High-contrast imaging through scattering media using structured illumination and Fourier filtering

We show in this Letter a novel approach for high-contrast imaging through scattering media by combining structured illumination and Fourier filtering (SIF). To assess the image contrast enhancement at different image spatial frequencies, the modulation transfer function is calculated for four detection schemes: (1) no filtering, (2) Fourier filtering, (3) structured illumination, and (4) SIF filtering. A scattering solution consisting of D = 7.3 μm polystyrene spheres immersed in distilled water and illuminated at λ = 671 nm is used here. We demonstrate the possibility of obtaining, with SIF, an image contrast up to 60% at an optical depth of OD = 10, improving the contrast by a factor of 40 over conventional transmission imaging