A method of evaluating the quality of a the quality of a match between two digitized images includes providing a pair of digitized images I.sub.1(x,y,z) and I.sub.2(x,y,z), each image comprising a plurality of intensities corresponding to a domain of points (x,y,z) on an 3-dimensional grid, calculating a motion quantification measure from said pair of images, the motion quantification measure |I.sub..DELTA..sup.-| defined by.DELTA..beta..times..times..function..DELTA..function..DELTA..f- unction.< ##EQU00001## wherein the sum is restricted to those I.sub..DELTA.<0, f is a function, .beta. is a constant, N.sup.- is the number of domain points with negative subtraction image values, and wherein I.sub..DELTA.(x,y,z)=I.sub.2(x,y,z)-I.sub.1(x,y,z). The images depict the same object but are acquired at different times.