S. Q. Duntley, J. Opt. Soc. Am. 53, 214 (1963).
C. J. Funk, Appl. Opt. 12, 301 (1973).
R. E. Morrison, Ph. D. thesis (Dept. of Meteorology and Oceanography, New York University, 1967).
L. E. Mertens and D. L. Phillips, "Measurements of the Volume Scattering Function of Sea Water," Air Force Eastern Test Range, Tech. Rep. 334, Patrick AFB, Florida (1972), obtainable from author (unpublished).
T. J. Petzold, "Volume Scattering Functions for Selected Ocean Waters," Scripps Inst. of Oceanography Visibility Laboratory, San Diego, Calif. (1972).
W. H. Wells, AGARD Lecture Series No. 61, Sec. 4. 1, p. 1, obtainable from Report Distribution Unit, NASA, Langley, Va. (1973).
Linear summation has been verified empirically for spatial frequencies below 10 000 cycles per rad—the region where salinity and thermal gradient structure in the water do not produce beam broadening (see Ref. 8 below).
R. T. Hodgson and D. R. Caldwell, J. Opt. Soc. Am. 62, 1434 (1972).
A receiver beam may be defined as the cylindrical volume whose umbral surface is bounded at the ends by the receiver aperture and by the image of the receiver field stop.
W. H. Wells, Ref. 6, Sec. 3. 4, p. 1.
E. C. Jordan, Electromagnetic Waves and Radiating Systems (Prentice-Hall, New York, 1950), p. 327.
W. H. Wells, J. Opt. Soc. Am. 59, 686 (1969).
W. H. Wells, Ref. 6, Sec. 3. 3, p. 1.
This relationship has been verified up to a range of 5. 7 attenuation lengths. The maximum range of its validity is not known.
H. Hodara, AGARD Lecture Series No. 61, Sec. 3. 4 (1973), see Ref. 6 for procurement.
W. H. Wells, Ref. 6, Secs. 3. 3 and 4. 3.
Equation (5) and others in the derivation assume that the spread functions are independent of position. This is true on spherical surfaces at a constant range. On plane surfaces, it represents an approximation useful over small fields.
V. R. Muratov and R. L. Struzer, Optical Tech. Theory Exper. 39, 519 (1972).
W. H. Wells, Ref. 6, Sec. 4. 3, p. 7.
A. Gordon, D. Cozen, C. Funk, P. Heckman, Jr., "Design Study of Advanced Underwater Optical Imaging Systems, Appendix B," Naval Undersea Research and Development Center, San Diego, Tech. Publ. 275 (1972) (unpublished).
By scattering calculations or from direct visual observations at a point outside a beam, it may be shown that the direction giving the maximum contribution to the illumination of a backscattering volume follows the direct line from the transmitter to the volume [dashed line of Fig. 8(b)], and the angular distribution of the flux falling on this backscattering volume is effectively only a few degrees wide. A similar observation applies to the flux backscattered from this volume and striking the receiver. Thus the dominant (back) scattering angle ηe for the incremental volume shown is approximately (π-G/r) rad over most of the scattering volume in a thin extended slab at range r, and the distribution of backscattering angles for this range is only a few degrees wide. Since the amplitude of the volume scattering function VSF varies only fractionally in a span of a few degrees when the mean scattering angle lies in the vicinity of π rad (Ref. 5), a similar accuracy will result if a single value of backscatter coefficient is used in the summation of the backscattering contribution from such a slab.
W. H. Wells, Ref. 6, Sec. 4. 3, p. 2.