An image coding and decoding technology for compressing motion pictures which makes use of critical point filter technology and that includes detection of scene changes to provide more accurate decoding. An image input unit acquires key frames. A scene change detector detects when there is a scene change between key frames, and notifies a matching processor to that effect. The matching processor then skips generation of correspondence data between those key frames. A stream generator generates a coded data stream in a manner that key frames and associated correspondence data are incorporated when there is no scene change, while key frames and associated correspondence disable data are incorporated when there is a scene change. This allows a decoder to more accurately decode the data stream and take account of scene changes.
