1. A method, comprising: accessing a combined signal evolution associated with relaxation of nuclei in an item that has experienced nuclear magnetic resonance (NMR) excitation, where relaxation information from which the combined signal evolution is derived is present in a first series of magnetic resonance (MR) images of the item and in a second series of MR images of the item, the first series of MR images having a first scale and the second series of MR images having a second, different scale, and where the first series of MR images and the second series of MR images were acquired from the item after the NMR excitation; and controlling a computer to compute a value for an NMR relaxation parameter for the item, where the computing is based on a computerized matching of the combined signal evolution to a set of combined comparative signal evolutions.