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Proceedings Paper

Modeling effects of terrain and illumination on visibility and the visualization of haze and aerosols
Author(s): Donald W. Hoock; John C. Giever
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Paper Abstract

Visibility and visual range are well established concepts that quantify the exponential attenuation of contrast and radiance along near-horizontal paths through the atmosphere. Scene visualization, however, requires that not only the attenuation of radiance from distant objects be modeled, but also the scattering of ambient radiance into the field of view all along the viewing path. This illumination effect is most pronounced under moderate to low visibility conditions of haze or fog viewed from near-horizontal paths near the surface. It is often provided for in scene generators that implement some form of range-dependent `fog' or `haze' functions as two parameters: the `atmospheric fading coefficient' and the `atmospheric blending factor.' We examine the physical meaning of these parameters and the effects of variable illumination and terrain reflectance along the viewing path for different meteorological visibility, solar angle and aerosol conditions. The error introduced through use of the same coefficients across the visible wavelength band is compared to use of wavelength- dependent extinction and scattering. Scene generation examples are shown comparing different rendering approaches and the trade-offs in computational speed versus accuracy between hardware and software implementations.

Paper Details

Date Published: 15 June 1994
PDF: 12 pages
Proc. SPIE 2223, Characterization and Propagation of Sources and Backgrounds, (15 June 1994); doi: 10.1117/12.177935
Show Author Affiliations
Donald W. Hoock, U.S. Army Research Lab. (United States)
John C. Giever, New Mexico State Univ. (United States)


Published in SPIE Proceedings Vol. 2223:
Characterization and Propagation of Sources and Backgrounds
Wendell R. Watkins; Dieter Clement, Editor(s)

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