基于累积直方图的视频镜头边界检测方法

提出了一种基于累积直方图的视频镜头边界检测方法,以累积直方图来代表视频帧图像的特征,其帧差充分反映了视频帧图像间的差异性;结合滑动窗的局部阈值分割处理,获得镜头边界检测对物体/摄像机的运动和光线变化的不敏感性。实验结果表明,本方法在镜头突变边界检测中达到95.97%的查全率和96.75%的查准率。     

一种自动选取阈值的视频镜头边界检测算法

镜头边界检测是实现基于内容的视频检索的一个重要步骤.文中介绍了现有的镜头边界检测的基本方法,并针对其不足提出了一种自动选取阈值的、综合考虑颜色和空间特征的镜头边界检测算法.该方法能较好地检测出镜头突变和物体运动以及光线变化等情况,对渐变镜头也能达到检测的目的.实验结果表明算法能够有效地检测出视频镜头边界.     

压缩域中基于支持向量机的镜头边界检测算法

针对如何进一步提高镜头边界检测精度问题,本文提出了一个基于支持向量机SVM (Support Vector Machine)的镜头边界检测算法.该算法利用视频压缩域中特征,如宏块类型,帧间对应宏块DC系数差和帧类型将视频帧分为发生切变的帧、发生渐变的帧和非镜头变换帧三类,从而实现视频的镜头分割.实验结果表明该算法对摄像机的运动和大物体的进入具有很好的鲁棒性,且没有大多数算法中阈值选择的困难,将我们的算法与2001 TREC评估中最佳指标进行了比较,在综合度量查全率和查准率的性能指标F1上,比2001 TREC评估中最佳指标高约8％.     

基于地理信息和图像识别的 新闻虚拟化制作系统

在大型航拍及摄像机外景借助交通工具的实时拍摄中,通过对行进中的交通工具的GPS定位、对摄像机镜头画面运动数据的精准捕获或者通过视频分析的方式,可以实现电视信号的实时包装和虚拟化制作,从而促进新闻报道制作手段的发展.     

一种快速有效的视频镜头边界检测方法

本文在分析现有的镜头边界检测方法的基础上,提出了一种层次化镜头边界检测方法.首先我们利用小波变换对信号奇异点的检测能力和对噪声具有较强的鲁棒性,实现了镜头边界的预检测.然后我们通过对候选镜头边界的虚警分析,有效地降低了闪光灯和快速运动对镜头边界检测产生的影响,并实现了镜头突变检测.在渐变类型分类中,我们分别实现了淡入淡出、扫换和溶解等三种重要镜头边界类型的检测.实验结果表明,本文方法能够快速、有效地实现视频镜头边界类型的检测,对运动和光线变化有较强的鲁棒性.     

一种MPEG压缩视频的镜头边界检测算法

提出一种工作在MPEG压缩域的检测算法.首先从压缩视频中提取DC图像和重构参考帧,然后经过全局运动补偿之后进行基于边对象变化率的镜头分割点检测,最后结合DC图直方图差法构成联合检测算法.本算法能准确地检测到镜头渐变,镜头切变,能得到渐变类型等特性.用AdobePremiere5.1生成的各类镜头转换视频片段进行检测,实验结果验证了算法的有效性.     

利用补偿矩阵的可变焦摄像机跟踪算法

变焦镜头的标定和跟踪技术已广泛应用于虚拟演播室,体育视频转播等领域.由于在长焦范围,普遍采用的针孔模型已不再适用,导致长焦镜头的标定和跟踪难以达到较高的精度.从分析变焦镜头内部结构出发,对变焦时透镜组之间的相互运动与摄像机外参之间的关系进行详细研究,提出用补偿矩阵来补偿变焦过程中产生的摄像机外参的偏移.该方法在不改变原...     

基于能流信息的视频分割

通过把视频序列中图像的像素看作运动的气体分子,本文提出了一个图像温度场的概念,并利用描述气体分子做无规则运动的麦克斯韦-玻尔兹曼分布律,来描述图像序列中像素的运动规律.与传统光流信息相比,由图像温度场估算出的能流信息更加精确地描述了图像间的运动场,把该能流信息进一步应用到视频镜头的自动分割中,仿真实验结果表明,基于能流分析的视频分割方法更加准确地检测出了镜头的切变和渐变.     

