A Method For Determining The Contrast Of Submerged Objects

Raymond C. Smith

doi:10.1117/12.946737

1 August 1968 A Method For Determining The Contrast Of Submerged Objects

Raymond C. Smith

Proceedings Volume 0012, Underwater Photo-Optical Instrumentation Applications II; (1968) https://doi.org/10.1117/12.946737
Event: Underwater Photo-Optical Instrumentation Applications, 1968, San Diego, United States

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.

Citation Download Citation

Raymond C. Smith "A Method For Determining The Contrast Of Submerged Objects", Proc. SPIE 0012, Underwater Photo-Optical Instrumentation Applications II, (1 August 1968); https://doi.org/10.1117/12.946737

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available