Fig. 2 |. Three-layer-model reconstruction algorithm and phantom-validation experiments.

a, Three-layer-model initialization and reconstruction procedures. b, Tissue-simulating-phantom experiment for validating the accuracy and depth sensitivity of the optical properties. A translation stage moves the source fibre across the phantom for measurements at SDSs ranging from 6.2 cm to 10 cm. Nonlinear semi-infinite fitting is performed to reconstruct phantom absorption and scattering coefficients $\left(\lambda =830nm\right)$. c, Schematic of a two-layer phantom experiment.