The invention relates to a device and method for estimating defects potentially present in an object comprising an outer surface, wherein the method comprises the steps of: a) illuminating the outer surface of the object with an inductive wave field at a predetermined frequency; b) measuring an induced wave field ({right arrow over (H)}) at the outer surface of the object; c) developing from the properties of the object's material a coupling matrix T associated with a depth Z of the object from the outer surface; d) solving the matrix system ( [ H → 0 → 0 → ] = T · J → ) to determine a vector ({right arrow over (J)}) at depth Z; e) extracting a sub-vector ({right arrow over (J)}S) from the vector ({right arrow over (J)}) corresponding to a potential defect on the object at depth Z; and f) quantitatively estimating the potential defect from the sub-vector ({right arrow over (J)}S) at depth Z, wherein the method is performed using a computer or processor.