Litchi leaf nitrogen, phosphorus and potassium content detection method based on unmanned aerial vehicle multispectral image

The invention relates to the technical field of agricultural detection, and discloses a litchi leaf nitrogen, phosphorus and potassium content detection method based on an unmanned aerial vehicle multispectral image. The litchi leaf nitrogen, phosphorus and potassium content detection method based on the unmanned aerial vehicle multispectral image comprises the following steps: S1, longitudinal image acquisition; s2, acquiring a transverse image; s3, processing the spectral image; according to the method, the litchi plants are subjected to spectral image shooting through the multi-spectral sensor carried by the human beings, then the nitrogen, phosphorus and potassium contents are obtained in a spectral image inversion mode, manual multi-point and multi-time sampling is not needed in the mode, and the defect that time and labor are wasted in a traditional detection method of chemical analysis can be overcome; when spectrum images are collected through the unmanned aerial vehicle, data of images collected at t