The conventional theory of image transfer through a scattering medium treats objects located upon reflecting surfaces. It is shown that, when an object is located inside a scattering medium and shields a part of space, ignoring the shadowing leads to incorrect results, especially for modern time-gating systems. We develop a general theory of image formation including the shadowing effect when an object is located inside a scattering medium. The example of the observation of a submerged object through a windy ocean surface is chosen to illustrate this theory. A few unexpected effects in imaging of a submerged object are found and discussed, including contrast conversion for a sinking object and higher contrast in the shadow image than in the image of the object itself. The conclusion that using the shadow image for detection of a submerged object can be more efficient than using the image of the object itself is of practical significance.
© 1999 Optical Society of America
(110.2970) Imaging systems : Image detection systems
(110.2990) Imaging systems : Image formation theory
(110.7050) Imaging systems : Turbid media
(240.6690) Optics at surfaces : Surface waves
(290.1350) Scattering : Backscattering
Iosif L. Katsev, Eleonora P. Zege, and Alexander S. Prikhach, "Image Formation with Regard to Object Shadow for Objects Inside a Scattering Medium," Appl. Opt. 38, 6849-6858 (1999)