Research notes on N status diagnosis of ramie by using digital image technology

For achieving the rapid diagnosis of ramie (Boehmeria nivea L.Gaud) nitrogen content，three nitrogen levels of ramie were planted in pots, and the standard images and the nitrogen content of ramie leaves were obtained respectively by using the information technique and the conventional method at different growth stages. Leaf images were processed by ramie leaf digital image processing software, and color features of leaf images were extracted. The relationship between color features and nitrogen contents were analyzed. The results show that most of the extracted color features are significantly correlated with total nitrogen contents of ramie leaves. Six regression models are built by using the selected color features to predict the total nitrogen contents of ramie leaves at each growth stage, and the average prediction accuracies are from 75.95% to 91.50%. Therefore, digital image processing technology can be used to diagnose total nitrogen status of ramie.