Fig. 6.

Correlations between $L*$ (measured with colorimeter) and ${{\mu }_s}^{\prime }$ (measured with SFDI) for the palm and ventral forearm. The best-fit line to each set of data points is shown in black. For the ventral forearm, where patients with dark skin have high pigmentation, there is a very strong correlation between $L*$ and measured ${{\mu }_s}^{\prime }$ at 471 and 659 nm, but this correlation vanishes at 851 nm and is not as strong for the palm, which has less pigmentation. This result suggests that the measured ${{\mu }_s}^{\prime }$ is being confounded by the presence of high pigmentation levels (low $L*$).