiencydetectors which permit threat levels of radioactivity to be detected at practical scanning

speeds (up to 30 km/hr is required in some cases to avoid impacting cargo throughput). Ifthe radioactive source is heavily shielded by dense, high-Z material the passive detection

technique may fail to detect the source. In this case, a complementary technique, such as

x-ray or gamma-ray radiography can aid by detecting the dense material. Imaging will

1


2/14

also help verify that the cargo container contents are consistent with the manifest; thus,

helping to resolve “nuisance alarms” from naturally radioactive material commonlyfound in cargo (for example, ceramic tiles, porcelain toilet bowls, kitty litter, etc.)

The primary Radiation Portal Monitors (RPM) typically are unable to determine the

specific radionuclide(s) responsible for initiating an alarm. Thus, containers triggering anRPM alarm require secondary inspection. A handheld isotope identification system can

perform a gamma-ray spectroscopic analysis near the suspect region of the container and

determine the specific isotope causing the alarm. This measurement is essential foridentifying “nuisance” alarms and allowing expeditious disposition of cargo in secondary

inspection. A material-specific non-intrusive technique such as fast and thermal neutron

elemental analysis can aid in verifying the presence of WMD materials such asexplosives, chemical agents, and nuclear materials (such as highly-enriched uranium)

which cannot usually be detected passively but can be detected using neutrons to induce

fission in the U-235.

When processing hundreds of containers and trucks per day at a sea or land border portwith multiple traffic lanes, it is essential to automate the positive identification of the

container and truck. For instance, this will ensure that the alarming truck or container is properly directed to secondary. Fortunately, technologies for (automatic license plate

readers) and cargo containers identification (video OCR systems) have been developed

for logistics purposes and can be readily adapted for security applications.

ICIS Description

ICIS consists of one or more Sensor Subsystems at the terminal gates, quay or otherlocations; the ICIS Server, which integrates and stores sensor data; and the ICIS Viewer,

which provides a graphic display of the integrated data. Each Sensor Subsystem can be

equipped with SAIC’s advanced gamma ray imaging, radiation scanning and OCRtechnologies. Following are descriptions of the ICIS components.

Gamma-ray Radiographic Imaging

SAIC’s Vehicle and Cargo Inspection System (VACIS®) gamma ray imaging technology

provides clear radiographic images (much like x-ray images) of containers, showing the

outlines and density of the contents. With its very low radiation dose, the VACIS scan ismuch safer than comparable x-ray systems. Over 170 VACIS units have been purchased

by the US Government (Customs and Border Protection and the Defense Department)

and foreign customs agencies for use at cargo facilities around the world.

The principle of operation of VACIS is similar to that of a line-scan x-ray system; except,VACIS uses a gamma-emitting radioisotope. The source, consisting of a pellet a few mmin diameter, is collimated to project a fan-shaped beam onto a linear array of very

sensitive NaI-photomultiplier scintillation gamma-ray detectors. The gamma-ray

energies are 662 keV for cesium-137, and an average of 1253 keV for cobalt-60. Theheart of all VACIS products is SAIC’s patented (U.S. patent number 6,507,025B1) high-

efficiency photon-counting technology. Portal VACIS and Mobile VACIS have both

been integrated with the Exploranium RPM. Unless mobility is required, the Portal

2


3/14

VACIS is optimum for use in the integrated system. Following are brief descriptions of

each.

• Mobile VACIS™ is extremely well suited to the port environment, and is

designed around a standard vehicular platform that can be easily serviced and

repaired. The Mobile VACIS, shown in operation at a port in Figure 1, can bedriven to an inspection point within a port, and set up and operational in less than

10 minutes. It does not permanently occupy scarce port real estate and requires

only a minimal footprint to perform inspections of the cargo at hand. It canoperate in both the scanning mode in which the truck/container is stationary or in

the stationary mode where the truck or container is driven past the Mobile VACIS

gamma-ray beam.

