Fig. 3.

A. 2D sensitivity map constructed from a Monte Carlo simulation with a 20 mm source-detector separation used as the weighting matrix for real-time visualization of FD-DOS data with a logarithmic color scale. The simulation volume had an absorption coefficient of 0.1 mm⁻¹ and a reduced scattering coefficient of 1 mm⁻¹. The area immediately surrounding the source, located at (20,30), and the detector, at (40,30), are the regions of highest sensitivity. The number of detected photons passing through each pixel rapidly decays as the distance from the line connecting the source and detector increases. B. Photo of the underside of the probe with source and detector fiber ends indicated by arrows. C. Photo of the top of the probe illustrating the checkerboard pattern used for pose estimation.