一种检测足球视频中射门镜头的方法

体育视频中事件的检测是基于内容的体育视频检索的前提.根据足球比赛视频的特点,提出了一种有效的射门镜头检测方法,即利用主颜色区域检测和投影法来检测射门镜头,从而实现了按射门镜头对视频进行检索.最后给出实验结果及分析.     

基于场边界线的多摄像机智能监控系统研究

伴随视频监控系统的普及,多摄像机智能视频监控技术得到了广泛的研究和应用。特别是视频监控中的运动目标检测分割、运动目标跟踪和多摄像机协同技术,成为计算机视觉领域研究的热点。单摄像机跟踪常被应用的监控范围限制,当监控场景是一个室外环境或需要一个较大的观测范围时,常需要多摄像机进行多物体跟踪。为了建立一套有效的多摄像机智能监控系统,提出一种基于摄像机视野的重叠区域的协同监控方法,找出重叠区域的边界线即场边界线,旨在解决单摄像机监控范围有限的问题,实现对某一场景进行全景监控。在多摄像机系统中各个摄像机的场边界线在其他摄像机中可见的情况下,给出寻找它们的方法。基于此,可基本确定在多摄像机中的运动目标对应关系,获取多摄像机的拓扑关系。     

A high-precision camera operation parameter measurement system andits application to image motion inferring

Information about camera operations such as zoom, focus, pan, tilt and dollying is significant not only for efficient video coding, but also for content-based video representation. In this paper we describe a high-precision camera operation parameter measurement system and apply it to image motion inferring. First, we outline the implemented system which is designed to provide camera operation parameters with a high precision required for image coding applications. Second, we calibrate the camera lens to determine its exact optical properties, A pin-hole camera model with the 2nd order radial lens distortion and a two-image calibration technique are employed. Finally, we use the pan, tilt and zoom parameters measured by the system to infer image motion. The experimental results show that the inferred motion coincides with the actual motion very closely. Compared to the motion analysis techniques that estimate camera motion from video sequences, our approach does not suffer from ambiguity, thus can provide reliable and accurate image global motion. The obtained motion can be applied to image mosaicing, moving object segmentation, object-based image coding, etc     

Video Annotation by Motion Interpretation Using Optical Flow Streams

A new approach to automatic annotation of video sequences by dominant camera motion interpretation is presented. Unlike other approaches, we separate the optical flow into two categories—singularandnon-singular—which, as we show, is a more natural way of classification for the purpose ofdominantcamera motion interpretation. We show that identification of patterns created by such natural categories, which can be observed from themeasuredoptical flow, can help focus the interpretation ofdominantcamera motion in video segments. For robust detection of such natural patterns, we propose the computation of optical flow streams (OFS) from the video data and analyze the OFS for the extraction of dominant motion content in the video segments. The advantage of the proposed approach is its robustness in the extraction of dominant motion content in a video segment. We demonstrate this on a variety of real video sequences by generating the automatic motion annotation of the video frames and comparing it with manual motion annotation.     

利用全景图的视频稳像算法

针对具有场景变换、景深变换较小的抖动视频,本文提出了一种利用全景图的视频稳像方法。不同于传统稳像方法,本文所提算法利用原始视频序列生成广角视图,通过后期抽取视频帧,以合成方式输出稳定视频。通过区域块的运动估计,获取相机的运动轨迹;在此基础上,为消除视频抖动导致的原始运动轨迹的非平滑问题,提出了一种基于运动矢量统计的相机运动模式判决方法,并以此选择相应的平滑方式。最后,通过平滑后的运动轨迹对全景图进行抽帧,合成平滑、稳定视频。实验结果表明,本文提出的稳像方法能有效去除较大抖动,同时避免了对视频宽度的裁剪等后处理,具有较好的稳像能力。      

Recognition of dynamic video contents with global probabilistic models of visual motion.

