基于改进Hu矩的异常行为识别

提出了基于改进Hu矩的异常行为识别算法,主要对跳、加速跑、摔倒、下蹲、挥手和手拿异物六种异常行为进行识别.对视频流首先要提取运动人体轮廓,然后对所得到的轮廓进行特征提取,这里主要提取人体运动的形状特征,最后,通过模板匹配的方法,采用Hausdorff距离计算所需识别的当前行为特征向量与模板行为(正常行走的行为)特征向量之间的相似性,并通过相应的阈值判定该行为是否为异常行为.实验证明,该方法对文中给出的样本异常行为的识别率达到100%,有一定实用价值.     

基于三维时空直方图特征的人体行为识别

提出一种基于三维时空直方图特征的人体行为识别方法。通过引入时间维度构建三维时空概念,探索时空中梯度方向信息,由梯度方向经过空间中不同的区域形成梯度直方图,获取时空特征矩阵,结合K均值聚类提取时空直方图特征来描述人体行为;采用图像显著性检测算法,获取人体行为轮廓,从轮廓图中提取二维轮廓特征;将获得的特征输入支持向量机进行训练以及人体行为识别。实验结果表明,相比其它特征描述的方法,该方案对人体行为的特征描述更丰富,识别准确率更高。     

基于聚类RBF神经网络的人体行为识别

提出基于聚类RBF神经网络的人体行为识别方法。通过基于单模态高斯背景模型的背景差分法提取动作轮廓;采用基于中心距的傅里叶描述子,对图像轮廓线进行处理,降低了特征的维数;利用谱聚类算法提取行为序列的关键特征向量,采用改进的基于聚类的RBF神经网络进行行为识别。仿真实验表明,该方法能有效识别人体行为类别,应用效果满足实际要求。     

基于星形距离和LDCRF模型的在线行为识别方法

提出一种基于星形距离轮廓特征和LDCRF模型的在线行为识别方法。对视频中已分割出的人物姿态提取轮廓,求取人体轮廓质心及其到轮廓采样点的星形距离向量,以该向量参数化人体运动姿态特征,对原始姿态特征向量进行小波变换,降维的同时获得姿态的多分辨细节信息。利用潜动态条件随机场模型（latent‐dynamic conditional random , LDCRF）对人体行为特征建模,进行在线识别。比对CRF、HCRF、LDCRF模型对10种不同行为的识别结果,对比结果表明,相比CRF和HCRF ,该模型对连续行为序列有较强的识别能力,具有更好的稳定性。     

基于小波变换和支持向量机的步态识别算法

为了快速准确地进行人体运动步态识别,基于运动人体的轮廓宽度特征,提出了一种新的步态识别算法。该算法首先对每个序列进行运动轮廓抽取,同时从3个方向(水平、垂直、斜向)对时变的2维轮廓进行投影扫描,并分别转换为对应的特征向量;然后通过对级联的特征向量进行离散正交小波变换来提取低维步态特征,并抑制噪声;在此基础上采用支持向量机训练步态分类器组,最后用支持向量机组进行步态识别。在一组30人构成的步态数据库中进行的实验结果表明,该算法具备快速、稳健的特征,识别率达到91%,初步具备了实际应用的价值。     

老年人异常行走步态特征提取

计算机视觉的步态分析主要用于实现人体的身份识别,而通过异常步态分析来识别老年人异常状况方面的研究却很少.为对老人异常步态进行识别,提出了一种新的步态特征提取的方法,主要用于老年人异常行走步态特征的提取.使用运动历史图像进行图像序列的表示,并且从中提取出Zernike矩特征用来反应步态的特征向量.同时为了保证获取的特征量的充分性与有效性,更完备地描述人体行为序列,利用信息论中的互信息来确定分类时采用的Zernike矩的最高阶次,并进行仿真.实验结果表明,利用提出的方法进行特征提取,在老年人异常行走步态特征提取中取得了很好的效果.     

