A HEVC Video Steganalysis Method Using the Optimality of Motion Vector Prediction

Among steganalysis techniques,detection against MV(motion vector)domain-based video steganography in the HEVC(High Efficiency Video Coding)standard remains a challenging issue.For the purpose of improving the detection performance,this paper proposes a steganalysis method that can perfectly detectMV-based steganography in HEVC.Firstly,we define the local optimality of MVP(Motion Vector Prediction)based on the technology of AMVP(Advanced Motion Vector Prediction).Secondly,we analyze that in HEVC video,message embedding either usingMVP index orMVD(Motion Vector Difference)may destroy the above optimality of MVP.And then,we define the optimal rate of MVP as a steganalysis feature.Finally,we conduct steganalysis detection experiments on two general datasets for three popular steganographymethods and compare the performance with four state-ofthe-art steganalysis methods.The experimental results demonstrate the effectiveness of the proposed feature set.Furthermore,our method stands out for its practical applicability,requiring no model training and exhibiting low computational complexity,making it a viable solution for real-world scenarios.

Real-time traffic information extraction based on compressed video with interframe motion vector

Extraction of traffic information from image or video sequence is a hot research topic in intelligenttransportation system and computer vision. A real-time traffic information extraction method based on com-pressed video with interframe motion vectors for speed, density and flow detection, has been proposed for ex-traction of traffic information under fixed camera setting and well-defined environment. The motion vectors arefirst separated from the compressed video streams, and then filtered to eliminate incorrect and noisy vectors u-sing the well-defined environmental knowledge. By applying the projective transform and using the filtered mo-tion vectors, speed can be calculated from motion vector statistics, density can be estimated using the motionvector occupancy, and flow can be detected using the combination of speed and density. The embodiment of aprototype system for sky camera traffic monitoring using the MPEG video has been implemented, and experi-mental results proved the effectiveness of the method proposed.

A Novel Video Reversible Data Hiding Algorithm Using Motion Vector for H.264/AVC

A novel reversible data hiding algorithm for H.264/AVC videos is proposed. Histogram Shifting （HS） of motion vector values is used efficiently in reversible data hiding to embed data. By designating a specific decoded reference frame, the distortion accumulation effects due to modification of the motion vectors is overcome. All the extracted information can be recovered without loss of the original compressed video carrier. The experimental results show that the proposed algorithm is simple, has higher capacity and invisibility than other existing schemes, and can adjust the relationship between capacity and invisibility according to embedded load.

Digital Watermarking Applied To MEPG-2 Coded Video Sequences Exploiting Motion Vector

This paper proposes a video watermarking technology to hide copyright information by a slight modification of the motion vector in MPEG-2 video bitstream. In this method, the watermark is embedded in the motion residual of the large value motion vector, then the motion residual is regularized into a modified bitstream, from which the watermark information can be retrieved easily and exactly. From the experimental results, this technology has the advantage of little influence on the MPEG decoding speed, degrading the perceptive effect little, and the capability to embed watermark in a short video sequence, and can be used to watermark directly on the compressed and uncompressed video sequence.

Multiresolution Video Watermarking Algorithm Exploiting the Block-Based Motion Estimation

This paper presents a novel technique for embedding a digital watermark into video frames based on motion vectors and discrete wavelet transform (DWT). In the proposed scheme, the binary image watermark is divided into blocks and each watermark block is embedded several times in each selected video frame at different locations. The block-based motion estimation algorithm is used to select the video frame blocks having the greatest motion vectors magnitude. The DWT is applied to the selected frame blocks, and then, the watermark block is hidden into these blocks by modifying the coefficients of the Horizontal sub-bands (HL). Adding the watermark at different locations in the same video frame makes the scheme more robust against different types of attacks. The method was tested on different types of videos. The average peak signal to noise ratio (PSNR) and the normalized correlation (NC) are used to measure the performance of the proposed method. Experimental results show that the proposed algorithm does not affect the visual quality of video frames and the scheme is robust against a variety of attacks.

