3D multiplicative regularized Gauss-Newton inversion

A rigorous three-dimensional (3D) inversion algorithm is presented. A Gauss-Newton minimization approach is employed using a multiplicative cost function. In order to enhance the robustness of the algorithm, a non-linear transformation is incorporated for constraining the minimum and maximum values of the conductivity distribution. A line-search procedure for enforcing the error reduction in the cost function in the optimization process is also employed.