基于改进余弦组合窗的解耦方程弹性波逆时偏移

弹性波矢量波场逆时偏移可以综合利用纵横波场信息，对地下空间进行清晰成像，且对于成像介质没有角度限制，可以对复杂构造进行更清晰的成像.而弹性波逆时偏移中最重要的就是求解波动方程的算法，其直接影响成像的精度以及效率.本文引进电力系统谐波分析中常用的余弦组合窗函数，并通过一种新的优化算法得到了改进的余弦组合窗函数从而得到优化后的有限差分算子.并将此算子应用于解耦方程的矢量波场分离算法从而提高了成像精度.数值测试表明基于新算法的逆时偏移的成像精度和清晰度得到了明显的提高.

Elastic wave reverse time migration of decoupling equation based on improved cosine combined window function

The reverse time migration (RTM) of elastic wave vector wave field can comprehensively use the vertical and horizontal field information to clearly image the underground space, and there is no angle limitation for the imaging medium, which can more clearly image the complex structure. The algorithm of solving the wave equation,which affect the accuracy and efficiency of imaging directly is the most important things for RTM. In this paper, the cosine combined window function (CCWF) used in harmonic analysis of power system was introduced. Then we obtained optimal finite-difference schemes based on improved CCWFs. Then a vector wave field separation algorithm based on decoupling equation is introduced to improve the imaging accuracy. Numerical tests show that the imaging accuracy of the reverse time migration based on the new algorithm are significantly improved.