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Proceedings Paper

An investigation of the relationship between ambient lighting and image manipulation behavior
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Paper Abstract

Purpose: This study examines the relationship between ambient lighting level and image manipulation. Method: Academic radiographers (n=10), with experience in observer performance studies, each assessed 70 postero-anterior projection radiographs of the wrist / scaphoid in both low (12.5 lux) and high (150 lux) ambient lighting. Half of the images featured one or more acute fractures and the remainder did not. Observers were encouraged to window the images to a level they felt was appropriate and, requested to rate their confidence that an acute fracture was present, marking the locations of any suspected acute fractures on the image. The images were displayed on a secondary-class monitor using Ziltron software, which recorded the adjustments to brightness and contrast made for each image. The images were presented in different orders for each lighting level to reduce potential memory effects. Results: Student’s t-tests were applied to compare the mean brightness and contrast adjustments made to the images in each ambient lighting level. Tests were carried out to include all images, only positive cases, and only cases where observers elected to change the brightness and/or contrast. No statistically significant differences were noted except when images where no brightness/contrast adjustments were made were discounted. In that case, mean brightness levels were slightly higher in the high ambient light level (p=0.049). Conclusion: No convincing difference in adjustments of brightness and contrast between high and low ambient lighting levels, although further research is warranted.

Paper Details

Date Published: 28 March 2013
PDF: 9 pages
Proc. SPIE 8673, Medical Imaging 2013: Image Perception, Observer Performance, and Technology Assessment, 867314 (28 March 2013); doi: 10.1117/12.2007690
Show Author Affiliations
Lee Shun Ming, Univ. College Dublin (Ireland)
Rachel J. Toomey, Univ. College Dublin (Ireland)
John T. Ryan, Ziltron (Ireland)
Louise A. Rainford, Univ. College Dublin (Ireland)

Published in SPIE Proceedings Vol. 8673:
Medical Imaging 2013: Image Perception, Observer Performance, and Technology Assessment
Craig K. Abbey; Claudia R. Mello-Thoms, Editor(s)

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