Night Vision and Electronic Sensors Directorate

Fort Belvoir, VA, United States

Night Vision and Electronic Sensors Directorate

Fort Belvoir, VA, United States
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News Article | April 17, 2017

A new technique that computes the eigenmodes of the eddy-current problem provides an aid to classification using broadband electromagnetic induction sensors. Electromagnetic induction (EMI) sensors excel at detecting even small fragments of metal that are buried underground. The sensors work according to the principle that time-varying magnetic fields cause electrical currents to flow in conductive media. These electrical currents, called eddy currents because of their circular path, produce a secondary magnetic field that signals the presence of nearby metal. This mechanism is shown in Figure 1. For many applications, such as landmine detection, establishing the presence of metal alone is not useful because of the ubiquity of metallic clutter. Broadband sensors, which transmit and receive signals over a large frequency band, provide a way around this problem. The additional data collected by these sensors can be used to determine whether a metal target is of interest or not. The broadband data can also be used to estimate the target's orientation and position underground.1, 2 The main challenge is to make effective use of the broadband data collected by the sensor. The target is characterized by how the flow of eddy currents changes when it is excited at different frequencies. However, the flow of eddy currents also depends on the target's positioning relative to the sensor and its orientation. Creating a dictionary for the responses of each target of interest at each position and orientation is not computationally feasible. A much more attractive approach is to perform a modal analysis of the target so that its frequency response is interpreted as the contribution of several eddy-current modes, each with a corresponding relaxation frequency.3 This is analogous to characterizing the vibration of a string as an excitation of different standing waves. In order to perform the modal analysis of a specific target type, first a linear system that describes the eddy-current response of the target to a magnetic field is constructed. This system is then decomposed using an eigenvalue solver to find its natural modes and their corresponding relaxation frequencies. Because the linear system is treated as an eigenvalue problem, the nature of the excitation does not factor in the analysis. Once the modes of the problem are known, it is possible to easily find the response of the target to any excitation, at any of the possible orientations of the target relative to the sensor. Since the relaxation frequencies of the target are independent of the excitation, they do not change as the sensor moves over a target. This is an important property that is used for target classification. Additionally, the magnetic dipole moment of each particular eddy-current mode captures all of its scattering behavior within six scalar values.4 We chose to use the finite integration technique (FIT) to model the electromagnetic interactions. FIT is a differential method where Maxwell equations in integral form are applied to a set of staggered grids.5 The linear systems that are constructed are very large and sparse, often with many millions of unknowns. This is because the analysis is three dimensional and because differential methods require that, in addition to the target, a large region surrounding it must be discretized as well. Finding the eigenmodes of these systems is challenging because of the size and structure of the system matrices. The nature of the problem requires that the smallest eigenvalues of the system be found. Storage and computational constraints mean that finding all the eigenmodes of the system is not possible. Additionally, the formulation of the linear system introduces a large, non-physical null space, which complicates the computation of the system's smallest eigenvalues. Traditionally, these types of problems are solved using a factorization of the system matrices and the application of a Lanczos-based eigensolver that computes only a subset of the eigenmodes. This is not a feasible strategy in this case because of the storage requirements of such a factorization. Instead, we implemented a Jacobi–Davidson eigensolver, which requires no factorization and which employs a special strategy to avoid the linear system's null space.6, 7 The approach taken also employs a form of domain decomposition that eliminates the degrees of freedom associated with fields exterior to the target. This is a necessary step to avoid the system's null space but it conveniently also reduces the storage requirements for the eigenmodes. Figure 2 shows cross sections of the computed magnetic induction associated with the first eddy-current modes of a spherical and cubical conductor. Using this approach, we decomposed the eddy-current response of arbitrarily shaped conductors into their fundamental modes. Using this approach, we decomposed the eddy-current response of arbitrarily shaped conductors into their fundamental modes. Such a decomposition is valuable because it captures a fundamental aspect of the conducting target's geometry and material properties. This aspect is independent of excitation and provides a reliable signature for targets of its type. The obtained compact signature allows for position and orientation inversion that jointly utilizes measurements that were taken at different positions over the target. With this Jacobi–Davidson-based approach, we can derive physical broadband models for conducting objects that can be used for both the detection and classification of buried objects. The use of broadband models greatly aids in minimizing the number of false alarms triggered by benign metallic clutter. In the future, we would like to improve the accuracy of the computed field interactions on the target's exterior, and we would also like to extend this work to permeable targets. This material is based upon work supported in part by the US Office of Naval Research as a Multi-disciplinary University Research Initiative on Sound and Electromagnetic Interacting Waves under grant N00014-10-1-0958, in part by the US Army REDCOM CERDEC Night Vision and Electronic Sensors Directorate, Science and Technology Division, Countermine Branch, and in part by the US Army Research Office under grant W911NF-11-1-0153.

