Skip to content Skip to navigation
University of Warwick
  • Study
  • |
  • Research
  • |
  • Business
  • |
  • Alumni
  • |
  • News
  • |
  • About

University of Warwick
Publications service & WRAP

Highlight your research

  • WRAP
    • Home
    • Search WRAP
    • Browse by Warwick Author
    • Browse WRAP by Year
    • Browse WRAP by Subject
    • Browse WRAP by Department
    • Browse WRAP by Funder
    • Browse Theses by Department
  • Publications Service
    • Home
    • Search Publications Service
    • Browse by Warwick Author
    • Browse Publications service by Year
    • Browse Publications service by Subject
    • Browse Publications service by Department
    • Browse Publications service by Funder
  • Help & Advice
University of Warwick

The Library

  • Login
  • Admin

Data for Modelling the Penumbra in Computed Tomography

Tools
- Tools
+ Tools

Kueh, Audrey, Warnett, J. W., Gibbons, Gregory John, Brettschneider, Julia, Nichols, Thomas E., Williams, M. A. (Mark A.) and Kendall, W. S. (2016) Data for Modelling the Penumbra in Computed Tomography. [Dataset]

[img] Archive (ZIP) (Zip file containing dataset files and description)
CeramicRod.zip - Published Version

Download (129Mb)
Official URL: http://wrap.warwick.ac.uk/78867

Request Changes to record.

Abstract

Background:

In computed tomography (CT), the spot geometry is one of the main sources of error in CT images. Since X-rays 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, both to confirm spot geometry from penumbra data, and to 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 a poor fit at the boundary. The mixture model (which adds a larger uniform spot) exhibits a much improved fit. 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.

Item Type: Dataset
Subjects: R Medicine > RC Internal medicine
Divisions: Faculty of Science, Engineering and Medicine > Science > Statistics
Faculty of Science, Engineering and Medicine > Engineering > WMG (Formerly the Warwick Manufacturing Group)
Type of Data: Zipfile containing TIFF images, and textfiles giving description and R code for reading TIFF files into R
Library of Congress Subject Headings (LCSH): Tomography -- Data processing
Publisher: University of Warwick, Department of Physics
Official Date: 26 April 2016
Dates:
DateEvent
26 April 2016Completion
Collection date:
Date fromDate to
1 January 201531 July 2015
Status: Not Peer Reviewed
Publication Status: Published
Media of Output (format): .txt
Access rights to Published version: Open Access (Creative Commons)
Description:

Penumbra data
==========

These data files correspond to the data discussed in Kueh et al (2016).

A 3mm ceramic rod was placed centrally on the manipulator in an approximately
vertical alignment such that the magnification was x4.45. Images were taken at a
constant voltage of 140kV, at each of the following 7 different exposure/power
settings: 0.177s/44W, 0.25s/30.6W, 0.354s/21W, 0.5s/14.6W, 0.708s/9.6W,
1s/6.4W, 1.415s/4W. Three images were taken for each parameter set, and these
are placed within their respective folder (labelled by magnification) as TIFF files.
Code which imports these files into the R environment is provided in Import.R.

File structure
========
Description.txt
Import.R

0.177s_44W:
44W_177ms_1.tif 44W_177ms_2.tif 44W_177ms_3.tif

0.25s_30.6W:
30-6W_250ms_1.tif 30-6W_250ms_2.tif 30-6W_250ms_3.tif

0.354s_21W:
21W_354ms_1.tif 21W_354ms_2.tif 21W_354ms_3.tif

0.5s_14.6W:
14.6W_500ms_1.tif 14.6W_500ms_2.tif 14.6W_500ms_3.tif

0.708s_9.6W:
9.6W_708ms_1.tif 9.6W_708ms_2.tif 9.6W_708ms_3.tif

1.415s_4W:
4.0W_1415ms_1.tif 4.0W_1415ms_2.tif 4.0W_1415ms_3.tif

1s_6.4W:
6.4W_1000ms_1.tif 6.4W_1000ms_2.tif 6.4W_1000ms_3.tif

Date of first compliant deposit: 3 May 2016
Date of first compliant Open Access: 3 May 2016
RIOXX Funder/Project Grant:
Project/Grant IDRIOXX Funder NameFunder ID
EP/K031066/1[EPSRC] Engineering and Physical Sciences Research Councilhttp://dx.doi.org/10.13039/501100000266
Related URLs:
  • Related item in WRAP

Request changes or add full text files to a record

Repository staff actions (login required)

View Item View Item

Downloads

Downloads per month over past year

View more statistics

twitter

Email us: wrap@warwick.ac.uk
Contact Details
About Us