| 摘要 |
<p>In order to reduce the data rate of digital pictures, the picture data are at first transformed batchwise (10), then coded (12) and finally temporarily stored (14) berore their output. A classification factor selected among a plurality of predetermined classes of different local resolutions is assigned (16) to each batch of data, depending on its own picture statistic distribution. The batches of picture data are differently coded (12) according to the class to which they belong. In order to prevent the storage from overflowing, a regulation value is derived (20) from the amount of data temporarily stored, this value being used to modify the amount of data in the batches of picture data. The reduction thus obtained of the amount of data in individual batches of picture data results in a troublesome degradation of the local resolution of one or several batches of picture data. The invention solves this problem, since the assignment of classes to the batches of picture data is modified depending on the regulation value. Although fewer structures are thus resolved, these can be reconstructed with less serious faults and give a better subjective impression.</p> |
