Security

Koftech team has extensive experience building state of the art systems to respond to various security needs, ranging from small parcel and baggage scanners to large cargo inspection systems. In many cases, no one single sensor modality may have the sensitivity and specificity to achieve performance targets. Koftech will help you select and fuse the optimal combination of modalities to meet your goals of detection and false alarm while keeping an eye on cost, throughput, and your operational flow.
Personnel Scanning The demand for personnel screening grow exponentially over the past few years given the nature of threats presented. We are continuously faced with more sophisticated threats that challenge the state of art technologies. When metallic threats, knives, guns, and conventional bombs, were the dominant threat types, metal detectors proved very useful in responding to these threats with their high sensitivity and throughput, and relatively low cost. The rise of non-metallic threats, such as carbon-fiber and ceramic knifes, glock guns, and plastic explosives required new personnel-screen modalities. Over the past decade, new imaging modalities were introduced. Most notably, infra-red, millimeter wave, and x-ray backscatter technologies. While these imaging systems demonstrated high-sensitivity against the new types of threats, they also raise privacy concerns for passengers as they reveal body details. In response, automated threat detection algorithms were introduced to detect anomalies without revealing human body parts. When designing a new security screening system, it is very important to understand the operational requirements and the public perceptions. Remember that pat-down search continues to be one of the most effective detection methods, but not used for primary screening because it is invasive, slow, and subject to human error.
Baggage Scanning X-ray scanners for carry-on baggage are relatively inexpensive with small footprint, have high sensitivity, and have high throughput and hence they are the primary inspection modality used in ports around the world. Similar to personnel scanning modalities, baggage scanners came as a response to metallic threats such as knives, guns, and bombs, boarding airplanes. X-rays are preferentially attenuated in materials with higher atomic numbers and hence have high contrast sensitivity when imaging metallic objects. This made them an ideal modality for baggage screening. To cut down the cost, linear detector array along with x-ray fan beams were used. To respond to non-metallic threats, x-ray scanners use dual-energy technologies to give some level of material discrimination. Basically, a pair of x-ray energies, high and low, are used for imaging where the x-ray attenuation ratios between the low and high-energies is used to calculate the material atomic number. Alternatively, x-ray backscatter technology has inherent high contrast sensitivity for non-metallic materials. Some systems actually combine both imaging modalities to meet sensitivity requirements. Advanced x-ray scanners use multiple views and may perform tomosynthetic 3D reconstruction of baggage. More expensive versions perform computed tomography to achieve 3D reconstruction of baggage. These advanced systems allow algorithms to compute the material density in addition to atomic number. Given both density and atomic number, ATR algorithms achieve good detection and false alarm rates. Today, many airports around the world use advanced x-ray scanners with ATR algorithms for checked in luggage with little human intervention.
Cargo Scanning X-rays are the most widely deployed modality for cargo inspection. In principle, an x-ray cargo inspection system is similar to a baggage scanning system but with a larger tunnel to fit large size cargo. Cargo inspection systems traditionally used x-ray transmission technology. Over the past decade, x-ray backscatter technology seized a growing market share, especially in mobile inspection systems. At the low-end, cargo inspection systems use active x-ray isotopes to generate gamma rays. Cobalt-60 (⁶⁰Co) relatively nexpensive, emits x-rays at energies of 1.17 and 1.33 MeV, and has a half-life time of over 5 years, making it a widely used active source for cargo inspection. Typical ⁶⁰Co can penetrate over 200 mm of steel. Given their relatively low dose, ⁶⁰Co sources are used in mobile systems since they require a small exclusion zone. Due to its low dose, active-source systems can not penetrate dense cargo. To scan dense cargo, higher-energy x-ray sources are used—mostly linear accelerator (linac) sources. Typical deployed linac sources use peak energies of 6 MeV and can penetra linacs are pulsed with a low duty cycle. Typical linacs operate at rates of 200 – 400 Hz, with a duty cycle of 1 – 2%. Most deployed linac systems generate dose levels that prohibits their use to scan people. Hence, when scanning a truck, the driver must get out of the truck and move outside the scanner exclusion zone. Hence, most linac systems are not suitable for drive-through operations, which negatively impacts throughput. Typical linac systems with a gantry can scan 18-22 trucks per hour. To overcome cost and throughput limitation of high-dose linacs, some applications revert to using lower dose linacs or betatron sources. The lower does reduces the exclusion zone for such scanners, make them easier to accommodate drive-through requirements, and simplify the operations in general. This comes on the expense of lower steel penetration. Newer versions of pulsed sources such as linacs and betatrons can generate dual-energy pulses. That is, they produce pulses of alternating energies that switch between low and high-energy. With low-energy pulses around 4 MeV and high-energy pulses around 6 MeV, attenuation ratios of the dual-energy pulses are used to calculate the atomic number of the cargo scanned differentiating between organic and metallic material. Backscatter x-ray technology uses x-ray energies in the range of 180-220 keV, much lower than energies used for transmission x-ray inspection. Due to their lower energies, Backscatter systems lack penetration and are considered more of a surface-imaging modality rather than a penetrating imaging modality. Hence, most deployed backscatter cargo inspection systems combine multiple scanners to inspect cargo from multiple sides; left, right, and top. Due to their low dose, backscatter inspection systems are suitable for drive-through inspection achieving throughput rates of over 100 trucks/hour. In cargo systems, it is very important to understand the operational constraints as they predominantly dictate the technology that best-fits the application. Understanding site limitations, throughput, cargo flow, exclusion zone and price are key for successful solutions.

