Scene change detection algorithms for content-based video indexingand retrieval

There is an urgent need to extract key information from video automatically for the purposes of indexing, fast retrieval, and scene analysis. To support this vision, reliable scene change detection algorithms must be developed. Several algorithms have been proposed for both sudden and gradual scene change detection in uncompressed and compressed video. In this paper some common algorithms that have been proposed for scene change detection are reviewed. A novel algorithm for sudden scene change detection for MPEG-2 compressed video is then presented. This uses the number of interpolated macroblocks in B-frames to identify the sudden scene changes. A gradual scene change detection algorithm based on statistical features is also presented     

一种基于特征检测的APT攻击防御方案

高级持续性威胁(APT)攻击具有持续渗透性,对网络的信息安全管理造成了严重威胁。在分析流量统计特征的基础上,提出了区分可信与非可信流量的方法,通过特征检测,实现对恶意攻击的识别,并建立了相应的APT攻击防御方案。以电力系统的管理网络为平台,验证了该方案的有效性,为防御APT攻击提供了一种可行的思路。     

压缩域快速视频拷贝检测算法

为了在大规模数据下有效提升拷贝检测速度,提出了一种压缩域视频拷贝检测算法,采用2级匹配框架,利用压缩域上DCT系数顺序度量特征进行相似度匹配,显著减少了查询视频解码操作;并为DCT系数顺序度量特征建立倒排索引,以加快第一级匹配的速度.实验结果表明,与已有的算法相比,所提出算法在保持相当的检测精度条件的同时,大幅提升了检测速度.     

Rotation and flipping robust region binary patterns for video copy detection

Many video fingerprints have been proposed to handle the video transformations problems when the original contents are copied and redistributed. However, most of them did not take into account flipping and rotation transformations. In this paper, we propose a novel video fingerprint based on region binary patterns, aiming to realize robust and fast video copy detection against video transformations including rotation and flipping. We extract two complementary region binary patterns from several rings in keyframes. These two kinds of binary patterns are converted into a new type of patterns for the proposed video fingerprint which is robust against rotation and flipping. The experimental results demonstrated that the proposed video fingerprint is effective for video copy detection particularly in the case of rotation and flipping. Furthermore, our experimental results proved that the proposed method allows for high storage efficiency and low computation complexity, which is suitable for practical video copy system.     

基于内容的视频分析技术研究

视频数据分析处理是实现基于内容的视频检索的一项关键技术,它直接影响到视频特征匹配和检索的精度。从分析视频数据的结构和特点出发,总结了基于内容检索的视频处理方法的一般过程,即视频分割、关键帧选取、静态和动态特征提取以及视频聚类等。对基于内容视频分析中的关键技术进行了深入的探讨研究,分析了各种方法的优缺点并介绍了一些新的方法,最后提出了一些值得进一步研究的问题。     

一种有效的基于内容的图像检索方法

本文针对基于内容的图像检索中特征和相似度问题，提出新的距离模式，并以彩色空间中扩展共发矩阵作为纹理描述，在测试系统iPhoto上，数据库为56600幅图像时，实验结果显示，本文方法优于传统方法。     

Automatic video segmentation and tracking for content-based applications

Advanced multimedia applications have to provide content-related functionalities such as search and retrieval of meaningful objects, detection and analysis of events, and understanding of scenes, which allow the user to access and manipulate the multimedia content with greater flexibility. This greatly depends on automatic techniques for extracting such objects from multimedia data. In this article we intend to provide a tutorial on the state-of-the-art in video segmentation and tracking technology with particular attention paid to the recent developments in attention-based object extraction. Performance results are included to highlight this emerging technology     

A perceptual scheme for fully automatic video shot boundary detection

In this paper, we propose a novel and robust modus operandi for fast and accurate shot boundary detection where the whole design philosophy is based on human perceptual rules and the well-known “Information Seeking Mantra”. By adopting a top–down approach, redundant video processing is avoided and furthermore elegant shot boundary detection accuracy is obtained under significantly low computational costs. Objects within shots are detected via local image features and used for revealing visual discontinuities among shots. The proposed method can be used for detecting all types of gradual transitions as well as abrupt changes. Another important feature is that the proposed method is fully generic, which can be applied to any video content without requiring any training or tuning in advance. Furthermore, it allows a user interaction to direct the SBD process to the user's “Region of Interest” or to stop it once satisfactory results are obtained. Experimental results demonstrate that the proposed algorithm achieves superior computational times compared to the state-of-art methods without sacrificing performance.     

