1. A method for characterizing an anomaly in a material, the method comprising: extracting contrast data; measuring a contrast evolution; filtering the contrast evolution; measuring a peak amplitude of the contrast evolution; determining a diameter and a depth of the anomaly, wherein determining the diameter and the depth of the anomaly called direct depth estimation comprises: calculating a multiplier M and a flaw size parameter A c using an amplitude constant C A equal to one for a first iteration of determining the diameter and the depth of the anomaly and for subsequent iterations of determining using an amplitude constant derived from an amplitude constant calibration curve; calculating an adjusted diameter to depth ratio γ′; estimating the depth of the anomaly using a diameter constant C D equal to one for the first iteration of determining the diameter and the depth and for subsequent iterations of determining using a diameter constant derived from a diameter constant calibration curve; estimating the diameter of the anomaly; comparing the estimate of the depth of the anomaly after each iteration of estimating to the prior estimate of the depth of the anomaly to calculate a change in the estimate of the depth of the anomaly; and repeating the step of determining the diameter and the depth of the anomaly until the change in the estimate of the depth of the anomaly is less than a set value.