Ballistic Imaging through Strongly Scattering Media by Using a Combination of Supercontinuum Illumination and Fourier Spatial Filtering

Abstract

Imaging through turbid media is important but has created challenging issues for a long time. Previous research studies have shown that the object hidden in a turbid medium might be seen just by effectively suppressing the speckles by using low-coherent light sources, such as random laser and supercontinuum. However, the image contrast was seriously degraded due to the background noise of scattered photons. In this work, we demonstrate ballistic imaging for an object hidden behind strongly scattering media, in which the speckles are suppressed by the supercontinuum (SC) illumination and lots of scattered photons are simultaneously filtered by the Fourier spatial gate. Compared with speckle-free imaging from using SC illumination and ballistic imaging by Fourier spatial filtering, this method combines their advantages and shows a degree of synergism. When the optical depth of the scattering medium reaches 14, the image using this combined method is able to increase the image identifiability and the relative image contrast by about two times and four times compared to the method using only SC illumination, respectively. Our work offers a way for direct imaging through strongly turbid media without a complex image process.