Figure 1. Mobile VACIS in use at seaports to inspect cargo containers

• Portal VACIS™ is a high-throughput imaging system for port gates and

roadways and provides a quick and effective tool to detect high-value stolen

goods before they leave the country, or illegal materials smuggled into thecountry. Engineered to operate in very small areas, Portal VACIS can be deployed

in conjunction with existing vehicle control points, such as weigh scales, and

provides permanent protection to port gates and roadways. Figure 2 shows the

geometry of Portal VACIS which uses two opposing sources and detector arrayswhich facilitate imaging an entire container or truck without requiring source-

detector separation distances greater than the width of a standard road lane. Thus,

Portal VACIS units can be installed on adjacent multiple lanes. The prototypePortal VACIS used to verify that “empty” trucks entering Mexico were indeed

empty is also shown in Figure 2. Figure 3 shows two Portal VACIS units installed

on adjacent traffic lanes at the Mexican seaport of Manzanillo. Portal VACIS canscan at speeds up to 8 km/hr allowing it to be used in tandem with a RPM in the

integrated system without impeding the flow of vehicles. The gamma beams areshuttered off as the tractor passes the area of the beams. Once the tractor and

driver have cleared the beam area, fast-acting shutters open to allow imaging of

3


4/14

the container (being pulled through on a chassis) or cargo portion of a truck. The

speed of the vehicle during the scan is monitored by a radar gun and used tocorrect the image distortion resulting from variable speed during a scan. The tight

collimation of the gamma beams ensures that the driver receives no radiation

dose. A stowaway in a scanned container would receive less than 5 microrem

(0.05 microSeiverts), equivalent to about 15 minutes of natural backgroundradiation at sea-level. A VACIS average radiation dose to cargo is more than an

order of magnitude less than the lowest dose 450 kV x-ray system and about three

orders of magnitude less than that of a 2 to 6 MeV x-ray system. (1)

Gamma Ray Source No. 1


Detector Tower No. 1with Shielding

Detector Tower No.

2 with Shielding




Detector Tower No.

2 with Shielding




Detector Tower No.

2 with Shielding




Detector Tower No.

2 with Shielding

Figure 2. Portal VACIS schematic (upper) and prototype used by MexicanCustoms at US border to inspect “empty” trucks (lower)

(1) Siraj Khan, Paul Nicholas, and Michael Terpilak, “Radiation to Stowaways in Vehicles”,

Proceedings of 2001 ONDCP International Technology Symposium, June 25-28, 2001, San

Diego, CA

4


5/14

Figure 3. Two Portal VACIS on adjacent traffic lanes at Manzanillo Port in

Mexico

Radiation Scanning

Radiation portal monitors (RPMs), consisting of large-area gamma-ray detectors(usually plastic scintillation detectors) and neutron detectors (He-3 detectors in

polyethylene moderator material), allow the passive detection of nuclear materials

or other radioactive materials to be detected in cargo containers or trucks enteringor leaving a port. The high detection sensitivity of RPMs allows 100% scanning

of cargo with minimal impact on throughput. However, false positive alarms

resulting from cargo which is naturally radioactive (e.g., certain ceramic

materials, kitty litter) can slow-down the flow of commerce unless efficient meansare provided for resolving these false positives.

Figure 4 shows RPMs installed at the Port of Felixstowe in the UK under a pilot

program. RORO (roll-on, roll-off) cargo entering this port is scanned by a

gamma-neutron passive portal monitor. Those trucks which alarm at the primary

detection station are diverted to a secondary inspection station where the truck isradiographed (either gamma-ray or x-ray) and a handheld isotope identifier unit is

5


6/14

used to determine the specific radioisotope responsible for triggering the portal

monitor alarm.

Figure 4. Radiation Portal Monitors installed at Port of Felixstowe (UK).

Automated Vehicle and Container Identification

SAIC’s advanced OCR technology reads the ID number of each container,enabling ICIS to automatically associate VACIS and RPM scanning data with

specific containers. SAIC OCR systems at terminals around the world currently

identify millions of containers and vehicles annually. One such system recentlydeployed at the American President Lines terminal at the Port of Los Angeles,

shown in Figure 5, automates the access control of trucks bringing cargo

containers to the terminal. Video cameras scan the cargo container from severaldirections to image the container identification number which is automatically

“read” using OCR software. Chassis identification numbers and the truck license

plate are similarly imaged and recorded.