PRINCETON, N.J., May 25, 2017 /PRNewswire/ -- BANC3 is pleased to announce its selection as a prime contractor for the Department of the Army's $37.4 Billion Responsive Strategic Sourcing for Services (RS3) contract. RS3, with a period of performance of 10 years, covers professional services for government programs with Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR) requirements. RS3 primary service areas include Engineering; Research, Development, Test and Evaluation (RDT&E); Logistics; Acquisition and Strategic Planning; Education and Training Services. This award continues BANC3's strong trend of successful contracts for the Department of Defense C4ISR community, reinforcing its powerful ability to compete and provide professional services in a multitude of diverse areas. RS3 is the largest ID/IQ contract won by BANC3, building upon other wins with customers including US Army Communications Electronics Research and Development Engineering Center (CERDEC) Night Vision and Electronic Sensors Directorate (NVESD) WEBS, CECOM Software Engineering Center (SEC) SSES NexGen, CERDEC Command Power and Integration Directorate (CP&ID), and Armament Research, Development and Engineering Center (ARDEC) Tactical Mission Command Applications (TMCA).

ARLINGTON, Va.--(BUSINESS WIRE)--CACI International Inc (NYSE: CACI) announced today that it was awarded a $31 million contract to support modeling and simulation technology for the U.S. Army Research, Development, and Engineering Command’s (RDECOM) Communications-Electronics Research, Development, and Engineering Center (CERDEC) Night Vision and Electronic Sensors Directorate (NVESD). This three-year task order, awarded under the R2-3G contract vehicle, represents new business in CACI’s Surveillance and Reconnaissance market area. CERDEC NVESD conducts research and development of advanced night vision and other sensor technologies, such as infrared weapon sights, and long-range surveillance and target acquisition systems, which enhance our Armed Forces’ operational advantage in daytime, nighttime, and limited visibility conditions. Under this contract, CACI will support the development of realistic electro-optic/infrared and SIGINT payload modeling and simulation capabilities and training systems. These training systems will enhance the readiness of the Army’s Airborne Intelligence, Surveillance, and Reconnaissance (A-ISR) tactical units, resulting in improved situational awareness to Army brigade combat teams. The company will also provide pilots and trainers to develop and execute A-ISR programs of instruction. John Mengucci, CACI’s Chief Operating Officer and President of U.S. Operations, said, “As a pioneer in modeling and simulation technology, CACI will leverage our extensive subject matter expertise and knowledge of this customer’s mission applications to develop highly realistic simulations in support of Army airborne intelligence, surveillance, and reconnaissance operations.” According to CACI President and Chief Executive Officer Ken Asbury, “With this award for new work, CACI is proud to expand our ongoing partnership with the U.S. Army’s Night Vision and Electronic Sensors Directorate. It continues CACI’s commitment to providing our government customers with the tools and resources to gather actionable intelligence for military decision-makers.” CACI provides information solutions and services in support of national security missions and government transformation for Intelligence, Defense, and Federal Civilian customers. A Fortune magazine World’s Most Admired Company in the IT Services industry, CACI is a member of the Fortune 1000 Largest Companies, the Russell 2000 Index, and the S&P SmallCap600 Index. CACI’s sustained commitment to ethics and integrity defines its corporate culture and drives its success. With approximately 20,000 employees worldwide, CACI provides dynamic career opportunities for military veterans and industry professionals to support the nation’s most critical missions. Join us! There are statements made herein which do not address historical facts, and therefore could be interpreted to be forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. Such statements are subject to factors that could cause actual results to differ materially from anticipated results. The factors that could cause actual results to differ materially from those anticipated include, but are not limited to, the risk factors set forth in CACI’s Annual Report on Form 10-K for the fiscal year ended June 30, 2016, and other such filings that CACI makes with the Securities and Exchange Commission from time to time. Any forward-looking statements should not be unduly relied upon and only speak as of the date hereof.

