Object delineation within turbid media by backscattering of phase-modulated light

Noise equalization in Stokes parameter images obtained by use of variable-retardance polarimeters

“…Stokes vector (SV) imaging polarimeters have been developed for use in remote-sensing applications and have been demonstrated to improve target contrast, 1,2 reduce clutter, 1 aid in the defeat of intervening scatterers, 2,3 and provide orientation information about target features. 1,2 Polarimeters employ strategies motivated by ellipsometry to measure components of the Stokes vector at each pixel in a frame; however, there are signif icant differences between ellipsometric and imaging applications that place restrictions on the design of SV polarimeters.…”

Enhancement of the point-spread function for imaging in scattering media by use of polarization-difference imaging

“…The dipole source produces radiation polarized in the ẑ direction only, and hence the portion of the PSF due to the source is identical in PS and PD imaging, so the decreased intensity of the corrupting portion of the PD PSF indicates that the dipole source would become more evident in PD images in scattering media. If the radiation from a particular location on a target were partially polarized, as is often the case in passive imaging with unpolarized illumination, 7,19,[21][22][23] the magnitude of the transmitted peak would be lowered in PDI. This is an important consideration that will help to determine the limits of visibility of partially polarizing target features in scattering media.…”

“…Even though the above analysis is simple, it may provide some insights into previous experimental studies that employed polarization sensitivity to improve image contrast and resolution at moderate optical thicknesses (0-10 transport mean free paths). 7,[21][22][23] The results also are applicable to time-resolved polarization imaging where improved two-point resolution was observed. 9,20 Even though the time-resolved imaging was performed at much greater optical thicknesses (Ͼ10 transport mean free paths), the use of time gating greatly reduces the number of multiply scattered photons that degrade the final image, thereby making the comparison with the results presented in this paper possible.…”

“…However, it has been shown that even at small optical thicknesses, polarization discrimination can enhance contrast, thereby improving target detectability. 7,22,23 Investigation of Figs. 5 and 6 indicates that the corrupting portion of the PD PSF is not only narrower than the corrupting portion of the PS PSF, but it is also lower in absolute intensity.…”

“…In Section 3 the analysis is extended by Monte Carlo methods to scattering regimes comparable to those studied previously. 7,19,[21][22][23] In Section 4 the results are summarized and their impact on experimental studies is discussed.…”