We investigate methods of linearizing the problem of diffuse reflectance spectroscopy. Simulations show the effective optical pathlength varying in a scattering medium as a function of wavelength, total absorption, and chosen polarization channels.
Polarization gating is a popular and widely used technique in biomedical optics to sense superficial tissues (collinear detection), deeper volumes (cross-linear detection), and also selectively probe deeper volumes (using elliptically polarized light). As opposed to the conventional linearly polarized illumination, we propose a new protocol of polarization gating that combines co-elliptical and counter-elliptical measurements to selectively enhance contrast of the images. In vivo experiments were performed on skin abnormalities of volunteers (to selectively probe and access subsurface information).
Polarization gating is a popular and widely used technique in biomedical optics to sense superficial tissues (colinear detection), deeper volumes (crosslinear detection), and also selectively probe subsuperficial volumes (using elliptically polarized light). As opposed to the conventional linearly polarized illumination, we propose a new protocol of polarization gating that combines coelliptical and counter-elliptical measurements to selectively enhance the contrast of the images. This new method of eliminating multiple-scattered components from the images shows that it is possible to retrieve a greater signal and a better contrast for subsurface structures. In vivo experiments were performed on skin abnormalities of volunteers to confirm the results of the subtraction method and access subsurface information.