【摘要】 为了提高时域逆时偏移成像的计算精度,基于辛几何算法能获得半解析解精度结果的特点,结合逆时偏移成像条件构建了时域辛几何逆时偏移成像算法.首先,用有限元软件建立含缺陷结构和未知缺陷结构的有限元离散模型,然后用勒让德变换将二阶微分方程组变换成保辛的一阶微分方程组,用精细积分方法求解该一阶微分方程组;最后,基于逆时偏移成像条件,通过偏移叠加算法获得含缺陷结构的成像结果.结果表明,成像结果与预设缺陷吻合良好,该方法可以精确地检测出结构内部的缺陷.更多还原

【Abstract】 In order to improve the calculation accuracy of timedomain reverse-time migration imaging, based on the characteristics of semi-analytical solution precision results of the symplectic geometric algorithm,we build the reverse-time migration imaging algorithm based on time-domain symplectic geometry combination of reverse-time migration imaging conditions.First of all,we establish finite element discrete model of a structure containing defects and an unknown defect structure by using finite element software,and put the second order differential equations into the first order differential equations with Legendre transformation,and then solve the first-order differential equations with the precise integration method;Finally,we obtain the imaging results of the structure containing defects with the imaging condition of reverse-time migration and migration stack algorithm.The results show that the imaging results are in good agreement with those obtained with the default defect,the method can accurately detect the defects within the structure.更多还原