Koftech team has extensive experience building state of the art systems to respond to various security needs, ranging from small parcel and baggage scanners to large cargo inspection systems.

In many cases, no one single sensor modality may have the sensitivity and specificity to achieve performance targets. Koftech will help you select and fuse the optimal combination of modalities to meet your goals of detection and false alarm while keeping an eye on cost, throughput, and your operational flow.

Personnel Scanning

The demand for personnel screening grow exponentially over the past few years given the nature of threats presented. We are continuously faced with more sophisticated threats that challenge the state of art technologies. When metallic threats, knives, guns, and conventional bombs, were the dominant threat types, metal detectors proved very useful in responding to these threats with their high sensitivity and throughput, and relatively low cost.

The rise of non-metallic threats, such as carbon-fiber and ceramic knifes, glock guns, and plastic explosives required new personnel-screen modalities. Over the past decade, new imaging modalities were introduced. Most notably, infra-red, millimeter wave, and x-ray backscatter technologies. While these imaging systems demonstrated high-sensitivity against the new types of threats, they also raise privacy concerns for passengers as they reveal body details. In response, automated threat detection algorithms were introduced to detect anomalies without revealing human body parts.

When designing a new security screening system, it is very important to understand the operational requirements and the public perceptions. Remember that pat-down search continues to be one of the most effective detection methods, but not used for primary screening because it is invasive, slow, and subject to human error.

Baggage Scanning

X-ray scanners for carry-on baggage are relatively inexpensive with small footprint, have high sensitivity, and have high throughput and hence they are the primary inspection modality used in ports around the world.

Similar to personnel scanning modalities, baggage scanners came as a response to metallic threats such as knives, guns, and bombs, boarding airplanes. X-rays are preferentially attenuated in materials with higher atomic numbers and hence have high contrast sensitivity when imaging metallic objects. This made them an ideal modality for baggage screening. To cut down the cost, linear detector array along with x-ray fan beams were used.

To respond to non-metallic threats, x-ray scanners use dual-energy technologies to give some level of material discrimination. Basically, a pair of x-ray energies, high and low, are used for imaging where the x-ray attenuation ratios between the low and high-energies is used to calculate the material atomic number. Alternatively, x-ray backscatter technology has inherent high contrast sensitivity for non-metallic materials. Some systems actually combine both imaging modalities to meet sensitivity requirements.

Advanced x-ray scanners use multiple views and may perform tomosynthetic 3D reconstruction of baggage. More expensive versions perform computed tomography to achieve 3D reconstruction of baggage. These advanced systems allow algorithms to compute the material density in addition to atomic number. Given both density and atomic number, ATR algorithms achieve good detection and false alarm rates. Today, many airports around the world use advanced x-ray scanners with ATR algorithms for checked in luggage with little human intervention.

Cargo Scanning

X-rays are the most widely deployed modality for cargo inspection. In principle, an x-ray cargo inspection system is similar to a baggage scanning system but with a larger tunnel to fit large size cargo. Cargo inspection systems traditionally used x-ray transmission technology. Over the past decade, x-ray backscatter technology seized a growing market share, especially in mobile inspection systems.

At the low-end, cargo inspection systems use active x-ray isotopes to generate gamma rays. Cobalt-60 (⁶⁰Co) relatively nexpensive, emits x-rays at energies of 1.17 and 1.33 MeV, and has a half-life time of over 5 years, making it a widely used active source for cargo inspection. Typical ⁶⁰Co can penetrate over 200 mm of steel. Given their relatively low dose, ⁶⁰Co sources are used in mobile systems since they require a small exclusion zone.

Due to its low dose, active-source systems can not penetrate dense cargo. To scan dense cargo, higher-energy x-ray sources are used—mostly linear accelerator (linac) sources. Typical deployed linac sources use peak energies of 6 MeV and can penetra linacs are pulsed with a low duty cycle. Typical linacs operate at rates of 200 – 400 Hz, with a duty cycle of 1 – 2%.

Most deployed linac systems generate dose levels that prohibits their use to scan people. Hence, when scanning a truck, the driver must get out of the truck and move outside the scanner exclusion zone. Hence, most linac systems are not suitable for drive-through operations, which negatively impacts throughput. Typical linac systems with a gantry can scan 18-22 trucks per hour.

To overcome cost and throughput limitation of high-dose linacs, some applications revert to using lower dose linacs or betatron sources. The lower does reduces the exclusion zone for such scanners, make them easier to accommodate drive-through requirements, and simplify the operations in general. This comes on the expense of lower steel penetration.

Newer versions of pulsed sources such as linacs and betatrons can generate dual-energy pulses. That is, they produce pulses of alternating energies that switch between low and high-energy. With low-energy pulses around 4 MeV and high-energy pulses around 6 MeV, attenuation ratios of the dual-energy pulses are used to calculate the atomic number of the cargo scanned differentiating between organic and metallic material.

Backscatter x-ray technology uses x-ray energies in the range of 180-220 keV, much lower than energies used for transmission x-ray inspection. Due to their lower energies, Backscatter systems lack penetration and are considered more of a surface-imaging modality rather than a penetrating imaging modality. Hence, most deployed backscatter cargo inspection systems combine multiple scanners to inspect cargo from multiple sides; left, right, and top. Due to their low dose, backscatter inspection systems are suitable for drive-through inspection achieving throughput rates of over 100 trucks/hour.

In cargo systems, it is very important to understand the operational constraints as they predominantly dictate the technology that best-fits the application. Understanding site limitations, throughput, cargo flow, exclusion zone and price are key for successful solutions.