Assessing the effect of sample orientation on dimensional X-ray computed tomography through experimental and simulated data

Villarraga-Gómez, Herminso; Amirkhanov, A.N.; Heinzl, Christoph; Smith, Stuart T.

doi:10.1016/j.measurement.2021.109343

Cited by 17 publications

(7 citation statements)

References 52 publications

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“…algorithms for edge detection and material boundary/surface determination [21][22][23][24][25]. Thereafter, the geometric characteristics of those surfaces can be used as a reference for dimensional metrology.…”

Section: Dimensional Metrologymentioning

confidence: 99%

Improving the dimensional accuracy of 3D x-ray microscopy data

Villarraga-Gómez

Kotwal

Parwani

et al. 2022

Meas. Sci. Technol.

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X-ray microscopy instruments have the unique ability to achieve nondestructive imaging with higher spatial resolutions than traditional X-ray computed tomography (CT) systems. This unique ability is of interest to industrial quality control entities, as they deal with small features in precision manufactured parts. Since many of today’s technology and manufacturing companies demand increasingly higher levels of precision, accuracy, and reliability for dimensional measurements on feature sizes that are much smaller than 5mm, it would be ideal to further expand the imaging capabilities of X-ray microscopy to the field of precision metrology. To address such demand, this paper describes the development of a measurement workflow, through a package consisting of hardware and software, to improve the accuracy of dimensional data obtained with 3D X-ray microscopes (XRM). The workflow, called Metrology Extension (MTX), was designed to adjust and configure the XRM instrument work-zone to perform dimensional measurements. The main adjustments of an XRM instrument through MTX workflow, which must be implemented before scanning parts of interest for dimensional evaluation, include applying a distortion map correction on the image projections produced by the X-ray detector and a voxel scale correction prior to data reconstruction. The main purpose of this article is to present, evaluate, and analyze the experimental results of various measurement tests to verify the metrological performance of several XRM systems operating with the MTX workflow. The main results show that these systems can produce repeatable and reproducible measurements, with repeatability standard deviations of the order of 0.1μm, reproducibility standard deviations of less than 0.5μm, and measurement accuracies comparable to those offered by high-precision tactile coordinate measurement machines (with deviations within the range of ±0.95µm). Therefore, once the MTX workflow is executed, XRM instruments can be used to measure small volumes, in the order of (5mm)3 or less, with improved dimensional accuracy.

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Section: Dimensional Metrologymentioning

confidence: 99%

Improving the dimensional accuracy of 3D x-ray microscopy data

Villarraga-Gómez

Kotwal

Parwani

et al. 2022

Meas. Sci. Technol.

Self Cite

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“…We propose to overcome this by simply inspecting the features of an object and then calculating the projection angles required to reconstruct them; no exhaustive XCT simulation is required, nor an optimisation algorithm. The aim of our method is to improve the quality of object surfaces, such that a surface model of an object can be extracted from a CT data set for subsequent analysis [14,15]. Our approach is inspired by that of Zheng et al [11] and Qunito et al [13] who noted that the surface of an object can only be reliably reconstructed if a ray-path is tangent to the surface; this was also recently exploited by Butzhammer et al [16].…”

Section: Introductionmentioning

confidence: 99%

IntelliScan: Improving the quality of x-ray computed tomography surface data through intelligent selection of projection angles

Lifton¹,

Poon

2023

XST

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X-ray computed tomography (XCT) enables the dimensional measurement and inspection of highly geometrically complex engineering components that are unmeasurable using optical and tactile instruments. Conventional XCT scans use a circular scan trajectory where X-ray projections are acquired with a uniform angular spacing; this approach treats all projections as being of equal importance, in practice, some projections contain more object information than others. In this work we capitalize on this concept by intelligently selecting projections with a view to improve the quality of surface models extracted from an XCT data-set. Our approach relies on using a priori object information to select X-ray projections in which the surfaces of the object are aligned with a ray-path, thus ensuring the surface of the object is fully sampled. Results are presented showing that the proposed method is able to reduce CAD comparison errors by 16%, reduce surface form error by 3%, and improve edge contrast by 14% for a machined aluminium component.

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“…Thus, it influences the downstream setup parameters, like the X-ray tube and the detector settings. Moreover, the workpiece orientation has a decisive influence on various CT artefacts such as beam hardening and cone beam artefacts [3,4], which in turn effect image and measurement quality. Especially for multimaterial components made from highdensity materials bedded in low-density materials, such CT artefacts are particularly pronounced and can even prevent a reliable measurement [2].…”

Section: Introductionmentioning

confidence: 99%

“…It is therefore important to understand the correlation between workpiece orientation, as well as image and measurement quality, and to devise methods that help to select optimum angles for orientation. The majority of previous publications in this field assume that orientation can be optimised on the basis of workpiece transmission length [3][4][5][6][7][8] and / or workpiece surface area perpendicular to the rotation axis [3,5,6,9]. These strategies aim to reduce beam hardening and cone beam artefacts.…”

Section: Introductionmentioning

confidence: 99%

“…Xue and Suzuki [11] investigated the influence of the orientation of a cylindrical monomaterial object on the entropy of the histogram and the measurement accuracy. Villarraga-Gómez et al [4] presented an experimental and simulative analysis of 12 monomaterial components. They measured components under different angles (step size of 5°) and analysed the deviations between the resulting dimensional CT data and tactile reference measurements.…”

Section: Introductionmentioning

confidence: 99%

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Influence of workpiece orientation for multimaterial measurements in dimensional computed tomography

Höger¹,

Schild²,

Lanza³

2022

eJNDT

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Computed tomography (CT) is a flexible measurement method for a variety of metrological tasks. However, to achieve reliable and accurate measurements, interrelated setting parameters must be chosen. The workpiece orientation is one of such parameters, especially for multimaterials. Current approaches to support optimal orientation do not adequately consider the effect on accuracy in complex measurement tasks. Additionally, only few experimental studies provide the therefore necessary insights. Consequently, this study aimed to investigate the influence of orientation of a multimaterial workpiece on the subsequent evaluation and measurement process. For this purpose, a workpiece containing multiple features was scanned in a total of 14 orientation configurations and the resulting effects on both image (based on contrast-to-noise-ratio) and measurement quality (based on measurement accuracy) were investigated. It was shown that components measurable in the medium power range of a CT system have a wide range of optimal angles for optimal orientation. The image quality is suited for its identification.

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Assessing the effect of sample orientation on dimensional X-ray computed tomography through experimental and simulated data

Cited by 17 publications

References 52 publications

Improving the dimensional accuracy of 3D x-ray microscopy data

Improving the dimensional accuracy of 3D x-ray microscopy data

IntelliScan: Improving the quality of x-ray computed tomography surface data through intelligent selection of projection angles

Influence of workpiece orientation for multimaterial measurements in dimensional computed tomography

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