Using the principle of least squares method to automatically obtain the global threshold,based on the histogram of the image grayscale,Otsu algorithm has a certain segmentation of an algorithm for the field Rape.However,its segmentation effect is very poor.The global threshold is obtained for rapeseed by optimal color index,finally it realized the Otsu threshold segmentation of field rapeseed.After experimental verification,by selecting the red index is better for Otsu threshold segme...