Enlargement and reduction of image/video via discrete cosine transform pair, part 2: reduction

bstract. Based on the novel matrix representations of the forward hree-dimensional (3-D) discrete cosine transform (DCT) and the nverse 3-D DCT, applications for reduction of sequence/image/ ideo are proposed. The original sequence/image/video is divided nto subunits, and then the reduction is implemented in the requency-domain by DCT. Two efficient algorithms are presented in ccordance with two kinds of reducing multiples, 1/s and o1 /o2, espectively. The proposed algorithms significantly eliminate ripple nd blocky effects. As a result, they can provide numerous applicaions in data compression as well. Simulation results show that proosed mechanisms enable good performances for reductions of seuences, images, and videos as expected. © 2007 SPIE and S&T. DOI: 10.1117/1.2804712