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Proceedings Paper

A Method For Determining The Contrast Of Submerged Objects
Author(s): Raymond C. Smith
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Paper Abstract

One of the most fundamental optical measurements which can be made in natural waters is the measurement of the radiance distribution of natural radiant energy as a function of depth. Radiance distribution data is an important input to the theory of radiative transfer for the study of electromagnetic radiation within the sea, it provides a biologically meaningful technique for measuring the radiant energy supporting the ecology of natural waters and, of more immediate interest to SPIE members, the radiance distribution leads directly to the determination of the inherent contrast of an object for any path of sight. Knowledge of the inherent contrast makes it practical to apply the equations of contrast reduction to the problems of underwater visibility. Without radiance distribution data, the inherent contrast must be assumed or measured directly neither of these has proved satisfactory in practice. This paper describes a proposal to record the radiance distribution of natural light underwater by a method employing a "fish-eye" camera, having a 180° field of view. From the films obtained, values of radiance can be determined by methods of photographic photometry. In addition, the application of radiance distribution data to the problem of determining the contrast of underwater objects is discussed.

Paper Details

Date Published: 1 August 1968
PDF: 6 pages
Proc. SPIE 0012, Underwater Photo-Optical Instrumentation Applications II, (1 August 1968); doi: 10.1117/12.946737
Show Author Affiliations
Raymond C. Smith, University of California (United States)

Published in SPIE Proceedings Vol. 0012:
Underwater Photo-Optical Instrumentation Applications II
Charles N. DeMund, Editor(s)

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