Recovering the optical properties of a tissue using maximum a posteriori based estimation

The spectral reflectance of a biological tissue is known to be affected by its physical and optical properties such as thickness, chromophore concentrations and scattering coefficient. There exist numerous methods that aim to extract the optical parameters of a tissue by relating reflectance measurements to a theoretical model of light transport. During the parameter recovery process, assumptions are often made about the characteristics of the tissue. However, incorrect assumptions lead to inaccurate or even erroneous results. We present a method based on the maximum a posteriori estimation technique to recover some optical properties of the biological tissue from reflectance measurements. The method provides correct results even in the presence of significant uncertainty in the underlying specification of the tissue. A light transport model of the inspected medium is developed and used in the estimation process. The analysis of the results obtained from simulated skin data and phantoms suggests that the proposed MAP based method is a good parameter recovery technique that provides accurate estimates and is robust against a high level of uncertainty in the tissue’s model.