Electrocardiogram (ECG) pattern modeling and recognition via deterministic learning

A method for electrocardiogram （ECG） pattern modeling and recognition via deterministic learning theory is presented in this paper. Instead of recognizing ECG signals beat-to-beat, each ECG signal which contains a number of heartbeats is recognized. The method is based entirely on the temporal features （i.e., the dynamics） of ECG patterns, which contains complete information of ECG patterns. A dynamical model is employed to demonstrate the method, which is capable of generating synthetic ECG signals. Based on the dynamical model, the method is shown in the following two phases： the identification （training） phase and the recognition （test） phase. In the identification phase, the dynamics of ECG patterns is accurately modeled and expressed as constant RBF neural weights through the deterministic learning. In the recognition phase, the modeling results are used for ECG pattern recognition. The main feature of the proposed method is that the dynamics of ECG patterns is accurately modeled and is used for ECG pattern recognition. Experimental studies using the Physikalisch-Technische Bundesanstalt （PTB） database are included to demonstrate the effectiveness of the approach.     

Human gait recognition by the fusion of motion and static spatio-temporal templates

In this paper, we propose a gait recognition algorithm that fuses motion and static spatio-temporal templates of sequences of silhouette images, the motion silhouette contour templates (MSCTs) and static silhouette templates (SSTs). MSCTs and SSTs capture the motion and static characteristic of gait. These templates would be computed from the silhouette sequence directly. The performance of the proposed algorithm is evaluated experimentally using the SOTON data set and the USF data set. We compared our proposed algorithm with other research works on these two data sets. Experimental results show that the proposed templates are efficient for human identification in indoor and outdoor environments. The proposed algorithm has a recognition rate of around 85% on the SOTON data set. The recognition rate is around 80% in intrinsic difference group (probes A-C) of USF data set.     

Hand gesture recognition using Leap Motion via deterministic learning

With the development of multimedia technology, traditional interactive tools, such as mouse and keyboard, cannot satisfy users’ requirements. Touchless interaction has received considerable attention in recent years with benefit of removing barriers of physical contact. Leap Motion is an interactive device which can be used to collect information of dynamic hand gestures, including coordinate, acceleration and direction of fingers. The aim of this study is to develop a new method for hand gesture recognition using jointly calibrated Leap Motion via deterministic learning. Hand gesture features representing hand motion dynamics, including spatial position and direction of fingers, are derived from Leap Motion. Hand motion dynamics underlying motion patterns of different gestures which represent Arabic numbers (0-9) and capital English alphabets (A-Z) are modeled by constant radial basis function (RBF) neural networks. Then, a bank of estimators is constructed by the constant RBF networks. By comparing the set of estimators with a test gesture pattern, a set of recognition errors are generated. The average L₁ norms of the errors are taken as the recognition measure according to the smallest error principle. Finally, experiments are carried out to demonstrate the high recognition performance of the proposed method. By using the 2-fold, 10-fold and leave-one-person-out cross-validation styles, the correct recognition rates for the Arabic numbers are reported to be 94.2%, 95.1% and 90.2%, respectively, for the English alphabets are reported to be 89.2%, 92.9% and 86.4%, respectively.     

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.     

Deterministic Learning and Rapid Dynamical Pattern Recognition

Recognition of temporal/dynamical patterns is among the most difficult pattern recognition tasks. In this paper, based on a recent result on deterministic learning theory, a deterministic framework is proposed for rapid recognition of dynamical patterns. First, it is shown that a time-varying dynamical pattern can be effectively represented in a time-invariant and spatially distributed manner through deterministic learning. Second, a definition for characterizing similarity of dynamical patterns is given based on system dynamics inherently within dynamical patterns. Third, a mechanism for rapid recognition of dynamical patterns is presented, by which a test dynamical pattern is recognized as similar to a training dynamical pattern if state synchronization is achieved according to a kind of internal and dynamical matching on system dynamics. The synchronization errors can be taken as the measure of similarity between the test and training patterns. The significance of the paper is that a completely dynamical approach is proposed, in which the problem of dynamical pattern recognition is turned into the stability and convergence of a recognition error system. Simulation studies are included to demonstrate the effectiveness of the proposed approach     

基于协同表示的步态识别

将基于稀疏表示的分类算法应用于步态识别中,会遇到小样本及计算耗时的问题。针对这一问题,提出一种基于协同表示的步态识别方法。该方法首先通过背景重建、目标提取等处理获得人体侧影轮廓,根据步态轮廓的宽度变化统计步态周期,得到步态能量图GEI;其次,以GEI为基础对测试样本进行协同表示;最后,通过最小重构误差进行识别。实验结果表明,该方法具有较好的识别性能,并且识别时间明显降低。     

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.     

