*2.8. Traditional Crop Lodging Identification Method*

The main process of traditional crop lodging identification is as follows. First, di fferent types of image features—color, spectral reflectance, vegetation index, GLCM texture, and canopy structure—are extracted from RGB and multispectral images. Certain image features are selected, and the optimal features are obtained by using the index method or prior knowledge. Finally, the optimal features and manually selected ROIs are input into the supervised classification model to obtain the recognition results of crop lodging in the plot.

There are three main di fferences between our new proposed method and the traditional method: (1) more image features (compared to less than 20 features in previous studies) are extracted to determine whether they are suitable for maize lodging identification under complicated field environments. (2) Both GLCM texture and GLDM texture are used for maize lodging recognition. In addition, the optimal GLCM and GLDM texture window sizes are determined. (3) The AIC method is used to screen the maize lodging identification features.
