Electronic Design

Defense and Security Symposium Highlights Latest In Sensor, Imaging, Optics, and Laser Technologies

With over 2200 technical presentations and 420 company exhibits, the 2006 Defense and Security Symposium, held April 17-21 in Orlando, Fla., saw the largest non-classified technical program and exhibition of infrared (IR) imaging equipment, sensors, and optical components in the U.S.

Held at the Gaylord Palms Hotel and Convention Center and sponsored by the Society of Photo-optical Instrumentation Engineers (SPIE), the event presented attendees with everything they could possibly need to know about the latest in electronics and electro-optics technologies.

Among the technologies that took center stage at the show were IR sensors, detectors, and systems; sensors and sensor networking; electronic imaging; optics; optoelectronic components; lasers; fiber lasers; cameras; CCD components; software; test equipment; and displays.

The technical program comprised 49 conferences, which primarily focused on sensors, imaging systems, signal and data processing, and networked systems—all for use in defense-related systems and services. Hot topics included discussions on sensors for command, control, communications, and intelligence; biometric technology for human identification; the role of optics and photonics in global homeland security; thermal sensing; IR technology and its applications; and passive millimeter-wave imaging. Other showstoppers included space-borne sensors; sensors for propulsion measurement; unmanned systems; unattended ground, sea, and air sensor technologies; multispectral imaging; and quantum communications and computations.

Tactical Imaging and Biometric Technologies
An invited paper presented by the University of Illinois discussed research on conductive biomolecules and their terahertz (THz) vibrational interactions. It proposed interesting implications for the design, development, and application of biosensors and bioelectronics. The research involves DNA strands bound to titanium-dioxide (TiO2) quantum dots in a liquid solution. TiO2 quantum dots have indirect band gaps. Therefore, they generate electron hole pairs that don’t recombine rapidly. The terahertz optical conductivity of these particular nanocrystalline structures elicits a charge transfer in the DNA that could theoretically be harnessed to make amperometric biosensors based on conducting nanotubes. Lawrence Livermore National Laboratory presented an overview of methods for using neutron radiation detection techniques for the examination of shipping containers. Neutron radiation interacts with materials through a number of methods. Neutrons can be scattered back and forth, generating gamma rays. By detecting the time of flight and angular distribution of these resultant particles, items inside a shipping container can be located in space and then identified through energy-spectrum measurements of the gamma ray particles.

Other presentations covered enhanced and synthetic vision technology developments, real-time implementation of test systems, and ideas for future synthetic vision applications. The use of data fusion in real-time vision applications reflected the focus of many presentations on applications for the end user.

Many of the presentations also covered distributed aperture systems and augmented vision systems. Distributed aperture systems consist of multiple cameras or sensors observing a target so users can extract the most information from the combination of the images in real time. Augmented vision systems project simulated images onto actual visual images to improve the user situation awareness.

In the biometrics arena, there were discussions on the issue of having multiple markets, yet different needs, for biometric technologies. There was also talk about the lack of a vendor base, the relative immaturity of the science, a lack of standardization, privacy concerns, cost, the difficulty of determining a return on investment (ROI), and the current regulatory environment.

One speaker from West Virginia University focused on the many ways a biometric system could be compromised, such as the creation of a fake biometric, the replay of old data, the overriding of a feature extractor, the interception of the channel, and other potential weak spots.

Another speaker from Carnegie Mellon University asked how we could ensure biometric recognition in non-cooperative situations. He pointed out that most image captures of suspects aren’t ideal. Many images are poorly illuminated or taken at odd angles, and they may incorporate some blur. A large challenge is the acquisition of good probe data, as even something as benign as eye-lid occlusion or too much iris dilation can hinder even a simple iris verification.

A speaker from Purdue University examined each biometric and listed its advantages and challenges. After listing all of the shortcomings of fingerprint, iris, and 2D and 3D face technologies, he came to the common conclusion that only multimodal biometrics would prove reliable.

Another speaker from Digital Persona Inc. took a different approach. He looked at biometric challenges in terms of customer needs. In his opinion, the true constraints are convenience, security, cost, size, computational resources, and biometric individuality. He explained that fundamental barriers will apply if any system is specified to operate at the extremes of its capability. He then came to the conclusion that while some may call biometrics technology "immature," it is in fact being deployed right now—and will grow.

Accurate Hurricane Forecasting Getting Better
A speaker from the Earth Science Directorate, NASA Goddard Space Flight Center, posed the sensitive question of what is needed most for security—should we concentrate on enhancing current sensor technologies, or should we be improving coordination among the many operating agencies?

The Katrina disaster was foremost in the speaker’s mind, and so was the obvious need to better mitigate future hurricanes. After the subsequent massive earthquake in Northern Pakistan that killed over 100,000 people and cost more than $100 billion in damage, he came to the conclusion that it is the responsibility of the scientific community, non-governmental organizations (NGOs), and government agencies to coordinate their efforts more effectively.

Unfortunately, most U.S. agencies are vertically aligned, so having a common understanding of a situation is never that simple. This is a detriment because communication and coordination are the most crucial elements in situation response. And while sensor technologies and networks can only assist in that coordination, better coordination among scientists, researchers, engineers, and disaster relief officials is needed to account for social, environmental, and economic factors when crafting and executing any disaster response.

As an example, the speaker pointed out that any understanding of Earth's environment must consider the sensing of earth-sun interaction, weather, surface temperatures, water cycles, and carbon cycles because they all contribute to "anthropogenic disaster phenomena." He proposed that the basic attributes of disaster mitigation should include increasing observations, developing better algorithms to increase predictions, and building a capacity to mitigate disasters by coordinating with many resources.

