Improved imaging through flame and smoke using blue LED and quadrature lock-in discrimination algorithm

Abstract

Visibility is a big issue in imaging through fire and smoke, a situation often encountered by firefighters. Emission from fire is significantly higher in intensity compared to the light reflected from an object obscured by fire, leading to a drastic reduction in the signal-to-noise ratio for visualization. On the other hand, the presence of smoke scatters light in random directions, further reducing visibility. By implementing quadrature lock-in discrimination algorithm on the images captured by a sCMOS camera in the presence of a modulated blue light source and blue filter, we report a significant improvement in the image contrast measured for an object in the presence of flame and smoke. Our methodology is straightforward to realize and facilitates reliable identification of objects that are otherwise concealed in real-life situations due to poor visibility.