METHOD AND DEVICE FOR DOWN-SAMPLING A DCT IMAGE IN THE DCT DOMAIN

摘要

A method and device that uses transform matrices to down-sample a DCT image directly in the DCT domain. The transform matrices have been selected to minimize an optimization problem which is a function of the visual quality of down-sampled images obtained using the matrices and the computational complexity associated with using the transform matrices. The transform matrices comprise a row transform matrix and a column transform matrix. A down-sampled image is produced by determining an intermediary matrix as the product of the DCT image and one of either the row transform matrix or the column transform matrix and then determining the down-sampled image as the product of the intermediary matrix and the transform matrix not already used to determine the intermediary matrix.