1. A method, comprising: acquiring magnetic resonance data for an area of interest of a subject that is associated with at least one physiological activity of the subject, wherein acquiring the magnetic resonance data comprises Cartesian sampling, and wherein the Cartesian sampling comprises Cartesian k-space measurement wherein undersampling is performed in a phase encoding direction and k-space is fully sampled or oversampled in a readout direction; and performing image reconstruction comprising Kalman filtering or smoothing on Cartesian images of a Cartesian dynamic image series associated with the acquired magnetic resonance data, wherein the image reconstruction comprises increasing at least one of spatial or temporal resolution of the Cartesian images, and wherein a direct one-dimensional Fourier transform is performed along the readout direction and a Kalman filter is applied for the image reconstruction along the phase encoding direction.