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Method of measuring contrast‐to‐noise ratio ( CNR ) in nonuniform image area in digital radiography
Author(s) -
Mori Masaki,
Imai Kuniharu,
Ikeda Mitsuru,
Iida Youko,
Ito Fukiko,
Yoneda Kazuo,
Enchi Yukihiro
Publication year - 2013
Publication title -
electronics and communications in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.131
H-Index - 13
eISSN - 1942-9541
pISSN - 1942-9533
DOI - 10.1002/ecj.11416
Subject(s) - contrast to noise ratio , imaging phantom , digital radiography , radiography , image quality , computed radiography , nuclear medicine , computer science , physics , image (mathematics) , medicine , computer vision , nuclear physics
Summary One of the physical indices for evaluating the image quality of digital radiography is the contrast‐to‐noise ratio ( CNR ). The CNR was reported to simulate human perception. Thus, the CNR is a variable index for evaluating detectability in digital radiography. However, it is difficult to evaluate the CNR in a nonuniform image area. In this study, we have devised a new method for measuring the CNR in a nonuniform image area on digital radiography using the top‐hat transform. Furthermore, we investigated the radiation dose dependence of CNR in the digital image of an anthropomorphic breast phantom containing a simulated calcification. We have shown that the CNR in a nonuniform image area can be analyzed with high accuracy by the devised method for measuring the CNR . As for the radiation dose dependence of the CNR , the CNR increased with the mAs values and fell depending on the increase in the density of mammary glands in the anthropomorphic breast phantom. © 2013 Wiley Periodicals, Inc. Electron Comm Jpn, 96(7): 32–41, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/ecj.11416