Measurement Tools for Non-Invasive Monitoring of the Plants Growth Conditions by Using Hyperspectral Imaging Methods: a Review

Portable spectroradiometers and hyperspectral cameras are increasingly being used to quickly assess the physiological state of plants. The operation of these devices is based on the registration of reflection or reflection and transmission spectra. (Research purpose) The research purpose is in analyzing the technical means and methods of non-invasive monitoring of the plant state based on the registration of the reflection spectra of leaves. (Materials and methods) The article presents a review of the work on the application of hyperspectral imaging methods. Authors classified and analyzed materials on spectroscopic radiometers and hyperspectral cameras, and outlined the prospects for implementation. Authors applied the methods of a systematic approach to the research problem. (Results and discussion) Hyperspectral imaging methods serve as an effective means of monitoring plants. It is possible to determine the pigment composition of plants, lack of nutrition, and detect biotic stress through hyperspectral imaging. The article presents methods of application of portable spectroradiometers and hyperspectral cameras. With the help of these devices it is possible to carry out measurements with high spectral resolution. The difficulty of accurately detecting the content of pigments in the leaves lies in the mutual overlap of the areas of light absorption by them. The main drawback of spectroradiometers is that they measure only at one point on a single sheet. The article presents the difficulties encountered in interpreting the results obtained by the hyperspectral camera. The background reflectivity of the soil, the geometry of the vegetation cover, and the uneven lighting can make errors in the measurements. (Conclusions) The article presents the disadvantages of the hyperspectral imaging method when using only the reflection spectrum. In order to increase the accuracy of the determination of pigments and stresses of various origins, it is necessary to develop a portable device that combines the methods of recording reflection and fluorescence.