Efficient DCT-based image retargeting in compressed domain

With the increasing requirement of efficient image retargeting, many algorithms have been proposed for adapting images contents to various display settings. However, most of these algorithms work in spatial domain of raw images. Since images are mostly stored in DCT-based compressed format such as JPEG, it will be very attractive to realize the image retargeting in compressed domain. In this paper, we propose a new low complexity DCT-based image retargeting method, which is completely performed in compressed domain. This proposed algorithm is based on the construction of block level importance map and calculation of block level forward energy. Experimental results prove that our proposed algorithm is able to significantly reduce image decoding complexity as well as image retargeting complexity, while providing the satisfying image retargeting quality compared with other methods.