新闻视频故事单元关联分析技术研究综述

新闻视频故事单元关联分析是将新闻视频分割所得的故事单元按照报道的新闻事件所进行的一种特殊聚类.故事单元是新闻视频各层次结构中包含有新闻事件完整语义的结构单元,是对新闻视频进行分析、检索、组织等应用的最佳层次.对新闻视频故事单元关联分析技术进行了综述;按照方法所利用的信息类型将现有方法分成三类:基于文本相似度的方法、基于多模态信息相似度的方法和基于关键帧视觉重复性的方法;讨论了每种方法的特点并对相关技术的发展趋势进行了探讨.     

多源新闻视频中相似关键帧分析研究

分析不同来源视频中关键帧的相似度是新闻视频分析与组织中一项重要的支持技术,当前工作直接利用图像匹配分析方法进行研究,而没有充分结合新闻视频表身的特点和特定的需求,因此存在种种局限.针对这些不足,本文提出了一种快速有效的层次化过滤方法来识别新闻视频关键帧.该方法首先对局部关键点的获取和精减技术进行了研究,在第一层过滤中应用基于熵的方法选择相似关键帧候选集,在第二层过滤分析中利用相似关键帧的对称性得到可信的识别结果.实验显示,这种方法显著的提高了匹配分析的适度,并且具有较好的识别效率.     

相似视频片段的检测与定位方法研究

相似视频片段探测可以辅助网络视频检索、内容关联分析等方面的研究,具有重要的意义。重点研究了位置随机的相似视频片段的探测与定位问题,首先在视频结构化分析与关键帧提取的基础上,对不同视频进行相似关键帧探测。为保证探测的精度与效率,针对视频关键帧的特点,采用了FAST检测子和BRIEF描述子相结合的方法,利用关键帧的局部特征进行相似关键帧探测;其次提出了一种相似关键帧距离度量的方法,利用相似关键帧所在源视频的位置来构建相似关键帧距离矩阵,保留矩阵中距离较小的相似关键帧,将寻找相似视频片段的过程转化为寻找矩阵对应的连通图的过程。最后对算法进行了实验,结果表明,该方法可以有效地探测处于各个位置的相似视频片段。     

基于改进词袋模型的相似关键帧匹配方法

对相似关键帧匹配中存在的低效率及无法很好反映语义特征的问题进行了分析,提出了基于词袋模型的关键帧描述方法,并进一步考虑了视觉词汇表的生成、降维以及词项权重赋予等关键问题,最后利用词袋特征对相似关键帧进行匹配。实验结果表明,提出的基于改进词袋模型的相似关键帧匹配方法不仅能在一定程度上提高匹配准确率,并且能够较大幅度地提高相似关键帧匹配的速度。     

基于关键帧和骨骼信息的人体动作识别方法

提出了一种基于关键帧和骨骼信息的动作识别新方法。通过深度传感器Kinect v2实时获取人体各骨骼点信息,通过采用加权K-means算法提取动作视频中的关键帧。通过每个关键帧中25个骨骼点的三维坐标值,计算出关节角度和向量模比值两种特征量,通过优化后的动态时间规整(DTW)算法计算关键帧序列与模板库中动作模板的相似度,从而识别人体的实时动作。通过对6种常见动作的识别实验对比,结果表明:所提方法在识别速度和准确率上较高,具有实际推广性。     

广义相似距核视频关键帧分层提取算法*

针对视频镜头关键帧特征提取矩阵可能尺寸大小不一致导致相似度无法计算的问题,提出一种广义相似距核视频关键帧分层聚类算法。首先,针对行数相同列不同的两个特征矩阵,基于矩阵运算方法提出一种广义相似距核相似度计算方法并给出其改进形式。其次,基于改进相似距核计算方法和层次聚类算法,设计了广义相似距核视频关键帧分层聚类算法。最后,通过在测试视频数据库及人造视频片段库上的仿真实验表明,该算法能够有效的完成视频关键帧的聚类和提取操作。     

基于图像相似度的关键帧提取算法

为了在视频管理数据库中提供有效的视频检索和浏览功能,必须用简明的方式表示视频的内容,关键帧提取技术是视频分析和视频检索的基础,现阶段关键帧提取技术已成为视频检索的一个重要研究方向。文中提出了一种改进的基于内容的视频关键帧提取方法-基于图像相似度的关键帧提取算法。实验结果表明这种方法可以较好地完成关键帧的提取工作,降低关键帧的冗余度,提高关键帧代表性。     