Vision-based fatigue crack detection using global motion compensation and video feature tracking

Fatigue cracks that develop in civil infrastructure such as steel bridges due to repetitive loads pose a major threat to structural integrity.Despite being the most common practice for fatigue crack detection,human visual inspection is known to be labor intensive,time-consuming,and prone to error.In this study,a computer vision-based fatigue crack detection approach using a short video recorded under live loads by a moving consumer-grade camera is presented.The method detects fatigue crack by tracking surface motion and identifies the differential motion pattern caused by opening and closing of the fatigue crack.However,the global motion introduced by a moving camera in the recorded video is typically far greater than the actual motion associated with fatigue crack opening/closing,leading to false detection results.To overcome the challenge,global motion compensation(GMC)techniques are introduced to compensate for camera-induced movement.In particular,hierarchical model-based motion estimation is adopted for 2D videos with simple geometry and a new method is developed by extending the bundled camera paths approach for 3D videos with complex geometry.The proposed methodology is validated using two laboratory test setups for both in-plane and out-of-plane fatigue cracks.The results confirm the importance of motion compensation for both 2D and 3D videos and demonstrate the effectiveness of the proposed GMC methods as well as the subsequent crack detection algorithm.

Real-time and Automatic Close-up Retrieval from Compressed Videos

This paper proposes a thorough scheme, by virtue of camera zooming descriptor with two-level threshold, to automatically retrieve close-ups directly from moving picture experts group （MPEG） compressed videos based on camera motion analysis. A new algorithm for fast camera motion estimation in compressed domain is presented. In the retrieval process, camera-motion-based semantic retrieval is built. To improve the coverage of the proposed scheme, close-up retrieval in all kinds of videos is investigated. Extensive experiments illustrate that the proposed scheme provides promising retrieval results under real-time and automatic application scenario.

Use of Accelerators for Biomechanical Analysis of Walking Motion Aided by Wheeled Walking Frames

Walkers improve self-reliability. We examined the effectiveness of a newly developed wheeled walking frame for use by physically handicapped persons. Unstable gaits in walker users were analyzed by tri-axial accelerometers and a motion capture system. Several markers were placed on subjects＇ backs and legs. Subjects were requested to walk around a test course at a comfortable speed, while their motion was recorded by two high-speed video cameras. The activities performed on the test course comprised standing, normal walking, fast walking, and walking over a barrier. Any accidental falls were also recorded. We established the characteristic rules of gait motion using a walker. Furthermore, we demonstrated that gait characteristics are more conveniently extracted from acceleration sensors than from motion capture systems, since the sensors can be affixed to subjects for self-monitoring and goal achievements. The methods employing acceleration sensors are considered suitable for determining the average gait motions of elderly persons living in nursing homes, and can be used to evaluate walking motion before and aider rehabilitation.

Pano Video:摄像机运动建模及从视频估计摄像机运动参数的一种方法

通过给摄像机平移、旋转与变焦等运动建模，并把运动模型与基于象素点亮度变化的方法相结合来估计摄像机运动参数。用得到的运动参数可以把视频构造成一幅全景图，全景图可广泛应用于视频压缩与检索。实验表明，该方法可成功地应用于视频会议系统中的视频压缩与视频检索。

Side Information Generation Based on Hierarchical Motion Estimation in Distributed Video Coding

The side information quality has an immense effect on the compression efficiency of the distributed video coding (DVC) sys- tem. This article, based on the hierarchical motion estimation (HME), proposes a new side information generation algorithm which is integrated into DVC system. First, forward motion estimation (FME) and bidirectional motion estimation (BME) on the basis of variable block size HME algorithm are used to acquire relatively accurate motion vectors. Second, a motion vector filter (MVF) is i...

