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Proceedings Paper

Measurement of visual performance through scattering visors and aerospace transparencies
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Paper Abstract

Light scattered from helmet visors and aerospace transparencies is known to reduce visual performance. One popular measurement technique, maintained by the American Society for Testing and Materials, is ASTM D 1003. It is a standard procedure used to measure haze inherent in transparent materials, which is defined as the percent of the total transmitted light that is scattered. However, research has shown that visual acuity measured through several different types of helmet visors does not correlate well with visor haze. This is most likely due to the fact that the amount of light scattered from a transparent material depends heavily on the light illuminating the transparency and on the viewing geometry, behavior that ASTM D 1003 does not characterized. Scattered light causes transparent parts to appear luminescent and imparts a veiling luminance when superimposed over a target, reducing target contrast and inducing a visual performance loss. This paper describes an experiment in which threshold target background luminance, the luminance at which a target was barely visible, was measured for a number of observers viewing a Landolt C target through several levels of veiling luminance. Threshold luminance was examined for predictable behavior with respect to veiling luminance.

Paper Details

Date Published: 22 August 2001
PDF: 10 pages
Proc. SPIE 4361, Helmet- and Head-Mounted Displays VI, (22 August 2001); doi: 10.1117/12.437994
Show Author Affiliations
Peter L. Marasco, Air Force Research Lab. (United States)
H. Lee Task, Air Force Research Lab. (United States)

Published in SPIE Proceedings Vol. 4361:
Helmet- and Head-Mounted Displays VI
Ronald J. Lewandowski; Loran A. Haworth; Henry J. Girolamo; Clarence E. Rash, Editor(s)

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