June 14, 2019


Writing about web page https://detectorchecker.azurewebsites.net/

Funded by an Alan Turing Institute seed grant, Julia Brettschneider and Wilfrid Kendall have worked with Martin O’Reilly, Tomas Lazauskas and Oscar Giles of the Turing Research Engineers Group to produce a web app DetectorChecker which can be used to help assess the quality of digital X-ray detectors based on spatial analysis of dysfunctional pixels.

The source for the web tool is also available from GitHub in the form of an R package coupled with a Shiny application.

A manual is available from the HELP tab on the web app. The PDF file DetectorChecker2.pdf gives a quick overview.

We are still improving and extending DetectorChecker and we very much welcome your feedback.

Julia Brettschneider

Wilfrid Kendall

April 19, 2016

Modelling the Penumbra in Computed Tomography

Kueh, A., Warnett, J. W., Gibbons, G. J., Brettschneider, J., Nichols, T. E., Williams, M. A., & Kendall, W. S. (2016). Modelling the Penumbra in Computed Tomography. Journal of X-Ray Science and Technology, to appear, 14pp.

BACKGROUND: In computed tomography (CT), spot geometry is one of the main sources of error in CT images. Since X-ray tubes do not arise from a point source, artefacts are produced. In particular there is a penumbra effect, leading to poorly defined edges within a reconstructed volume. Penumbra models can be simulated given a fixed spot geometry and the known experimental setup.

OBJECTIVE: This paper proposes to use a penumbra model, derived from Beer’s law, to confirm spot geometry from penumbra data, as well as quantify blurring in the image.

METHODS: Two models for the spot geometry are considered; one consists of a single Gaussian spot, the other is a mixture model consisting of a Gaussian spot together with a larger uniform spot.

RESULTS: The model consisting of a single Gaussian spot has fits which are poor. The mixture model (which adds a larger uniform spot) exhibits much improved fits. The parameters corresponding to the uniform spot are similar across all powers, and further experiments suggest that the uniform spot produces only soft X-rays of relatively low-energy.

CONCLUSIONS: Thus, the precision of radiographs can be estimated from the penumbra effect in the image. The use of a thin copper filter reduces the size of the effective penumbra.

December 10, 2013

Neuroimaging Statistics Research at Warwick

Writing about web page http://www.warwick.ac.uk/tenichols/research/neuro-stat

There are weekly meetings on Thursdays, 12-1, in Zeeman C1.06 on Neuroimaging Statistics, where we discuss papers and our on-going research. All are welcome to join in! Details of each week's topic are in the referenced web-page.

Applied Topology and Stochastic Geometry fortnightly seminar

Writing about web page http://www2.warwick.ac.uk/fac/sci/statistics/staff/academic-research/kueh/topgeomseminar/

A fortnightly seminar to survey recent progress in the two fields mentioned in the title. Details in attached web-page. All are welcome.

June 11, 2013

EPSRC announcement

Writing about web page http://www.epsrc.ac.uk/newsevents/pubs/mags/connect/2013/90/Pages/futuremanufacturingwithmathematicalsciences.aspx

The grant for this project is one of six forming an announcement on EPSRC's webpages:


May 23, 2013

£1.6m funding at the interface of statistics, healthcare and manufacturing

See http://www2.warwick.ac.uk/newsandevents/pressreleases/16316m_funding_at/ for a press release partly about the award of this grant.

May 01, 2013

EPSRC Project Proposal

Writing about web page http://gow.epsrc.ac.uk/NGBOViewGrant.aspx?GrantRef=EP/K031066/1

Here is a PDF of the successful proposal for this EPSRC-funded project. It is placed here for the benefit of anyone interested in applying for the Statistics PDRA post which currently being advertised.

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  • The paper describing this webapp is now available (open access!) at: Brettschneider, Julia A, Oscar … by Wilfrid Kendall on this entry

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