Abstract: The invention relates to a method for carrying out post-processing on a first set of samples measuring the magnitude of a WASAB1 signal delivered by a magnetic-resonance medical-imaging apparatus. Such a method comprises a step of detecting the samples of a first set Z, for which samples the respective polarities of the values of the measured signal are known, and of constructing a second set Y of “polarised” samples. Such a method further comprises a step of fitting a determined model to said second set Y, the two parameters of the determined model describing the static magnetic field B0 and excitation magnetic field B1 of the magnetic-resonance medical-imaging apparatus, respectively, and of producing an estimation of the parameters B0 and B1 of the model. Such a method relates to any magnetic-resonance-imaging application in which a correction for inhomogeneities in the fields B0 and B1 is required.