基于贝叶斯网络的步态识别

步态作为一种重要的生物特征由于其远距离身份识别能力而逐渐受到人们的重视。本文提出了一种基于贝叶斯网络的步态识别方法。首先应用背景差方法获得运动人体侧面二值图像,将侧面像分为七部分来提取特征,采用最大方差法对训练集进行离散化,对各部分分别建立贝叶斯网络,最后利用“投票”规则将网络推理结果进行组合。将该方法在Soton步态数据库上进行试验,取得了比较理想的识别效果。     

Fault detection for nonlinear discrete-time systems via deterministic learning

Recently, an approach for the rapid detection of small oscillation faults based on deterministic learning theory was proposed for continuous-time systems. In this paper, a fault detection scheme is proposed for a class of nonlinear discrete-time systems via deterministic learning. By using a discrete-time extension of deterministic learning algorithm, the general fault functions (i.e., the internal dynamics) underlying normal and fault modes of nonlinear discrete-time systems are locally-accurately approximated by discrete-time dynamical radial basis function (RBF) networks. Then, a bank of estimators with the obtained knowledge of system dynamics embedded is constructed, and a set of residuals are obtained and used to measure the differences between the dynamics of the monitored system and the dynamics of the trained systems. A fault detection decision scheme is presented according to the smallest residual principle, i.e., the occurrence of a fault can be detected in a discrete-time setting by comparing the magnitude of residuals. The fault detectability analysis is carried out and the upper bound of detection time is derived. A simulation example is given to illustrate the effectiveness of the proposed scheme.     

基于PCA和SVM的步态识别

提出了一种新颖的沿中线投影得到特征的步态识别方法。首先,应用背景差方法分割出运动人体轮廓,对外轮廓沿人体中线投影可以得到前后两个向量,合成1D向量作为步态特征。然后,通过主成分分析对得到的一维向量进行特征提取和压缩,对得到的识别量应用支持向量机进行步态的分类和识别。实验中,该方法取得了很好的识别性能。     

A framework for online gait recognition based on multilinear tensor analysis

The gait recognition is to recognize an individual based on the characteristics extracted from the gait image sequence. There are many researches for the gait recognition which use diverse kinds of information such as shape of gait silhouette, motion variation caused by walking, and so on. In general, shape information is more useful for recognition. However, shape information is influenced by a variety of factors, which degrade the recognition performance. Moreover, the information used in most of those studies might be able to be extracted after all of one or more sequences of the gait cycle are known. And it is also hard to discriminate the gait cycle from given gait sequences exactly by the online approach. In regard to these difficulties, we propose a novel gait recognition method based on the multilinear tensor analysis. To recognize the cyclic characteristic of gait without an exact division for the gait cycle, this paper’s propose is the method to form the accumulated silhouette and then describes those as the tensor. For the accumulated silhouette proposed by this paper, the image sequence of one gait cycle is divided into four sections in the training phase. However, discrimination for the gait cycle in the training phase is not directly related to the recognition phase, thus the online approach is possible. We first form the accumulated silhouettes for every individual using gait silhouettes within each section. And then, we represent these accumulated silhouettes as the tensor. Using a multilinear tensor analysis, we compute the core tensor which governs the interaction between factors organizing the original tensor, and then compose the basis to recognize the individual in the online recognition framework. Finally, we recognize the individual using the computation of similarity based on the Euclidean distance, which is more suitable to our method. We verify the superiority of the proposed approach via experiments with real gait sequences.     

