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<article article-type="research-article" dtd-version="1.1" xml:lang="en"><front xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:c="http://ns.iop.org/namespaces/content" xmlns:fn="http://www.w3.org/2005/xpath-functions" xmlns:m="http://ns.iop.org/namespaces/meta"><journal-meta><journal-id journal-id-type="publisher-id">met</journal-id><journal-id journal-id-type="coden">MTRGAU</journal-id><journal-title-group><journal-title xml:lang="en">Metrologia</journal-title><abbrev-journal-title abbrev-type="IOP" xml:lang="en">MET</abbrev-journal-title><abbrev-journal-title abbrev-type="publisher" xml:lang="en">Metrologia</abbrev-journal-title></journal-title-group><issn pub-type="ppub">0026-1394</issn><issn pub-type="epub">1681-7575</issn><publisher><publisher-name>IOP Publishing</publisher-name></publisher><notes notes-type="publishing-partner"><p>Bureau International des Poids et Mesures</p></notes></journal-meta><article-meta><article-id pub-id-type="publisher-id">metac7926</article-id><article-id pub-id-type="doi">10.1088/1681-7575/ac7926</article-id><article-id pub-id-type="manuscript">ac7926</article-id><article-id pub-id-type="other">MET-102197.R1</article-id><article-categories><subj-group subj-group-type="display-article-type"><subject>Paper</subject></subj-group><subj-group subj-group-type="special"><subject>Focus on Length Metrology</subject></subj-group></article-categories><title-group><article-title>Effects of fast x-ray cone-beam tomographic measurement on dimensional metrology</article-title></title-group><contrib-group><contrib contrib-type="author" corresp="no" xlink:type="simple"><contrib-id authenticated="false" contrib-id-type="orcid">0000-0002-7547-0256</contrib-id><name name-style="western"><surname>Rossides</surname><given-names>Charalambos</given-names></name><xref ref-type="aff" rid="affiliation01">1</xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Towsyfyan</surname><given-names>Hossein</given-names></name><xref ref-type="aff" rid="affiliation02">2</xref></contrib><contrib contrib-type="author" xlink:type="simple"><contrib-id authenticated="true" contrib-id-type="orcid">0000-0002-2636-3032</contrib-id><name name-style="western"><surname>Biguri</surname><given-names>Ander</given-names></name><xref ref-type="aff" rid="affiliation03">3</xref></contrib><contrib contrib-type="author" corresp="no" xlink:type="simple"><contrib-id authenticated="false" contrib-id-type="orcid">0000-0002-9095-2069</contrib-id><name name-style="western"><surname>Deyhle</surname><given-names>Hans</given-names></name><xref ref-type="aff" rid="affiliation04">4</xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Lindroos</surname><given-names>Reuben</given-names></name><xref ref-type="aff" rid="affiliation05">5</xref></contrib><contrib contrib-type="author" xlink:type="simple"><contrib-id authenticated="true" contrib-id-type="orcid">0000-0002-3956-2866</contrib-id><name name-style="western"><surname>Mavrogordato</surname><given-names>Mark</given-names></name><xref ref-type="aff" rid="affiliation01">1</xref></contrib><contrib contrib-type="author" corresp="no" xlink:type="simple"><contrib-id authenticated="false" contrib-id-type="orcid">0000-0002-4008-0098</contrib-id><name name-style="western"><surname>Boardman</surname><given-names>Richard</given-names></name><xref ref-type="aff" rid="affiliation01">1</xref></contrib><contrib contrib-type="author" xlink:type="simple"><contrib-id authenticated="true" contrib-id-type="orcid">0000-0001-5888-111X</contrib-id><name name-style="western"><surname>Sun</surname><given-names>Wenjuan</given-names></name><xref ref-type="aff" rid="affiliation06">6</xref></contrib><contrib contrib-type="author" corresp="yes" xlink:type="simple"><contrib-id authenticated="true" contrib-id-type="orcid">0000-0002-7489-265X</contrib-id><name name-style="western"><surname>Blumensath</surname><given-names>Thomas</given-names></name><xref ref-type="aff" rid="affiliation01">1</xref><xref ref-type="aff" rid="affiliation02">2</xref><xref ref-type="fn" rid="metac7926afn1">*</xref><email>thomas.blumensath@soton.ac.uk</email></contrib><aff id="affiliation01">
               <label>1</label>µ-VIS X-Ray Imaging Centre, <institution xlink:type="simple">University of Southampton</institution>, Southampton, SO17 1BJ, United Kingdom</aff><aff id="affiliation02">
               <label>2</label>Institute of Sound and Vibration Research, <institution xlink:type="simple">University of Southampton</institution>, Southampton, SO17 1BJ, United Kingdom</aff><aff id="affiliation03">
               <label>3</label>Department of Applied Mathematics and Theoretical Physics, <institution xlink:type="simple">University of Cambridge</institution>, Cambridge, CB3 0WA, United Kingdom</aff><aff id="affiliation04">
               <label>4</label>
               <institution xlink:type="simple">Diamond Light Source Ltd</institution>, Harwell Science and Innovation Campus, Didcot, OX11 0DE, United Kingdom</aff><aff id="affiliation05">
               <label>5</label>Department of Computer Science, <institution xlink:type="simple">The University of Bath</institution>, Bath, BA2 7AY, United Kingdom</aff><aff id="affiliation06">
               <label>6</label>
