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本文提出了一种新的在MPEG-4编码过程中提高实时性的算法。算法采用双重筛选机制,充分利用了运动估计的结果提取运动对象。首先在运动估计过程中加入背景优先准则进行第一重筛选;然后根据运动估计后宏块的最小平均绝对差值分利用区域自适应门限进行第二重筛选,从而获得运动区域掩模;最后对掩模进行形态滤波和填充消除噪声点,最终得到运动区域。算法分别在硬件和软件平台上进行测试,结果表明提出的算法得到了理想的分割效果,较传统的在编码前进行运动对象提取的方法实时性大大提高了。 相似文献
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一种有效的基于运动矢量场的压缩域运动对象分割算法 总被引：1，自引：0，他引：1
In this paper an efficient compressed domain moving object segmentation algorithm is proposed, in which the motion vector (MV) field parsed from the compressed video is the only cue used for moving object segmentation. First the MV field is temporally and spatially normalized, and then accumulated by an iterative backward projection to enhance salient motions and alleviate noisy MVs. The accumulated MV field is then segmented into motion-homogenous regions using a modified statistical region growing approach. Finally, moving object regions are extracted in turn based on minimization of the joint prediction error using the estimated motion models of two region sets containing the candidate object region and other remaining regions, respectively. Experimental results on several H.264 compressed video sequences demonstrate good segmentation performance. 相似文献
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WU Xue-dong SONG Zhi-huan 《浙江大学学报(A卷英文版)》2007,8(10):1604-1613
Determination of relative three-dimensional (3D) position, orientation, and relative motion between two reference frames is an important problem in robotic guidance, manipulation, and assembly as well as in other fields such as photogrammetry. A solution to pose and motion estimation problem that uses two-dimensional (2D) intensity images from a single camera is de- sirable for real-time applications. The difficulty in performing this measurement is that the process of projecting 3D object features to 2D images is a nonlinear transformation. In this paper, the 3D transformation is modeled as a nonlinear stochastic system with the state estimation providing six degrees-of-freedom motion and position values, using line features in image plane as measuring inputs and dual quaternion to represent both rotation and translation in a unified notation. A filtering method called the Gaussian particle filter (GPF) based on the particle filtering concept is presented for 3D pose and motion estimation of a moving target from monocular image sequences. The method has been implemented with simulated data, and simulation results are provided along with comparisons to the extended Kalman filter (EKF) and the unscented Kalman filter (UKF) to show the relative advantages of the GPF. Simulation results showed that GPF is a superior alternative to EKF and UKF. 相似文献
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为了从视频序列中获取初始视频对象,提出了一种改进的基于运动连通性的初始视频对象提取算法.视频中的运动对象高度连通结构化,这就使得运动连通性是适用于视频对象分割的高级特征.据此首先对反映对象的一致性运动的累计帧差图进行尖锐噪声滤除,然后应用自适应阈值算法提取对象运动区域,接着根据运动连通性标记出最大连通区域,通过后处理得到视频对象的分割模版从而有效提取出初始视频对象.对比实验结果表明,该算法能自动、快速、准确地提取出初始视频对象,获得了理想的主客观分割效果. 相似文献
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A method was presented to implement the detecting and tracking of moving targets through omnidirectional vision.The method combined optical flow with particle filter arithmetic.in which optical flow field was used to detect and locate moving targets and particle filter was used to track the detected moving objects.According to the circular image character of omnidirectionaI vision.the calculation equation of optical flow field and the tracking arithmetic of particle filter were improved based on the polar coordinates at the omnidirectional center.The edge of a randomly moving object could be detected by optical flow field and was surrounded by a reference region in the particle filter.A dynamic motion model was established to predict particle state.Histograms were used as the features in the reference region and candidate regions.The mutual information(MI)and Gaussian function were combined to calculate particle weights.Finally,the state of tracked object was computed by the total particle states with weights.Experiment results show that the proposed method could detect and track moving objects with better realtime performance and accuracy. 相似文献
