Level set method for edge detection of SAR images of airport roads

Abstract

The invention discloses a level set based method for edge detection of SAR images, which mainly overcomes the defect that the existing methods for edge detection of SAR images can not well suppress the impacts of speckle noises. The method comprises the following steps: (1) inputting the SAR images and carrying out median filtering and brightness transform in sequence to obtain the enhanced images; (2) manually selecting initialized seed points on the enhanced images and beginning area growth; (3) carrying out morphological close operation and removal operation on the area growth result in sequence to obtain the edge profile of the smoothened destination area; (4) obtaining a level set evolved initialized zero level set according to the edge profile of the destination area, which is obtained through area growth; and (5) carrying out level set evolution until the preset iterative evolution frequency is met to obtain the final edge profile of the destination area. The method can effectively overcome the impacts of speckle noises of the SAR images on edge detection, is accurate in edge detection and can be used for edge detection of the SAR images of airport runways and roads.

Description

technical field [0001] The invention belongs to the technical field of image processing and relates to image edge detection, in particular to a level set-based SAR image airport road edge detection method, which can be used for edge detection of synthetic aperture radar images. Background technique [0002] Synthetic Aperture Radar (SAR) is a high-resolution imaging radar. SAR has all-weather, multi-polarization, multi-view, multi-depression angle data acquisition capabilities and the ability to penetrate some ground objects, so it is not only widely used in military, but also in agriculture, meteorology, topography, disaster monitoring and other civil applications. There are also tons of applications. However, since SAR emits coherent waves, these coherent waves undergo coherent effects with ground objects, especially the backscattering effect of ground objects, which causes the target echo signal to attenuate. This attenuation is manifested in the image as coherent speckl...

AI Technical Summary

Problems solved by technology

At present, the level set method is mainly used in the field of medical images. If the level set method is only applied to SAR images, satisfactory results cannot be obtained.

For example, in Professor Li Chunming's article "Level SetEvolution Without Re-initialization: A New Variational Formulation", the level set method is mainly applied to the field of medical images, but when this method is directly applied to SAR images, it cannot effectively overcome the noise band interference, and need to manually input the initialization zero level set, which brings too much unnecessary manual intervention, and ultimately cannot obtain a good edge detection effect

Images