Abstract:The main objective was to analyze the relationship between canopy image parameters and ear morphology parameters of drip irrigated maize in Ningxia. A mathematical method for fitting the growth characteristics of corn ear with crop canopy image parameters was proposed. The dynamic estimation model of ear development during corn filling stage was established to realize the nondestructive monitoring of corn ear morphology based on crop canopy digital image processing technology. The mobile phone camera technology was used to obtain the canopy image of the drip irrigated maize under different nitrogen treatments, and the canopy image parameters of maize filling stage were extracted to determine the morphological parameters such as ear length, ear diameter and ear volume. Correlation analysis was carried out by using R language to find out the normalized canopy cover factor (Cc) as the image feature parameter with high correlation between maize and ear morphological parameters. The Origin software was used to establish an estimation model between Cc and ear morphological parameters, and the accuracy of the model was estimated by R2, RMSE and nRMSE. The results showed that the morphological parameters of Cc and ear length, ear diameter and ear volume of maize satisfied the exponential function, and the prediction accuracy of Cc and ear length was the highest, the coefficient of determination R2 was 0.714, and the prediction accuracy of ear diameter was the second with R2 of 0.601 and R2 of ear volume was 0.575. From the model test and evaluation results, it can be seen that the accuracy of Cc and maize ear morphology parameters was higher, and the R2 was no less than 0.523, the ear volume RMSE value did not exceed 68.986cm3, and nRMSE was no more than 33621%. Therefore, the estimation results of maize ear growth and development based on canopy image normalized coverage coefficient Cc had certain practicality, which can provide reference for estimation of ear shape parameters and non-destructive monitoring of large area maize.
