POLARIZATION-DIFFERENCE IMAGING - A BIOLOGICALLY INSPIRED TECHNIQUE FOR OBSERVATION THROUGH SCATTERING MEDIA

Many animals have visual systems that exploit the polarization of ligh t, and some of these systems are thought to compute difference signals in parallel from arrays of photoreceptors optimally tuned to orthogon al polarizations. We hypothesize that such polarization-difference sys tems can improve the visibility of objects in scattering media by serv ing as common-mode rejection amplifiers that reduce the effects of bac kground scattering and amplify the signal from targets whose polarizat ion-difference magnitude is distinct from the background. We present e xperimental results obtained with a target in a highly scattering medi um, demonstrating that a manmade polarization-difference system can re nder readily visible surface features invisible to conventional imagin g.