Detecting video frame rate up-conversion based on frame-level analysis of average texture variation

Multimedia Tools and Applications - Frame rate up-conversion (FRUC) refers to frame interpolation between adjacent video frames to increase the motion continuity of low frame rate video, which can...     

Blind MV-based video steganalysis based on joint inter-frame and intra-frame statistics

Multimedia Tools and Applications - Despite all its irrefutable benefits, the development of steganography methods has sparked ever-increasing concerns over steganography abuse in recent decades....     

Double up-conversion of video frame rate based on bidirectional motion compensation

An algorithm for video sequence frame rate double up-conversion is described. The algorithm is based on bidirectional motion compensation. The algorithm has no smoothing in the time domain implying the absence of the image sharpness oscillations in the transformed video sequence. A special post-processing step with adaptively controlled degree of smoothing makes it possible to considerably decrease the “blocking” artifact while retaining the maximum number of image details. The absence of complicated mathematical computations allows realtime hardware implementation of the algorithm and real-time video processing.     

基于SHVC的帧间算法研究

为了减小算法复杂度,针对SHVC,结合了CU分割、PU预测模式两个方面,提出了一种快速算法。该算法在PSNR与码率有略微变化(可忽略不计)的前提下,平均编码时间降低了约30%~45%。并将HEVC的帧间预测技术创造性地升华到SHVC中,在一定程度上对SHVC的帧间算法研究进行了改进。根据在测试模型SHM的实验证明,该算法可行、有效。     

基于帧间预测模式的插值滤波器

为了进一步降低计算复杂度,提高视频图像的质量,通过对帧间预测模式的运动补偿分析及图像的频谱分析,提出了一种基于帧间预测模式的插值滤波器算法.该算法对每个不同的分块编码模式使用不同阶次的插值滤波器,为每一个分块编码模式选择最优的插值滤波器.实验结果表明,该算法不仅能有效地降低计算复杂度,还能提高信噪比,使图像的质量得到进一步的改善.     

Inter-frame passive-blind forgery detection for video shot based on similarity analysis

Multimedia Tools and Applications - Frame insertion, deletion and duplication are common inter-frame tampering operations in digital videos. In this paper, based on similarity analysis, a...     

基于图聚类和序列信息的蛋白质远同源性探测

远同源蛋白间的序列相似性很低,处于随机涨落区域边缘,很难区分通过比对获得的序列特征是进化过程中功能约束还是随机突变导致的结果。为了从具有高度噪音的比对分数中提取关于同源性的微弱信号,本文将基于模块度优化的图聚类算法应用于蛋白质相似性网络来探测远同源性,并与已有的性能表现较好的方法进行比较,实验结果表明,该方法能较好地探测到蛋白质远同源性,输出的集团在很大程度上对应着蛋白质超家族,输出的集团数目接近数据集中超家族的个数,得到的结果明显优于其他方法。     

Evaluation of similarity measures for video retrieval

Multimedia Tools and Applications - Similarity measures are very crucial especially in the field of information retrieval. Thus, various distance/similarity measures were proposed throughout the...     

基于词汇语义计算的文本相似度研究

基于《知网》的词汇语义计算方法揭示了词汇间的语义信息。根据文本的向量空间模型描述形式,采用了基于《知网》的词汇语义计算方法来计算两篇文章向量的相关性,并用最大匹配算法来获得这两篇文章的相似度,通过该计算过程达到揭示文本所蕴涵概念的目的,并用实验对该方法的有效性进行了验证,提出了今后的改进方向。     

Fast similarity search and clustering of video sequences on the world-wide-web

We define similar video content as video sequences with almost identical content but possibly compressed at different qualities, reformatted to different sizes and frame-rates, undergone minor editing in either spatial or temporal domain, or summarized into keyframe sequences. Building a search engine to identify such similar content in the World-Wide Web requires: 1) robust video similarity measurements; 2) fast similarity search techniques on large databases; and 3) intuitive organization of search results. In a previous paper, we proposed a randomized technique called the video signature (ViSig) method for video similarity measurement. In this paper, we focus on the remaining two issues by proposing a feature extraction scheme for fast similarity search, and a clustering algorithm for identification of similar clusters. Similar to many other content-based methods, the ViSig method uses high-dimensional feature vectors to represent video. To warrant a fast response time for similarity searches on high dimensional vectors, we propose a novel nonlinear feature extraction scheme on arbitrary metric spaces that combines the triangle inequality with the classical Principal Component Analysis (PCA). We show experimentally that the proposed technique outperforms PCA, Fastmap, Triangle-Inequality Pruning, and Haar wavelet on signature data. To further improve retrieval performance, and provide better organization of similarity search results, we introduce a new graph-theoretical clustering algorithm on large databases of signatures. This algorithm treats all signatures as an abstract threshold graph, where the distance threshold is determined based on local data statistics. Similar clusters are then identified as highly connected regions in the graph. By measuring the retrieval performance against a ground-truth set, we show that our proposed algorithm outperforms simple thresholding, single-link and complete-link hierarchical clustering techniques.     

