Two approaches to the solution of coefficient inverse problems for wave equations

Two approaches to solving coefficient inverse problems for wave equations are compared. One approach is based on integral representations obtained with the help of the Green’s function for the wave equation. In the other approach, the gradient of the error functional is directly computed in terms of the solution of the adjoint problem for a partial differential equation. The methods developed are intended for finding inhomogeneities in homogeneous media and can be applied in medicine diagnostics, acoustic and seismic near surface exploration, engineering seismics, etc.