1. Apparatus for detecting a scene change in a sequence of images, said apparatus comprising: (i) a correlation surface calculating circuit for calculating a plurality of correlation surfaces, each correlation surface representing image correlation between a search block of image data within a current image and portions of a temporally adjacent image displaced by differing displacement vectors from said search block; (ii) a correlation maximum detecting circuit responsive to said correlation surfaces calculated by said correlation surface calculating circuit for identifying correlation maximum points within said correlation surfaces corresponding to maximum image correlation between current image and said temporally adjacent image; (iii) an image correlation quality circuit responsive to correlation values indicative of correlation associated with said correlation maximum points for said current image for generating an image correlation quality value indicative of the degree of correlation between said current image and said temporally adjacent image; and (iv) a comparator for comparing said image correlation quality value with a predetermined threshold value to generate a scene change signal in response to said image correlation quality value being indicative of less correlation between said current image and said adjacent image than represented by said threshold value.