Fig. 5.

Measured contrast decreases exponentially with depth for (a) SFDI at all compression levels and (b) single source–detector separation NIRS. Although depth during compression was not known precisely, the estimate used here shows the expected exponential relationship, with dependence on ${\mu }_{\mathrm{a},\text{inclusion}}$. The dashed lines in (a) represent the approximate depth threshold for inclusion detection, 12 mm. At lower depths, contrast is greater than 0.05 for each of the four exponential fits. Open circles represent measurements of uncompressed phantoms. For each of the 16 phantoms, (c) compares optical contrast from SFDI at highest compression level to that measured with single source–detector separation NIRS, demonstrating that a similar level of contrast can be achieved by this method.