A Modified Block Matching Motion Estimation Algorithm for the Very Low Bit-Rate video Coding

Block matching motion estimation techniques have been widely used in video coding applications. However, they also show their deficiency in the coherence of motion vectors and antinoise ability. This paper proposes a modified algorithm which can adopt any one of existing search algorithms and pays more attention to the correlation of neighboring blocks.It will be shown that the proposed algorithm is simple and significantly reduces the computational complexity. Simulation results also show that this algorithm improves the smoothness of the motion field, hence reducing the cost to code the motion vectors while keeping good performance comparable with the conventional block matching motion estimation algorithm.

多通道运动矢量排序的可逆视频信息隐藏

针对现有基于运动矢量排序的视频可逆信息隐藏算法无法根据视频帧视觉特性自适应调节嵌入容量且容量有限的问题,提出一种多通道矢量排序的可逆视频信息隐藏算法.该算法通过计算参考帧的纹理复杂度和运动复杂度情况决定后续帧是否嵌入信息,从而实现后续帧的自适应信息嵌入,算法同时对多通道像素值排序(multi-pass pixel value ordering, multi-pass PVO)技术进行改进,将其应用于视频信息隐藏,有效提升可逆隐藏算法嵌入容量.实验结果表明,相较于同类算法,PSNR和SSIM的变化值分别降低14.5%和8.5%,嵌入容量提升7.4%,在视觉质量和嵌入容量方面有显著提高.

基于次镜像移补偿的折反式航测相机光机系统设计

针对航测相机对地摆扫成像过程中的动态像移问题,采用两镜望远系统的矢量像差理论,将次镜作为像移补偿元件,通过次镜多维运动实现航测相机的综合像移补偿。次镜在对像移进行补偿的过程中会发生偏心和倾斜,导致次镜离轴,影响成像质量,因此,建立了失调折反光学系统成像模型,研究次镜像差场偏移矢量与次镜失调量之间的关系,并分析次镜多维运动对成像质量的影响。为验证次镜多维运动的像移补偿能力,搭建实验平台对该航测相机进行了实验室内以及外场成像试验。结果表明,采用该像移补偿技术的航测相机动态分辨率可达74 lp/mm,且像移补偿精度优于0.5个像素,达到设计预期。

基于运动向量修改的保持块间扰动最小的HEVC信息隐藏算法

高效视频编码(High Efficiency Video Coding, HEVC)标准能够大幅度提升压缩效率,正被广泛应用中。为提高基于运动向量修改的HEVC视频隐写算法的安全性,本文结合了HEVC标准中帧间预测编码的新技术,并利用在运动向量域进行信息嵌入扰动较小的优点,提出了一种基于运动向量修改的保持块间扰动最小的HEVC信息隐藏算法。首先,该算法量化了修改运动向量后对当前高级运动向量预测(Advanced Motion Vector Prediction, AMVP)单元和其相邻融合(Merge)模式预测单元产生的扰动代价,将运动向量垂直分量和水平分量之和作为原始载体元素。其次,结合校验网格码(Syndrome Trellis Codes, STC),寻找扰动代价最小的嵌入路径,通过修改运动向量中绝对值较大的分量将信息嵌入在AMVP模式的预测单元运动向量上。此外,为减小对视频质量的影响,利用修改后的运动向量更新运动向量差值。实验结果表明,所提方法对视频序列进行信息嵌入后,由于本文引入的扰动代价判断可以有效控制视频质量变化,对视频序列的峰值信噪比、码率影响较小,所以该方法对视频的扰动很小。而且本文算法不仅在视频质量保护上有良好的性能,还对运动向量域专用隐写分析具有良好的抗检测能力,有利于基于HEVC视频码流的隐蔽通信的进一步发展。

