**Wave-equation migration velocity analysis**The inversion solves the problem in Equation (1), where the model is represented by slowness perturbation, and the data is given by the measured image perturbation Biondi and Sava (1999); Sava and Biondi (2000).

**Least-squares inversion**The inversion solves the problem in Equation (1), where the model is the seismic image in the angle-domain, and is the recorded seismic data Prucha et al. (2001); Rickett (2001).

4/16/2001