Development of a spectral repository for the identification of western Himalayan medicinal plants using machine learning techniques

Abstract

The identification of medicinal plant species is a crucial task for assessing the status of our bioresources. Conventional methods primarily rely on taxonomy and laboratory-based instruments, which are time-consuming and require the requisite expertise. Thus, there is an escalating demand for efficient techniques that can quickly identify these precious species. The advent of Hyperspectral Remote Sensing (HRS) with artificial intelligence has significantly increased the scope of HRS techniques by offering rapid and precise plant identification. This study utilised non-imaging HRS handheld sensors to build a spectral repository for 10 important medicinal plant species from diverse locations across Indian Himalayan states, representing varying altitudinal and ecological conditions. The spectral repository encompasses 1237 distinct spectral signatures obtained from the leaves and canopies of the targeted plant species. Subsequently, an identification model has been developed using Random Forest (RF) with several feature selection methods, and it has been revealed that the RF model, coupled with wrapper-based feature selection, is an effective combination for classifying the targeted plant species. The calibration and test datasets accounted for accuracies of 87.87% and 91.39%, respectively, with corresponding kappa coefficients of 0.85 and 0.89. Furthermore, the developed RF model was applied to ‘PRISMA’ satellite data to identify Saussurea costus crops in farmers' croplands, achieving a classification accuracy of 81.31% and a kappa coefficient of 0.76. Therefore, the study highlights the potential of integrating RF, in-situ HRS, and satellite HRS for the non-destructive, precise, and accurate identification of medicinal plants that can significantly contribute to biodiversity conservation and sustainable resource management.