6


7/14

7

200 lbs

Figure 5. OCR System at APL Terminal in Los Angeles

Material Specific Scanning using Neutron Interrogation

PELAN uses pulsed 14 MeV neutrons from a small neutron generator to excite

characteristic gamma-rays from nuclear reactions. Automatic analysis of the

resulting gamma-ray spectra provides a measure of elemental compositions ofcarbon, oxygen, nitrogen and hydrogen which can verify the presence of

explosives or chemical agents. Figure 6 shows SAIC’s PELAN being used toverify the presence of explosives in a van.

Figure 6. SAIC PELAN detecting 200 lbs ANFO Explosive in van.


8/14

Integrated Display (ICIS Viewer)

Figure 7 shows ICIS at SAIC’s Rancho Bernardo (San Diego) facility and anintegrated display of the VACIS gamma radiographic image with the

Exploranium RPM trace (total counting rate and counting rates from energy

windows as a function of position along the vehicle) properly registered. The

RPM background level can be increased (impacting sensitivity) if the RPM islocated close to the VACIS gamma-ray source. Thus, the RPM should be located

at least 30 m from VACIS source unless additional shielding is used. Therefore,

means for spatially correlating the RPM and VACIS data relative to the truck orcontainer have been developed.

Figure 7. ICIS prototype being tested at SAIC’s San Diego facility (upper)

and ICIS integrated display computer screen.

8


9/14

For added flexibility, the ICIS sensor subsystems are available in both fixed and mobile

configurations. The mobile subsystem can be set up in minutes virtually anywhere in theterminal—ideal for inspecting containers on the quay. The mobile subsystem

communicates with the ICIS Server over a high-speed wireless network. ICIS can also

include other capabilities to streamline terminal operations, such as SAIC’s EmptyView

system to automatically verify empty containers, and enhanced cameras and viewingsoftware for online damage inspection.

ICIS Benefits

With these capabilities, ICIS offers significant benefits for Customs. ICIS systems

installed at U.S. ports of entry would enable CBP to screen a large percentage of inboundcontainers to identify high-risk containers. And installed at foreign terminals around the

world, ICIS would enable CBP to screen a large percentage of containers bound for the

U.S. before they ever reach our shores. Terminal operators around the world haveeconomic incentives to integrate ICIS systems into their operations because such systems

would add value for their customers. Perhaps most important, ICIS scanning, as part ofCBP security procedures, may help qualify containers for expedited processing, thereby

reducing shipping costs. In addition, terminal operators can assure their customers thattheir terminals are less vulnerable to terrorist activity, and will reopen faster in the wake

of an incident or threat at the terminal or elsewhere. SAIC anticipates that these economic

incentives will promote the adoption of ICIS within the industry—accelerating theenhancement of security for CBP.

ICIS Demonstration at Port of Hong Kong

SAIC is currently in discussions with the Hong Kong Container Terminal Operators

Association (CTOA) regarding a fully integrated ICIS demonstration system. The goal of

the project is to demonstrate to Customs authorities and the global port community thatICIS can scan all inbound export containers as part of the terminal’s normal operations

without impeding traffic, and that the information it provides will help Customs

authorities identify high-risk containers for further inspection. As currently envisioned,SAIC will install a prototype ICIS system (including one or more VACIS units, RPMs

and OCR components) to scan export containers entering the terminal by truck or barge.

With its high capacity, the system will handle the terminal’s full volume of up to 14,000

Twenty-Foot Equivalent Units (TEUs) per day. The information from the ICIS sensorcomponents will be integrated by the ICIS Server for evaluation by Customs and others.

SAIC intends to begin the demonstration project in Fall 2004.

Automatic Empty Container Verification System

Introduction

Many inter-modal terminals expend significant resources verifying that shipping

containers designated “empty” are actually empty at terminal gates. Typically, truck

drivers park in the gate lanes or in a dedicated inspection area, exit the truck, and openthe rear doors so that an inspector near the truck or at a central video station can visually

verify that the container is empty. This process can take a minute or more per truck,

9


10/14

wasting hours of gate and inspector time every day and putting drivers and inspectors at

risk in traffic.

We describe and show performance results for an automatic empty container verification

system (patent pending) which provides a faster, safer solution. The system automatically

scans closed containers as trucks drive through, detects objects inside, and alertsinspectors for non-empty containers. Gamma-ray scanning technology images the interior

of closed containers moving at up to 10 mph (16 km/h) in 5–10 seconds. Automated

software analyzes the container image to detect objects inside the container, including pallets and other wooden objects, cardboard boxes, even plastic wrap. When an object is

detected, it issues an alert to inspectors or the terminal’s information system. The system

has demonstrated a probability of detection of about 97%.

