A novel ship detection method for SAR images based on nonlinear diffusion filtering and Gaussian curvature

This letter takes account of the radiation feature of ships in SAR images and proposes a novel automatic approach to achieve high ship–sea contrast for ship detection. The proposed method consists of two steps. Nonlinear diffusion filtering is used to produce a smooth image, a regular surface. After the filtering process, the Gaussian curvature of the regular surface is calculated using the coefficients of the fundamental form defined on the surface. The variational level set method is applied to locate reflective small regions in the revised Gaussian curvature matrix. In this manner, ships on the sea area are detected. Experimental results show that the proposed method can accurately detect targets from the surrounding sea clutter.