OBJECT DELINEATION WITHIN TURBID MEDIA BY BACKSCATTERING OF PHASE-MODULATED LIGHT

Backscattering of phase-modulated light is shown to reveal the presenc e of targets embedded in visually opaque suspensions of diffusively sc attering particles. Signals at the modulation frequency I(f) and first harmonic I(2f) give nearly instantaneous measures of the difference i n intensities of orthogonal states of circular and linear polarization s, respectively. Examination of different kinds of targets demonstrate s the sensitivity of polarization-selective imaging to (a) edges, (b) surface texture, and (c) polarization-dependent absorption of the embe dded object. (C) 1997 Elsevier Science B.V.