Patent ID: 7587074

Claim:
A method for obtaining a cyclic motion within a series of images depicting a moving object subject to composite motion containing a cyclic motion component having a cyclic period and a non-cyclic consistent component of a lower frequency than the cyclic motion component, the method comprising: a computer performing the steps of: (a) computing the composite motion between at least one pair of successive images, the composite motion represented by at least one vector; (b) computing the non-cyclic consistent component as an integral of the composite motion over the cyclic period; (c) computing a proportional part of the non cyclic consistent component for each of the at least one pair of successive images; and (d) for each of the at least one pair of successive images, subtracting the proportional part of the non-cyclic consistent component from the composite motion so as to obtain the cyclic motion component, wherein the series of images comprises an at least one series of N images acquired during a cyclic period, each frame having an index i within the cyclic period, i=1 . . . N, and wherein the proportional part of the non cyclic component for each of the at least one pair of successive images i-1 and i is determined by dividing the non cyclic component by N and multiplying by i-1.