一种基于人体轮廓宽度特征的步态识别方法

步态识别是一种新的生物识别技术,它通过人行走的姿势来实现对人身份的鉴别。提出了一种新的基于人体轮廓宽度特征的步态识别方法,将视频序列中检测出的步态轮廓提取三种宽度特征并计算步态序列中宽度的变化特征,从而构成描述步态序列的特征向量。实验表明提出的方法具有较好的识别性能,是一种有效的步态识别方法。     

一种新的异常行为检测算法

行人异常行为的自动检测与识别是计算机视觉领域的重点和难点,同时也是智能监控系统中研究的热点问题。针对这一问题,提出了一种基于人体形态特征的异常检测算法。利用轮廓信息将目标从视频序列中分割出来,再对分割出来的目标进行轮廓拟合,根据所得到的拟合信息提取文中所定义的形态特征因子,将特征因子经过行为分类器的判定,从而决策出该行为是否异常。实验结果表明该方法实现简单,具有较好的实时性与鲁棒性,可以作为实时监控系统中异常行为检测的有效方法。     

人耳图像特征提取方法及其在矿工身份识别中的应用

针对现有人耳特征提取方法主要采用几何形状法和代数法提取,存在偏差较大的问题,提出了一种新的人耳图像特征提取方法,并将其应用到矿工身份识别中。该方法利用三尺度canny算子提取人耳边缘图像,运用凸包算法提取人耳边缘特征点,采用轮廓搜索算法提取人耳外轮廓,在极平面上用外耳轮廓上的点到极点的距离与人耳长轴的比值构成人耳特征向量,解决了几何形状法提取人耳特征偏差大的问题。将用该方法提取的人耳图像特征用于矿工身份识别,正确识别率达96%。     

基于改进Canny算子和神经网络的人体行为识别模型

为了提高了人体行为识别的正确率,提出了一种基于改进Canny算子和神经网络的人体行为识别模型（ICanny-RBF）。采用改进Canny算子对人体行为图像进行预处理,提取人体行为轮廓,提取7个不变矩特征作为RBF神经网络的输入向量,训练出能够识别人体行为的RBF神经网络模型,并采用取k-means算法确定RBF神经网络聚类中心,采用Weizmann数据集进行仿真实验。仿真结果表明,与传统方法相比,提出的ICanny-RBF模型提高了人体行为的识别正确率。     

Recognizing body poses using multilinear analysis and semi-supervised learning

This paper presents an approach to full-body human pose recognition using features extracted from stereo silhouettes via multilinear analysis in a semi-supervised learning framework. Inputs to the proposed approach are pairs of silhouette images obtained from wide baseline binocular cameras. Through multilinear analysis, low dimensional view-invariant pose coefficient vectors can be extracted from these stereo silhouette pairs. Taking these pose coefficient vectors as features, a recently proposed state-of-the-art semi-supervised learning method, Universum, is adopted for pose recognition. Experiment results obtained using real image data showed the efficacy of the proposed approach.     

Improved gait recognition by multiple-projections normalization

Recognizing people by gait promises to be useful for identifying individuals from a distance; in this regard, improved techniques are under development. In this paper, an improved method for gait recognition is proposed. Binarized silhouette of a motion object is first represented by four 1-D signals that are the basic image features called the distance vectors. The distance vectors are differences between the bounding box and silhouette, and extracted using four projections to silhouette. Fourier Transform is employed as a preprocessing step to achieve translation invariant for the gait patterns accumulated from silhouette sequences that are extracted from the subjects’ walk in different speed and/or different time. Then, eigenspace transformation is applied to reduce the dimensionality of the input feature space. Support vector machine (SVM)-based pattern classification technique is then performed in the lower-dimensional eigenspace for recognition. The input feature space is alternatively constructed by using two different approaches. The four projections (1-D signals) are independently classified in the first approach. A fusion task is then applied to produce the final decision. In the second approach, the four projections are concatenated to have one vector and then pattern classification with one vector is performed in the lower-dimensional eigenspace for recognition. The experiments are carried out on the most well-known public gait databases: the CMU, the USF, SOTON, and NLPR human gait databases. To effectively understand the performance of the algorithm, the experiments are executed and presented as increasing amounts of the gait cycles of each person available during the training procedure. Finally, the performance of the proposed algorithm is comparatively illustrated to take into consideration the published gait recognition approaches.     

Human Gait Recognition Based on Kernel PCA Using Projections

This paper presents a novel approach for human identification at a distance using gait recognition. Recognition of a person from their gait is a biometric of increasing interest. The proposed work introduces a nonlinear machine learning method, kernel Principal Component Analysis （PCA）, to extract gait features from silhouettes for individual recognition. Binarized silhouette of a motion object is first represented by four 1-D signals which are the basic image features called the distance vectors. Fourier transform is performed to achieve translation invariant for the gait patterns accumulated from silhouette sequences which are extracted from different circumstances. Kernel PCA is then used to extract higher order relations among the gait patterns for future recognition. A fusion strategy is finally executed to produce a final decision. The experiments are carried out on the CMU and the USF gait databases and presented based on the different training gait cycles.     

