Computed Tomography

Buzug, Thorsten M.

doi:10.1007/978-3-540-74658-4_16

Cited by 185 publications

(200 citation statements)

References 3 publications

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“…This approximates a Poisson-distributed number of X-ray quanta with high expectation (Buzug, 2008). Notice that for each detector location ξ and rotation angle γ the recorded intensity I γ (ξ ) has a normal distribution.…”

Section: Simulation Of Ideal and Noisy Projectionsmentioning

confidence: 96%

“…FBP is widely utilized in computed tomography using X-rays (Buzug, 2008) as well as electrons (Carazo et al, 2005). In the following we will briefly summarize the mathematical foundations of FBP.…”

Section: Filtered Backprojectionmentioning

confidence: 99%

“…Substituting polar coordinates in the formula of the inverse Fourier transform and a subsequent application of the Fourier slice theorem yields the identity (for details cf. Buzug, 2008) …”

Section: Filtered Backprojectionmentioning

confidence: 99%

“…For a comprehensive introduction and important aspects of applications see, e.g., Frank (2005), Banhart (2007), and Buzug (2008). Tomographic reconstructions can be computed by a variety of different techniques such as filtered backprojection (FBP) (Feldkamp et al, 1984;Kak and Slaney, 1988), algebraic reconstruction techniques (ART) (Gilbert, 1972;Carazo et al, 2005), geometric tomography (Gardner, 1995) or discrete tomography (Batenburg, 2005;Herman and Kuba, 2007).…”

Section: Introductionmentioning

confidence: 99%

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Statistical Analysis of Tomographic Reconstruction Algorithms by Morphological Image Characteristics

Lück¹,

Kupsch²,

Lange³

et al. 2011

Image Anal Stereol

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We suggest a procedure for quantitative quality control of tomographic reconstruction algorithms. Our task-oriented evaluation focuses on the correct reproduction of phase boundary length and has thus a clear implication for morphological image analysis of tomographic data. Indirectly the method monitors accurate reproduction of a variety of locally defined critical image features within tomograms such as interface positions and microstructures, debonding, cracks and pores. Tomographic errors of such local nature are neglected if only global integral characteristics such as mean squared deviation are considered for the evaluation of an algorithm. The significance of differences in reconstruction quality between algorithms is assessed using a sample of independent random scenes to be reconstructed. These are generated by a Boolean model and thus exhibit a substantial stochastic variability with respect to image morphology. It is demonstrated that phase boundaries in standard reconstructions by filtered backprojection exhibit substantial errors. In the setting of our simulations, these could be significantly reduced by the use of the innovative reconstruction algorithm DIRECTT.

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Section: Simulation Of Ideal and Noisy Projectionsmentioning

confidence: 96%

Section: Filtered Backprojectionmentioning

confidence: 99%

“…Substituting polar coordinates in the formula of the inverse Fourier transform and a subsequent application of the Fourier slice theorem yields the identity (for details cf. Buzug, 2008) …”

Section: Filtered Backprojectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Statistical Analysis of Tomographic Reconstruction Algorithms by Morphological Image Characteristics

Lück¹,

Kupsch²,

Lange³

et al. 2011

Image Anal Stereol

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“…The matrix A is often called design matrix or system matrix in the literature [11]. This should clarify that A is constructed using information about the structure of the observed measurement region.…”

Section: Introductionmentioning

confidence: 99%

Ultrasound Tomography for Spatially Resolved Melt Temperature Measurements in Injection Moulding Processes

Hopmann¹,

Wipperfürth²

2017

J Appl Mech Eng

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In injection moulding processes, the measurement of the temperature distribution is very important for the validation of models used for simulative part design due to the high influence on shrinkage and warpage of the moulded part, but is also very challenging to measure. During the injection moulding process high mould pressures occur and the cavity is not easily accessible. Therefore, contact sensors cannot be used since they induce shear stress into the melt, which changes the flow behaviour of the melt and thus the temperature field. In this work, we present a method for the contactless determination of the temperature distribution of a moulded part during injection moulding using ultrasound tomography. With time-of-flight ultrasound measurements from different directions it is possible to reconstruct the distribution of ultrasound velocity in the cross-section of a moulded part. With this distribution, the temperature field can be calculated using additional material characteristic properties. Based on this concept, an injection mould was designed, that allows performing ultrasound tomography with 20 ultrasound transducers radially arranged around a cylindrical shaped cavity. This allows the temperature determination under real process conditions with a spatial resolution of 3.5 mm 2 . A highly parallelised measurement device allows recording of several complete datasets before no more signals can be detected due to shrinkage of the moulded part. During several injections moulding-cycles all sensor positions were able to detect noticeable signals. Due to internal signal processing of the measurement device, it is not yet possible to calculate arrival times of the ultrasound signal but amplitude-scans show the general feasibility of ultrasound tomography during injection moulding..

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A Review of X‐Ray Imaging at the BAMline(BESSY II)

et al. 2023

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The hard X‐ray beamline BAMline at BESSY II (Berlin, Germany) has now been in service for 20 years. Several improvements have been implemented in this time, and this review provides an overview of the imaging methods available at the BAMline. Besides classic full‐field synchrotron X‐ray computed tomography (SXCT), also absorption edge CT, synchrotron X‐ray refraction radiography (SXRR), and synchrotron X‐ray refraction tomography (SXRCT) are used for imaging. Moreover, virtually any of those techniques are currently coupled in situ or operando with ancillary equipment such as load rigs, furnaces, or potentiostats. Each of the available techniques is explained and both the current and the potential usage are described with corresponding examples. The potential use is manifold, the examples cover organic materials, composite materials, energy‐related materials, biological samples, and materials related to additive manufacturing. The article includes published examples as well as some unpublished applications.

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Computed Tomography

Cited by 185 publications

References 3 publications

Statistical Analysis of Tomographic Reconstruction Algorithms by Morphological Image Characteristics

Statistical Analysis of Tomographic Reconstruction Algorithms by Morphological Image Characteristics

Ultrasound Tomography for Spatially Resolved Melt Temperature Measurements in Injection Moulding Processes

A Review of X‐Ray Imaging at the BAMline(BESSY II)

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