Inst. fuer Theor. Nachrichentech. and Informationsverarbeitung, Hannover Univ.
IEEE Trans Image Process. 1992;1(1):111-6. doi: 10.1109/83.128036.
The general conditions of exact reconstruction and a recursive design procedure for lapped orthogonal transform (LOT) with arbitrary length of overlapping are presented. It is shown that LOT can be realized with any standard block transform, discrete cosine transform (DCT), for example, and an additional processing. This processing must also satisfy the same conditions for exact reconfigurations and it may be pretransform processing in the time domain or post-transform processing in the transform domain. In a few examples it is shown that the LOT has a higher coding gain and smaller blocking effects then DCT. With the proposed LOT design procedure, two optimizations, the coding gain maximization and the blocking effect minimization, are presented and compared.
提出了重叠任意长度的正交拉普拉斯变换（LOT）的精确重构的一般条件和递归设计过程。结果表明，LOT 可以用任何标准的块变换（例如离散余弦变换（DCT））加上额外的处理来实现。这种处理也必须满足精确重构的相同条件，它可以是在时域中的预变换处理，也可以是在变换域中的后变换处理。在一些例子中，表明 LOT 比 DCT 具有更高的编码增益和更小的块效应。利用所提出的 LOT 设计过程，提出并比较了两种优化，即编码增益最大化和块效应最小化。
