Hierarchical PCA-NN for retrieving the optical properties of two-layer tissue model

Abstract

In the preceding paper [1], PCA-NN was successfully introduced to deduce the optical properties of semi-infinite tissue model from spatially resolved diffuse reflectance. However, tissue often has a layered structure. Therefore, a new hierarchical PCA-NN (HPCA-NN) algorithm was presented in this paper for extracting the optical properties of multi-layer tissue model from the spatially resolved reflectance. For simplicity, we concentrated on the twolayer model that simulated a skin layer with thickness of 5 mm and the semiinfinite underlying muscle layer. The results showed that the method can achieve high predictive accuracy with the rms errors (RMSEs) < 1% for the toplayer optical properties and the RMSEs < 5% for the bottom-layer optical properties. All the results were based on Monte Carlo simulations. © Springer-Verlag 2004.