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Proceedings Paper

An Overview Of Human Observer Characteristics And Their Effect On Image Transmission And Display
Author(s): Thomas G. Stockham Jr.
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Paper Abstract

The science and technology of image transmission and display has evolved primarily from the diciplines of computer science, electrical engineering and physics. Thus, it is only natural that techniques and attitudes which have developed are characterized by the style in which people in these areas approach the subject of images and their transmission, display, and processing. For example, one finds many important differences between the methods of television and those of photography. Moreover, an even greater contrast is found when comparing the methods of electrical engineering, physics, television and photography with those now understood to be employed by the human eye and the human visual system. Specifically, let us contrast the method by which television, photography and the human visual system, represent image information. In television (particularly digital imaging), image values are represented by signals analogous to quantities of light. They are called intensities. In photography, on the other hand, the representing quantities are concentrations of silver or dyes. Consequently, due to the natural exponentiating laws governing the interaction of light with these media, they are analogous to the logarithm of quantities of light. They are called densities. The human visual system, on the other hand, (while being generally logarithmically sensitive) moves a large step further away from representation by physical quantities of light and produces at very early stages in its processing highly modified versions of the patterns of light or their logarithms. The natural question then arrises, why should the human visual system try to do this; and since it does, what consequences are implied in terms of the television and photographic presentations normally employed?

Paper Details

Date Published: 30 October 1975
PDF: 3 pages
Proc. SPIE 0066, Efficient Transmission of Pictorial Information, (30 October 1975); doi: 10.1117/12.965343
Show Author Affiliations
Thomas G. Stockham Jr., University of Utah (United States)

Published in SPIE Proceedings Vol. 0066:
Efficient Transmission of Pictorial Information
Andrew G. Tescher, Editor(s)

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