Ricciardi P.,National Gallery of Art | Delaney J.K.,National Gallery of Art | Delaney J.K.,George Washington University | Facini M.,National Gallery of Art | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2012

In situ analysis: Near infrared imaging spectroscopy (1000-2500 nm) is used to map the use of a fat-containing paint binder, likely egg yolk, in situ on a work of art for the first time. The identification of the use of egg tempera on a 15th century illuminated manuscript leaf (Praying Prophet by Lorenzo Monaco) sheds light on the relationship between painters and illuminators and can inform preservation decisions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Leach J.H.,Night Vision and Electronic Sensors Directorate | Chinn S.R.,Fulcrum Company | Goldberg L.,Night Vision and Electronic Sensors Directorate | Mathews S.A.,Catholic University of America
Applied Optics | Year: 2015

A rangefinder based on a fiber-coupled, monostatic system that transmits and receives through the same aperture has been developed. Some of the advantageous characteristics include elimination of the requirement for precision alignment of the receiver detector and smaller size than bistatic systems using separate transmit and receive apertures. Because there is no parallax between transmit and receive beam paths, optimum receiver alignment is maintained for all ranges. The system operates at 50 kpps and uses a 27 mm diameter/40 mm focal length transmit/receive lens. The standard deviation range precision of the system is 7.8 mm at 50 m with 3.3 ?J pulses. © 2015 Optical Society of America.

Oreifej O.,University of Central Florida | Shu G.,University of Central Florida | Pace T.,Night Vision and Electronic Sensors Directorate | Shah M.,University of Central Florida
Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition | Year: 2011

Several attempts have been lately proposed to tackle the problem of recovering the original image of an underwater scene using a sequence distorted by water waves. The main drawback of the state of the art [18] is that it heavily depends on modelling the waves, which in fact is ill-posed since the actual behavior of the waves along with the imaging process are complicated and include several noise components; therefore, their results are not satisfactory. In this paper, we revisit the problem by proposing a data-driven two-stage approach, each stage is targeted toward a certain type of noise. The first stage leverages the temporal mean of the sequence to overcome the structured turbulence of the waves through an iterative robust registration algorithm. The result of the first stage is a high quality mean and a better structured sequence; however, the sequence still contains unstructured sparse noise. Thus, we employ a second stage at which we extract the sparse errors from the sequence through rank minimization. Our method converges faster, and drastically outperforms state of the art on all testing sequences even only after the first stage. © 2011 IEEE.

Pellegrino J.G.,Night Vision and Electronic Sensors Directorate | Dewames R.,Night Vision and Electronic Sensors Directorate | Perconti P.,Night Vision and Electronic Sensors Directorate | Billman C.,Night Vision and Electronic Sensors Directorate | Maloney P.,Night Vision and Electronic Sensors Directorate
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

Mid wave infrared (MWIR) imaging in the 3-5 um spectral band has traditionally been performed by InSb sensors. InSb technology is presently limited to a near 80K operating temperature and the hunt has been on for a higher operating temperature (HOT) technology that does as well at 150K as InSb at 80K, but with reduced power requirements. Amongst these alternative technologies are photovoltaic sensors consisting of heterostructures of HgCdTe (MCT). In previous work we assessed the device performance of several alternative MWIR HOT technologies (MCT on Si, MCT on GaAs) as a function of operating temperature. In this work we compare the NEDT histograms for these alternative technologies with InSb to better understand how their performance can be improved at higher temperatures. We also present analysis formalism for quantitatively assessing the number of FPA pixels which reside in the central versus the shoulder portions of the histogram.Begin the Introduction two lines below the Keywords. The manuscript should not have headers, footers, or page numbers. It should be in a onecolumn format. References are often noted in the text1 and cited at the end of the paper. © 2012 SPIE.