基于运动矢量场和方向自适应的快速运动估计算法

该文提出了一种基于运动矢量场和方向自适应的快速搜索算法。算法针对序列图像的运动矢量场所具有的中心偏置性和时空相关性进行预判,对静止块设定阈值直接中止搜索;根据运动类型自适应选择搜索起始点和搜索策略;采用了两种新的混合搜索方法,对小运动和大运动宏块使用线性-菱形搜索,对中等运动块使用六边形-菱形搜索算法,搜索模板具有强烈的方向特性。实验结果表明,该文算法的搜索速度和搜索精度优于现有的快速运动估计算法,而搜索精度非常接近于全搜索法。

压缩视频流中主要运动的定性分析

随着视频数据量的急剧增加 ,如何为海量视频数据建立高效索引并提供查询和检索能力成为目前信息检索领域重要的研究课题 .许多研究表明 ,通过对视频中主要运动的定性分析 ,有助于实现视频内容的索引和检索 .该文根据运动矢量的分布特性、运动矢量之间的相对关系特性等 ,提出了一种压缩视频流中主要运动的定性分析算法 .实验结果表明该算法具有速度快、精度高、鲁棒性好等特征 ,非常适合于视频信息检索方面的应用 .

基于运动矢量的摄像机运动定性分类方法

在视频序列中 ,摄像机运动在某种程度上反映了当前视频的部分语义信息 ,知道了摄像机运动将能够更好地实现对视频的浏览以及检索 .针对现有的依据光流分布来求摄像机运动参数算法中的不足 ,给出了一种定性分析相机运动的方法 ,该方法能够在相机聚焦中心—— FOE(focus- of- expansion)不在成像平面中心时检测出给定类型的摄像机运动 .

基于运动方向的异常行为检测

提出了一种基于运动方向的异常行为检测方法.根据不同行为的运动方向具有不同的规律性,该方法采用块运动方向描述不同的动作,并利用支持向量机(Support vector machine,SVM)对实时监控视频进行异常行为检测.为了减少噪声运动的影响,同时有效保留小幅度运动的前景目标,在行为描述之前,本文采用了背景边缘模型对每一视频帧进行前景帧(有目标出现的视频帧)判断.在行为描述时,先提取相应视频段的所有前景帧的块运动方向,然后对这些运动方向进行归一化直方图统计得到该视频段的行为特征.在走廊等公共场景中的实验结果表明,该方法能够对单人以及多人的复杂行为进行有效检测,对运动过程中目标大小的变化、光照的变化以及噪声等具有较好的鲁棒性,而且计算复杂度小,能够实现实时监控.

一种基于秘密共享与运动矢量的视频水印算法

本文在"压缩嵌入联合编码"框架下,提出一种基于秘密共享和信息分级保护的水印生成算法.与用算术编码压缩水印相比,本文的秘密共享方案在保证水印可认证性的前提下大幅度减少了信息嵌入量,同时对嵌入的信息依其重要程度进行分级保护,有效地增强了水印的鲁棒性.在此基础上,利用当前宏块与其周围宏块的运动矢量的相关性,提出一种基于运动矢量的自适应视频水印算法,可有效控制运动矢量的修改幅度,保证视频质量.实验表明该方案能保持很小的峰值信噪比损失和较好的视觉效果,且对于删帧攻击具有较强的鲁棒性.

面向增强视频的基于结构和运动恢复的摄像机定标

提出了一种高效鲁棒的长序列摄像机定标算法,能稳定处理焦距未知且变化的视频序列,适用于增强视频的应用.该算法从长视频序列中根据特征匹配点提炼出相互之间具有较长基线的关键帧,以保证求解的稳定性.算法先在关键帧序列上渐进式求解,以准确恢复特征匹配点的三维结构信息;利用精确恢复的三维点,求解整个序列的摄像机运动参数.该算法选择最适合初始化的三帧求解,并将解及时从射影空间转换到欧氏空间.实验结果显示了所恢复的摄像机参数和三维点的高度精确性,证明了该方法稳定高效,能够满足增强视频的高端要求.