[1] N. Takai, H. Kadono, and T. Asakura, Opt. Eng. 25, 627 (1986).

[2] Q. Wang, Opt. Commun. 120, 1 (1995).

[3] A. Ishimaru, Wave Propagation and Scattering in Random Media, Vol.1, Single Scattering and Transport Theory (Academic Press, New York, 1978) Part 1, Chap.4.

[4] J. W. Goodman, in Laser Speckle and Related Phenomena, J. C. Dainty (ed.) (Springer-Verlag, Berlin, 1975) p.9.