Decay behavior and optical parameter identification for spatial-frequency domain imaging by the radiative transport equation
The decay behavior of the specific intensity is considered for the spatial-frequency domain imaging (SFDI). It is shown that the decay is given by a superposition of different decay modes. The decay rates of these modes are determined by spatial frequencies and Case's eigenvalues. Then we determine optical properties of the top layer of a solid phantom making use of the fact that light with nonzero spatial frequency rapidly decays. A fast parameter identification is achieved by the combination of the method of rotated reference frames for the radiative transport equation and the Levenberg-Marquardt algorithm.