A scene change detector sums the correlation maximum values of correlation surfaces produced by a motion vector determining circuit (2) across a current image and compares this with a threshold value (Thres) to detect scene changes. A statistical analysis of signals (V.sub.x, V.sub.y, Y) representing the current image may be made and a resulting value differentiated. Peaks in this differentiated value represent scene changes. Finally, rapid changes in the number of valid vectors found in a motion analysis of a current image may also be used to indicate a scene change.