| There are some prominent merits of GPR (Ground Penetrating Radar) technique ingeophysical exploration and shallow surface surveying, such as speediness, non-destructiveness,high accuracy, etc. Now, it has been one of the most potential techniques for shallow surfaceremote sensing. At present there are lots of studies on it worldwide, but the practicality of GPRin China is not satisfactory due to some key techniques including data acquisition, dataprocessing and visualization, etc.In combination with the Ministry of Science and Technology and Jiangsu Province’sinternational cooperative research projects, in this thesis deep research are put on some keyprocessing techniques, such as the scattering modeling, target recognition and extraction, areasurvey, visualization of underground pipeline, and integration with the3S technology, etc. Thestudy goal is to improve the measurement efficiency and accuracy and data management andexpression level. The main works and innovations of this thesis are listed as follows:1. A summarization of GPR technology was given on the current status. And an analysis wasmade on the remote sensing characteristics of the underground targets, and the basic principlesand processes of GPR detection and imaging. Based upon the analysis, the significance for GPRin the shallow surface surveying and mapping was clarified.2. Using2D and3D finite difference time domain method simulation of radar wave in thelossy medium propagation process based on classical Maxwell equations. And scatteringmodeling and imaging tests were carried out on typical underground targets. GPR detection incomplex terrain and high-loss media was molded and tested. The correctness of high loss modelscattering modeling and imaging was verified. A method GPR data processing methodconsidering topographic correction was proposed, based on the analysis of topographic factorsinfluence on radar profile image.3. The hyperbolic characteristics underground pipeline imaging model was established forB-scan radar data. It provides a theoretical foundation for the radar data interpretation andquantitative detection of pipeline. A hyperbolic underground pipeline extraction method based ongeneralized Hough transform was proposed. The mathematical model between the radarreflectivity wave and diameter of the pipeline was established. Two diameter measurementmethods based on hyperbolic fitting and interval of repeatedly reflected waves were verified.4. The complete regional measurement programs of GPR was designed based on quantitativeanalysis of the survey line spacing, survey point spacing in GPR area survey. Athree-dimensional reconstruction based on the sequence of the B-scan image was proposed for underground targets.5. A three-dimensional data integration model for the pipeline network was proposed basedon space distribution characteristics of the underground pipeline network. Visual modeling andthree-dimensional display of the various elements of the pipeline was achieved based on thecomprehensive utilization of the COM (component object model), the GDAL (Geospatial DataAbstraction Library) technology. A vertex blending based pipeline smoothing method wasproposed convergence to improve the three-dimensional visualization of the pipeline elements.6. The3S technology was integrated to GPR data acquisition, expression and management.The method of area survey with GPS supporting was designed. A prototype system ofunderground pipeline network detection data processing and visualization was designed andimplemented. Some sorts of GPR equipment for the underground pipeline detection and dataprocessing were used, such as, the Italy RIS-type, the Canada Pulse EKKO type, etc. Thereliability of the prototype system was validated by these measurements. |
