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Viewing angle performance of medical liquid crystal displays
Author(s) -
Samei Ehsan,
Wright Steven L.
Publication year - 2006
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2168430
Subject(s) - medical imaging , viewing angle , optics , materials science , liquid crystal display , medical physics , computed radiography , computer graphics (images) , computer science , computer vision , physics , artificial intelligence , image quality , image (mathematics)
Cathode‐ray tube (CRT) and liquid crystal display (LCD) are currently two main technologies for displaying medical images. LCDs possess a number of advantages, but their performance varies as a function of viewing angle. Our purpose in this study was to characterize the angular response performance of five medical‐grade LCDs, and to substantiate their impact on their compliance with the DICOM gray scale display function (GSDF). Furthermore, the study aimed to test a framework to define an angular acceptance range for medical LCDs based on the recent AAPM TG18 guidelines. Measurements were made on five calibrated dual‐domain LCDs, including two 3 megapixel monochrome LCDs, two 5 megapixel monochrome LCDs, and one 9 megapixel color LCD. The luminance performance of each display device was measured as a function of the viewing angle at 17 discrete levels using TG18‐LN test patterns and a Fourier‐optics‐based luminance meter. The luminance data were analyzed according to the AAPM TG18 methodology. The displays showed notable variation in luminance and contrast performance as a function of the viewing angle, particularly in diagonal viewing orientations. Overall, the luminance ratio remained greater than 175 within ± 20 ° and ± 33 ° viewing angle cones ( β 175 = 20 ° − 33 ° ) . Aiming to maintain a maximum deviation from the GSDF contrast less than 0.3, i.e.,κ 17 ⩽ 0.3 , acceptable viewing angle cones of ± 22 ° and ± 35 ° were indicated ( α 0.3 = 22 ° − 35 ° ) . The findings demonstrate the significant impact of angular response on image contrast, and the utility ofα 0.3andβ 175quantities for defining the viewing angle cones within which a medical LCD device can be effectively utilized.