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 ima ge directly in the DCT domain. The transform matrices have been selected to minimize an optimization problem which is a function of the visual quality o f down-sampled images obtained using the matrices and the computational comp lexity associated with using the transform matrices. The transform matrices comprise a row transform matrix and a column transform matrix. A down-sample d 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 trans form matrix and then determining the down-sampled image as the product of th e intermediary matrix and the transform matrix not already used to determine the intermediary matrix.