Imaging through fog using quadrature lock-in discrimination
preprintposted on 2023-01-11, 22:48 authored by Shashank Kumar, Bapan Debnath, Meena M. S., Julien Fade, Sankar Dhar, Mehdi Alouini, Fabien Bretenaker, Hema Ramachandran
We report experiments conducted in the field in the presence of fog, that were aimed at imaging under poor visibility. By means of intensity modulation at the source and two-dimensional quadrature lock-in detection by software at the receiver, a significant enhancement of the contrast-to-noise ratio was achieved in the imaging of beacons over hectometric distances. Further by illuminating the field of view with a modulated source, the technique helped reveal objects that were earlier obscured due to multiple scattering of light. This method, thus, holds promise of aiding in various forms of navigation under poor visibility due to fog.