Dr. Alan M. Jacobs Profile

Dr. Alan M. Jacobs

Professor at Univ of Florida

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Author

Publications (18)

Proceedings Article | 24 September 2007 Paper

An adapted modulation transfer function for x-ray backscatter radiography by selective detection

Nissia Sabri, Edward Dugan, Alan Jacobs, Daniel Shedlock

Proceedings Volume 6706, 670614 (2007) https://doi.org/10.1117/12.739070

KEYWORDS: Modulation transfer functions, Fourier transforms, Imaging systems, Image quality, X-rays, Radiography, Point spread functions, Sensors, X-ray imaging, Backscatter

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Proceedings Article | 17 September 2005 Paper

Optimization of an RSD x-ray backscatter system for detecting defects in the space shuttle external tank thermal foam insulation

Daniel Shedlock, Benjamin Addicott, Edward Dugan, Alan Jacobs

Proceedings Volume 5923, 59230S (2005) https://doi.org/10.1117/12.618591

KEYWORDS: Sensors, X-rays, Foam, Backscatter, Collimators, Aluminum, X-ray detectors, X-ray imaging, Defect detection, Monte Carlo methods

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A new Compton x-ray backscatter imaging technique, backscatter radiography by selective detection (RSD), has been used for inspection of the spray-on-foam-insulation (SOFI) on the space shuttle external tank. RSD employs detection of selected backscatter field components, by using specially designed detectors with movable detector collimators, to achieve high image contrast. The optimization study utilized test panels with simulated and natural defects in the spray-on foam insulation. Some of the test panels include structural features, stiffener-stringers and connection flanges, which were bolted to an aluminum base plate representative of the external tank. The SOFI was then layed down over the base plate and structural components with thicknesses varying from a few tens of mm up to a few hundred mm. The simulated defects range in cross-sectional size from 6 × 6 mm to 50 × 50 mm. Natural defects including roll-over voids and knit-line delaminations have a wide range of sizes, geometries, and orientations with a minimum critical cross-sectional size of 6 mm. Imaging registration is currently obtained at 0.05 seconds per 2 mm pixel, or about 19 minutes per 0.093 m²(1 ft²). The current system is being evaluated to enhance the detection of natural defects of a minimal critical size. Monte Carlo (MC) simulations with MCNP5 are being used to determine the history and corresponding spectrum of the detected photons that are responsible for improving defect image contrast. The simulation results are used in combination with experimental data to select optimal detector configurations. Detector configurations are sensitive not only to the type of defect being detected, but also the defect's depth in SOFI, distance from aluminum substrate, and defect orientation. Additional parameters including detector type, detection mode, and x-ray illumination beam size were also evaluated. Both NaI and plastic (BC404) scintillation detectors in pulse and integral mode were used to determine their effect on image quality and defect detection sensitivity. The x-ray illumination beam geometry (round versus square) and beam spot size were varied to determine resolution and the effect on defect contrast. The current system using pulse mode NaI detectors, and a 2 mm round x-ray illumination beam can detect the presence of the smallest critical size defects at a scan rate of 0.05 seconds per 2 mm pixel.

Proceedings Article | 26 October 2004 Paper

Detection of defects in foam thermal insulation using lateral migration backscatter x-ray radiography

Edward Dugan, Alan Jacobs, Dan Shedlock, Dan Ekdahl

Proceedings Volume 5541, (2004) https://doi.org/10.1117/12.559719

KEYWORDS: Sensors, Foam, Collimators, X-rays, Radiography, Backscatter, Aluminum, Defect detection, X-ray imaging, Mouth

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Proceedings Article | 30 December 2003 Paper

Detection of flaws and defects using lateral migration x-ray radiography

Edward Dugan, Alan Jacobs, Laurent Houssay, Dan Ekdahl

Proceedings Volume 5199, (2003) https://doi.org/10.1117/12.504361

KEYWORDS: Sensors, X-rays, Aluminum, Corrosion, X-ray imaging, Collimators, Skin, Lead, Image processing, Radiography

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Proceedings Article | 30 December 2003 Paper

