FIELD: physics; computer engineering.
SUBSTANCE: invention relates to compressing digital multimedia through lapped transform. Efficient lapped transform realised using pre- and post-filters (or reversible overlap operators) composed of unit determinant component matrices, is proposed. Pre- and post-filters are realised as a series of planar rotational transforms and unit determinant planar scaling transforms. The planar scaling transforms can be implemented using planar shears or lifting steps. Further, the planar rotations and planar shears have an implementation as reversible lossless operations, as a result, providing a reversible overlap operator.
EFFECT: more efficient lossless compression/retrieval of data.
18 cl, 15 dwg
