Location of objects in multiple-scattering media P. N. den Outer and Th. M. Nieuwenhuizen

When a small object is placed in a multiple-scattering medium the stationary diffusion equation can be used to derive the disturbance in the transmitted and backscattered light intensity. The diffusion equation will de-scribe the intensity outside and inside the object. The object is characterized by a size, a diffusion constant, and an absorption length. In this way absorbing objects as well as nonabsorbing objects can be treated. The results are derived for two and three dimensions. Experiments are performed on suspended titanium dioxide particles in glycerine, wherein objects could be placed. There is good agreement between theory and experi-ment. This work shows that with the use of continuous light sources, it may be possible to recover the location of objects accurately inside a diffusive scattering medium. 1