Detection of land mines using lateral migration backscatter x-ray radiography

Edward Dugan, Alan Jacobs, Zhong Su, Laurent Houssay, Dan Ekdahl

Proceedings Volume 5199, (2003) https://doi.org/10.1117/12.504364

KEYWORDS: Sensors, Mining, Image processing, Collimation, X-rays, Image sensors, Collimators, X-ray imaging, Land mines, Photons

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Proceedings Article | 11 September 2003 Paper

Status of XMIS x-ray backscatter radiography landmine detection system

Edward Dugan, Alan Jacobs, Zhong Su, Laurent Houssay, Dan Ekdahl

Proceedings Volume 5089, (2003) https://doi.org/10.1117/12.485860

KEYWORDS: Sensors, Mining, Image processing, X-rays, Collimation, Image sensors, Collimators, X-ray imaging, Land mines, Imaging systems

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Proceedings Article | 26 November 2002 Paper

Lateral migration radiography: a new x-ray backscatter imaging technique

Alan Jacobs, Edward Dugan, Stephanie Brygoo, Dan Ekdahl, Laurent Houssay, Zhong Su

Proceedings Volume 4786, (2002) https://doi.org/10.1117/12.451613

KEYWORDS: Land mines, X-rays, Sensors, Mining, X-ray imaging, Radiography, Collimation, Imaging systems, Image processing, Photodetectors

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A new Compton backscatter imaging (CBI) technique, described as lateral migration radiography (LMR), has been developed and applied successfully to two difficult diagnostic problems: Detection of buried, plastic landmines, and detection of material flaws which lie close to, and parallel to, a surface, the method is based on image contrast generated by alteration of photon lateral migration relative to the illuminating beam direction. It is extraordinarily sensitive to density and/or atomic number variation along the photon lateral-direction travel paths. In LMR, relevant information-carrying photon detection efficiencies are two to three orders-of-magnitude greater than other CBI techniques such that the electric energy requirement for x-ray generation is only about one joule per acquired image pixel. The resulting small product of pixel illumination dwell time and x-ray generator electric power implies that current, easily accessible technology can be used to fabricate LMR systems with practical usage protocols. Three have been designed and built at the University of Florida: A laboratory device for perfecting buried landmine acquisition; a mobile system for field-demonstrating landmine detection; and, a laboratory system for detection of material defects in small structural parts. The LMR images, acquired in a laboratory landmine detection setting, are so definitive that identification of the mine-type, as well as presence, can be often accomplished. Results of a field test are near-perfect, both in determining buried landmine presence and in lack of false positive response. Images acquired in material flaw detection indicate ability to detect lateral cracks or delaminations with thickness less than 100 microns, as well as corrosion on surfaces between layers of structural sheets. These applications provide evidence of the viability of a new, one-sided x-ray radiography technique which images hidden structures of objects which have here-to-fore been difficult, or impossible, to detect with practical image aquisition times.

Proceedings Article | 13 August 2002 Paper

Development and field testing of a mobile backscatter x-ray lateral migration radiography land mine detection system

Edward Dugan, Alan Jacobs, Zhong Su, Laurent Houssay, Dan Ekdahl, Stephanie Brygoo

Proceedings Volume 4742, (2002) https://doi.org/10.1117/12.479082

KEYWORDS: Sensors, Mining, Image processing, X-rays, Image sensors, Collimation, Collimators, Land mines, General packet radio service, X-ray imaging

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Proceedings Article | 18 December 2000 Paper

X-ray lateral migration radiography system for the application of land mine detection

Zhong Su, Alan Jacobs, Edward Dugan, Dan Ekdahl

Proceedings Volume 4142, (2000) https://doi.org/10.1117/12.410558

KEYWORDS: Land mines, Mining, X-rays, Radiography, Collimation, Sensors, Image sensors, Photons, X-ray imaging, X-ray detectors

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SPIE Journal Paper | 1 September 2000

Lateral migration radiography application to land mine detection, confirmation and classification

Zhong Su, Alan Jacobs, Edward Dugan, Joseph Howley, Jennifer Jacobs

OE, Vol. 39, Issue 09, (September 2000) https://doi.org/10.1117/12.10.1117/1.1288364