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姚艳玲 《常熟理工学院学报》2020,(3):73-79,109
日语以自他动词接辞形态转换的形式区分路径要素相同的自移事件和致移事件。这种接辞形态转换可以划分为他动化、非他动化及中立化三种类型。自移与致移的形态标记在语义上表现出自移动词具有较高的“意志性”;致移动词具有较高的“受影响性”。在路径要素的编码方式上自移动词既有完全融入型编码,也会有不完全融入型编码;而致移动词则较多呈现出完全融入型的编码方式。考察不同位移事件类型中同一路径要素编码方式的差异性,可以为我们以形态标记的有标性探讨位移事件的语言类型学特征提供新的视角。 相似文献
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A method was presented to implement the detecting and tracking of moving targets through omnidirectional vision. The method
combined optical flow with particle filter arithmetic, in which optical flow field was used to detect and locate moving targets
and particle filter was used to track the detected moving objects. According to the circular image character of omnidirectional
vision, the calculation equation of optical flow field and the tracking arithmetic of particle filter were improved based
on the polar coordinates at the omnidirectional center. The edge of a randomly moving object could be detected by optical
flow field and was surrounded by a reference region in the particle filter. A dynamic motion model was established to predict
particle state. Histograms were used as the features in the reference region and candidate regions. The mutual information
(MI) and Gaussian function were combined to calculate particle weights. Finally, the state of tracked object was computed
by the total particle states with weights. Experiment results show that the proposed method could detect and track moving
objects with better real-time performance and accuracy.
Supported by Tianjin Higher Education Technology Development Foundation (No.20071308), Tianjin Natural Science Foundation
(06YFJMJC03600) and National Natural Science Foundation of China (No.60773073).
YANG Shuying, born in 1964, female, Dr, Prof. 相似文献
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针对运动图像盲去模糊问题,基于生成对抗网络,提出利用一种端对端方式恢复模糊图像算法。运用生成对抗神经网络方法对运动模糊图像直接复原,跳过估计模糊核过程,增加感知损失作为损失项,使图片内容和全局结构接近。此外,增加结构相似性损失函数作为约束项,进一步提升生成图片与清晰图片的相似性。实验结果表明,新算法可有效去除运动图像模糊。与其它算法相比,所提算法获得的图像更加清晰。 相似文献
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台风结构的非对称性对台风运动的影响 总被引：2，自引：0，他引：2
吴池胜 《中山大学学报论丛》1994,(5)
本文分析了台风中心附近涡度局地变化■／■t的非对称性对台风加（减）速运动的影响结果表明，突然加速的台风，其前方和后方的■／■t分别为较大的正值和较小的负值；而突然减速的台风，其■／■t的分布则正相反此外，设计了一个综合考虑引导气流、涡旋结构以及涡度变化等因子作用的台风运动的预测方案。 相似文献
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为了提高人体运动位姿误差检测能力,提出基于双目视觉的运动位姿误差检测方法。采用双目视觉跟踪融合识别方法对运动位姿的样本动态特征点进行采样,以全局人体姿态信息为候选样本,进行运动位姿双目视觉特征高分辨提取,采用模板匹配方法,构建人体部位姿态候选样本轮廓分布集,获取模板大小,根据模板大小计算运动位姿的误差概率分布,利用相邻图像帧之间的运动特征分布集,构建运动位姿图像的位置信息检测模型,在此基础上,采用自适应颜色覆盖方法对运动位姿的误差概率分布做极小化处理,完成对人体运动位姿误差检测。仿真结果表明,采用该方法进行运动位姿误差检测的特征分辨能力很好,降低了检测误差,提高了运动位姿双目视觉跟踪识别能力。 相似文献
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The onset of motion was used to study stimulus-driven visual attention in 14-week-olds. The movement of an object did not capture attention reflexively at 14 weeks of age. The attention-getting properties of a moving stimulus depended significantly on its color in combination with the colors of other objects in the visual field. Specifically, detection of a green moving target was masked in the presence of mixed red and green static objects. No such masking was observed when the moving target was red or when the green target moved in a visual field that was populated only with green objects. The same effect was observed to a lesser extent when the green bars were replaced with gray bars. The number of distractors in the visual field exerted an effect on the accuracy of detection only when their appearance in the visual field was coincident with the onset of target motion. Attention to motion at this age is not independent of the structure of the visual field; chromatic preferences play a role in how readily infants attend to a moving object. These effects may be mediated by a difficulty in disengaging attention (from distractors) or in suppressing attention to competing objects once attention is engaged on a target. 相似文献
