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In this paper, we improve co-segmentation performance by repairing bad segments based on their quality evaluation and segment propagation. Starting from co-segmentation results of the existing co-segmentation method, we first perform co-segmentation quality evaluation to score each segment. Good segments can be filter out based on the scores. Then, a(More)
According to the compressed sensing (CS) theory, we can sample a sparse signal at a rate that is (much) lower than the required Nyquist rate, while still enabling a nearly exact reconstruction. Image signals are sparse when represented in a certain domain, and because of this, a large number of CS-based image sampling and reconstruction techniques have been(More)
In this paper, we extend image stitching to video stitching for videos that are captured for the same scene simultaneously by multiple moving cameras. In practice, videos captured under this circumstance often appear shaky. Directly applying image stitching methods for shaking videos often suffers from strong spatial and temporal artifacts. To solve this(More)
In this paper, a graph cut based fast Coding Unit (CU) decision algorithm is proposed for HEVC inter frames. Firstly, a feature called pyramid variance of the absolute difference (PVAD) is designed for the CU selection. Secondly, the CU decision is modeled as a Markov Random Field (MRF) inference problem, which can be optimized by the graph cut algorithm.(More)
Perceptual video encryption, in which a user can still obtain some visible video contents (but at a very annoying quality) even without knowing the encryption key, is becoming more and more interesting in video applications such as video-on-demand (VoD) and pay-TV. Since not all visual information is corrupted, the quality assessment methods that are used(More)
An alternative-transforms-based scheme has recently been proposed to achieve perceptual encryption of video signals in which multiple transforms are designed by using different rotation angles at the final stage of the discrete cosine transforms (DCTs) butterfly flow-graph structure. More recently, it is found that a set of more efficient alternative(More)
In this letter, we propose a novel video encryption technique that is used to achieve partial encryption where an annoying video can still be reconstructed even without the security key. In contrast to the existing methods where the encryption usually takes place at the entropy-coding stage or the bit-stream level, our proposed scheme embeds the encryption(More)
In our earlier work [1], we proposed for the first time that the perceptual video encryption be performed at the transformation stage by selecting one out of multiple unitary transforms according to the encryption key. In this letter, we aim to design some more efficient transforms to be used in this framework. Two criteria are followed for designing such(More)
It has been demonstrated in our earlier works [1, 2] that perceptual video encryption can be effectively achieved by using multiple transforms where the block size 4×4 has been considered. In this paper, we study the extension to the transforms of size 8×8. In this case, a more complex flow-graph structure is resulted, thus leading to a larger room for(More)