1. A computer system for real-time determination of a motion vector of a frame element within an image frame in a stream of video image frames, the stream including at least a first image frame and a second image frame, the system comprising a plurality of operatively connected elements including: an image stream receiver to receive the stream of image frames; an image decomposer to decompose each of the image frames into a plurality of frame elements, each of the frame elements including a plurality of pixels and a plurality of associated pixel values; an image normalizer to normalize the pixel values of the frame elements of each of the image frames thereby yielding a plurality of normalized frame elements having a plurality of associated normalized pixel values; an image processor to apply an image processing filter to one of the normalized frame elements of the first image frame, yielding a filtered frame element having a plurality of associated filtered pixel values; a pixel selector to select a first reference pixel from the filtered frame element, such that the first reference pixel has the highest value of the filtered pixel values; an optic flow module to determine a first optic flow based on an optic flow equation applied at a location of the first reference pixel; a pattern matching module to perform pattern matching between the normalized pixel values of: the one normalized frame element of the first image frame; and the normalized frame elements of the second image frame, being test frame elements, yielding a plurality of pattern matching scores, each of the test frame elements having one of the pattern matching scores, wherein the pattern matching is performed such that for each one of the test frame elements, a displacement vector between a location of the one normalized frame element and a location of the one test frame element is restricted by a region which is at least partially based on the first optic flow; and a motion vector determiner to determine a motion vector at least partially based on the displacement vector associated with one of the test frame elements having a lowest one of the pattern matching scores, wherein the pattern matching module is operative to define the region as being bounded by a first line and a second line, such that: the first line intersects the second line at an intersection; a third line bisects an angle between the first line and the second line; the third line is in a direction based at least partly on a direction of the first optic flow; and the third line and the first line subtend an angle epsilon.