Efficient data hiding algorithms have been developed for video coders such as MPEG-4 and H.264/AVC, to deliver embedded information. Lin et al. proposed an error propagation free discrete cosine transform (DCT) based data hiding algorithm in H.264/AVC intra-coded frames. However, the state-of-the-art video codec, high efficiency video coding (HEVC), adopts both DCT and discrete sine transform (DST) such that the previous DCT based data hiding algorithms cannot afford to fully utilize available capacity for data hiding under the HEVC framework. We proposed to investigate the block DCT and DST coefficient characteristics to specify the transformed coefficients that can be perturbed without propagating errors to neighboring blocks. Experiments on four different complexity test videos justified the efficiency of the proposed algorithm in performing intra-frame error propagation free data hiding, providing higher embedding capacity in low bitrate coding, and yielding better reconstructed video quality.
Assume that an input mosaic image with arbitrary CFA struc ture has lost its header, this paper presents a novel efficient method for recognizing its CFA structure using the frequency domain ap proach. The proposed method consists of a training-based scheme and an identification scheme. Initially, based on a set of train ing mosaic images with different CFA structures, a training-based scheme is proposed to build up a model map for every CFA struc ture. Firstly, the proposed three-step identification scheme per forms the same steps used in the construction of model maps for the header-less input mosaic image to obtain the query map. Then, a matching scheme is proposed to identify the corresponding CFA structure of the query map from the model maps based on the distance criterion.
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