Document Detail

Accurate color measurement methods for medical displays.
MedLine Citation:
PMID:  20175468     Owner:  NLM     Status:  MEDLINE    
PURPOSE: The necessity for standard instrumentation and measurements of color that are repeatable and reproducible is the major motivation behind this work. Currently, different instrumentation and methods can yield very different results when measuring the same feature such as color uniformity or color difference. As color increasingly comes into play in medical imaging diagnostics, display color will have to be quantified in order to assess whether the display should be used for imaging purposes. The authors report on the characterization of three novel probes for measuring display color with minimal contamination from screen areas outside the measurement spot or from off-normal emissions. They compare three probe designs: A modified small-spot luminance probe and two conic probe designs based on black frusta. METHODS: To compare the three color probe designs, spectral and luminance measurements were taken with specialized instrumentation to determine the luminance changes and color separation abilities of the probes. The probes were characterized with a scanning slit method, veiling glare, and a moving laser and LED arrangement. The scanning slit measurement was done using a black slit plate over a white line on an LCD monitor. The luminance was measured in 1 mm increments from the center of the slit to +/- 15 mm above and below the slit at different distances between the probe and the slit. The veiling glare setup consisted of measurements of the luminance of a black spot pattern with a white disk of radius of 100 mm as the black spot increases in 1 mm radius increments. The moving LED and laser method consisted of a red and green light orthogonal to the probe tip for the light to directly shine into the probe. The green light source was moved away from the red source in 1 cm increments to measure color stray-light contamination at different probe distances. RESULTS: The results of the color testing using the LED and laser methods suggest a better performance of one of the frusta probes at shorter distances between the light sources, which translates to less contamination. The tails of the scans indicate the magnitude of the spread in signal due to light from areas outside the intended measurement spot. The measurements indicate a corresponding glare factor for a large spot of 140, 500, and 2000 for probe A, B1, and B2, respectively. The dual-laser setup suggests that color purity can be maintained up to a few tens of millimeters outside the measurement spot. CONCLUSIONS: The comparison shows that there are significant differences in the performance of each probe design, and that those differences have an effect on the measured quantity used to quantify display color. Different probe designs show different measurements of the level of light contamination that affects the quantitative color determination.
Anindita Saha; Edward F Kelley; Aldo Badano
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Publication Detail:
Type:  Evaluation Studies; Journal Article    
Journal Detail:
Title:  Medical physics     Volume:  37     ISSN:  0094-2405     ISO Abbreviation:  Med Phys     Publication Date:  2010 Jan 
Date Detail:
Created Date:  2010-02-23     Completed Date:  2010-04-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0425746     Medline TA:  Med Phys     Country:  United States    
Other Details:
Languages:  eng     Pagination:  74-81     Citation Subset:  IM    
Division of Imaging and Applied Mathematics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug, 10903 New Hampshire Avenue, WO 62-3116, Silver Spring, Maryland 20993, USA.
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MeSH Terms
Colorimetry / instrumentation*
Computer Terminals*
Computer-Aided Design
Data Display*
Equipment Design
Equipment Failure Analysis
Lighting / instrumentation*
Reproducibility of Results
Sensitivity and Specificity

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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