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Proceedings Paper

Measurements of the perceived dynamic range of a medical imaging workstation
Author(s): Robert S. Kenney; David S. Channin; Fred W. Prior
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Paper Abstract

Murch and Weiman have demonstrated that greater than 11 bits of contrast information are perceivable by a human observer. Digital display controllers with 10 or 12 bit digital to analog converters are becoming available. Before attempting to determine if these technologies improve the clinical effectiveness of medical imaging workstations it is first necessary to determine if measurable differences can be produced in the perceived dynamic range (PDR) of the displays. A set of experiments have been performed to determine a baseline PDR for an 8- bit per pixel display. This data will be used as the control for future measurements at 10 bits per pixel. The experimental design includes all psychovisual factors that affect an observer's perception of contrast. Stimulus display duration, physical size of the stimulus and training factors were all studied and controlled in the experiments. Simple images are used to avoid complicating the observer's task and display time is kept short to prevent adaptation and boredom effects. Data was collected using four non-radiologists and four radiologists. Each subject had at least normal corrected vision and wore his corrective lenses during each session. All experiments were conducted on a SUN SPARC workstation using an Image Systems (M21P-47SO1-2KHB) portrait monitor driven by a modified DOME Imaging Systems (Md2/SUN) 10-bit, grayscale, video board initially configured to run in 8-bit mode. Specially developed software was used to control the experiments and to gather and analyze the data. Pizer and Chan's methodology for computing PDR was adapted for the above hardware and software environment. A rating experiment was used to determine the just noticeable difference in contrast for a given reference intensity. Integration over the range of the monitor provides the PDR for that display for one observer. This data is then averaged with all other observations to determine a baseline PDR. These experiments allow for the determination of a baseline PDR for comparison with future hardware configurations. All calibration, control and analysis software is in place such that new hardware can be easily evaluated.

Paper Details

Date Published: 27 March 1996
PDF: 8 pages
Proc. SPIE 2712, Medical Imaging 1996: Image Perception, (27 March 1996); doi: 10.1117/12.236851
Show Author Affiliations
Robert S. Kenney, The Pennsylvania State Univ. College of Medicine (United States)
David S. Channin, The Pennsylvania State Univ. College of Medicine (United States)
Fred W. Prior, The Pennsylvania State Univ. College of Medicine (United States)

Published in SPIE Proceedings Vol. 2712:
Medical Imaging 1996: Image Perception
Harold L. Kundel, Editor(s)

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