Sikora, T.T.SikoraBauer, S.S.BauerMakai, B.B.Makai2022-03-032022-03-031995https://publica.fraunhofer.de/handle/publica/18747410.1109/76.401104We introduce a formula to compute an optimum 2-D shape-adaptive Karhunen-Loeve transform (KLT) suitable for coding pels in arbitrarily-shaped image segments. The efficiency of the KLT on a 2-D AR(1) process is used to benchmark two other shape-adaptive transforms described in literature. It is shown that the optimum KLT significantly outperforms the well known shape-adaptive DCT method introduced by Gilge et al. (1989) for coding Segments of arbitrary shape in intraframe coding mode. A statistical transform gain close to the Gilge-method can be achieved with a shape-adaptive DCT algorithm introduced by Sikora and Makai (see Proc. Workshop Image Anal. Image Coding, Berlin, FRG, Nov. 1993) which is implemented with much lower complexity.enadaptive signal processingdiscrete cosine transformsimage codingimage segmentationtransform codingtransformskarhunen-loeve transformarbitrarily shaped image segmentsshape-adaptive 2-d transformskltshape-adaptive dct methodintraframe codingstatistical transform gainshape-adaptive dct algorithmlower complexityefficiency621journal article