1. A system for analyzing a sequence of datasets representing sequential images of an object, a dataset associating data values with positions, the images having an image region having a first border and a second border associated with the object, the system comprising a ray establishing means for establishing for each individual image an analysis ray connecting the first and second border of the image region, the analysis rays being in a respective position representing a substantially same position with respect to the object, wherein the sequential images of the object are a time series of images of a same location of the object, a gradient establishing means for establishing, for each of the individual analysis rays, a gradient value which is representative of a rate of change in the data values along the analysis ray from the first border to the second border.