一种新的HEVC快速帧间预测单元模式判决算法

针对HEVC中帧间预测模式判断所带来的高复杂度计算,根据视频时域上高度相关性的特点,提出了一种减少AMVP模式执行次数的低计算复杂度的快速帧间预测模式判决的方法。基于相邻帧的相同位置编码单元(CU)的预测单元(PU)模式上的时域相关性,跳过当前PU模式选择过程中一些冗余的AMVP模式的计算,以此来降低编码的复杂度。实验结果表明,在编码效率和峰值信噪比(PSNR)损失很小的情况下,比现有HEVC帧间预测算法减少了33.04%的编码时间。     

基于上转换发光技术的便携式食品安全检测仪设计

针对当前食品安全快速检测设备存在灵敏度低、无法准确定量检测等问题,设计了一种定量、快速的便携式食品安全检测仪,其能够快速筛查食品中多种食品危害因子。利用上转换材料处理食品样品产生特征荧光,设计了以STM32F103C8T6单片机为核心的检测仪进行检测荧光信号,包括信号检测光路系统和信号处理电路系统,以及嵌入式主控程序软件设计。实验结果表明:检测仪功耗低,体积小,准确度高,实际样品检测回收率在97. 5%～105%之间,满足快速检测的需求。     

Malicious inter-frame video tampering detection in MPEG videos using time and spatial domain analysis of quantization effects

In this paper, a new algorithm is proposed for forgery detection in MPEG videos using spatial and time domain analysis of quantization effect on DCT coefficients of I and residual errors of P frames. The proposed algorithm consists of three modules, including double compression detection, malicious tampering detection and decision fusion. Double compression detection module employs spatial domain analysis using first significant digit distribution of DCT coefficients in I frames to detect single and double compressed videos using an SVM classifier. Double compression does not necessarily imply the existence of malignant tampering in the video. Therefore, malicious tampering detection module utilizes time domain analysis of quantization effect on residual errors of P frames to identify malicious inter-frame forgery comprising frame insertion or deletion. Finally, decision fusion module is used to classify input videos into three categories, including single compressed videos, double compressed videos without malicious tampering and double compressed videos with malicious tampering. The experimental results and the comparison of the results of the proposed method with those of other methods show the efficiency of the proposed algorithm.     

Efficient video encryption scheme based on advanced video coding

A video encryption scheme combining with advanced video coding (AVC) is presented and analyzed in this paper, which is different from the ones used in MPEG1/2 video encryption. In the proposed scheme, the intra-prediction mode and motion vector difference are encrypted with the length-kept encryption algorithm (LKE) in order to keep the format compliance, and the residue data of the macroblocks are encrypted with the residue data encryption algorithm (RDE) in order to keep low cost. Additionally, a key distribution scheme is proposed to keep the robustness to transmission errors, which assigns sub-keys to different frames or slices independently. The encryption scheme’s security, time efficiency and error robustness are analyzed in detail. Experimental results show that the encryption scheme keeps file format unchanged, is secure against replacement attacks, is efficient in computing, and is robust to some transmission errors. These properties make it a suitable choice for real-time applications, such as secure IPTV, secure videoconference or mobile/wireless multimedia, etc.

基于视频的角色动画

现有的计算机动画制作普遍存在投资大、效率不高等缺陷.为此,提出了利用计算机视觉技术中的一种基于特征的跟踪方法-KL(Kanade-Lucas)算法.首先捕获视频中角色的二维运动信息,然后进行三维重建生成满足动画要求的三维角色运动序列,最后将三维角色运动序列重定向到动画模型中去,从而得到逼真的角色动画.实际运行结果表明,从来源广、成本低的视频中完成角色运动提取与合成,从而生成逼真动画的可行性.     

Skull similarity comparison based on SPCA

Multimedia Tools and Applications - As an important biological feature of the human, the skull plays an active role in assisting criminal investigation, victim identification, etc. This paper...     

基于相似度的区间数排序

为设计一种简便而又科学的区间数排序方法,在综合考虑区间数的特点、提取区间数中的隐形数据、对数据进行处理等基础上,根据各个区间数与目标区间数相似度程度的不同,提出了一种新的对区间数进行排序的方法,并提出了这种排序方法的一些优良性质,如:序关系完全性、传递性、等价替换性、区间数长度相等且区间数的属性为效益型时中心越大越好、区间数中心重合时区间越小越好等,充分表明了这种方法的科学性与可行性。最后,通过一个算例说明这种简单、方便、科学的排序方法的操作过程。     

基于单词相似度的文本聚类

研究了现有的基于向量空间模型的文本聚类算法,发现这些算法都存在数据维度过高和忽略了单词之间语义关系的缺点.针对这些问题,提出一种基于单词相似度的文本聚类算法,该算法首先利用单词相似度对单词进行分类获得单词间的语义关系,然后利用产生的单词类作为向量空间的项表示文本降低了向量空间的维度,最后采用基于划分聚类方法对文本聚类.实验结果表明,相对于传统基于向量空间模型的聚类算法,该算法具有较好的聚类效果.     

基于部件的文本相似度计算

相似度的计算在信息检索及文档复制检测等领域具有广泛的应用前景.研究了文本相似度的计算方法,以汉字数学表达式理论为基础,提出了一种新的文本部件粒度表示方法,根据部件频次建立文本特征向量空间模型,并在此模型基础上给出了相应的文本相似度计算公式及算法,用于计算两文本之间的相似度.实验结果表明,该算法与现有典型的相似度计算方法相比,具有实现精度高、计算简便等优点.