Seismic waves generated in elastic media by ellipsoidal cavities driven by low frequency pressure can be solved by Eshelby′s method. In this paper we prove that this method, originally presented for elastostatic elli...Seismic waves generated in elastic media by ellipsoidal cavities driven by low frequency pressure can be solved by Eshelby′s method. In this paper we prove that this method, originally presented for elastostatic ellipsoidal inclusion problems, can also be applied to dynamic problems on the assumption that wavelengths are much longer than the dimensions of cavities. Comparison between the approximate solution for spherical cavities and its relevant precise solution shows that this method may be used for radii of cavities smaller than 100 m and for frequencies below 10 Hz. By this approach we show that, for low frequency seismic waves in the far field an explosive load on an ellipsoidal cavity can be equivalent to three dipoles oriented along the principal axes of that cavity. Seismic radiation patterns are given analytically and results thus obtained show that an explosion detonated in an ellipsoidal cavity may radiate significant S waves.展开更多
Zernike moments (ZMs) are a set of orthogonal moments which have been successfully used in the fields of image processing and pattern recognition. A combination of edge blurring with ZMs computation was introduced. In...Zernike moments (ZMs) are a set of orthogonal moments which have been successfully used in the fields of image processing and pattern recognition. A combination of edge blurring with ZMs computation was introduced. In this study, several kinds of artificial binary stripe images were used to investigate the effects of edge blurring on the absolute mean error of reconstructed image from high-order ZMs. After the blurring process, the reconstruction errors were increased dramatically at edge pixels, but decreased on non-edge pixels. The experimental results demonstrated that 2-pixel blurring approach provided better performance for reducing reconstruction error. Finally, a template matching between two real images was simulated to illustrate the effectiveness of the proposed method.展开更多
In this paper,we advanced a new fast algorithm of 2-D moment in-variant based on image projection,by means of projection transformation it can com-press the information of a 2-D image into 1-D information.Thus,the amo...In this paper,we advanced a new fast algorithm of 2-D moment in-variant based on image projection,by means of projection transformation it can com-press the information of a 2-D image into 1-D information.Thus,the amount ofcomputation and data size are decreased greatly and,moreover,the projection trans-formation,which is merely an operation of additions,is easier to be achieved onhardwares.The results of computer simulation proved the correctness and quicknessof our method.展开更多
文摘Seismic waves generated in elastic media by ellipsoidal cavities driven by low frequency pressure can be solved by Eshelby′s method. In this paper we prove that this method, originally presented for elastostatic ellipsoidal inclusion problems, can also be applied to dynamic problems on the assumption that wavelengths are much longer than the dimensions of cavities. Comparison between the approximate solution for spherical cavities and its relevant precise solution shows that this method may be used for radii of cavities smaller than 100 m and for frequencies below 10 Hz. By this approach we show that, for low frequency seismic waves in the far field an explosive load on an ellipsoidal cavity can be equivalent to three dipoles oriented along the principal axes of that cavity. Seismic radiation patterns are given analytically and results thus obtained show that an explosion detonated in an ellipsoidal cavity may radiate significant S waves.
文摘Zernike moments (ZMs) are a set of orthogonal moments which have been successfully used in the fields of image processing and pattern recognition. A combination of edge blurring with ZMs computation was introduced. In this study, several kinds of artificial binary stripe images were used to investigate the effects of edge blurring on the absolute mean error of reconstructed image from high-order ZMs. After the blurring process, the reconstruction errors were increased dramatically at edge pixels, but decreased on non-edge pixels. The experimental results demonstrated that 2-pixel blurring approach provided better performance for reducing reconstruction error. Finally, a template matching between two real images was simulated to illustrate the effectiveness of the proposed method.
文摘In this paper,we advanced a new fast algorithm of 2-D moment in-variant based on image projection,by means of projection transformation it can com-press the information of a 2-D image into 1-D information.Thus,the amount ofcomputation and data size are decreased greatly and,moreover,the projection trans-formation,which is merely an operation of additions,is easier to be achieved onhardwares.The results of computer simulation proved the correctness and quicknessof our method.
基金河北省自然科学基金(the Natural Science Foundation of Hebei Province of China under Grant No.A2006000941)河北省教育厅2006年科研计划(No.2006408)河北省科学技术研究与发展指导计划(No.072135142)。
