Diffraction originating from small-scale bodies is treated as noise in routine processing;however,it contains much information about the small-scale geological bodies,which may improve the resolution of the image.The first step of diffraction imaging is separating diffraction from the full record,since the energy of the diffraction is much weaker than the reflection.In this paper,the authors studied diffraction imaging which was separated directly on shot gather by using SVD algorithm.Compared with other separation methods,the theory and achievement of the separation directly on shot gather are easier.Numerical results show that SVD can separate diffraction from the full record well,even when noise is added to the data.The key of the method is to solve the problem as to which parts of the singular values should be intercepted while the remains could be used to reconstruct the wave-field,which requires testing various kinds of data.The results of the diffraction wave imaging are useful for the identification of small-scale geological bodies,and integrating diffraction wave imaging results with full wave imaging results can lead to a better interpretation.
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