As one of the classic threshold methods for image segmentation

Otsu algorithm has been widely applied in image processing. Based on the analysis of the original 2D Otsu which has the disadvantages such as histogram area partition and time consuming

this paper introduces a new method of area partition in terms of speckle noise in SAR images

and brings forward a new rule of threshold selection which fits the image model better. The experiments show that the segmentation effect of the improved algorithm is better and its computational speed has been greatly improved.