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基于微小运动的人脸活体检测算法
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作者 崔家礼 郭华 贾瑞明 《计算机应用与软件》 北大核心 2024年第7期150-158,191,共10页
针对人脸识别过程中容易受到打印攻击、视频重放攻击的问题,提出一种利用微小运动的人脸活体检测算法。该算法对视频进行运动放大处理以增强微小运动;使用运动强度和运动方向描述微小运动,生成两种运动特征图并进行融合;使用基于注意力... 针对人脸识别过程中容易受到打印攻击、视频重放攻击的问题,提出一种利用微小运动的人脸活体检测算法。该算法对视频进行运动放大处理以增强微小运动;使用运动强度和运动方向描述微小运动,生成两种运动特征图并进行融合;使用基于注意力机制的VGG16网络进行真伪判别。在Replay-attack数据集上半错误率(HTER)为1.35%,在CASIA FASD数据集上等错误率(EER)为2.5%,证明了微小运动对人脸防伪的有效性。 展开更多
关键词 人脸活体检测 运动放大 面部运动 运动特征图 VGG16
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基于运动前景效应图特征的人群异常行为检测 被引量:6
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作者 张俊阳 谢维信 植柯霖 《信号处理》 CSCD 北大核心 2018年第3期296-304,共9页
异常行为检测是智能监控领域的研究热点之一,针对人群中的异常行为,提出了一种基于运动前景效应图特征的人群异常行为检测算法。该算法首先通过自适应混合高斯模型的前景检测方法分割得视频帧序列的前景区域,而后对视频帧图像采用分块处... 异常行为检测是智能监控领域的研究热点之一,针对人群中的异常行为,提出了一种基于运动前景效应图特征的人群异常行为检测算法。该算法首先通过自适应混合高斯模型的前景检测方法分割得视频帧序列的前景区域,而后对视频帧图像采用分块处理,结合获得的前景区域计算运动前景目标块的运动效应图,并提取其各个空时分块的运动效应图特征,通过一种改进的优化初始聚类中心的K均值聚类算法对数据进行训练和测试。实验结果表明,与现有算法相比,本文算法有效地提高了异常行为的检测准确率,并可定位异常行为的位置。 展开更多
关键词 异常行为检测 前景分割 运动效应特征 改进的K均值聚类
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基于多运动特征融合的微表情识别算法 被引量:6
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作者 苏育挺 王蒙蒙 +2 位作者 刘婧 费云鹏 何旭 《激光与光电子学进展》 CSCD 北大核心 2020年第14期345-350,共6页
直接使用原始微表情序列对微表情进行识别的效果一般,且已有的算法往往利用单一的特征图而没有对多种特征图进行融合来识别微表情。针对这些问题,提出一种新的微表情识别算法,该算法对多种运动特征图进行特征提取之后再进行融合,以获得... 直接使用原始微表情序列对微表情进行识别的效果一般,且已有的算法往往利用单一的特征图而没有对多种特征图进行融合来识别微表情。针对这些问题,提出一种新的微表情识别算法,该算法对多种运动特征图进行特征提取之后再进行融合,以获得更准确的识别结果。所提算法利用卷积神经网络(CNN)和长短期记忆(LSTM)网络结合的深度学习框架。在CASMEII微表情数据库上对不同算法进行测试。实验结果表明,与其他识别算法相比,所提算法取得了更加优良的效果。 展开更多
关键词 机器视觉 微表情识别 运动特征图 人脸关键点 光流 光学应变
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Motion texture using symmetric property and graphcut algorithm
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作者 SHEN Jian-bing JIN Xiao-gang +1 位作者 ZHOU Chuan ZHAO Han-li 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第7期1107-1114,共8页
In this paper, a novel motion texture approach is presented for synthesizing long character motion (e.g., kungfu) that is similar to the original short input motion. First, a new motion with repeated frames is generat... In this paper, a novel motion texture approach is presented for synthesizing long character motion (e.g., kungfu) that is similar to the original short input motion. First, a new motion with repeated frames is generated by exploiting the symmetric properties of the frames and reversing the motion sequence playback in a given motion sequence. Then, the order of the above motion sequence is rearranged by putting the start and the end frames together. The graphcut algorithm is used to seamlessly synthesize the transition between the start and the end frames, which is noted as graphcut-based motion-texton. Finally, we utilize the motion-textons to synthesize long motion texture, which can be patched together like the image texture synthesis method using graphcut algorithm, and automatically form a long motion texture endlessly. Our approach is demonstrated by synthesizing the long kungfu motion texture without visual artifacts, together with post-processing including our new developed graphcut-based motion blending and Poisson-based motion smoothing techniques. 展开更多
关键词 Motion capture Motion texture Character animation Graphcut
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A Mixed Reality System for Investigating Expert Characteristics on Recall of Situation Including Self-Motion
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《Computer Technology and Application》 2012年第4期283-288,共6页
To study recall accuracy of the offensive and defensive situations including movements of elite-athlete/novice oneself, a novel experimental system was developed where defensive actions were performed by the subject w... To study recall accuracy of the offensive and defensive situations including movements of elite-athlete/novice oneself, a novel experimental system was developed where defensive actions were performed by the subject with a CG (Computer Graphics) player who presented predetermined offensive actions. Both the CG player's movements and subject's movements were reproduced by a video using mixed reality technology for recall examination. This system was also designed to rearrange the natural sequence of image frames resulting in a reproducible video in which the time relation of offense and defense was falsified. Displacement of timing in the false video was twofold; delayed from the truth or advanced from the truth. Using this two-video, true/false imagery method, the subject was asked to select the true video by recall; thus it became possible to examine the recall accuracy quantitatively by controlling the timing displacement. Results of the experiment using this system revealed that karate expert possessed a skill to recognize the time relation between the opponent's movement and one's own movement perceptually that was more developed than that of the novice. It was further identified that the expert as well as the novice recognized delayed displacement more accurately than they could recognize advanced displacement. 展开更多
关键词 Mixed reality recall paradigm perceptual cognitive skill computer graphics displacement of timing.
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Experiment and analysis on microscopic characteristics of pedestrian movement in building bottleneck 被引量:4
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作者 TIAN Wei SONG WeiGuo +1 位作者 LU Wei FANG ZhiMing 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第7期1730-1736,共7页
In this paper, evacuation experiments are carried out to study pedestrian movement behaviors in building bottleneck. An image processing method based on mean-shift algorithm is used to extract pedestrian movement traj... In this paper, evacuation experiments are carried out to study pedestrian movement behaviors in building bottleneck. An image processing method based on mean-shift algorithm is used to extract pedestrian movement trajectory. Based on the extracted trajectory, we analyze the microscopic movement characteristics of pedestrians such as lane formation, change of velocity and distance between two sequential pedestrians. A pedestrian lane is a group of pedestrians moving in a column. The lane formation is verified by the pedestrian trajectory and distribution of pedestrian’s lateral positions (x direction in the paper): lane number changes from one to two, three or even more with the increasing bottleneck width when pedestrians pass through the bottleneck. By analyzing the pedestrian movement behaviors in the same pedestrian lane, we find three typical movement modes in the bottleneck: time-lag acceleration, synchronous acceleration, and avoiding deceleration. Through analyzing the time intervals when successive pedestrians pass through the bottleneck, we find that most pedestrians adjust their velocities according to the distance to the forward pedestrians. Results also indicate that due to different cultures, pedestrians flux in China and Germany may have some differences besides their similarities. 展开更多
关键词 EVACUATION TRAJECTORY Mean-shift algorithm pedestrian lane time interval
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