Fresnel zone wavepath tomography

摘要

In the present paper, an inversion algorithm using Fresnel zone wavepath in the space-time domain is proposed. Fresnel zone wavepath is a frequency dependent function and when the frequency is low, the Fresnel zone wavepath becomes wide. On the other hand, when the frequency is high, the Fresnel zone wavepath becomes narrow. In the high frequency, Fresnel zone wavepath becomes similar to the ray path. In the application of Fresnel zone wavepath to tomography inversion, a ray tracing procedure is unnecessary. A case of sparse data shows that the inversion result using Fresnel zone wavepath is better than that using the ray path.We also propose several techniques to enhance the inversion results based on Fresnel zone wavepath. These include the first Fresnel zone restriction, the hybrid inversion and the polychromatic wavepath. From the computational studies by synthetic data, we conclude that the above mentioned techniques provide enhancement in the inversion result.