According to an example aspect of the present invention, there is provided generating, Low-Field-Magnetic Resonance Imaging, LF-MRI, or Ultra-Low-Field Magnetic Resonance Imaging, ULF-MRI, data with respect to an image frame, determining a sensorwise agreement of the data with determined sensitivity profiles, and determining a mapping between the image frame and a sensor frame, such that the sensorwise agreement has been fulfilled.