Active hyperspectral mid-infrared imaging based on a widely tunable quantum cascade laser for early detection of plant water stress

Plant water stress has been extensively studied using hyperspectral visible- and near-infrared systems. Thermal imaging the recent availability of widely tunable infrared quantum cascade laser (QCL) allow us to propose an active system operating in mid-infrared (MIR) band, where output consists a series narrowband subimages arranged across reflectance spectrum sample, forming hypercube data acquired by “staring” acquisition technique. To evaluate more precisely capabilities imaging, we composed four powerful QCL covering 3.9- 4.7-μm 7.5- 11-μm wavelengths ranges. Two cameras are used for detection: InSb cooled camera ranging from 3 5 μm bolometer 7.5 13 range. This is validated applying growing plants early detection. Finally, present discuss results partial least squares discriminant analysis classification technique characterize status different plants, separated two classes: control subjects were maintained at 80% amount soil saturation ratio stressed 20%. Initial discrimination have shown efficiency proposed system.