Configuration

The system uses a Cs-137 source of photons. The gamma-ray energy of 662 keV provides good contrast for a wide range of materials, including small amounts of wood,

cardboard, etc. The detector array is a single column of relatively large scintillation photon detectors to enable efficient photon detection and better counting statistics.

A change from the COTS version of the Portal VACIS is in the beam angle. COTS

Portal VACIS systems are intentionally designed to offset the collimated source beam

angle at about 10 degrees from perpendicularity to allow an oblique view through frontand back walls of a container. This was a feature requested by operators since this is a

favored location for false compartments, etc. and the oblique angle-of-incidence makes

such compartments easier to detect. However, it was easier to develop automatedalgorithms to reliably detect front and rear walls with a truly perpendicular beam. This

also significantly improves the ability to detect small objects placed against these walls.

A single operator’s booth can be used to monitor several lanes of outbound traffic. This

is because the image analysis software operates essentially autonomously, and onlyrequires operator intervention in the rare cases when the algorithm is uncertain of its

results or if a container is actually non-empty.

CONOPS (Concept of Operations)

Some of the operational aspects depend upon the business rules in use at a particular site.

A generalized operational concept is discussed here.

The EmptyView portals are setup on the outbound lanes of a terminal. There is a gate

and driver-activated button on an extended arm in the appropriate position to be reached

from a truck cab when stopped at the gate. When the driver presses the button, the gatelifts, allowing the driver to proceed. As the driver pulls away, the EmptyView portal

records the gamma-ray scan and vehicle speed.

An additional capability currently in testing is trying to eliminate the need for the driver

to stop at all. A drive-thru capability uses a suite of sensors to detect the end of the

driver’s cab and the beginning of the cargo area. Sensing this gap allows the system to

10


11/14

know when to open the source shutter to begin recording data. An additional capability

that required development was a fast-acting shutter, since the original design had arelatively long cycle time with large variance. This design is complete and undergoing

life-cycle testing. The combination of end-of-cab sensors and a fast-acting shutter, with

appropriate control software updates, means that a drive-thru system is now possible.

After automated data acquisition, the system software sends the image to the analysis

algorithm. The algorithm determines a result of GREEN (=empty=truck may leave),

YELLOW(=software uncertain, operator verify), or RED (=truck not empty, divert forinspection). If the result is green, the truck is allowed to exit with no additional

interference. If yellow, the image is sent to the operator’s booth for analysis, where the

operator may determine that the container is empty and the truck may exit, or that thecontainer requires further inspection and sends the driver to an inspection area. Finally, a

red output is automatically sent to the inspection area.

Image Analysis

Two independent algorithms were developed to automatically analyze the data anddetermine if a container is empty or not. One algorithm is rule-based and the other relies

on statistical methods. The statistical algorithm can learn from operator feedback onuncertain cases. Because the algorithms tend to have different reasons for mis-

identifying a container, we ultimately hope to create a voting scheme using both

algorithms to reduce false alarm rates even further. Currently the algorithms are runindependently for testing and characterization. For the remainder of this paper, only the

rule-based algorithm will be discussed.

A critical first step in the automatic analysis of cargo scans is segmenting the image into

various major portions, such as open space, trailer chassis, container floor/walls/roof, andcargo area. This step required a large amount of effort to teach the algorithms about

slanted roofs (short trailers have an appreciable angle), walls that are not quite

perpendicular, etc. Other real-world effects that had to be accounted for includecontainer patches, tie-down hooks, and other routinely-encountered bits of hardware

built-in to the container. Multiple trailer configurations are also common in some areas

and the system control logic as well as the image analysis routines had to be programmed

to handle them.

Results

Several sets of experimental tests were conducted to aid in development, to test thesensitivity of the algorithms, and determine accuracy and false alarm rate. By way of

example, Figure 8 shows a container image which the algorithm correctly identified as

non-empty. Figure 9 shows an image that was a false positive – the algorithm identifiedthe container as non-empty when in fact it was empty.

11


12/14

Figure 8. An accurately identified image showing empty space (purple), chassis and

roof (red), cargo area walls (green), and object in cargo area (blue). Note the two

container patches along the top edge that are correctly identified as part of the

container.

