A method for the eddy current inspection of a part, the method comprising: applying a plurality of multifrequency excitation signals to an eddy current probe to induce eddy currents in the part being inspected and generate a plurality of multifrequency response signals, wherein the plurality of multi-frequency response signals are included in a multi-frequency response dataset; performing a multifrequency phase analysis on the multifrequency response signals to inspect a subsurface of the part; wherein performing the multifrequency phase analysis comprises: identifying a reference dataset from the multi-frequency response dataset, wherein the reference dataset comprises at least two frequency response signals (x 1 (t), x 2 (t)), and wherein the at least two frequency response signals comprise distinct frequency ranges (f 1, f 2); mixing the at least two frequency response signals of the reference dataset to determine a plurality of processing parameters (k d (t), k n (t)); and applying the processing parameters to the multifrequency response signal dataset to generate a noise-filtered dataset; and performing a phase analysis on the noise-filtered dataset, wherein the phase analysis comprises obtaining phase information and magnitude information associated with the noise filtered dataset; wherein each of the frequency response signals of the reference dataset comprises a real component and an imaginary component, and wherein mixing the at least two frequency response signals (x 1 (t), x 2 (t)) comprises rotating the phase of at least one (x 2 (t)) of the at least two frequency response signals and subtracting a first frequency response signal (x 1 (t)) from a rotated and scaled second frequency response signal (x 12 (t)). applying a plurality of multifrequency excitation signals to an eddy current probe to induce eddy currents in the part being inspected and generate a plurality of multifrequency response signals, wherein the plurality of multi-frequency response signals are included in a multi-frequency response dataset; performing a multifrequency phase analysis on the multifrequency response signals to inspect a subsurface of the part; wherein performing the multifrequency phase analysis comprises: identifying a reference dataset from the multi-frequency response dataset, wherein the reference dataset comprises at least two frequency response signals (x 1 (t), x 2 (t)), and wherein the at least two frequency response signals comprise distinct frequency ranges (f 1, f 2); mixing the at least two frequency response signals of the reference dataset to determine a plurality of processing parameters (k d (t), k n (t)); and applying the processing parameters to the multifrequency response signal dataset to generate a noise-filtered dataset; and performing a phase analysis on the noise-filtered dataset, wherein the phase analysis comprises obtaining phase information and magnitude information associated with the noise filtered dataset; wherein each of the frequency response signals of the reference dataset comprises a real component and an imaginary component, and wherein mixing the at least two frequency response signals (x 1 (t), x 2 (t)) comprises rotating the phase of at least one (x 2 (t)) of the at least two frequency response signals and subtracting a first frequency response signal (x 1 (t)) from a rotated and scaled second frequency response signal (x 12 (t)). identifying a reference dataset from the multi-frequency response dataset, wherein the reference dataset comprises at least two frequency response signals (x 1 (t), x 2 (t)), and wherein the at least two frequency response signals comprise distinct frequency ranges (f 1, f 2); mixing the at least two frequency response signals of the reference dataset to determine a plurality of processing parameters (k d (t), k n (t)); and applying the processing parameters to the multifrequency response signal dataset to generate a noise-filtered dataset; and performing a phase analysis on the noise-filtered dataset, wherein the phase analysis comprises obtaining phase information and magnitude information associated with the noise filtered dataset; wherein each of the frequency response signals of the reference dataset comprises a real component and an imaginary component, and wherein mixing the at least two frequency response signals (x 1 (t), x 2 (t)) comprises rotating the phase of at least one (x 2 (t)) of the at least two frequency response signals and subtracting a first frequency response signal (x 1 (t)) from a rotated and scaled second frequency response signal (x 12 (t)).