Optimal estimation reconstruction of the optical properties of a two-layered tissue phantom from time-resolved single distance measurements

In this work, we have tested the optimal estimation (OE) algorithm for the reconstruction of the opticalproperties of a two-layered liquid tissue phantom from time-resolved single-distance measurements. The OEallows a priori information, in particular on the range of variation of fit parameters, to be included. The purposeof the present investigations was to compare the performance of OE with the Levenberg-Marquardt method fora geometry and real experimental conditions typically used to reconstruct the optical properties of biologicaltissues such as muscle and brain. The absorption coefficient of the layers was varied in a range of values typicalfor biological tissues. The reconstructions performed demonstrate the substantial improvements achievable withthe OE provided a priori information is available. We note the extreme reliability, robustness, and accuracy ofthe retrieved absorption coefficient of the second layer obtained with the OE that was found for up to six fitparameters, with an error in the retrieved values of less than 10%. A priori information on fit parametersand fixed forward model parameters clearly improves robustness and accuracy of the inversion procedure.