Next, he opined that there’s no problem with having enough data. We already have petabytes of data from the many sensors deployed with the intent to increase temporal, spatial, and spectral resolution, he pointed out. This is far more data than we are currently equipped to handle. He suggested that we look to an economic model as an analogy of what an overload of information will do to disaster prediction.

Defense and Security Devices Getting Miniaturized
Microelectromechanical systems (MEMS) and nanotechnologies are heavily weighing in for defense and security applications. An interesting presentation from Sandia National Laboratories outlined the development of a number of analytical techniques on the micro scale with security- and defense-related applications. The work is aimed at developing complete lab-on-a-chip capabilities to provide the analytical techniques of mass spectroscopy, gas chromatography, and calorimetry on the micro scale for chemical and biological agent detection. MEMS devices produced incorporate chemical preconcentrators, gas chromatography columns, detector arrays, valves, and heaters.

An overview presentation by the Defense Advanced Research Projects Agency (DARPA) Microsystems Technology Office (MTO) discussed device developments for warfighter aircraft and emergency first responders. MTO is pioneering research in integrated sensing microsystems as platforms-on-a-chip to enable revolutionary performance and functionality for future military systems. Sensing modalities extend across the entire electromagnetic spectrum, from dc to light, and include biological and chemical sensing.

An industry panel session on fiber lasers reviewed and commented on their great advantages. These include small size, high efficiency, high reliability, low power requirements, excellent beam quality, and their ability to operate in multiple wavelengths at very high repetition rates. Such attributes make fiber lasers very attractive for military vehicles, as well as telecommunications and medical uses.

The U.S. Displays Consortium (USDC) offered an invited overview presentation on flexible displays and electronics technology. It focused on the why, what, and when of displays, particularly flexible displays. It showed that serious work has been done over the last five years to accommodate the U.S. Army’s interest in advancing flexible display technology, as well as to secure DARPA funding.

Terahertz imaging was another hot topic at the conference. A panel session on this subject debated the pros and cons of this technology. Participants ultimately came to the conclusion that while the technology holds great potential for non-contact imaging of objects and human beings at a distance, it still must come down enough in price to make it more cost-effective. Although such images are said to be capable of operating roughly in the range of 300 GHz (1-mm wavelengths) to 10 THz (30-µm wavelengths), practical applications have limited its capability to 500 to 600 GHz (see Figure 1).

New Products
In the exhibit area, a slew of new products and capabilities complemented the technical presentation. A particular hot product category was un-cooled IR thermal imaging arrays, which are much lower in cost and smaller than cooled IR thermal imaging arrays. Such arrays are also known as microbolometers and IR focal-plane arrays (FPAs).

RedShift Systems catapulted the uncooled imaging array technology last year with the introduction of a platform of mass-market applications (see "Uncooled Thermal Imaging Has Mass Market Appeal," ED Online 10742). At the show, RedShift showed off an improved version of its Thermal Light Valve with significant improvements in resolution (160 by 120 pixels, or four times greater), a 64% reduction of pixel size down to 30 µm, and an 18x greater ability to pack more die per 6-in. glass wafer.

Israeli company Opgal showed off a miniaturized uncooled-IR engine, the EYE-R25, which is based on a 384- by 288-pixel or 320- by 240 pixel user-selectable format. The unit features an NETD of 508 mK at a 12-ms time constant (50-Hz frame rate) and 708 mK at a 5-ms time constant (60-Hz frame rate). (NETD refers to the noise rating of an IR FPA detector. It specifies the amount of radiation required of an imager to produce an output signal equal to the detector’s own noise—due to inner component heat.) The EYE-R25 is tuned to a long-wave sensitivity of less than 0.0508C when using an F/1.0 lens (see Figure 2).

Ulis, a subsidiary of the French Sofradir Company, introduced three new amorphous-silicon uncooled IR FPA imagers with signal response of 7 mV/K. The FPAs feature a spectral range of 8 to 14 µm and 7-ms thermal time constants. The three models include the 160- by 120-pixel UL02051 with a 35-µm pixel pitch, the 384- by 288-pixel UL03041 with a 35-µm pixel pitch, and the 640- by 480-pixel UL04171 with a 25-µm pixel pitch.

Sofradir is one of two companies producing major high-performance advanced IR thermal detectors based on mercury-cadmium-telluride (MCT) technology and used in military, space, and industrial applications. The other company is Raytheon. Both Sofradir and Raytheon were major exhibitors at the show. Sofradir showed off its newest product, a quantum well IR photodetector (QWIP) based on MCT technology.

ThruVision Co also displayed new passive THz imagers. The company says that its T-4000 is the first truly passive THz imaging system for revealing concealed objects on people walking at a distance designed for use by customs, police, and corporate security operators. As mentioned earlier, THz imagers are non-invasive and non-ionizing (like X-rays), and they do not require contact with the imaged object (like ultrasound waves) (see Figure 3).

Autonomous and unmanned security robots are now a reality for many industrial and governmental security applications. One such robot, the Seekur from MobileRobots (which retails for approximately $60,000), kept busy navigating the exhibit isles and examining attendees and their surroundings via its camera and sensors (see Figure 4).

MobileRobots says it’s first indoor/outdoor robotic rover is designed for work in garages, hangars, storage facilities, security booths, and outdoors. The all-weather four-wheel unit is very maneuverable with a 20% grade traversability. Its wheels can turn sideways in place, enabling it to maneuver with ease within tight spaces. It has a 70-kg load capacity.

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