Image data decoding method and apparatus

摘要

An image data encoding apparatus for encoding continuous image data comprising: reference frame holding means (861) for holding image data of a reference frame; dividing means (862) for dividing the image data of a present frame into a plurality of regions; determining threshold value outputting means (863) for outputting a threshold value to be used to detect the existence of change in the image in the respective block in the respective regions in the present frame from the corresponding image in the respective block in the respective region in the reference frame, each respective regions comprising a plurality of blocks and being provided by the dividing means (862); block change determining means (864) for obtaining the amount of change in the value of the predetermined element in the block of the present frame from the corresponding image element in the block in the reference frame held in the reference frame holding means (861), with regard to the respective blocks in the respective regions of the present frame which are obtained in accordance with the output of the dividing means (862), comparing the amount of change with the threshold value inputted from the determining threshold value outputting means (863) and for determining the existence of change in the image in the respective blocks regarding the respective regions of the present frame from the corresponding image in the block in the reference frame at the same position; encoding means (865) for encoding only a valid block which is determined as having changed the image in the reference frame by means of block change determining means (864); and block information outputting means (866) for outputting the result of the determination as the block information, by the block change determining means (864); wherein the reference frame holding means (861) replaces the block in the reference frame at the same position as the valid block in the reference frame by the valid block of the present frame, based on the result of the determination by the block change determining means (864). <IMAGE>