| 摘要 |
<p>PURPOSE:To efficiently access compressed data in accordance with resolution by compressing original picture data efficiently and accumulating them hierarchically. CONSTITUTION:In a cosine conversion part 17-2, a consine conversion is performed to f(m, n)0<=m<=N-1, 0<=n<=N-1 which is the partial picture data (density value) of NXN picture elements. In a hierarchization part 17-3, cosine conversion data F(u, v) are divided into four classes of classes 1-4 in sequence from the one whose space frequency, that is, resolution is low. In a restoration part 9, the cosine conversion data F(u, v) accumulated in an accumulation part 18 are successively read out and the pictures are restored. Here, when retrieving what the accumulated pictures are, the picture of low resolution is first displayed in a short time, and when the picture is identified, the processing is stopped at that time, therefore, they can be retrieved very efficiently.</p> |
