Fig. 2: Validation of halftone-SFDI on an array of phantoms with a wide range of optical properties.

a White light image of the fabricated array of 16 optical phantoms. b Comparison of diffuse reflectance at 650 nm of five spatial frequencies measured by the continuous-tone SFDI and the proposed halftone-SFDI for three representative phantoms. c Extracted optical properties of the three representative phantoms in (b). The hatch pattern was added to aid data interpretation. d Comparison of measured R_d values from 650 nm to 850 nm with 50 nm increments with five spatial frequencies for all the 16 phantoms. e Corresponding optical absorption values of the 16 phantoms at five wavelengths by the two competing methods, with a percent difference of −1.6 ± 1.8%. f Corresponding reduced scattering values of the 16 phantoms at five wavelengths by the two competing methods, with a percent difference of 0.6 ± 0.6%