感知哈希（Perceptual Hashing ）是多媒体数据集到集的单向映射，为多媒体数字内容的标识、检索、认证等应用提供了安全可靠的技术支撑。本文提出一种融合视觉感知及时空域特征的视频感知哈希算法。算法首先对视频序列每一帧进行随机可重叠分块，并计算每个分块以像素为单位的亮度均值，在某一步长下，以同一帧的分块亮度差作为视频帧空域特征，以不同视频帧相同位置的分块亮度差作为时域特征，通过哈希量化得到时空域感知哈希，通过时空域感知哈希融合，最后得到简洁的视频唯一标识---哈希。实验结果表明，该算法表现出较好的鲁棒性与区分性，通过相似度拟合图算法分析，可以实现视频篡改的准确检测及定位。%Perceptual hashing is a one-directional mapping from multimedia data sets to the abstract sets ,which provides a safe and reliable tool for identification ,retrieval ,and authentication of multimedia digital contents .This paper proposes a video per-ceptual hashing algorithm fuseing visual perception and spatiotemporal features .The algorithm first randomly divides each video frame into a number of overlapping blocks ,and then calculates the average brightness (AB) of each block .While spatial features are described by differences of the AB among blocks in the same frame ,the features in time domain is represented by the differences of the same bock across time .Finally ,the two features are quantized and fused to generate the unique id ,i .e .abstract hashing for each video .The experimental results show that the features are robust ,discriminative ,and can effectively detect and accurately locate video tampering using correlation analysis .
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