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arXiv 2008.08944cs.CV
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从弱标记视频中定位异常

Localizing Anomalies from Weakly-Labeled Videos

Nanjing University of Science and Technology(南京理工大学)

Hui Lv, Chuanwei Zhou, Chunyan Xu, Zhen Cui, Jian Yang

摘要:

视频级标签下的视频异常检测目前是一项具有挑战性的任务。以往的工作在判别视频序列是否含有异常方面取得了一定的进展。然而,他们中的大多数未能准确地定位视频中的异常事件在时间域。在本文中,我们提出了一种弱监督异常定位(WSAL)方法,专注于在时间上定位异常视频中的异常片段。受异常视频中外观差异的启发,评估相邻时间段的演变以定位异常段。为此,提出了一种高阶上下文编码模型,不仅可以提取语义表示,而且可以测量动态变化,以便有效地利用时间上下文。此外,为了充分利用空间上下文信息,直接从段表示中导出即时语义。动态变化以及即时语义,有效地聚合,以获得最终的异常分数。针对异常检测中噪声干扰和定位指导缺失的问题,提出了一种增强策略。此外,为了满足异常检测基准的多样性要求,我们还收集了一个新的流量异常数据集,该数据集指定了流量条件,与当前流行的异常检测评估基准有很大不同,我们进行了大量的实验来验证不同组件的有效性,我们提出的方法在UCF-Crime和流量异常数据集上实现了新的最先进的性能。

英文摘要:

Video anomaly detection under video-level labels is currently a challenging task. Previous works have made progresses on discriminating whether a video sequencecontains anomalies. However, most of them fail to accurately localize the anomalous events within videos in the temporal domain. In this paper, we propose a Weakly Supervised Anomaly Localization (WSAL) method focusing on temporally localizing anomalous segments within anomalous videos. Inspired by the appearance difference in anomalous videos, the evolution of adjacent temporal segments is evaluated for the localization of anomalous segments. To this end, a high-order context encoding model is proposed to not only extract semantic representations but also measure the dynamic variations so that the temporal context could be effectively utilized. In addition, in order to fully utilize the spatial context information, the immediate semantics are directly derived from the segment representations. The dynamic variations as well as the immediate semantics, are efficiently aggregated to obtain the final anomaly scores. An enhancement strategy is further proposed to deal with noise interference and the absence of localization guidance in anomaly detection. Moreover, to facilitate the diversity requirement for anomaly detection benchmarks, we also collect a new traffic anomaly (TAD) dataset which specifies in the traffic conditions, differing greatly from the current popular anomaly detection evaluation benchmarks.Extensive experiments are conducted to verify the effectiveness of different components, and our proposed method achieves new state-of-the-art performance on the UCF-Crime and TAD datasets.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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