Investigation On InSAR Phase Unwrapping Based On Path-following Approach

Phase unwrapping is the most difficult step in the InSAR data processing, The pros and cons of the algorithm directly affects the accuracy of the final DEM or ground deformation information obtained by In SAR. So how to improve the accuracy of phase unwrapping algorithm is the key point. The research mainly uses four kinds of path tracking method: branch method, quality map guidance algorithm, mask cut method and network planning method.then carrys on the simulation experiment using the four method. On the basis, the theory knowledge of path tracing method is studied and analyzed. The improved branch method can effectively change the isolated island phenomenon, which is easily formed by the traditional branch method. Compared to traditional mehod e=243.9, the improved branch method has certain advantages, e=253.9;While using the quality map guidance algorithm, e=352.4, but e=263.4 when the quality map guidance algorithm is combined with the three B- spline fitting method; The e=246.4 using new mask cut method which is combined by the improved branch cut algorithm and the quality guided phase unwrapping algorithm; The e=562.3,after using Snaphu method which has been a mature algorithm. When the SNR of the image is low, the results using Snaphu method is not satisfactory, but the e=263.3 after combining TMLS with Snaphu method. In comparison, the mehod combined by the TMLS and Snaphu has the highest accuracy, but its operation time is 15 s, which is relatively long.The branch method has the fastest operation time, 2s, but its precision is the lowest. On the basis of the comparison and analysis of the algorithm and the improved algorithm of the path tracking, D-InSAR is used to deal with the 6 scene ALOS images of a mining area in our country. In the data processing, the mehod combined by TMLS and Snaphu is used for phase unwrapping. And the validity and reliability of the method is verified in the process of extracting the surface deformation of the mining area, so the research of phase unwrapping has important theoretical and practical application value. It is expected that the research can help to extract the ground elevation and deformation information, also proved that In SAR technology has great advantages and potential.