Method for shimming a magnetic field in an examination space of a nuclear magnetic resonance apparatus including use of fuzzy logic

摘要

Nuclear magnetic resonance signals are multiply excited and a plurality of data sets corresponding to the nuclear magnetic resonance signals are obtained and are used for calculating the coefficients of a spherical harmonic function that describes the magnetic field distribution in the examination space. Each data set acquired in this way has a weighting that correlates with the plausibility (reliability) of the data set allocated to it. Taking the respective weighting into consideration, coefficients of the spherical harmonic functions are acquired from the data sets acquired and are used to calculate respective currents that are supplied to the corresponding shim coils.