The exploitation of video data requires methods able to extract high-level information from the images. Video summarization, video retrieval, or video surveillance are examples of applications. In this paper, we tackle the challenging problem of recognizing dynamic video contents from low-level motion features. We adopt a statistical approach involving modeling, (supervised) learning, and classification issues. Because of the diversity of video content (even for a given class of events), we have to design appropriate models of visual motion and learn them from videos. We have defined original parsimonious global probabilistic motion models, both for the dominant image motion (assumed to be due to the camera motion) and the residual image motion (related to scene motion). Motion measurements include affine motion models to capture the camera motion and low-level local motion features to account for scene motion. Motion learning and recognition are solved using maximum likelihood criteria. To validate the interest of the proposed motion modeling and recognition framework, we report dynamic content recognition results on sports videos.     

MPEG-2压缩域中鲁棒性摄像机运动估计算法的研究

在视频检索的很多应用中,比如对象轨迹追踪,都需要首先分离摄像机运动。现提出一种MPEG-2压缩域中鲁棒性摄像机运动估计——自适应尺度残差一致性ASRC（Adaptive-Scale Residual Consensus）算法,只使用P帧的运动向量,并对多重结构噪声可达到80%的击穿点,使MPEG矢量场中奇异值的影响降到最小。对比经典LMedS估计,提出的ASRC具有更好的鲁棒性和击穿点。实验结果显示出令人满意的效果。     

Motion Compensated Subband Video Coding with Arbitrarily Shaped Region Adaptivity

The performance of Motion Compensated Discrete Cosine Transform (MC‐DCT) video coding is improved by using the region adaptive subband image coding [18]. On the assumption that the video is acquired from the camera on a moving platform and the distance between the camera and the scene is large enough, both the motion of camera and the motion of moving objects in a frame are compensated. For the compensation of camera motion, a feature matching algorithm is employed. Several feature points extracted using a Sobel operator are used to compensate the camera motion of translation, rotation, and zoom. The illumination change between frames is also compensated. Motion compensated frame differences are divided into three regions called stationary background, moving objects, and newly emerging areas each of which is arbitrarily shaped. Different quantizers are used for different regions. Compared to the conventional MC‐DCT video coding using block matching algorithm, our video coding scheme shows about 1.0‐dB improvements on average for the experimental video samples.     

A Stereoscopic Video Generation Method Using Stereoscopic Display Characterization and Motion Analysis

Stereoscopic video generation methods can produce stereoscopic content from conventional video filmed with monoscopic cameras. In this paper, we propose a stereoscopic video generation method using motion analysis which converts motion into disparity values and considers multi-user conditions and the characteristics of the display device. The field of view and the maximum and minimum disparity values were calculated in the stereoscopic display characterization stage and were then applied to various types of 3D displays. After motion estimation, we used three cues to decide the scale factor of motion-to-disparity conversion. These cues were the magnitude of motion, camera movements and scene complexity. A subjective evaluation showed that the proposed method generated more satisfactory video sequence.     

Threshold‐Based Camera Motion Characterization of MPEG Video

We propose an efficient scheme for camera motion characterization in MPEG‐compressed video. The proposed scheme detects six types of basic camera motions through threshold‐based qualitative interpretation, in which fixed thresholds are applied to motion model parameters estimated from MPEG motion vectors (MVs). The efficiency and robustness of the scheme are validated by the experiment with real compressed video sequences.     

基于MPEG压缩域的快速、鲁棒的全局运动信息提取方法

全局运动信息在视频分析中起着重要的作用.本文根据MPEG编码特点,提出了一种从MPEG压缩域中快速有效地进行全局运动参数估计的算法.该算法充分利用了MPEG压缩码流中的信息,通过提取预测残差DC图像的运动背景区域,估计全局运动参数,从而保证了参数估计的准确性,有效地克服了已有文献中仅仅采用运动矢量进行全局运动估计的局限性.根据不同的MPEG测试序列的对比分析,结果表明,本算法可快速准确地对MPEG视频序列进行全局运动信息估计,同时具有很高的鲁棒性.