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Video Inter-Frame Forgery Identification Based on Consistency of Correlation Coefficients of Gray Values 被引量:4
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作者 Qi Wang Zhaohong Li +1 位作者 Zhenzhen Zhang Qinglong Ma 《Journal of Computer and Communications》 2014年第4期51-57,共7页
Identifying inter-frame forgery is a hot topic in video forensics. In this paper, we propose a method based on the assumption that the correlation coefficients of gray values is consistent in an original video, while ... Identifying inter-frame forgery is a hot topic in video forensics. In this paper, we propose a method based on the assumption that the correlation coefficients of gray values is consistent in an original video, while in forgeries the consistency will be destroyed. We first extract the consistency of correlation coefficients of gray values (CCCoGV for short) after normalization and quantization as distinguishing feature to identify interframe forgeries. Then we test the CCCoGV in a large database with the help of SVM (Support Vector Machine). Experimental results show that the proposed method is efficient in classifying original videos and forgeries. Furthermore, the proposed method performs also pretty well in classifying frame insertion and frame deletion forgeries. 展开更多
关键词 inter-frame Forgeries CONTENT CONSISTENCY VIDEO FORENSICS
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支持QoS的IEEE 802.11 EDCA性能研究 被引量:16
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作者 毛建兵 毛玉明 +1 位作者 冷鹏 白翔 《软件学报》 EI CSCD 北大核心 2010年第4期750-770,共21页
随着无线网络应用的不断发展,为了适应网络中不同类型业务的区分服务需要,IEEE802.11工作组在IEEE802.11DCF(distributed coordination function)的基础上推出了支持QoS的IEEE802.11EDCA协议.针对EDCA(enhanced distributed channel acc... 随着无线网络应用的不断发展,为了适应网络中不同类型业务的区分服务需要,IEEE802.11工作组在IEEE802.11DCF(distributed coordination function)的基础上推出了支持QoS的IEEE802.11EDCA协议.针对EDCA(enhanced distributed channel access)协议的优先级区分信道接入特性,提出了一种基于Markov链的协议性能模型分析方法.与已有文献不同,该模型分析同时包含了EDCA主要的3个关键区分信道接入机制:Wmin/Wmax,AIFS(arbitration inter-frame space),TXOP(transmission opportunity).通过模型分析,获得了EDCA协议各优先级接入的传输吞吐量、信道接入延迟、数据丢失率等性能分析.不仅分析了饱和情形下的EDCA性能,而且还对非饱和情形下的EDCA性能进行了分析.仿真验证结果表明,模型分析结果和仿真结果取得了很好的一致性.利用给出的模型分析方法,提出了一种基于TXOP动态调整的D-TXOP(dynamic TXOP)接纳控制算法.算法根据网络中业务流的QoS要求,在动态调整各优先级的TXOP参数设置的基础上,对网络中新到业务流进行接纳控制,达到提高网络的业务承载能力的目的. 展开更多
关键词 IEEE 802.11 EDCA AIFS(arbitration inter-frame space) TXOP(transmission opportunity) 性能分析模型 非饱和系统性能 接纳控制算法
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Image Deblurring of Video Surveillance System in Rainy Environment 被引量:6
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作者 Jinxing Niu Yajie Jiang +2 位作者 Yayun Fu Tao Zhang Nicola Masini 《Computers, Materials & Continua》 SCIE EI 2020年第10期807-816,共10页
Video surveillance system is used in various fields such as transportation and social life.The bad weather can lead to the degradation of the video surveillance image quality.In rainy environment,the raindrops and the... Video surveillance system is used in various fields such as transportation and social life.The bad weather can lead to the degradation of the video surveillance image quality.In rainy environment,the raindrops and the background are mixed,which lead to make the image degradation,so the removal of the raindrops has great significance for image restoration.In this article,after analyzing the inter-frame difference method in detecting and removing raindrops,a background difference method is proposed based on Gaussian model.In this method,the raindrop is regarded as a moving object relative to the background.The principle and procedure of the method are given to detect and remove raindrops.The parameters of the single Gaussian background model are studied in this article.The important parameter of the learning rate of Gaussian model is explored in order to better detection and removal of raindrops.Experiment shows that the results of removal of raindrops by using the proposed algorithm are better than that by using the inter-frame difference method.The image processing effect is the best when the learning rate is 0.6.The research results can provide technical reference for similar research on eliminating the influence of rainy weather. 展开更多
关键词 inter-frame difference method Gaussian model RAINDROP background difference
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An Effective CU Depth Decision Method for HEVC Using Machine Learning 被引量:1
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作者 Xuan Sun Pengyu Liu +3 位作者 Xiaowei Jia Kebin Jia Shanji Chen Yueying Wu 《Computer Systems Science & Engineering》 SCIE EI 2021年第11期275-286,共12页
This paper presents an effective machine learning-based depth selection algorithm for CTU(Coding Tree Unit)in HEVC(High Efficiency Video Coding).Existing machine learning methods are limited in their ability in handli... This paper presents an effective machine learning-based depth selection algorithm for CTU(Coding Tree Unit)in HEVC(High Efficiency Video Coding).Existing machine learning methods are limited in their ability in handling the initial depth decision of CU(Coding Unit)and selecting the proper set of input features for the depth selection model.In this paper,we first propose a new classification approach for the initial division depth prediction.In particular,we study the correlation of the texture complexity,QPs(quantization parameters)and the depth decision of the CUs to forecast the original partition depth of the current CUs.Secondly,we further aim to determine the input features of the classifier by analysing the correlation between depth decision of the CUs,picture distortion and the bit-rate.Using the found relationships,we also study a decision method for the end partition depth of the current CUs using bit-rate and picture distortion as input.Finally,we formulate the depth division of the CUs as a binary classification problem and use the nearest neighbor classifier to conduct classification.Our proposed method can significantly improve the efficiency of interframe coding by circumventing the traversing cost of the division depth.It shows that the mentioned method can reduce the time spent by 34.56%compared to HM-16.9 while keeping the partition depth of the CUs correct. 展开更多
