Mid-infrared speckle reduction technique for hyperspectral imaging
Résumé
Recently, we proposed an active mid-infrared (MIR) hyperspectral imaging system for early detection of plant water stress. A quantum cascade tunable laser powered this stand-off detection system, in which "speckle" in images due to coherent nature of laser radiation. The speckle affects the spatial resolution of the images. In this article, we evaluate several speckle suppression methods suitable for the mid-infrared region. To quantify the reduction of speckle, we compare their spatial contrast. We combined optical techniques and showed their ability to reduce the speckle contrast from its initial value 0.41s down to 0.11, representing a 73% reduction.