| 摘要 |
<p>PURPOSE:To attain a reversible coding applicable to a function required for a filing device by constituting a bit plane for each bit of a picture data, and dividing the result into plural hierarchical image data groups. CONSTITUTION:A memory 1 stores a digital picture having n-bit-gradations. A bit plane division part 2 divides picture data into n-pieces of bit planes in the unit of bit, and further divide thus generated bit planes into hierarchical picture data groups constituted of plural bit plane classes of plural, for instance, n-pieces of and m-pieces of bit planes among the n-pieces, to produce picture data having 2<k>-gradations and 2<m>-gradations independent of each other. Thus divided data are stored in hierarchical picture data storage part 3a, 3b. Coding parts 4a, 4b converts a reference value and a gradation difference to entropy codes. Thus coded data are stored in a code data storage memory 5.</p> |
