With the available unmanned aerial vehicles (UAVs), appropriate sensors (cameras) installed on them, and remote sensing software, we can assess the condition of the crop very accurately. Of different camera types, conventional RGB and multispectral cameras are the most widely used remote sensing sensors in agriculture. The sensors must be properly calibrated and the images corrected by computer so that agronomically important data can be deduced from them. By measuring the reflection or emission of electromagnetic waves from plants and vegetation, we arrive at estimates of important vegetation and physiological parameters, such as water and nutrient content in the plant, plant height, crop biomass, soil nutrient availability, etc. Vegetation indices are often calculated for data interpretation, among which the NDVI vegetation index is the most widely used. Here, different examples of the use of UAVs and appropriate sensors for the detection of important crop parameters are presented. In addition to describing the advantages of such methods of crop assessment, their shortcomings are also stated. Of the latter, it is particularly important to be aware that different crop and plant conditions can have similar effects on the spectral signature of a given vegetation. In addition to remote sensing, we can also perform some agro-technical measures with UAVs, such as spraying and fertilizing.
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