IMAGING THROUGH SCATTERING MEDIA BY THE USE OF AN ANALYTICAL MODEL OFPERTURBATION AMPLITUDES IN THE TIME-DOMAIN

A method of generating images through highly scattering media is prese nted that involves comparing measurements of the time-dependent intens ity of transmitted light with an analytical model describing the sensi tivity of that intensity on localized changes in optical properties. A least-squares fitting procedure is employed to derive the amplitudes of the measurement perturbations caused by embedded absorbers and scat terers located along a line of sight between the source and detector. Images are presented of a highly scattering, solid plastic phantom wit h optical properties closely matched to those of human breast tissue a t near-infrared wavelengths. The phantom is a 54-mm-thick slab, contai ning four small cylinders of contrasting scatter and absorption. Resul ts show that embedded absorbers can be distinguished from embedded sca tterers, and that the diffusion perturbation amplitude provides inhere ntly greater spatial resolution than the absorption perturbation ampli tude. (C) 1996 Optical Society of America