               <institution xlink:type="simple">National Physical Laboratory</institution>, Hampton Road, Teddington, TW11 0LW, United Kingdom</aff></contrib-group><author-notes><fn id="metac7926afn1"><label>7</label><p>Author to whom any correspondence should be addressed.</p></fn></author-notes><pub-date pub-type="ppub"><day>01</day><month>8</month><year>2022</year></pub-date><pub-date pub-type="epub"><day>12</day><month>7</month><year>2022</year></pub-date><pub-date pub-type="open-access"><day>12</day><month>7</month><year>2022</year></pub-date><volume>59</volume><issue>4</issue><elocation-id content-type="artnum">044003</elocation-id><supplementary-material content-type="colour-figures" orientation="portrait" position="float" xlink:type="simple"/><history><date date-type="received"><day>28</day><month>4</month><year>2022</year></date><date date-type="rev-recd"><day>1</day><month>6</month><year>2022</year></date><date date-type="accepted"><day>15</day><month>6</month><year>2022</year></date><date date-type="oa-requested"><day>13</day><month>6</month><year>2022</year></date></history><permissions><copyright-statement>© 2022 BIPM &amp; IOP Publishing Ltd</copyright-statement><copyright-year>2022</copyright-year><license license-type="cc-by" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>
                  <graphic content-type="print" orientation="portrait" position="float" xlink:href="https://cfn-live-content-bucket-iop-org.s3.amazonaws.com/journals/0026-1394/59/4/044003/revision2/metac7926license.eps?AWSAccessKeyId=AKIAYDKQL6LTV7YY2HIK&amp;Expires=1657902365&amp;Signature=%2FkzxxQ1tZrhCRADGj2CF2KGCP1I%3D" xlink:type="simple"/>
                  <graphic content-type="online" orientation="portrait" position="float" xlink:href="https://cfn-live-content-bucket-iop-org.s3.amazonaws.com/journals/0026-1394/59/4/044003/revision2/metac7926license.gif?AWSAccessKeyId=AKIAYDKQL6LTV7YY2HIK&amp;Expires=1657902365&amp;Signature=PQuNaQNRLCEdctKq65nNE6u9kX0%3D" xlink:type="simple"/>Original content from this work may be used under the terms of the <ext-link ext-link-type="uri" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple">Creative Commons Attribution 4.0 licence</ext-link>. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.</license-p></license></permissions><self-uri content-type="pdf" xlink:href="https://cfn-live-content-bucket-iop-org.s3.amazonaws.com/journals/0026-1394/59/4/044003/revision2/met_59_4_044003.pdf?AWSAccessKeyId=AKIAYDKQL6LTV7YY2HIK&amp;Expires=1657902365&amp;Signature=Mnquf%2B9A1WbGxhE9b3u6yZobMlU%3D" xlink:type="simple"/><abstract><title>Abstract</title><p>X-ray computed tomography (XCT) is increasingly used for dimensional metrology, where it can offer accurate measurements of internal features that are not accessible with other techniques. However, XCT scanning can be relatively slow, which often prevents routine uptake for many applications. This paper explores the feasibility of improving the speed of XCT measurements while maintaining the quality of the dimensional measurements derived from reconstructed volumes. In particular, we compare two approaches to fast XCT acquisition, the use of fewer XCT projections as well as the use of shortened x-ray exposure times for each projection. The study shows that the additional Poisson noise produced by reducing the exposure for each projection has significantly less impact on dimensional measurements compared to the artefacts associated with strategies that take fewer projection images, leading to about half the measurement error variability. Advanced reconstruction algorithms such as the conjugate gradient least squares method or total variation constrained approaches, are shown to allow further improvements in measurement speed, though this can come at the cost of increased measurement bias (e.g. 2.8% increase in relative error in one example) and variance (e.g. 25% in the same example).</p></abstract><kwd-group kwd-group-type="author"><kwd>x-ray tomography</kwd><kwd>dimensional metrology</kwd><kwd>conjugate gradient least squares</kwd><kwd>total variation constraints</kwd><kwd>iterative reconstruction</kwd></kwd-group><funding-group><award-group xlink:type="simple"><funding-source xlink:type="simple">Engineering and Physical Sciences Research Council<named-content content-type="funder-id" xlink:type="simple">https://doi.org/10.13039/501100000266</named-content>
               </funding-source><award-id>EP/R002495/1</award-id></award-group><award-group xlink:type="simple"><funding-source xlink:type="simple">European Association of National Metrology Institutes<named-content content-type="funder-id" xlink:type="simple">https://doi.org/10.13039/100012329</named-content>
               </funding-source><award-id>17IND08</award-id></award-group></funding-group><counts><page-count count="11"/></counts><custom-meta-group><custom-meta xlink:type="simple"><meta-name>ccc</meta-name><meta-value>1681-7575/22/044003+11$33.00</meta-value></custom-meta><custom-meta xlink:type="simple"><meta-name>printed</meta-name><meta-value>Printed in the UK</meta-value></custom-meta><custom-meta xlink:type="simple"><meta-name>crossmark</meta-name><meta-value>yes</meta-value></custom-meta></custom-meta-group></article-meta></front></article>