| 摘要 |
<p>An image indexing system comprising a video frame store, an averager which provides a first signal indicative of the average brightness level of each frame stored, an image splitter and averager which divides each frame into contiguous blocks of pixels, and provides for each block, a second signal indicative of its average brightness level, a comparator which compares each of the second signals with the first signal so as to produce in respect of each block a binary signal indicative of whether or not its brightness level, as indicated by the first signal, is greater or less than the average brightness level for the frame as indicated by the first signal, thereby to produce for each frame, an index signal comprising one binary bit for each block which serves to identify each frame for indexing purposes.</p> |
