محمدرضا تابان، محمد مهدي نقش

1397/10/19

كتابنامه

برق و كامپيوتر

مهندسي برق و كامپيوتر

ID12883

Analysis and Improvement of Void Detection via Ground Penetrating Radar Mahdi Jahani Hosein Abadi m jahani@ec iut ac ir September 18 2018 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree Master of Science Language PersianSupervisor Dr Ehsan Yazdian yazdian@cc iut ac irr Supervisor Dr Seyed Mahmoud Modarres Hashemi Modarres@cc iut ac ir Advisor Dr Reza Ahmadi r ahmadi@arakut ac ir Abstract Ground penetrating radar is a high resolution geophysical method which uses the reflections of radio waves emitted tothe earth to depict structures and objects under the ground All of the materials under the surface have certain electromagnetic properties that indicate their electromagnetic radi ation permeability The electromagnetic wave that returns from the earth contains information such as dielectric constant magnetic permeability and electrical conductivity of objects inside the earth which construct the frequency equation of thereflected wave Changing the electromagnetic characteristics of different layers in the ground results in a change in the powerreturned to the radar receiver These changes are visible in the radar receiver by changing the brightness of the constructedimage In this research to investigate the effect of different parameters of target such as shape size and dimensions depthand physical properties of the host environment on the receiver radar signal The GPR responses of many types of objectsare evaluated in geotechnical applications Also the GPR responses are simulated in three software environments Reflexwsoftware Gprmax and extended numerical of finite difference in MATLAB Comparing these methods we have shownthat the extended finite difference numerical simulation method has more clear response to the ceil and floor of targets Also using the hyperbolic mathematical equations we have been extracted the relationships between geometric parametersof a horizontal cylindrical objective with parameters of GPR response Hence we have obtained the linear relationshipsbetween changes in diameter and depth of the cylindrical target and the dielectric passage rate of the host environment Thisrelationships can be used to determine the geometric characteristics of buried cylindrical targets under the ground surface Finally we examine the mathematical and theoretical results using the idea behind the Hough transform to detect hy perbolic response of voids and propose an algorithm which reduces the processing time comparing with the current methodswhich can accurately measure the radius depth and distance of targets We also examined the proposed algorithm for realdata which yielded desirable results The proposed algorithm is designed in such a way that all stages of the identificationand estimation of the geometric parameters of buried objects are automatically estimated with minimal user intervention Key Words Ground penetrating radar GPR Void Hough transform Forward modeling the geometric characteristics of cylindrical voids

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محمدرضا تابان، محمد مهدي نقش