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Hall, Thomas E

Publications and source records attributed to Hall, Thomas E.

11 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Passive millimeter wave differential interference contrast polarimetry

Differential polarization imaging systems include an axicon configured to provide a displacement of ray bundles associated with different image patches. The displaced ray bundles are directed to antenna horns and orthomode transducers so as to provide outputs correspond to orthogonal linear states of polarization (SOPs). The outputs are directed to a differential radiometer so that Stokes parameter differences between image patches can be obtained. The ray bundle displacements can be selected to correspond to a mechanical spacing of antenna horns. In some examples, ray bundle displacement corresponds to a displacement less than the diffraction limit.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2012

Passive Fully Polarimetric W-Band Millimeter-Wave Imaging

We present the theory, design, and experimental results obtained from a scanning passive W-band fully polarimetric imager. Passive millimeter-wave imaging offers persistent day/nighttime imaging and the ability to penetrate dust, clouds and other obscurants, including clothing and dry soil. The single-pixel scanning imager includes both far-field and near-field fore-optics for investigation of polarization phenomena. Using both fore-optics, a variety of scenes including natural and man-made objects was imaged and these results are presented showing the utility of polarimetric imaging for anomaly detection. Analysis includes conventional Stokes-parameter based approaches as well as multivariate image analysis methods.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2012

Cleareye In-Ground and In-Concrete DIV Inspections: FY11 Final Report

This report summarizes the results of a series of feasibility testing studies for in-ground and in-concrete imaging/detection technologies including radar imaging and acoustic time-of flight method. The objectives of this project are: (1) Design Information Verification (DIV) Tools for In-Concrete Inspections - To determine the feasibility of using holographic radar imaging (HRI), radar imaging, and acoustic time-of-flight (TOF) non-destructive evaluation technologies to detect, locate and identify pipes and voids embedded in standard-density and high-density concrete walls that typify those the IAEA will need to verify during field inspections; (2) DIV Tools for In-Ground Inspections - To determine the feasibility of using HRI and radar imaging non-destructive evaluation technologies to detect, locate, and identify objects buried at various depths made of various materials (metal, plastic, wood, and concrete) and representing geometries that typify those the IAEA will need to verify during field inspections; and (3) Based on the results of the studies, recommend the next steps needed to realize fieldable tools for in-concrete and in-ground inspections (including detection of deeply buried polyvinyl chloride [PVC] pipes) that employ the technologies shown to be feasible.

09 BIOMASS FUELS↗
DOE OSTI2011

Calibration, Reconstruction, and Rendering of Cylindrical Millimeter-Wave Image Data

Cylindrical millimeter-wave imaging systems and technology have been under development at the Pacific Northwest National Laboratory for many years. This technology has been commercialized, and systems are currently being deployed widely across the United States and internationally. These systems are effective at screening for concealed items of all types, however, new sensor designs, image reconstruction techniques, and image rendering algorithms, could potentially improve performance. At PNNL, a number of specific techniques have been developed recently to improve cylindrical imaging methods including wideband techniques, combining data from full 360 degree scans, polarimetric imaging techniques, calibration methods, and 3-D data visualization techniques. Many of these techniques exploit the three-dimensionality of the cylindrical imaging technique by optimizing the depth resolution of the system and using this information to enhance detection. Other techniques, such as polarimetric methods, exploit scattering physics of the millimeter-wave interaction with concealed targets on the body. In this paper, calibration, reconstruction, and three-dimensional rendering techniques will be described that optimize the depth information in these images and the display of the images to the operator.

concealed-weapon detection↗
DOE OSTI2011

Phenomenology Studies Using a Scanning Fully Polarimetric Passive W-Band Millimeter Wave Imager

We present experimental results obtained from a scanning passive W-band fully polarimetric imager. In addition to a conventional approach to polarimetric image analysis in which the Stokes I, Q, U, and V images were formed and displayed, we present an alternative method for polarimetric image exploitation based upon multivariate image analysis (MIA). MIA uses principal component analysis (PCA) and 2D scatter or score plots to identify various pixel classes in the image compared with the more conventional scene-based image analysis approaches. Multivariate image decomposition provides a window into the complementary interplay between spatial and statistical correlations contained in the data.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2010

Holographic imaging of natural-fiber-containing materials

The present invention includes methods and apparatuses for imaging material properties in natural-fiber-containing materials. In particular, the images can provide quantified measures of localized moisture content. Embodiments of the invention utilize an array of antennas and at least one transceiver to collect amplitude and phase data from radiation interacting with the natural-fiber-containing materials. The antennas and the transceivers are configured to transmit and receive electromagnetic radiation at one or more frequencies, which are between 50 MHz and 1 THz. A conveyance system passes the natural-fiber-containing materials through a field of view of the array of antennas. A computing device is configured to apply a synthetic imaging algorithm to construct a three-dimensional image of the natural-fiber-containing materials that provides a quantified measure of localized moisture content. The image and the quantified measure are both based on the amplitude data, the phase data, or both.

Bunch, Kyle J↗
DOE OSTI2010

Detection of a concealed object

Disclosed are systems, methods, devices, and apparatus to determine if a clothed individual is carrying a suspicious, concealed object. This determination includes establishing data corresponding to an image of the individual through interrogation with electromagnetic radiation in the 200 MHz to 1 THz range. In one form, image data corresponding to intensity of reflected radiation and differential depth of the reflecting surface is received and processed to detect the suspicious, concealed object.

Keller, Paul E↗
DOE OSTI2010

Near-Field Three-Dimensional Radar Imaging Techniques and Applications

Three dimensional radio frequency imaging techniques have been developed for a variety of near field applications including radar cross-section imaging, concealed weapon detection, ground penetrating radar imaging, through-barrier imaging, and non-destructive evaluation. These methods employ active radar transceivers that operate at various frequency ranges covering a wide range from less than 100 MHz to in excess of 350 GHz with the frequency range customized for each application. Computational wavefront reconstruction imaging techniques have been developed that optimize the resolution and illumination quality of the images. In this paper, rectilinear and cylindrical three-dimensional imaging techniques are described along with several application results.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2010

Standoff concealed weapon detection using a 350 GHz radar imaging system

The Pacific Northwest National Laboratory is currently developing a 350 GHz, active, wideband, three-dimensional, radar imaging system to evaluate the feasibility of active sub-mm imaging for standoff concealed weapon detection. The prototype radar imaging system is based on a wideband, heterodyne, frequency-multiplier-based transceiver system coupled to a quasi-optical focusing system and high-speed rotating conical scanner. The wideband operation of this system provides accurate ranging information, and the images obtained are fully three-dimensional. Recent improvements to the system include increased imaging speed using improved balancing techniques, wider bandwidth, and image display techniques.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