1. A segmentation unit for assigning a first pixel of a first image of a sequence of images to a segment, comprising a processor configured to perform the acts of: receiving the first image and a second image; assigning a first homogeneity value to the first pixel on basis of the first image and a second homogeneity value to a second pixel of the second image of the sequence of images, the first pixel and the second pixel being related by a motion vector; setting a weighting factor to a high value when a quality of the motion vector is a high amount, and setting the weighting factor to a low value when quality of the motion vector is a low amount, wherein the high value is higher than the low value and the high amount is higher than the low amount; calculating a weighted average homogeneity value using the weighting factor in averaging the first homogeneity value and the second homogeneity value; comparing the weighted average homogeneity value with a threshold; and determining whether the first pixel belongs to the segment based on results of the comparng act.