Correction to "Scale-based diffusive image filtering preserving boundary sharpness and fine structures"

Abstract

mm , and for the clear layer, and mm , mm , and for highly scattering layers. The dotted line in the figure shows the backward scattering pulse profile of the homogeneous slab without the clear layer at the 20 mm away from laser illumination points. The profile changes by adding the clear layer especially in the trailing edge of the pulse retaining the peak amplitude. When absorption coefficient in the third layer was increased from mm to mm , the decay of the reflectance is also increased as shown in the figure. This means that the absorption changes inside the clear layer are estimated by the time profile changes of the reflectance. The sensitivity for the absorption changes becomes maximum when source detector separation is 20 mm. The mean path lengths are 200, 660, 825, and 870 ps for the source detector spacing 10, 20, 30, and 37.5 mm, respectively. The mean path length saturate for the spacing larger than 25 mm, which are coincident with results reported by Monte Carlo and FEM simulation [9]. V. C ONCLUSION FDTD method has been successfully formulated for analysis of pulse responses in biological tissues. Boundary conditions have been defined using fluence rate at the scattering and no scattering material interfaces. The conditions to give stabilities for numerical solutions have been become clear in terms of scattering coefficients and mean cosine of scattering angles. Using the formulation, the reflectance of three-layered slabs containing a clear layer has been calculated. As a result, it has been become clear that absorption coefficient changes of the highly scattering media beyond the clear layer are estimated from the time profiles of the reflectance. The analysis is easily extended to calculate pulse responses in tissues with 3-D inhomogeneous optical parameters, which is effective for image reconstruction in practical diffused optical tomography.