Halftone-SFDI principles and data flow (IMAGE)
Caption
a, Spatially modulated light patterns are generated by the DMD and projected onto the sample. Remitted light is collected by a camera. b, A Monte Carlo based model is used to extract optical absorption (μa) and reduced scattering (μs’) from calibrated diffuse reflectance (Rd) at two spatial frequencies, in this case 0 mm-1 and 0.1 mm-1. c, Raw reflectance images are demodulated and calibrated to extract the spatial frequency response of the sample (i.e., diffuse reflectance). The Monte Carlo based inversion model is used to extract optical properties (absorption and reduced scattering) on a pixel-by-pixel basis. Here, an 8 × 6 cm region of human hand was imaged at 650 nm and the extracted optical absorption and reduced scattering maps are shown for the measured wavelength. d, Conventional 8-bit continuous-tone illumination pattern is converted to halftone 1-bit pattern which increases the maximum projection rate from 290 Hz to 23 kHz, by approximately two orders of magnitude. e, Raw images are collected for the same turbid sample region (i.e., human hand) with the conventional continuous-tone and the proposed halftone illumination patterns, respectively. While the binary discontinuity is visible in the halftone patterns after zoomed-in, the corresponding collected images have identical appearance with the ones from continuous-tone patterns as a result of low-pass filtering effect of turbid media.
Credit
by Yanyu Zhao, Bowen Song, Ming Wang, Yang Zhao, and Yubo Fan
Usage Restrictions
Credit must be given to the creator.
License
CC BY