| 摘要 |
<p>PURPOSE:To enhance the efficiency by encoding only an effective block in which there is a variation in the same position of the previous image and the present image and omitting code data in the whole image, and also, to prevent deterioration of the picture quality by deciding it to be a scene change, when the effective block is above a threshold, and encoding the whole image. CONSTITUTION:Image data is written in a buffer 11, and thereafter, sent to a variation deciding part 13 by one block each, compared with a reference image of a reference frame holding part 12, its variation is compared with a threshold of a discriminating threshold holding part 14, and a result of deciding whether it is an effective block or not is inputted to an information holding part 16. Subsequently, only the effective block is encoded by an encoding part 19, and on the other hand, the number of effective blocks of one frame is counted by a counting part 15, and when it exceeds a threshold of a scene change discriminating threshold holding part 17, it is devided to be a scene change frame and all the blocks are changed to the effective blocks and encoded. In such a way, the block which is scarcely varied is not encoded and the efficiency is enhanced, and also, even at the time of scene change, deterioration of the image can be prevented.</p> |
