1. A magnetic resonance imaging (MRI) apparatus comprising: a data processor configured to time-serially perform undersampling on MR signals respectively received by coil channels of a radio frequency (RF) multi-coil to acquire undersampled K-t space data; and an image processor configured to determine noise information of the coil channels, acquire a time-space correlation coefficient, based on the determined noise information of the coil channels, and restore pieces of unacquired line data from the undersampled K-t space data by using the time-space correlation coefficient, to acquire restored K-t space data.