人体运动视频关键帧优化及行为识别

在行为识别过程中,提取视频关键帧可以有效减少视频索引的数据量,从而提高 动作识别的准确性和实时性。为提高关键帧的代表性,提出一种关键帧序列优化方法,并在此 基础上进行行为识别。首先根据3D 人体骨架特征利用K-均值聚类算法提取人体运动视频序列 中的关键帧,然后根据关键帧所在序列中的位置进行二次优化以提取最优关键帧,解决了传统 方法中关键帧序列冗余等问题。最后根据最优关键帧利用卷积神经网络(CNN)分类器对行为视 频进行识别。在Florence3D-Action 数据库上的实验结果表明,该方法具有较高的识别率,并且 与传统方法相比大幅度缩短了识别时间。     

矩阵约束下的频繁项集挖掘方法研究

数据挖掘中的关联分析技术旨在发现大量数据项集之间有趣的关联关系,其核心问题是寻找频繁项集。针对传统的基于矩阵的关联挖掘算法中矩阵规模和事务数据库大小相关,在处理超大型事务数据库时,仍会存在内存瓶颈的问题,提出了一个矩阵规模和事务数据库大小无关、通过矩阵约束预挖掘后验证的频繁项集发现算法。实验结果显示,该算法提高了频繁项集的挖掘速度。     

分布式数据库中关系数据正负关联规则挖掘

针对传统分布式数据库中关系数据正负关联规则挖掘的准确度较低、挖掘效率较低等问题,提出一种新的分布式数据库中关系数据正负关联规则挖掘方法.在关联规则基本概念和性质分析基础上,利用多级支持度从频繁项集中生成正关联规则,结合根据频繁项集和非频繁项集生成负关联规则,通过最小支持度合理设置相关置信度,引入不同权重值于各数据库中,实现分布式数据库中关系数据正负关联规则的挖掘.仿真结果表明,以上算法可有效识别结果规则集中的负关联规则和弱关联规则,确保数据库中关联数据挖掘更加准确;在不同最小支持度或不同事务数条件下,挖掘速度较快,提升了挖掘效率.     

Efficient subsequence matching over large video databases

Video similarity matching has broad applications such as copyright detection, news tracking and commercial monitoring, etc. Among these applications, one typical task is to detect the local similarity between two videos without the knowledge on positions and lengths of each matched subclip pair. However, most studies so far on video detection investigate the global similarity between two short clips using a pre-defined distance function. Although there are a few works on video subsequence detection, all these proposals fail to provide an effective query processing mechanism. In this paper, we first generalize the problem of video similarity matching. Then, a novel solution called consistent keyframe matching (CKM) is proposed to solve the problem of subsequence matching based on video segmentation. CKM is designed with two goals: (1) good scalability in terms of the query sequence length and the size of video database and (2) fast video subsequence matching in terms of processing time. Good scalability is achieved by employing a batch query paradigm, where keyframes sharing the same query space are summarized and ordered. As such, the redundancy of data access is eliminated, leading to much faster video query processing. Fast subsequence matching is achieved by comparing the keyframes of different video sequences. Specifically, a keyframe matching graph is first constructed and then divided into matched candidate subgraphs. We have evaluated our proposed approach over a very large real video database. Extensive experiments demonstrate the effectiveness and efficiency of our approach.     

基于多向量和实体模糊匹配的话题关联识别

本文在对新闻报道理论分析及实验验证的基础上,提出一种多向量表示模型,使其在尽量不丢失信息的情况下,对特征集合尽可能细地划分。基于该模型,本文设计了一种模糊匹配的方法用于计算命名实体子向量之间的关联度,它们和多个向量相似度一起用支持向量机进行整合,形成报道模型间的相似度。本文选用TDT4中文语料作为测试语料,将上述模型及模糊匹配技术用于话题关联识别。实验表明,多向量模型能够改进话题关联识别的性能,模糊匹配技术也在一定程度上弥补了精确匹配带来的性能损失。     

Exploiting Near‐Duplicate Relations in Organizing News Archives

Huge numbers of documents are being generated on the Web, especially for news articles and social media. How to effectively organize these evolving documents so that readers can easily browse or search is a challenging task. Existing methods include classification, clustering, and chronological or geographical ordering, which only provides a partial view of the relations among news articles. To better utilize cross‐document relations in organizing news articles, in this paper, we propose a novel approach to organize news archives by exploiting their near‐duplicate relations. First, we use a sentence‐level statistics‐based approach to near‐duplicate copy detection, which is language independent, simple but effective. Since content‐based approaches are usually time consuming and not robust to term substitutions, near‐duplicate detection approach can be used. Second, by extracting the cross‐document relations in a block‐sharing graph, we can derive a near‐duplicate clustering by cross‐document relations in which users can easily browse and find out unnecessary repetitions among documents. From the experimental results, we observed high efficiency and good accuracy of the proposed approach in detecting and clustering near‐duplicate documents in news archives.     