一种基于轮廓与背景消除的红外视频移动目标检测方案

针对红外视频的移动目标检测算法在还原目标时,目标的轮廓还原准确率较低的问题,提出一种基于轮廓与背景消除的红外视频移动目标检测方案。首先,从视频中选取一些不含目标对象的帧,对选取的帧进行统计处理并建立背景帧;分析背景的场景变化建立变化的自适应背景帧,并将背景帧的杂波过滤掉;然后,使用Canny边缘检测和K-means聚类检测目标轮廓并将目标轮廓从背景提取出来;使用形态学的边缘连通算法将目标轮廓进行关闭与Flood-fill填充处理获得目标对象的形状。对比实验结果证明,相较于其他红外视频移动目标检测算法,该算法获得了较好的目标轮廓与形状,同时,该算法的检测率与虚警率性能以及每帧的处理时间均较优。     

一种改进的视频切变检测方法

在分析视频切变类型、常用切变检测算法及问题的基础上，提出了一种改进的累积平均差值视频渐变检测算法，降低了阈值选取难度，取得了较好的实验效果。     

Adaptive weighted fusion with new spatial and temporal fingerprints for improved video copy detection

In this paper, we propose a new and novel modality fusion method designed for combining spatial and temporal fingerprint information to improve video copy detection performance. Most of the previously developed methods have been limited to use only pre-specified weights to combine spatial and temporal modality information. Hence, previous approaches may not adaptively adjust the significance of the temporal fingerprints that depends on the difference between the temporal variances of compared videos, leading to performance degradation in video copy detection. To overcome the aforementioned limitation, the proposed method has been devised to extract two types of fingerprint information: (1) spatial fingerprint that consists of the signs of DCT coefficients in local areas in a keyframe and (2) temporal fingerprint that computes the temporal variances in local areas in consecutive keyframes. In addition, the so-called temporal strength measurement technique is developed to quantitatively represent the amount of the temporal variances; it can be adaptively used to consider the significance of compared temporal fingerprints. The experimental results show that the proposed modality fusion method outperforms other state-of-the-arts fusion methods and popular spatio-temporal fingerprints in terms of video copy detection. Furthermore, the proposed method can save 39.0%, 25.1%, and 46.1% time complexities needed to perform video fingerprint matching without a significant loss of detection accuracy for our synthetic dataset, TRECVID 2009 CCD Task, and MUSCLE-VCD 2007, respectively. This result indicates that our proposed method can be readily incorporated into the real-life video copy detection systems.     

Digital watermarking for DVD video copy protection

We illustrate the various issues that play a role in designing a copy-protection system for digital versatile disk (DVD) video as perceived by Millennium, one of the two contenders in the DVD-video copy-protection standardization activity. We present the Millennium watermark system, the systems proposed for DVD video copy protection by Philips, Macrovision, and Digimarc. We also address some specific system aspects, such as watermark detector location and copy generation control     

一种抗误码能力强的视频压缩SPIHT改进算法

基于小波域的3D-SPIHT算法是一种高效的视频压缩编码方法,但其抗误码能力仍有待提高.本文提出了一种改进的3-D DWT-SPIHT分树编码方法.在不改变原算法小波树结构的前提下,插入编解码链表同步点,将整个帧组分为多棵子树独立编码和传输,从而将差错传播局限在每棵独立子树内,控制了差错传播范围.通过仿真实验证明了该算法与原算法相比具有较高的抗误码能力.     