一种基于隐马尔科夫模型的步态识别算法

步态是指人体走路时的姿态,步态识别是近年来生物特征识别领域一个备受关注的研究方向。步态阶段的区分是步态识别的重要内容。以隐马尔科夫模型(HMM)为基础,基于安装在膝关节的编码器和大腿部的加速度传感器,在外骨骼辅助行走中识别步态的不同阶段。首先进行数据预处理和特征提取;其次对隐马尔科夫步态识别算法进行设计,包括结构的建立、参数的训练和最终的识别;最后对性能进行评估,总体正确率达到91.06%,说明HMM用于步态阶段识别具有较好的性能。     

基于视频残差神经网络的深度步态识别

步态识别是根据人体的行走方式进行身份识别. 目前, 大多数步态识别方法通过浅层神经网络进行特征提取, 在室内步态数据集表现良好, 然而在近年新公布的室外步态数据集中性能表现不佳. 为了解决室外步态数据集带来的严峻挑战, 提出了一种基于视频残差神经网络的深度步态识别模型. 在特征提取阶段, 基于提出的视频残差块构建深层3D卷积神经网络(3D CNN), 提取整个步态序列的时空动力学特征; 然后, 引入时序池化和水平金字塔映射降低采样特征分辨率并提取局部步态特征; 使用联合损失函数驱动训练过程, 最后通过BNNeck平衡损失函数并调整特征空间. 实验分别在公开的室内 (CASIA-B)、室外(GREW、Gait3D)这3个步态数据集上进行. 实验结果表明, 该模型在室外步态数据集中的准确率以及收敛速度优于其他模型.     

Gait flow image: A silhouette-based gait representation for human identification

In this paper, we propose a novel gait representation—gait flow image (GFI) for use in gait recognition. This representation will further improve recognition rates. The basis of GFI is the binary silhouette sequence. GFI is generated by using an optical flow field without constructing any model. The performance of the proposed representation was evaluated and compared with the other representations, such as gait energy image (GEI), experimentally on the USF data set. The USF data set is a public data set in which the image sequences were captured outdoors. The experimental results show that the proposed representation is efficient for human identification. The average recognition rate of GFI is better than that of the other representations in direct matching and dimensional reduction approaches. In the direct matching approach, GFI achieved an average identification rate 42.83%, which is better than GEI by 3.75%. In the dimensional reduction approach, GFI achieved an average identification rate 43.08%, which is better than GEI by 1.5%. The experimental result showed that GFI is stronger in resisting the difference of the carrying condition compared with other gait representations.     

基于人体轮廓宽度特征的步态识别

基于人体轮廓宽度特征提出了一种步态识别算法。首先对每个序列进行运动轮廓抽取,将这些时变的二维轮廓形状转换为对应的一维横向宽度信号,通过主元分析法(PCA)来提取低维步态特征,在此基础上采用线性判决分析(LDA),以获取最佳投影方向,达到提高数据分类能力的目的。在NLPR、CMU和UMF步态数据库中进行实验,结果表明算法具备快速、稳健特征,在实际应用中具备较大的价值。     

基于核主成分分析的步态识别方法

为了从多帧步态序列中更有效地提取步态特征并实时性地进行身份识别,提出一种有效的基于平均步态能量图(MGEI)的核主成分分析(KPCA)的身份识别方法。通过预处理技术提取出运动人体的侧面轮廓,根据步态下肢的摆动距离统计出步态周期,得到MGEI。KPCA采用非线性方法提取主成分,描述待识别图像中多个像素之间的相关性。利用KPCA的方法在高维空间对MGEI提取特征,选择合适的核函数,用方差倒数加权欧氏距离进行身份识别。实验结果表明,该算法具有较好的识别性能,并且耗时大大缩短。     

Gait recognition using linear time normalization

We present a novel system for gait recognition. Identity recognition and verification are based on the matching of linearly time-normalized gait walking cycles. A novel feature extraction process is also proposed for the transformation of human silhouettes into low-dimensional feature vectors consisting of average pixel distances from the center of the silhouette. By using the best-performing of the proposed methodologies, improvements of 8-20% in recognition and verification performance are seen in comparison to other known methodologies on the “Gait Challenge” database.     

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。     

Individual recognition using gait energy image

In this paper, we propose a new spatio-temporal gait representation, called gait energy image (GEI), to characterize human walking properties for individual recognition by gait. To address the problem of the lack of training templates, we also propose a novel approach for human recognition by combining statistical gait features from real and synthetic templates. We directly compute the real templates from training silhouette sequences, while we generate the synthetic templates from training sequences by simulating silhouette distortion. We use a statistical approach for learning effective features from real and synthetic templates. We compare the proposed GEI-based gait recognition approach with other gait recognition approaches on USF HumanID Database. Experimental results show that the proposed GEI is an effective and efficient gait representation for individual recognition, and the proposed approach achieves highly competitive performance with respect to the published gait recognition approaches.