关键词 HEVC inter-frame coding CU depth
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Authentication of Video Evidence for Forensic Investigation: A Case of Nigeria 被引量:1
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作者 Beatrice O. Akumba Aamo Iorliam +2 位作者 Selumun Agber Emmanuel Odeh Okube Kenneth Dekera Kwaghtyo 《Journal of Information Security》 2021年第2期163-176,共14页
Video shreds of evidence are usually admissible in the court of law all over the world. However, individuals manipulate these videos to either defame or incriminate innocent people. Others indulge in video tampering t... Video shreds of evidence are usually admissible in the court of law all over the world. However, individuals manipulate these videos to either defame or incriminate innocent people. Others indulge in video tampering to falsely escape the wrath of the law against misconducts. One way impostors can forge these videos is through inter-frame video forgery. Thus, the integrity of such videos is under threat. This is because these digital forgeries seriously debase the credibility of video contents as being definite records of events. <span style="font-family:Verdana;">This leads to an increasing concern about the trustworthiness of video contents. Hence, it continues to affect the social and legal system, forensic investigations, intelligence services, and security and surveillance systems as the case may be. The problem of inter-frame video forgery is increasingly spontaneous as more video-editing software continues to emerge. These video editing tools can easily manipulate videos without leaving obvious traces and these tampered videos become viral. Alarmingly, even the beginner users of these editing tools can alter the contents of digital videos in a manner that renders them practically indistinguishable from the original content by mere observations. </span><span style="font-family:Verdana;">This paper, however, leveraged on the concept of correlation coefficients to produce a more elaborate and reliable inter-frame video detection to aid forensic investigations, especially in Nigeria. The model employed the use of the idea of a threshold to efficiently distinguish forged videos from authentic videos. A benchmark and locally manipulated video datasets were used to evaluate the proposed model. Experimentally, our approach performed better than the existing methods. The overall accuracy for all the evaluation metrics such as accuracy, recall, precision and F1-score was 100%. The proposed method implemented in the MATLAB programming language has proven to effectively detect inter-frame forgeries.</span> 展开更多
关键词 inter-frame Video Forgery Correlation Coefficients Forensic Investigation Threshold
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A channel distortion model for video over lossy packet networks
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作者 CHENG Jian-xin GAO Zhen-ming ZHANG Zhi-chao 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第z1期48-53,共6页
Error-resilient video communication over lossy packet networks is often designed and operated based on models for the effect of losses on the reconstructed video quality. This paper analyzes the channel distortion for... Error-resilient video communication over lossy packet networks is often designed and operated based on models for the effect of losses on the reconstructed video quality. This paper analyzes the channel distortion for video over lossy packet networks and proposes a new model that, compared to previous models, more accurately estimates the expected mean-squared error distortion for different packet loss patterns by accounting for inter-frame error propagation and the correlation between error frames. The accuracy of the proposed model is validated with JVT/H.264 encoded standard test sequences and previous frame concealment, where the proposed model provides an obvious accuracy gain over previous models. 展开更多
关键词 CHANNEL distortion PACKET loss inter-frame error propagation Correlation VIDEO communication
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一种饱和状态下EDCA机制新的性能分析模型
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作者 李杰 《工业控制计算机》 2013年第8期79-80,共2页
针对支持QoS的IEEE 802.11e协议的优先级区分信道接入特性,提出了一种新的性能分析模型方法。考虑在饱和状态下,该模型分析包含了EDCA主要三个方面:AIFS(arbitribution inter-frame space)区分机制,信道和帧拥塞机制以及不同的竞争窗口... 针对支持QoS的IEEE 802.11e协议的优先级区分信道接入特性,提出了一种新的性能分析模型方法。考虑在饱和状态下,该模型分析包含了EDCA主要三个方面:AIFS(arbitribution inter-frame space)区分机制,信道和帧拥塞机制以及不同的竞争窗口大小。在不同的传输负荷,节点数和网络结构条件下。模型分析的值与仿真值在各个优先级接入的传输吞吐量,信道接入延迟和数据丢失率等性能有很好的一致性。 展开更多
关键词 IEEE802 11eEDCA AIFS(arbitribution inter-frame space) 性能分析 饱和状态
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Screen image sequence compression method utilizing adaptive block size coding and hierarchical GOP structure