An efficient optimisation scheme for scalable surveillance centric video communications

State-of-the-art coders have been optimised over years according to the needs of the broadcasting industry. There are however key applications of coding technology whose challenges and requirements substantially differ from broadcasting. One of these key applications is surveillance. In this paper an efficient approach for surveillance centric joint source and channel coding is proposed. Contrasting conventional coders, the proposed system has been developed according to the requirements of surveillance application scenarios. It aims at achieving bit-rate optimisation and adaptation of surveillance videos for storing and transmission purposes. In the proposed approach the encoder communicates with a video content analysis (VCA) module that detects events of interests in video captured by CCTV. Bit-rate optimisation and adaptation is achieved by exploiting the scalability properties of the employed codec. Temporal segments containing events relevant to surveillance application are encoded using high spatio-temporal resolution and quality while the portions irrelevant from the surveillance standpoint are encoded at low spatio-temporal resolution and/or quality. Furthermore, the approach jointly optimises the bit allocation between the wavelet-based scalable video coder and forward error correction codes. The forward error correction code is based on the product code constituting of LDPC codes and turbo codes. Turbo codes show good performance at high error rates region but LDPC outperforms turbo codes at low error rates. Therefore, the concatenation of LDPC and TC enhances the performance at both low and high signal-to-noise (SNR) ratios. The proposed approach minimises the distortion of reconstructed video, subject to constraint on the overall transmission bit-rate budget. Experimental results clearly demonstrate the efficiency and suitability of the proposed approach in surveillance applications.     

基于AVS视频解码的错误检测方法

针对AVS视频传输过程中出现的码流错误,提出了一种基于健康度记录与双阈值判别的错误检测方法。在解码过程中,对每一个宏块都用邻域相关性来计算其健康度,并记录健康度较差的宏块号,健康度判别中使用双阈值,出现首个大于较大的阈值一的宏块后则改为使用较小的阈值二进行判别;若出现语法/语义错误,则再利用宏块内部相关性对出错宏块号进行微调,最后把所有被记录下的宏块都标记为出错。实验结果表明,该错误检测方法能较准确定位出错宏块位置,特别是对于出错宏块不连续和相关性增幅不够大的错误类型,与传统的逐个向前检测的方法相比,能有更好的检测效果。     

基于内容的多层次语义视频对象提取方法研究

视频对象的提取在序列图像的分析中起着重要作用.提出一个基于内容的多层次视频的对象提取算法,利用高斯马尔可夫模型对其进行颜色和纹理的混合特征图像分割.利用Normalize-cut准则,对其运动信息进行分析,然后进行区域聚合,即得到具有语义的视频对象.对于背景运动信息较丰富的序列图像可以取得良好的提取效果.     

一种基于内容表示的图像序列运动分割算法

提出了一种MPEG－4标准所规范的基于内容表示的图像序列运动分割算法。首先进行图像序列二维运动估计并计算位移帧差,然后,将位移帧差作为将运动物体从静止背景中分离出来的标准进行分割;最后对分割结果进行形态滤波。实验结果显示,在物体存在整体运动的情况下,分割结果表现出了很好的准确度,可以成功地提取图像序列中的运动物体。     

An optimal quadtree-based motion estimation and motion-compensatedinterpolation scheme for video compression

We propose an optimal quadtree (QT)-based motion estimator for video compression. It is optimal in the sense that for a given bit budget for encoding the displacement vector field (DVF) and the QT segmentation, the scheme finds a DVF and a QT segmentation which minimizes the energy of the resulting displaced frame difference (DFD). We find the optimal QT decomposition and the optimal DVF jointly using the Lagrangian multiplier method and a multilevel dynamic program. We introduce a new, very fast convex search for the optimal Lagrangian multiplier lambda*, which results in a very fast convergence of the Lagrangian multiplier method. The resulting DVF is spatially inhomogeneous, since large blocks are used in areas with simple motion and small blocks in areas with complex motion. We also propose a novel motion-compensated interpolation scheme which uses the same mathematical tools developed for the QT-based motion estimator. One of the advantages of this scheme is the globally optimal control of the tradeoff between the interpolation error energy and the DVF smoothness. Another advantage is that no interpolation of the DVF is required since we directly estimate the DVF and the QT-segmentation for the frame which needs to be interpolated. We present results with the proposed QT-based motion estimator which show that for the same DFD energy the proposed estimator uses about 25% fewer bits than the commonly used block matching algorithm. We also experimentally compare the interpolated frames using the proposed motion compensated interpolation scheme with the reconstructed original frames.