1. A motion detection apparatus for use with an input image having a plurality of lines and a plurality of pixels on each line, said apparatus comprising: average measurement means adapted to add the value of pixels within at least one first region of a given line to form a region summation and to output the summation at the end of said first region to a signature determination means; and edge measurement means comprising pixel difference means adapted to measure a multitude of difference measures between portions of neighbouring pixels in at least one second region and to forward the absolute values of said difference measures to one of a plurality of storage bins, said storage bins being adapted to receive said absolute value of said difference measures and to determine a new maximum current value being the maximum of a previous current value and said absolute value; wherein said signature determination means is connected to said average measurement means and to said edge measurement means and is adapted to receive a set of determination values comprising said maximum values from said edge measurement means for each of said second regions of a line, and said summation from said average measurement means from said second regions of a line, and to determine a priority value From said determination values and a previously stored set of determination values from a previous input image frame, and storing said determination values.