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Proceedings Paper

Acutance And Granulance
Author(s): Edward M. Crane
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Paper Abstract

"Acutance," an established concept, is an objective prediction of picture sharpness, which is subjective. "AMT acutance" is 100 + 66 log R, where R is the ratio of the area under the modulation transfer curve of a complete imaging system including a human eye to that under the eye curve alone, which is Gaussian with standard deviation 13 cycles per degree. AMT acutance 100 is excellent, 90 is good, 80 fair, and 70 just passable. We propose a new measure of acceptability so far as noise is concerned, on the same scale, to be called "granulance." It is based on the rms deviation, in 240-μm circular samples, from mean lightness in areas meant to be uniform. A tentative formula for granulance of a paper print is: minimum value of 100 - 40 log [650 x rmsL(film) x scene lightness x slope of the curve of paper lightness vs. scene lightness].

Paper Details

Date Published: 28 December 1981
PDF: 8 pages
Proc. SPIE 0310, Image Quality, (28 December 1981); doi: 10.1117/12.932859
Show Author Affiliations
Edward M. Crane, Eastman Kodak Company (United States)

Published in SPIE Proceedings Vol. 0310:
Image Quality
Patrick S. Cheatham, Editor(s)

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