TY - JOUR

T1 - An estimate of the average cosine for the radiance distribution resulting from a point source in the ocean

AU - Voss, Kenneth J.

AU - Maffione, Robert A.

N1 - Funding Information:
This work has been supported by the ocean optics division of the Office of Naval Research. Additional support for field measurements was provided by the Applied Physics Laboratory, Johns Hopkins University. We also thank Albert Chapin for his help in the field measurements.
Publisher Copyright:
© 1994 SPIE. All rights reserved.
Copyright:
Copyright 2019 Elsevier B.V., All rights reserved.

PY - 1994/10/26

Y1 - 1994/10/26

N2 - We have shown in an earlier paper that by measuring the decay of the irradiance field due to a point source, the absorption coefficient of the medium can be determined. A central parameter in this method is the average cosine of the radiance distribution at each measurement point. From measurements of the Point Spread Function (PSF), an estimate of the average cosine can be determined. However, experimentally the PSF is routinely measured only to 12 degrees. We have also previously shown a method which relates the small angle PSF measurements to an empirically derived analytic formulation of the Beam Spread Function (BSF) which extends to 90 degrees. We will present an independent test of this method, and then use the BSF to determine the average cosine for varying ranges (from the point source) and water properties. In this way we can estimate how rapidly the average cosine varies, and its relative importance in the field measurements of the absorption coefficient with these techniques.

AB - We have shown in an earlier paper that by measuring the decay of the irradiance field due to a point source, the absorption coefficient of the medium can be determined. A central parameter in this method is the average cosine of the radiance distribution at each measurement point. From measurements of the Point Spread Function (PSF), an estimate of the average cosine can be determined. However, experimentally the PSF is routinely measured only to 12 degrees. We have also previously shown a method which relates the small angle PSF measurements to an empirically derived analytic formulation of the Beam Spread Function (BSF) which extends to 90 degrees. We will present an independent test of this method, and then use the BSF to determine the average cosine for varying ranges (from the point source) and water properties. In this way we can estimate how rapidly the average cosine varies, and its relative importance in the field measurements of the absorption coefficient with these techniques.

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U2 - 10.1117/12.190069

DO - 10.1117/12.190069

M3 - Conference article

AN - SCOPUS:85076982118

VL - 2258

SP - 256

EP - 263

JO - Proceedings of SPIE - The International Society for Optical Engineering

JF - Proceedings of SPIE - The International Society for Optical Engineering

SN - 0277-786X

T2 - Ocean Optics XII 1994

Y2 - 13 June 1994 through 15 June 1994

ER -