A method of evaluating the quality of a deformation field includes providing a deformation field from a first domain to a second domain, where a deformation field .PHI.=(.phi..sub.x,.phi..sub.y,.phi..sub.z) that transforms a point (x,y,z) in the first domain to a point (X,Y,Z) in the second domain is defined by.PHI..function..function..PHI..function..function..PHI..function..funct- ion. ##EQU00001## where u.sub.x, u.sub.y, u.sub.z are displacement fields, and calculating a quality factor as a function of the of the displacement fields and the Jacobian matrix D.PHI.(x,y,z) of the deformation fields. The quality factor is a measure of the quality of said deformation field.