Fk Filtering Technique For Gpr

Being used to detect the underground objects, Ground Penetrating Radar (GPR) can't be avoided to receive a lot of clutter which often take much energy and serious trails. All of these clutter may cover the signals reflected from the objects, thus it is difficult to detect and discriminate the objects. How to remove and reduce these clutters is the first task in signal processing of GPR. If these clutters can't be suppressed effectively, the next processing tasks such as imaging, detecting and discrimination, media delamination won't go well. In this thesis, for suppressing the direct wave clutter in various environment and the clutter reflected from objects on the ground or in the air, we studied the methods thoroughly, and the clutter were suppressed effectively.Starting from the GPR scan mode, the basic theories about frequency wavenumber (FK) were introduced. For the GPR data, the thesis analyzed the differences between direct wave and target signals in the FK domain. Based on it, a model was built and the basic FK filtering theory was introduced.It has been taken into account that the direct wave reflected from the fluctuant surface. Firstly, the influence to the FK transform of received signals exerted by the magnitude of fluctuant surface was analyzed quantificationlly. Secondly, based on the theory of FK filtering design, the method of designing 2-D FK bandstop filter with Hann window and Kaiser window for the fluctuant surface was proposed. Finally, comparing with RLS algorithm, the actually measured data in GPR was exploited and testified. The experimental results and performance evaluation indicated the 2-D FK filter could suppress the clutter more effectively.The influence of the clutter reflected from objects on the surface or in the air has been studied also. Based on the apparent velocity, the thesis introduced the filtering theory of this clutter. For the characteristics of different objects, different mathematical models were proposed, then a 2-D slice filter was designed. To testify the efficiency of the filter, the data of EKKO GPR was exploited. The experimental results and performance evaluation indicated the filter could suppress the clutter effectively. Finally, some improvements about FK filter were proposed, and the effectiveness of the improved FK filter was tested by a set of real data.