一种采用高斯模型的步态轮廓分割算法

步态识别中大多采用步态轮廓作为识别特征,因此提取完整封闭的运动人体轮廓以准确表达步态特征是正确识别的前提。本文提出一种采用高斯模型的步态轮廓分割算法。在人的运动方向与摄像机成像面平行和摄像机静止的条件下,假设序列图像所有帧中对应像素点背景时刻的灰度值在时间轴上是高斯分布,而目标时刻不满足这种分布,采用统计推断的方法分割出运动目标轮廓。实验结果表明,本文算法不仅能够提取出完整的人体轮廓,并且能有效地去除噪声,对阴影抑制也有一定效果,能够提高步态识别率。算法直接在RGB空间或灰度空间进行,无需进行颜色空间转换,也无需建立单独的背景图像,计算量小,处理实时性高。     

一种基于多区域不变矩的步态识别方法

步态识别是一种新的生物识别技术,它通过人行走的姿势来实现对人身份的鉴别。本文提出了一种基于多区域不变矩的步态识别方法,将视频序列中检测出的步态侧影分为五个子区域,提取每个子区域的不变矩特征并计算步态序列中不变矩的变化特征,从而构成描述步态序列的特征向量。最后的实验表明,提出的方法具有较好的识别性能,是一种有效的步态识别方法。     

基于多特征融合的运动人体行为识别

提出了一种基于特征级融合的运动人体行为识别方法。应用背景差分法和阴影消除技术获得运动人体区域和人体轮廓;采用R变换提取人体区域特征,采用小波描述子提取人体轮廓特征;然后将这两种具有一定互补性的特征采用K-L变换进行融合,得到一个分类能力更强的特征;最后,在传统支持向量机的基础上,结合模糊聚类技术和决策树构建多级二叉树分类器,从而实现行为多类分类。该方法在Weizmann行为数据库上进行了实验,实验结果表明所提出的识别方法具有较高的识别性能。     

基于改进RCE和RBF神经网络的静态手势识别

针对手势识别的手区域分割、手势特征提取和手势分类的三个过程,提出了一种新的静态手势识别方法。改进了传统的RCE神经网络用于手区域的分割,具有更高的运行速度和更强的抗噪能力。依Freeman链码方向提取手的边缘到掌心的距离作为手势的特征向量。将上一步得到的手势特征向量作为RBF神经网络的输入,进行网络的训练和分类。实验验证了该方法的有效性和可行性,并用其实现了人和仿人机器人的剪刀石头布的猜拳游戏。     

Improved gait recognition through gait energy image partitioning

Recently, human gait pattern has turned into an essential biometric feature to recognize an individual remotely. Gait as a feature becomes challenging owing to variation in appearance under different covariate conditions (eg, shoe, surface, haul, viewpoint and attire). The covariates may alter few fragment of gait while other fragment stay unaltered, leading to lower the probability of correct identification. To overcome such variation, an improved gait recognition strategy is proposed in this article by gait energy image partitioning and selection processing. Our method involves pre-processing of raw video for silhouette extraction, gait cycle detection, segmentation into different regions, and histogram of gradients feature extraction from selected segments. In this way, the specific features across complete gait cycles are extracted precisely. Finally, recognition is done by using K-NN. The proposed strategy has been assessed using the CASIA B gait database. Our outcomes shows a particular proposed strategy accomplishes high recognition rate and outperforms the advanced gait recognition mechanism.     

A fast recognition algorithm for suspicious behavior in high definition videos

Detecting suspicious behavior from high definition (HD) videos is always a complex and time-consuming process. To solve that problem, a fast suspicious behavior recognition method is proposed based on motion vectors. In this paper, the data format and decoding features of HD videos are analyzed. Then, the characteristics of suspicious activities and the ways of obtaining motion vectors directly from the video stream are concluded. Besides, the motion vectors are normalized by taking the reference frames into account. The feature vectors that display the inter-frame and intra-frame information of the region of interest are extracted. Gaussian radial basis function is employed as the kernel function of the support vector machines (SVM). It also realizes the detection and classification of suspicious behavior in HD videos. Finally, an extensive set of experiments are performed and this method is compared with some of the most recent approaches in the field using publicly available datasets as well as a new annotated human action dataset including actions performed in complex scenarios.