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作者 武星 梅亮 +2 位作者 袭奇 张申生 陈延伟 《Journal of Central South University》 SCIE EI CAS 2010年第4期786-794,共9页
To compress screen image sequence in real-time remote and interactive applications,a novel compression method is proposed.The proposed method is named as CABHG.CABHG employs hybrid coding schemes that consist of intra... To compress screen image sequence in real-time remote and interactive applications,a novel compression method is proposed.The proposed method is named as CABHG.CABHG employs hybrid coding schemes that consist of intra-frame and inter-frame coding modes.The intra-frame coding is a rate-distortion optimized adaptive block size that can be also used for the compression of a single screen image.The inter-frame coding utilizes hierarchical group of pictures(GOP) structure to improve system performance during random accesses and fast-backward scans.Experimental results demonstrate that the proposed CABHG method has approximately 47%-48% higher compression ratio and 46%-53% lower CPU utilization than professional screen image sequence codecs such as TechSmith Ensharpen codec and Sorenson 3 codec.Compared with general video codecs such as H.264 codec,XviD MPEG-4 codec and Apple's Animation codec,CABHG also shows 87%-88% higher compression ratio and 64%-81% lower CPU utilization than these general video codecs. 展开更多
关键词 screen image sequence compression adaptive block size hierarchical GOP structure intra-frame coding inter-frame coding
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Integrated visual navigation based on angles-onlymeasurements for asteroid final landing phase 被引量:1
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作者 Ronghai Hu Xiangyu Huang Chao Xu 《Astrodynamics》 EI CSCD 2023年第1期69-82,共14页
Visual navigation is imperative for successful asteroid exploration missions.In this study,an integrated visual navigation system was proposed based on angles-only measurements to robustly and accurately determine the... Visual navigation is imperative for successful asteroid exploration missions.In this study,an integrated visual navigation system was proposed based on angles-only measurements to robustly and accurately determine the pose of the lander during the final landing phase.The system used the lander's global pose information provided by an orbiter,which was deployed in space in advance,and its relative motion information in adjacent images to jointly estimate its optimal state.First,the landmarks on the asteroid surface and markers on the lander were identified from the images acquired by the orbiter.Subsequently,an angles-only measurement model concerning the landmarks and markers was constructed to estimate the orbiter's position and lander's pose.Subsequently,a method based on the epipolar constraint was proposed to estimate the lander's inter-frame motion.Then,the absolute pose and relative motion of the lander were fused using an extended Kalman filter.Additionally,the observability criterion and covariance of the state error were provided.Finally,synthetic image sequences were generated to validate the proposed navigation system,and numerical results demonstrated its advance in terms of robustness and accuracy. 展开更多
关键词 asteroid final landing phase visual navigation angles-only measurements inter-frame motion estimation state fusion
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Plantar ROI Characterization during the Stance Phase of Gait Based on a Low-cost Pressure Acquisition Platform
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作者 Zhanyong Mei Guoru Zhao +1 位作者 Qingsong Zhu Lei Wang 《Journal of Bionic Engineering》 SCIE EI CSCD 2012年第3期343-352,共10页
Plantar Region of Interest (ROI) detection is important for the early diagnosis and treatment ofmorphologic defects of the foot and foot bionic research. Conventional methods have employed complex procedures and exp... Plantar Region of Interest (ROI) detection is important for the early diagnosis and treatment ofmorphologic defects of the foot and foot bionic research. Conventional methods have employed complex procedures and expensive instruments which prohibit their widespread use in healthcare. In this paper an automatic plantar ROIs detection method using a customized low-cost pressure acquisition device is proposed. Plantar pressure data and 3D motion capture data were collected from 28 subjects (14 healthy subjects and 14 subjects with hallux valgus). The maximal inter-frame difference during the stance phase was calculated. Consequently, the ROIs were defined by the first-order difference in combination with prior anatomic knowl- edge. The anatomic locations were determined by the maximal inter-frame difference and second maximal inter-frame differ- ence, which nearly coincided. Our system can achieve average recognition accuracies of 92.90%, 89.30%, 89.30%, 92.90%, 92.90%, and 89.30% for plantar ROIs hallux and metatarsi I-V, respectively, as compared with the annotations using the 3D motion capture system. The maximal difference of metatarsus heads II-V, and the impulse of the medial and lateral heel features made a significant contribution to the classification ofhallux valgus and healthy subjects with ≥ 80% sensitivity and specificity. Furthermore, the plantar pressure acquisition system is portable and convenient to use, thus can be used in home- or commu- nity-based healthcare applications. 展开更多
关键词 dynamic plantar pressure ROIs inter-frame difference foot biomechanics Fisher discrimination
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