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Presentations of a visible moving object immediately suppressed ongoing distress vocalization in newly hatched ducklings, but presentations of only the auditory features of the object initially had no effect. However, as the ducklings received more and more exposure to the visible moving object, the object’s auditory features gradually acquired the ability to suppress distress calls themselves. These auditory features failed to develop suppressive properties in ducklings which received prolonged exposure to those features but never saw the object in motion. The gradual acquisition of behavioral control by the auditory features of a moving object is taken to represent the essence of the imprinting process. 相似文献
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针对复杂环境下的多目标跟踪问题提出了一种新的跟踪方法．在检测部分,采用第三级离散小波变换和背景差分进行了目标分割．在跟踪部分,首先利用卡尔曼滤波器和缩放因子估计目标在下一帧中的中心位置和矩形框尺寸,然后在中心关联和区域关联的基础上提出了投射率和遮挡率的概念,并结合投射率和遮挡率推断目标行为．最后针对具体目标行为,自适应地调整跟踪方案和卡尔曼参数实现了多目标跟踪．在遮挡情况下利用部分观测调整估计框以获得目标测量值和最优框尺寸．提出的方法对处于遮挡、新出现以及稳定等情况下的运动目标均具有鲁棒的跟踪性能．实验结果表明提出的方法是有效的． 相似文献
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王云飞 《石家庄职业技术学院学报》2013,25(4):1-5
研究发现,物体运动导致时空偏转,时空偏转角的正弦等于运动速度与光速之比.匀速运动的时空偏转角为常数,时空平直;变速运动的时空偏转角为变量,时空弯曲.惯性是时空保持自身平直的属性,惯性力是平直时空为抵抗弯曲变形,对变速运动物体施加的作用力;惯性力与引力性质相同,都源于物体与时空的相互作用.用激光干涉仪对物体变速运动导致时空弯曲进行了试验验证,结果表明,理论预言与试验完全一致. 相似文献
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研究自旋航天器处于无力矩状态，运动附件作为摄动项对其姿态的影响．利用Melnikov方法预测航天器受微小扰动存在混沌运动。并在高维空间进行数值模拟验证此结论的正确性． 相似文献
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Educational research has shown that high school and university students also follow the Aristotelian idea about motion; for example, a continuous action of a force is necessary to keep an object in motion. The survey presented in this article aims at a deeper investigation of secondary education students' ideas about the forces involved in objects moving under the sole influence of gravity. The main objectives are: (1) to investigate other ideas or difficulties, which intervene and determine students' mental models about motion and force, and (2) to reveal how the students in the sample are grouped according to their alternative conceptions. Our study has been mainly determined by the revision in Science Curriculum established in Greece three years ago. A survey has been administered to a total of 146 students (15–16 years old) attending six typical public high schools in Greece. The results presented show that the traditional instruction is pertinent while the approaches of the New Physics Curriculum have not been effectively expanded to the schools. The majority of the students exhibited the idea that the original force is continuously exerted to the ball during its motion. On the other hand, multivariate analysis has identified three discernible groups of students which have exhibited a persistent and rather consistent approach: (1) An extended group of students having the above misconception, (2) a second group of students which, generally, responded correctly to the tasks, and (3) a third group of students, which ignored the presence of the gravitational force and/or believe that the action-reaction forces are both exerted to the ball during its motion. 相似文献
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杨作玲 《河北北方学院学报(社会科学版)》2012,(4):18-20,24
先秦趋向动词的句法表现复杂,其差异主要表现在两个方面:一是是否必须带处所宾语;二是是否有使动交替形式。根据这两方面的表现以及非宾格动词的判断式,趋向动词中的一部分可归为非宾格动词,一部分归入及物动词或非作格动词,少数动词还可以两属。先秦趋向动词并不是典型的非宾格动词语义类,影响非宾格性的主要因素为客体论元在语义上是接近施事还是接近受事。 相似文献