  Information about tissue oxygen saturation ($StO_2$) and other related
important physiological parameters can be extracted from diffuse reflectance
spectra measured through non-contact imaging. Three analytical optical
reflectance models for homogeneous, semi-infinite, tissue have been proposed
(Modified Beer-Lambert, Jacques 1999, Yudovsky 2009) but these have not been
directly compared for tissue parameter extraction purposes. We compare these
analytical models using Monte Carlo simulated diffuse reflectance spectra and
controlled gelatin-based phantoms with measured diffuse reflectance spectra and
known ground truth composition parameters. The Yudovsky model performed best
against Monte Carlo simulations and measured spectra of tissue phantoms in
terms of goodness of fit and parameter extraction accuracy followed closely by
Jacques' model. In this study, Yudovsky's model appeared most robust, however
our results demonstrated that both Yudovsky and Jacques models are suitable for
modelling tissue that can be approximated as a single, homogeneous,
semi-infinite slab.
