Angle-domain common-image gathers in generalized coordinates

ADCIG theory

The ADCIG theory presented in this section draws from that presented in (). In the ensuing development, $\boldsymbol{x}=[x_1,x_3]$ denotes the Cartesian variables and $\boldsymbol{\xi}=[\xi_1,\xi_3]$ represents a generalized Riemannian coordinate system. I also use a convention where the extrapolation axis is oriented in the $x_3$ ($\xi_3$) direction for Cartesian (Riemannian) coordinates. Coordinates $x_2=\xi_2=0$ are assumed throughout.