Delaney J.K.,National Gallery of Art | Zeibel J.G.,Night Vision and Electronic Sensors Directorate | Thoury M.,National Gallery of Art | Littleton R.,Night Vision and Electronic Sensors Directorate | And 4 more authors.
Applied Spectroscopy | Year: 2010

Reflection imaging spectroscopy is a useful technique to remotely identify and map minerals and vegetation. Here we report on the mapping and identification of artists' materials in paintings using this method. Visible and infrared image cubes of Picasso's Harlequin Musician are collected using two hyperspectral cameras and combined into a single cube having 260 bands (441 to 1680 nm) and processed using convex geometry algorithms. The resulting 18 spectral end members are identified by comparison with library spectra, fitting by nonlinear mixing, and using results from luminescence imaging spectroscopy. The results are compared with those from X-ray fluorescence spectrometry, polarized light microscopy, and scanning electron microscopy-energy dispersive spectrometry (SEM/EDS). This work shows the potential of reflection imaging spectroscopy, in particular if the shortwave infrared region is included along with information from luminescence imaging spectroscopy. © 2010 Society for Applied Spectroscopy.

The probability P(t) of target acquisition, for a single observer who has unlimited time to search a field of view (FOV) for a single target, is expressed in terms of search parameters P∞ and τ under conditions where these parameters are independent of time. It has been assumed that P ∞ has been determined for a particular target, scene clutter and imaging system and, for a given scenario, τ is determined empirically from P∞. The equation for P(t) is then extended to include time-limited search and field of regard (FOR) search, where it is assumed the target has an equal probability of being anywhere in the FOR. Equations are derived for the mean time to find a target for two cases: (1) an arbitrary number of observers using a single sensor search a single FOV or FOR for a single target; (2) two observers using two sensors search independently for a single target. The condition that P∞ and τ be independent of time is relaxed and this leads to the time dependent search parameter (TDSP) search model. The TDSP search model is used to calculate P(t) in: (1) search from a moving vehicle, (2) FOR search where the condition that the target has an equal probability of being anywhere in the FOR is relaxed, and (3) in multitarget search. © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE).

PubMed | Wilmer Eye Institute, Madigan Army Medical Center, U.S. National Institutes of Health, Fort Belvoir Community Hospital and Night Vision and Electronic Sensors Directorate
Type: Journal Article | Journal: Military medicine | Year: 2017

To compare visual performance, marksmanship performance, and threshold target identification following wavefront-guided (WFG) versus wavefront-optimized (WFO) photorefractive keratectomy (PRK).In this prospective, randomized clinical trial, active duty U.S. military Soldiers, age 21 or over, electing to undergo PRK were randomized to undergo WFG (n = 27) or WFO (n = 27) PRK for myopia or myopic astigmatism. Binocular visual performance was assessed preoperatively and 1, 3, and 6 months postoperatively: Super Vision Test high contrast, Super Vision Test contrast sensitivity (CS), and 25% contrast acuity with night vision goggle filter. CS function was generated testing at five spatial frequencies. Marksmanship performance in low light conditions was evaluated in a firing tunnel. Target detection and identification performance was tested for probability of identification of varying target sets and probability of detection of humans in cluttered environments.Visual performance, CS function, marksmanship, and threshold target identification demonstrated no statistically significant differences over time between the two treatments. Exploratory regression analysis of firing range tasks at 6 months showed no significant differences or correlations between procedures. Regression analysis of vehicle and handheld probability of identification showed a significant association with pretreatment performance.Both WFG and WFO PRK results translate to excellent and comparable visual and military performance.

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