Sub-pixel porosity revealed by x-ray scatter dark field imaging

Revol, Vincent; Jerjen, Iwan; Kottler, Christian; Schütz, Philipp; Kaufmann, R.; Lüthi, T.; Sennhauser, U.; Straumann, U.; Urban, Claus

doi:10.1063/1.3624592

Cited by 100 publications

(63 citation statements)

References 16 publications

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“…The information, which today is retrieved from DPC images is threefold and is extracted in the form of three separate images: (a) The attenuation signal which corresponds to the line integrals of the material's linear absorption coefficient; (b) The differential phase-contrast which can be integrated to an image of the phase gradient, which is the refractive index or electron density gradient; (c) The visibility or so-called scattering or dark-field contrast (DFC), that is linked to the integrated scattering power of the investigated specimen. The latter has been identified to encode sub-sampling structural details in the visibility of the signal, whereby visibility shows a decrease when passing through the scatter media [4][5][6][7]. This scattering is mostly elastic and originates from microscopic inhomogeneities, which are smaller than the pixel size.…”

Section: Introductionmentioning

confidence: 99%

Projection angle dependence in grating-based X-ray dark-field imaging of ordered structures

Bayer¹,

Zabler²,

Brendel³

et al. 2013

Opt. Express

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Abstract:Over the recent years X-ray differential phase-contrast imaging was developed for the hard X-ray regime as produced from laboratory X-ray sources. The technique uses a grating-based Talbot-Lau interferometer and was shown to yield image contrast gain, which makes it very interesting to the fields of medical imaging and non-destructive testing, respectively. In addition to X-ray attenuation contrast, the differential phase-contrast and dark-field images provide different structural information about a specimen. For the dark-field even at length scales much smaller than the spatial resolution of the imaging system. Physical interpretation of the dark-field information as present in radiographic and tomographic (CT) images requires a detailed look onto the geometric orientation between specimen and the setup. During phase-stepping the drop in intensity modulation, due to local scattering effects within the specimen is reproduced in the dark-field signal. This signal shows strong dependencies on micro-porosity and micro-fibers if these are numerous enough in the object. Since a gratinginterferometer using a common unidirectional line grating is sensitive to X-ray scattering in one plane only, the dark-field image is influenced by the fiber orientations with respect to the grating bars, which can be exploited to obtain anisotropic structural information. With this contribution, we attempt to extend existing models for 2D projections to 3D data by analyzing dark-field contrast tomography of anisotropically structured materials such as carbon fiber reinforced carbon (CFRC).

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Section: Introductionmentioning

confidence: 99%

Projection angle dependence in grating-based X-ray dark-field imaging of ordered structures

Bayer¹,

Zabler²,

Brendel³

et al. 2013

Opt. Express

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“…It has been shown that the USAXS can be expressed in terms of variations of the electronic density of the material at the microscopic level [14]. The scattering image is thus a perfect tool to probe the microscopic texture of composite materials and detect porosity, cracks and variations of the fibre density or orientation [15].…”

Section: Grating-based Phase Contrast X-ray Imaging (Xpci)mentioning

confidence: 99%

EVITA Project: Comparison Between Traditional Non-Destructive Techniques and Phase Contrast X-Ray Imaging Applied to Aerospace Carbon Fibre Reinforced Polymer

et al. 2016

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The EU-project EVITA (Non-Destructive EValuation, Inspection and Testing of Primary Aeronautical Composite Structures Using Phase Contrast X-Ray Imaging) aims at bringing Grating-based Phase Contrast X-ray imaging technology to Non-Destructive Evaluation and Inspection of advanced primary and/or complex aerospace composite structures. Grating-based Phase Contrast X-Ray Imaging is based on the so-called Talbot-Lau interferometer, which is made of the combination of a standard X-ray apparatus with three transmission gratings as documented in the literature. This paper presents a comparison of two traditional non-destructive techniques (NDT): ultrasonic through transmission (immersed and water jet) and ultrasonic phased-array pulse echo, with the developed phase contrast XRay Imaging applied to advanced aerospace carbon fibre reinforced polymer. Typical defects produced during manufacture is examined as part of the testing and validation procedure. The following defects have been identified as being those most likely to be detected more effectively by the Grating-based Phase Contrast X-Ray Imaging process than other state of the art industrial NDT techniques: porosity, foreign objects, cracks, resin rich, cut fibres, and wavy fibres. The introduction of this innovative methodology is expected to provide the aeronautical industry with a reliable and detailed insight of the integrity of thin and thick Appl Compos Mater (2017)

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“…The dark-field image is thus an image of the granularity or fibrousness of the sample. It was shown that biological, human and inanimate objects with different microstructural properties can produce contrasts in the dark-field image [9][10][11]. This information on the microstructure of the sample, not necessarily accessible with standard radiography, is of special interest for an eventual application in medical imaging [12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Energy weighted x-ray dark-field imaging

Pelzer¹,

Zang²,

Anton³

et al. 2014

Opt. Express

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Abstract:The dark-field image obtained in grating-based x-ray phasecontrast imaging can provide information about the objects' microstructures on a scale smaller than the pixel size even with low geometric magnification.In this publication we demonstrate that the dark-field image quality can be enhanced with an energy-resolving pixel detector. Energy-resolved x-ray dark-field images were acquired with a 16-energy-channel photon-counting pixel detector with a 1 mm thick CdTe sensor in a Talbot-Lau x-ray interferometer. A method for contrast-noise-ratio (CNR) enhancement is proposed and validated experimentally. In measurements, a CNR improvement by a factor of 1.14 was obtained. This is equivalent to a possible radiation dose reduction of 23%. x-ray dark-field imaging using a grating interferometer," Nat. Mater. 7, 134-137 (2008). 5. A. Momose, T. Takeda, Y. Itai, and K. Hirano, "Phasecontrast xray computed tomography for observing biological soft tissues," Nat. Med. 2(4), 473-475 (1996). 6. F. Pfeiffer, T. Weitkamp, O. Bunk, and C. David, "Phase retrieval and differential phase-contrast imaging with low-brilliance x-ray sources," Nat. Phys. 2(4), 258-261 (2006). 7. T. Weitkamp, C. David, O. Bunk, J. Bruder, P. Cloetens, and F. Pfeiffer, "X-ray phase radiography and tomography of soft tissue using grating interferometry," Eur. J. Radiol. 68(3), 13-17 (2008

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Sub-pixel porosity revealed by x-ray scatter dark field imaging

Cited by 100 publications

References 16 publications

Projection angle dependence in grating-based X-ray dark-field imaging of ordered structures

Projection angle dependence in grating-based X-ray dark-field imaging of ordered structures

EVITA Project: Comparison Between Traditional Non-Destructive Techniques and Phase Contrast X-Ray Imaging Applied to Aerospace Carbon Fibre Reinforced Polymer

Energy weighted x-ray dark-field imaging

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