| 摘要 |
PURPOSE:To store the pictures in their high quality maintained by reversibly compressing some pictures of the inactive data via a selection means with other pictures undergoing the reversible expansion and transferring these pictures to a 2nd storage means after the irreversible compression when the reversible compression data stored in a 1st storage means becomes inactive. CONSTITUTION:The specific one of pictures equivalent to the inactive data that should be kept in a reversible compression state is decided by a preset or prescribed algorithm. Otherwise a selection means 8 performs a control operation under the conditions set with a proper operation performed based on the judgement of an operator. Thus some pictures equivalent to the inactive data which are transferred to a 2nd storage means 7 from a 1st storage means 6 are kept in a reversible compression state. Meanwhile other pictures equivalent to the inactive data are all reversibly expanded and irreversibly compressed and then transferred. In such a constitution, a small picture of a matrix like a CT image, for example, that is read out of a data base 2 and sent to a work station 3 for display can be stored for a fixed period in high quality. |
