Mp. Rowe et al., POLARIZATION-DIFFERENCE IMAGING - A BIOLOGICALLY INSPIRED TECHNIQUE FOR OBSERVATION THROUGH SCATTERING MEDIA, Optics letters, 20(6), 1995, pp. 608-610
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.