1. A magnetic resonance imaging method for forming a magnetic resonance image, wherein magnetic resonance signals are acquired by means of receiving antennas via a plurality of signal channels, which individual receiving antennas have respective sensitivity profiles, and the noise correlation between individual signal channels is represented by a noise correlation matrix, where the magnetic resonance signals are acquired with sub-sampling, regularly resampled magnetic resonance signals are resampled on a regular sampling grid from the acquired magnetic resonance signals, the noise correlation matrix is approximated by a block diagonal matrix or a band diagonal matrix, the matrix elements situated outside a predetermined band around the main diagonal of the approximated noise correlation matrix have the value zero, and the magnetic resonance image is reconstructed from the regularly resampled magnetic resonance signals which have been sampled from acquired magnetic resonance signals on the basis of the sensitivity profiles and the approximated noise correlation matrix.