| 摘要 |
<p>PURPOSE:To obtain high compressing efficiency even when a change in a time direction is large by setting a forecasting coefficient so that forecasting error can be made small corresponding to the size of the change in the time direction and preventing transform in the time direction from being executed in three-dimensional discrete sine transform when the change is larger than a set condition. CONSTITUTION:After encoding the picture element signal train of a three-dimensional block obtained from a source picture stored in a first storing means 1, the signal train is compared with a forecasting signal train forecasted based on the picture element signal train of the already restored three-dimensional block, and the difference becomes a forecasting error train. Concerning the value of each picture element in the three-dimensional block, an evaluating means 9 evaluates how much the change is in the time direction, and corresponding to the size of the change, the forecasting coefficient is adaptively set so that the forecasting error can be made small. When the change in the time direction is larger than the set condition, the transform in the time direction is prevented from being executed in the three-dimensional discrete sine transform. Thus, even concerning a picture with the large change in the time direction, the compressing efficiency can be prevented from lowering.</p> |
