Study Of Stable Point Targets Detection And Its Application

With the advantages of All-weather,wide coverage,high accuracy and low cost in acquiring the seismic deformation field,Time-Series Interferometric SAR has develop rapidly and has been a hot topic in the field of international remote sensing currently. The conventional DInSAR technique is vulnerable to be affected by loss coherence of interferograms and atmospheric retardation.In order to overcome the problem of DInSAR technology,Time-Series Interferometric SAR detect and analyse the highly-coherence targets.The identification and selection of stable point target is a major subject for Time-Series Interferometric SAR.Today the methods of detecting stable point target require high professional competence.The technology should set up thresholding manually and it bring obstacle to the textension of time-Series Interferometric SAR and make the result of ground deformation monitoring unstable. With the improvement of the radar technology, radar image gradually step into the age of high resolution SAR image and it brings new inspiration to detecting stable point target.Based on the deep understanding of the time series InSAR technology theory, this article focuses on the methods of detecting stable point target for high resolution SAR image automaticly.Specific studies include the following:1) Make a study of the characteristic of the stable point target and summarize the interpretation of high resolution SAR images and introduct the algorithm and process of three classical stable point target detection methods. Based on the three-thresholding method, three-thresholding half-automatic method for Stable point target detection which could set thresholdings automatically was proposed in the paper. According to the correspondence between the persistent scatterer and the target feature, typical artificial construction areas were selected as the PS point region,while typical territorial water areas or farmland areas were selected as the non-PS region.Analyzing all of the pixels in the PS point region and the non-PS region,the suggested method could judge the optimal combination of the correlation coefficient thresholding and amplitude dispersion index thresholding.2) The experiments of stable point target detection by three-thresholding half-automatic method ware performed using 25 high resolution TerraSAR-X images. With summarizing the results of the experiments,it confirms the suggested method showed an effective way of judging the thresholdings optimal combination.3) We apply the suggested method and retrieve the surface subsidence of Beijing from June,2011to July,2015 by using 23 high resolution TerraSAR-X images of Beijing’s main urban area. The precision testing for the surface subsidence results used 13 leveling data of Beijing from 2012 to 2015.The precision testing results showed that the maximum of error was 8.77mm/year and the minimum of error was-5.36mm/year and the root mean square error was 4.30mm/year.It shows a good agreement with historical data and verifies the validity and reliability of this method.