Cho Seong Hwan, Kim Eung Sung

The Transactions of the Korea Information Processing Society (1994 ~ 2000), Vol. 1, No. 1, pp. 81-91, May. 1994
10.3745/KIPSTE.1994.1.1.81,   PDF Download:

Abstract

A DCT map and new codebook design algorithm based on a two-dimension discrete cosine transform (2D-DCT) is presented for coder of image using vector quantizer. We divide the image into smaller subblocks, then using 2D DCT, separate it into blocks which are hard to code but it bears most of the visual information and easy to code but little visual information, and DCT map is made. According to this map, the significant features of training image are extracted by using the 2D DCT. A codebook is generated by partitioning the training set into a binary tree based on tree-structure. Each training vector at a nonterminal node of the binary tree is directed to one of the two descendants by comparing a single feature associated with that node to a threshold. Compared with the pairwise nearest neighbor (PNN) and classified VQ (CVQ) algorithm, about ''Lenna'' and ''Boat'' image, the new algorithm results in a reduction in computation time and shows better picture quality with 0.45dB and 0.33dB differences as to PNN, 0.05dB and 0.1dB differences as to CVQ respectively.

Statistics
Cite this article