KEYWORDS: Sensors, Land mines, Mining, Photons, Collimation, X-rays, Image sensors, X-ray detectors, Radiography, Monte Carlo methods

Proceedings Article | 22 August 2000 Paper

Suitability of simulated land mines for detection measurements using x-ray lateral migration radiography

Christopher Wells, Zhong Su, Anthony Allard, Sabrina Salazar, Edward Dugan, Alan Jacobs

Proceedings Volume 4038, (2000) https://doi.org/10.1117/12.396286

KEYWORDS: Mining, Land mines, Sensors, Photons, Collimation, Signal detection, X-rays, Radiography, X-ray detectors, Solids

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Proceedings Article | 2 August 1999 Paper

Lateral migration-measured image signatures in the detection and identification of buried land mines

Christopher Wells, Zhong Su, Jeffrey Moore, Edward Dugan, Alan Jacobs

Proceedings Volume 3710, (1999) https://doi.org/10.1117/12.357112

KEYWORDS: Sensors, Mining, Land mines, Image sensors, Collimation, Photons, X-rays, Imaging systems, X-ray imaging, Radiography

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Proceedings Article | 4 September 1998 Paper

Discernibility of land mines using lateral migration radiography

Zhong Su, Joseph Howley, Jennifer Jacobs, Edward Dugan, Alan Jacobs

Proceedings Volume 3392, (1998) https://doi.org/10.1117/12.324257

KEYWORDS: Sensors, Land mines, Photons, Mining, Collimation, Image sensors, X-rays, Monte Carlo methods, X-ray detectors, Radiography

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Proceedings Article | 4 September 1998 Paper

Examination of cross-talk between adjacent x-ray generator-detector systems

Jennifer Jacobs, Edward Dugan, Alan Jacobs, Grant Lockwood, Steve Shope, Joseph Wehlburg

Proceedings Volume 3392, (1998) https://doi.org/10.1117/12.324256

KEYWORDS: Sensors, Image segmentation, X-rays, Land mines, Photons, X-ray detectors, Collimation, Mining, Raster graphics, X-ray imaging

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Proceedings Article | 22 July 1997 Paper

Geometric considerations relating to lateral migration radiography (LMR) as applied to the detection of land mines

Joseph Wehlburg, Shyam Keshavmurthy, Edward Dugan, Alan Jacobs

Proceedings Volume 3079, (1997) https://doi.org/10.1117/12.280864

KEYWORDS: Sensors, Collimation, Land mines, Signal detection, Radiography, Photons, Solids, Image enhancement, Metals, Computing systems

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Proceedings Article | 31 May 1996 Paper

Analytical studies of a backscatter x-ray imaging landmine detection system

Shyam Keshavmurthy, Edward Dugan, Joseph Wehlburg, Alan Jacobs

Proceedings Volume 2765, (1996) https://doi.org/10.1117/12.241254

KEYWORDS: Sensors, Mining, Collimation, Land mines, Collimators, Raster graphics, Imaging systems, Particles, Scattering, Backscatter

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Proceedings Article | 31 May 1996 Paper

Experimental measurement of noise-removal techniques for Compton backscatter imaging systems as applied to the detection of landmines

Joseph Wehlburg, Shyam Keshavmurthy, Edward Dugan, Alan Jacobs

Proceedings Volume 2765, (1996) https://doi.org/10.1117/12.241253

KEYWORDS: Sensors, Land mines, Collimation, Mining, Signal detection, Metals, Backscatter, Detection and tracking algorithms, Photons, Image enhancement

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Proceedings Article | 20 June 1995 Paper

Image restoration techniques using Compton backscatter imaging for the detection of buried land mines

Joseph Wehlburg, Shyam Keshavmurthy, Yoichi Watanabe, Edward Dugan, Alan Jacobs

Proceedings Volume 2496, (1995) https://doi.org/10.1117/12.211329

KEYWORDS: Sensors, Collimation, Land mines, Mining, Detection and tracking algorithms, Image sensors, Data acquisition, Imaging systems, Backscatter, Control systems

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Showing 5 of 18 publications

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