Coastline Detection And Tracing In SAr Images

Images of coastlines generated by Synthetic Aperture Ra-'s) suRer from a n u ~b e r of d e ~c ~e n c ~e s which arise from the f the speckle effect and the strong signal return from a windroughened, Wa~e-mQdu~a~ed sea.The frequent lack of contrast caused by these effects makes coastline detection difficult by most c o n v e n t ~o ~a ~ proced~res such as gray-level thresho~d~ng or segmentation by edge magnitude.This paper describes an algorithm for the global detection of coastlines based on a sequence of basic image-processing procedures and a new edge tracing algorithm.The application of the proposed procedure to Seasat SAR and SIR-B (Shuttle imaging Radar B) images demonstrates that with only a modest c o m ~u ~a ~~o n a ~ burden it produces a good visual match between the detected coastline and the coastline of original image.A d d ~~~o n a l ~y , the separation of land from water achieved by this algor~thm permits clean pseu ocoloring of coastal area images.