OM-based video shot retrieval by one-to-one matching

This paper proposes a new approach for shot-based retrieval by optimal matching (OM), which provides an effective mechanism for the similarity measure and ranking of shots by one-to-one matching. In the proposed approach, a weighted bipartite graph is constructed to model the color similarity between two shots. Then OM based on Kuhn–Munkres algorithm is employed to compute the maximum weight of a constructed bipartite graph as the shot similarity value by one-to-one matching among frames. To improve the speed efficiency of OM, two improved algorithms are also proposed: bipartite graph construction based on subshots and bipartite graph construction based on the same number of keyframes. Besides color similarity, motion feature is also employed for shot similarity measure. A motion histogram is constructed for each shot, the motion similarity between two shots is then measured by the intersection of their motion histograms. Finally, the shot similarity is based on the linear combination of color and motion similarity. Experimental results indicate that the proposed approach achieves better performance than other methods in terms of ranking and retrieval capability.

一种基于二分图最优匹配的重复记录检测算法

信息集成系统中存在重复记录,重复记录的存在为数据处理和分析带来了困难.重复记录检测已经成为当前数据库研究中的热点问题之一.目前的方法主要集中在计算具有同样数据类型属性的相似性上,而现实系统中存在大量具有不同数据类型、不同模式的记录.针对具有多种类型不同模式数据的重复记录检测问题,提出了一种基于二分图的最优匹配的记录相似度计算方法,并基于这种记录相似性提出了重复记录检测算法.理论分析和实验结果都表明了方法的正确性和有效性.     

Segmentation,indexing and retrieval of TV broadcast news bulletins using Gaussian mixture models and vector quantization codebooks

In this paper we proposed two-stage segmentation approach for splitting the TV broadcast news bulletins into sequence of news stories and codebooks derived from vector quantization are used for retrieving the segmented stories. At the first stage of segmentation, speaker (news reader) specific characteristics present in initial headlines of news bulletin are used for gross level segmentation. During second stage, errors in the gross level segmentation (first stage) are corrected by exploiting the speaker specific information captured from the individual news stories other than headlines. During headlines the captured speaker specific information is mixed with background music, and hence the segmentation at the first stage may not be accurate. In this work speaker specific information is represented by using mel frequency cepstral coefficients, and captured by Gaussian mixture models (GMMs). The proposed two-stage segmentation method is evaluated on manual segmented broadcast TV news bulletins. From the evaluation results, it is observed that about 93 % of the news stories are correctly segmented, 7 % are missed and 6 % are spurious. For navigating the bulletins, a quick navigation indexing method is developed based on speaker change points. Performance of the proposed two-stage segmentation and quick navigation methods are evaluated using GMM and neural networks models. For retrieving the target news stories from news corpus, sequence of codebook indices derived from vector quantization is explored. Proposed retrieval approach is evaluated using queries of different sizes. Evaluation results indicating that the retrieval accuracy is proportional to size of the query.     

基于向量空间模型的视频语义相关内容挖掘

对海量视频数据库中所蕴涵的语义相关内容进行挖掘分析，是视频摘要生成方法面临的难题。该文提出了一种基于向量空间模型的视频语义相关内容挖掘方法：对新闻视频进行预处理，将视频转化为向量形式的数据集，采用主题关键帧提取算法对视频聚类内容进行挖掘，保留蕴涵场景独特信息的关键帧，去除视频中冗余的内容，这些主题关键帧按原有的时间顺序排列生成视频的摘要。实验结果表明，使用该视频语义相关内容挖掘的算法生成的新闻视频具有良好的压缩率和内容涵盖率。     

Structuring low-quality videotaped lectures for cross-reference browsing by video text analysis

This paper presents an unified approach in analyzing and structuring the content of videotaped lectures for distance learning applications. By structuring lecture videos, we can support topic indexing and semantic querying of multimedia documents captured in the traditional classrooms. Our goal in this paper is to automatically construct the cross references of lecture videos and textual documents so as to facilitate the synchronized browsing and presentation of multimedia information. The major issues involved in our approach are topical event detection, video text analysis and the matching of slide shots and external documents. In topical event detection, a novel transition detector is proposed to rapidly locate the slide shot boundaries by computing the changes of text and background regions in videos. For each detected topical event, multiple keyframes are extracted for video text detection, super-resolution reconstruction, binarization and recognition. A new approach for the reconstruction of high-resolution textboxes based on linear interpolation and multi-frame integration is also proposed for the effective binarization and recognition. The recognized characters are utilized to match the video slide shots and external documents based on our proposed title and content similarity measures.