Leaf grading for cotton verticillium wilt based on VFNet-Improved and Deep Sort

Cotton is one of the most important economic crops in the world, and verticillium wilt is the number one disease in major cotton production areas in the world. Verticillium wilt causes the leaves to wilt, fade and even fall off by infecting the roots of cotton, resulting in severe decline both cotton quality and its yield. The national standard divides the leaves suffering from verticillium wilt into five grades. The traditional detection method mainly relies on manual labor, which has problems such as subjectivity, inefficiency, and poor repeatability. The cotton verticillium wilt disease classification method, which is based on VFNet-Improved, Deep Sort, and collision line matching mechanisms as the main algorithm framework, realizes the statistics of the number of diseased leaves and the classification of the disease level under the condition of rotating video input. Based on the VFNet target detection network, the research first combined multi-scale training, dynamic convolution and other optimization methods to achieve accurate positioning of diseased leaves in rotating videos. Then the Deep Sort tracker was used to realize the correlation of the same leaf in the front and back frames, and a mask collision line matching mechanism was designed for the ID jump problem in the tracking process; finally, OpenCV was used to perform feature extraction and disease classification of leaves passing the mask line. The results showed that the VFNet-Improved model could achieve the best effect in the object detection algorithms with 0.906 mAP₇₅, which was 0.012 higher than the VFNet model, and the FPS reached 12.9 frames/s. The tracking result MOTA of the Deep Sort was 0.835. R², RMSE, MAE and MAPE of VFNet-Improved were 0.890, 5.138, 4.300 and 14.967% respectively, which performed high consistency with manual measurements. In conclusion, this study has demonstrated a novel tool for the accurate and efficient evaluation of cotton verticillium wilt, which would be of great significance for the cotton breeding and genetic analysis research.