Lateral Migration Radiography

Dugan, Edward T.; Jacobs, Alan M.; Keshavmurthy, Shyam P.; Wehlburg, Joseph C.

doi:10.1007/pl00003902

Cited by 10 publications

(3 citation statements)

References 9 publications

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“…note the two sizes of collimated detector panels employed. Such information, along with extensive Monte Carlo numerical calculation simulations 11,12 and some additional conjecture, form the basis for a, practical prototype system. Based on the single, very limited, test on the mine lanes at Fort A.P.…”

Section: Comments Regarding Landmine Detectionmentioning

confidence: 99%

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

et al. 2002

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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 acquisition times.

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Section: Comments Regarding Landmine Detectionmentioning

confidence: 99%

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

et al. 2002

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“…Lateral migration radiography (LMR), a type of backscatter x-ray radiography based upon selective detection of scatter field velocity components, was first applied at the University of Florida (UF) to the detection of buried land mines [1][2][3][4][5][6][7][8][9][10] . The resulting images were stunning in their definitive detail.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2004

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A new Compton x-ray backscatter imaging technique called lateral migration radiography (LMR) has been successfully applied to the detection of voids and delaminations in the foam thermal insulation used on the shuttle external tank. LMR employs detection of selected scatter field velocity components, by using specially designed detectors and detector collimators, to achieve high image contrast.LMR is based on image contrast generated by migration of probe x-ray radiation in directions transverse to the illumination radiation beam. Because LMR is sensitive to electron density variations in these directions, thin, but large density variations, such as cracks and delaminations, generate signal-to-background ratios sufficient to produce images of features which are not even detectable in the usually interrogated thin dimension.The examined foam thermal insulation test panels consist of aluminum plates onto which the sprayed-on foam insulation (SOFI) is applied. Some of the test panels include structural features bolted to the base plate. The SOFI was layed down over the base plate and structure with a thickness varying from a few tens of mm up to a few hundred mm. The test panels included voids and simulated delaminations in the SOFI ranging in cross-sectional size from 6 x 6 mm to 50 x 50 mm. High quality images were acquired using pixels of 2 to 3 mm and irradiation times of as low as 0.05 s per pixel.

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“…The purpose of this investigation is to present and explain the different approaches that have been taken to develop a Modulation Transfer Function adapted to the Radiography by Selective Detection RSD imaging system [1][2][3][4][5][6][7][8][9][10][11][12] for the purpose of defining a process to measure system response by evaluating the image quality. Figure 1 shows a picture of the RSD system in which an X-ray tube is at a center of four detectors.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2007

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The Modulation Transfer Function (MTF) is a quantitative function based on frequency resolution that characterizes imaging system performance. In this study, a new MTF methodology is investigated for application to Radiography by Selective Detection (RSD), an enhanced single-side x-ray Compton backscatter imaging (CBI) technique which detects selected scatter components. The RSD imaging modality is a unique type of real-time radiography that uses a set of fin and sleeve collimators to preferentially select different components of the x-ray backscattered field. Radiography by selective detection has performed successfully in different non-destructive evaluation (NDE) applications. A customized RSD imaging system was built at the University of Florida for inspection of the space shuttle external tank spray-on foam insulation (SOFI). The x-ray backscatter RSD imaging system has been successfully used for crack and corrosion detection in a variety of materials. The conventional transmission x-ray image quality characterization tools do not apply for RSD because of the different physical process involved. Thus, the main objective of this project is to provide an adapted tool for dynamic evaluation of RSD system image quality. For this purpose, an analytical model of the RSD imaging system response is developed and supported. Two approaches are taken for the MTF calculations: one using the Fourier Transform of a line spread function and the other one using a sine function pattern. Calibration and test targets are then designed according to this proposed model. A customized Matlab code using image contrast and digital curve recognition is developed to support the experimental data and provide the Modulation Transfer Functions for RSD.

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Lateral Migration Radiography

Cited by 10 publications

References 9 publications

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

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

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

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

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