Journal ArticleDOI
Investigations of moiré artifacts induced by flux fluctuations in X-ray dark-field imaging
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TLDR
In this paper , the dependence of moiré artifacts on flux fluctuation factors was derived by using a first-order Taylor series expansion, and the results of synchrotron radiation experiments verify the validity of derived analytical formulas.Abstract:
X-ray dark-field imaging using a grating interferometer has shown potential benefits for a variety of applications in recent years. X-ray dark-field image is commonly retrieved by using discrete Fourier transform from the acquired phase-stepping data. The retrieval process assumes a constant phase step size and a constant flux for each stepped grating position. However, stepping errors and flux fluctuations inevitably occur due to external vibrations and/or thermal drift during data acquisition. Previous studies have shown that those influences introduce errors in the acquired phase-stepping data, which cause obvious moiré artifacts in the retrieved refraction image. This work investigates moiré artifacts in X-ray dark-field imaging as a result of flux fluctuations. For the retrieved mean intensity, amplitude, visibility and dark-field images, the dependence of moiré artifacts on flux fluctuation factors is theoretically derived respectively by using a first-order Taylor series expansion. Results of synchrotron radiation experiments verify the validity of derived analytical formulas. The spatial frequency characteristics of moiré artifacts are analyzed and compared to those induced by phase-stepping errors. It’s illustrated that moiré artifacts can be estimated by a weighted mean of flux fluctuation factors, with the weighting factors dependent on the moiré phase and different greatly for each retrieved image. Furthermore, moiré artifacts can even be affected by object’s features not displayed in the particular contrast. These results can be used to interpret image correctly, identify sources of moiré artifacts, and develop dedicated algorithms to remove moiré artefacts in the retrieved multi-contrast images.read more
Citations
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Journal ArticleDOI
Analysis of fringe visibility in X-ray interferometer using dual triangular phase gratings
TL;DR: In this paper , the authors investigated the fringe visibility of the dual triangular phase grating interferometer as a function of the grating spacing under monochromatic and different polychromatic illumination, respectively.
References
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Journal ArticleDOI
X-ray phase imaging with a grating interferometer.
Timm Weitkamp,Ana Diaz,Christian David,Franz Pfeiffer,Marco Stampanoni,Peter Cloetens,Eric Ziegler +6 more
TL;DR: Using a high-efficiency grating interferometer for hard X rays (10-30 keV) and a phase-stepping technique, separate radiographs of the phase and absorption profiles of bulk samples can be obtained from a single set of measurements.
Journal ArticleDOI
Hard-X-ray dark-field imaging using a grating interferometer
Franz Pfeiffer,Franz Pfeiffer,Martin Bech,Oliver Bunk,P. Kraft,E. F. Eikenberry,Christian Brönnimann,Christian Grünzweig,Christian David +8 more
TL;DR: This letter reports a new approach on the basis of a grating interferometer that can efficiently yield dark-field scatter images of high quality, even with conventional X-ray tube sources and is fully compatible with conventional transmission radiography and a recently developed hard-X-ray phase-contrast imaging scheme.
Journal ArticleDOI
On the origin of visibility contrast in x-ray Talbot interferometry
TL;DR: The visibility-reduction contrast observed by x-ray grating interferometry can be understood in relation to the structural parameters of the microstructures, and the relation between the three parameters and the features of the micron-sized structures is discussed.
Journal ArticleDOI
Inverse geometry for grating-based x-ray phase-contrast imaging
Tilman Donath,Michael Chabior,Franz Pfeiffer,Oliver Bunk,Elena Reznikova,Juergen Mohr,Eckhard Hempel,Stefan Popescu,Martin Hoheisel,Manfred Schuster,Joachim Baumann,Christian David +11 more
TL;DR: In this article, an inverse interferometer geometry is investigated that offers significant advantages for grating fabrication and for the application of the method in computed tomography (CT) scanners, where the sample should be placed in front of or behind the phase grating.
Journal ArticleDOI
Noise in x-ray grating-based phase-contrast imaging.
Thomas Weber,Peter Bartl,Florian Bayer,Jürgen Durst,Wilhelm Haas,Thilo Michel,André Ritter,Gisela Anton +7 more
TL;DR: The authors used a least squares fitting algorithm to calculate the noise behavior of the three quantities absorption, differential phase, and dark-field image and found that the variance of the reconstructed phase is only dependent of the total number of photons used to generate the phase image and the visibility of the experimental setup.