Hyperspectral Sensors and Imaging Technologies in Phytopathology: State of the Art

Abstract

Plant disease detection represents a tremendous challenge for research and practical applications. Visual assessment by human raters is time-consuming, expensive, and error prone. Disease rating and plant protection need new and innovative techniques to address forthcoming challenges and trends in agricultural production that require more precision than ever before. Within this context, hyperspectral sensors and imaging techniques-intrinsically tied to efficient data analysis approaches-have shown an enormous potential to provide new insights into plant-pathogen interactions and for the detection of plant diseases. This article provides an overview of hyperspectral sensors and imaging technologies for assessing compatible and incompatible plant-pathogen interactions. Within the progress of digital technologies, the vision, which is increasingly discussed in the society and industry, includes smart and intuitive solutions for assessing plant features in plant phenotyping or for making decisions on plant protection measures in the context of precision agriculture.

Relation of Photochemical Reflectance Indices Based on Different Wavelengths to the Parameters of Light Reactions in Photosystems I and II in Pea Plants

“…In particular, the increase can be based on the development of methods of remote sensing, which constitute the basis of "precision agriculture" and are an important tool for crop protection under the action of stressors [9]. Using optical methods, which are very sensitive to plant changes under the action of stressors and are relatively simple, is a potential way of plant remote sensing [10,12]. Measurements of the reflectance of leaves are a widely-used method of analysis of physiological processes in plants [11][12][13][14][15]67].…”

“…Using optical methods, which are very sensitive to plant changes under the action of stressors and are relatively simple, is a potential way of plant remote sensing [10,12]. Measurements of the reflectance of leaves are a widely-used method of analysis of physiological processes in plants [11][12][13][14][15]67]. It is important that intensities of the reflected light can be used for the calculation of reflectance indices, because analysis based on these indices has low errors in comparison with the analysis of absolute values of the reflected light [10].…”

“…Early and remote detection of stressor-induced changes forms the basis of the timely use of methods of plant protection, i.e., it is important for agriculture 2 of 24 and environmental conservation [10]. Optical methods are widely used for this purpose [11,12]; in particular, the measurement of plant reflectance is a perspective solution to target this problem [12][13][14][15].…”

“…), the changes in biochemical content (including concentrations of chlorophylls [29][30][31], carotenoids [32][33][34], nitrogen compositions [35,36], etc. ), or the plant damage caused by abiotic [17,20] and biotic stressors [11,12,15]. The calculation of numerous reflectance indices, which are often based on measurements of changes in intensity of the reflected light at specific wavelengths in comparison with one at a reference wavelength, can strongly improve the analysis of plant reflectance [10,[13][14][15].…”

In-Field Detection of Yellow Rust in Wheat on the Ground Canopy and UAV Scale

“…Spectral sensors might be tools able to contribute to site-specific disease management [6,7]. Spectral sensors measure the light reflected from the crop canopy [1].…”