Figure 9. A false positive image. The reinforced vertical spars tricked the algorithm

into calling this non-empty. The cargo tie-downs were correctly ignored by the

algorithm.

We tested both algorithms with several thousand test images. The rule-based algorithmachieved an accuracy of 97.2% and false negative rate of 0.4%, while the statistical

algorithm reached an accuracy of 96.5% and false negative rate of 2.3%. The false

negative rates are considered most important by initial customers, so we are working hardto reduce them. There are still many fertile areas for improving performance and we are

confident the false negative rates will continue to drop.

VACIS High Resolution System

Introduction

While the VACIS systems are well-suited to the original goal of narcotics detection, thereis opportunity to improve the performance with respect to new priorities such as locating

bombs, etc. To this end, one parameter of interest is improved spatial resolution.

Fundamental simultaneous design constraints include maintaining or improving system

throughput, minimizing the scope of the changes, and, of course, minimizing cost.

After analyzing many different possible techniques and detectors to achieve these designgoals in the VACIS product line, we have decided to use block detectors, of the type used

in nuclear medicine PET studies. This provides a high-resolution option (patent pending)

for the VACIS product line. These detectors, with associated image reconstruction

software, will enable an improvement in spatial resolution of approximately a factor ofthree while maintaining throughput. VACIS systems are photon limited by design, so the

12


13/14

highest resolution will only be achieved with low-attenuation objects. As attenuation

increases, it is planned that the software will re-bin the data into larger virtual pixels toachieve a step-wise tradeoff between pixel count density and spatial resolution.

Configuration

A series of analytic models, ray-tracing code runs, and Monte Carlo code runs indicatethat for the VACIS product line, a pixel size of approximately 6 mm is ideal for

achieving maximum resolution. Factors that preclude smaller pixels include out-

scattering from the pixels (effectively reducing contrast), source brightness and scantime.

Figure 10. Prototype block detector. 8x8 pixel array is at far end, electronics

package at near end, showing DB-15 and RJ-45 connectors.

A significant amount of work was performed to design the block detector unit as a nearly

self-contained, field replaceable unit (see Figure 10). Integral to the detector housing is

the HV power supply, analog preamplifier, ADCs, an FPGA and an embedded micro-controller. The block detector inputs are low-voltage DC power and two master control

lines on a single DB-15 connector. The output is an Ethernet data stream on a standardRJ-45 connector.

Image Reconstruction

The data binning and manipulation required to reconstruct an image at maximum spatialresolution is substantial, and is still a work in progress. The parallax observed by each

pixel is significant relative to the pixel size. We have achieved success correcting for this

parallax manually by aligning the data for thin objects, and are working on automated

techniques to handle complex, thick objects.

Results

A detector array consisting of up to 20 block detectors is operating on an engineeringVACIS unit, providing nearly 130 cm of active imaging height. This prototype array has

been used to characterize performance and gather test data. Figure 11 shows an image of

a test object scanned with an existing VACIS-II platform and the new detectors.Although this represents the best-case improvement expected, additional testing with

thick, dense loads still indicate significant improvement.

13


14/14

Figure 11. Early data comparing the existing VACIS-II performance (left) with the

Next Generation Detector performance (right). The iron “wedge” target is 51 cm in

diameter. This represents the best-case improvement of a high-contrast, thin object

in air.

Summary and Conclusions

The Integrated Container Inspection System (ICIS) comprised of a Portal VACIS,

Radiation Portal Monitor (RPM), OCR Automated Container Identification, radioisotopeidentification, material specific inspection using neutron interrogation and an integrated

data display and analysis system shows considerable promise for significantly enhancing

capability to detect nuclear weapons and nuclear and other radioactive material in

containers. The VACIS and RPM have complementary capabilities since VACIS candetect the attempt to shield a radioactive source using dense materials by imaging the

dense material anomaly.

The VACIS product line continues to evolve into new applications and to adapt to

changing user requirements. The automated empties system provides a commercial platform that will ultimately reduce costs and improve safety and performance atcontainer terminals. The next generation of high-resolution detectors provides

significantly enhanced spatial resolution for low-attenuation objects while maintainingsystem throughput.

14

3a orphan paper

Documents