A Self-updating Template Approach for Human Action Recognition Using Improved DTW

In this paper, a stereo camera-based novel approach for Human Activity Recognition (HAR) is presented using robust 3-D human body joint features and joint-specific Hidden Markov Models (HMMs). At f...

Recognising human activity can be advantageous in a number of different scenarios including elder care, healthcare or for training purposes. It can be of direct use to support humans in doing different activities, but is still a challenge for systems to correctly classify the activity in a way that is valuable for the user, as they often times lack the robustness or simplicity for day-to-day use. In this paper an approach for human activity recognition based on object interactions is presented. The proposed system consists of a wireless sensor network, with each sensor node measuring the received signal strength indication (RSSI) to its neighbouring nodes. The accumulated RSSI data is then analyzed by a machine learning algorithm which tries to infer one of several cooked dishes from that data. Experimental studies demonstrate promising results and therefore potential for this technology for recognising human activity in the form of cooking, but its generalised approach makes it suitable for other environments, too.

In this paper, we present a “key segment” mining approach for human action recognition. Our model is able to locate discriminative segments for action samples via multiple instance learning. Moreover, we propose a dynamic pooling approach to automatically find the optimal length of segment for each action sample. In addition, an effective feature is proposed for action recognition with 3D skeleton joints. It can effectively capture informative motion and shape cues of skeletons, and leads to a compact and discriminative representation. The experimental results validate the effectiveness of the proposed human action recognition method on two benchmark datasets (i.e., MSR Action3D and UCF-Kinect). Moreover, our method demonstrates superior accuracy than previous methods of using only skeleton data on MSR Action3D, and achieves the state-of-the-art performance on UCF-Kinect.Keywordsaction recognitionmultiple instance learningskeleton featuredynamic pooling

Motion is the most informative cue for human action recognition. Regions with high motion saliency indicate where actions occur and contain visual information that is most relevant to actions. In this paper, we propose a novel approach for human action recognition based on oriented motion salient regions (OMSRs). Firstly, we apply a bank of 3D Gabor filters and an opponent inhibition operator to detect OMSRs of videos, each of which corresponds to a specific motion direction. Then, a new low-level feature, named as oriented motion salient descriptor (OMSD), is proposed to describe the obtained OMSRs through the statistics of the texture in the regions. Next, we utilize the obtained OMSDs to explore the oriented characteristics of action classes and generate a set of class-specific oriented attributes (CSOAs) for each class. These CSOAs provide a compact and discriminative middle-level representation for human actions. Finally, an SVM classifier is utilized for human action classification and a new compatibility function is devised for measuring how well a given action matches to the CSOAs of a certain class. We test the proposed approach on four public datasets and the experimental results validate the effectiveness of our approach.KeywordsVideo SequenceAction ClassGabor FilterHuman Action RecognitionCompatibility FunctionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Human action recognition has been an active research area in recent years. However, building a robust human action recognition system still remains a challenging task due to the large variations in action classes, varying human appearances, illumination changes, camera motion, occlusions and background clutter. Most previous work focus on the goal of improving recognition rates. This paper describes a computationally fast votingbased approach for human action recognition, in which the action in the video sequence is recognized based on the support of the local spatio-temporal features. The proposed technique requires no parameter tuning and can produce recognition rates that are comparable to those in recent published literature. Moreover, the technique can localize the single human action in the video sequence without much additional computation. Recognition results on the KTH and Weizmann action dataset are presented.

Human action recognition is a research hotspot in the field of ambient intelligence, serving as a foundation for the Internet of Healthcare Things (IoHT) and smart home wellness, with extensive application value. Currently, most research primarily focuses on the performance of single-modal approach for human action recognition. However, single-modal data cannot adequately capture the action characteristics of the human body. For instance, camera data lacks detailed micro-motion information, while radar data lacks visual appearance information. This limitation makes human action recognition systems susceptible to complex covariate influences. To address this issue, this paper proposes a Multi-Modal Fusion Model, M2FM, to accurately recognize various complex human action from millimeter-wave radar signals and video data. In the millimeter-wave radar branch, a LFNet network is constructed to capture richly hierarchical human action representation by extracting micro-Doppler feature and cadence velocity feature simultaneously. Specially, a Linear Feedforward Neural Network (LFNN) module is designed for modeling global-local feature of human action. In the video branch, a lightweight Transformer-based video analysis and action recognition network, STL-Former, is developed. Specially, an Agent downSampling (AS) attention module and a Linear Maxpooling (LM) attention module are designed to achieve context-aware downsampling with global receptive field and spatial vector sequence downsampling, respectively. Additionally, a multi-scale Linear attention (Litner) module is designed for modeling the spatio-temporal information of human action. Finally, the outputs from two branches are fused by a filter-based Dempster-Shafer theory. The experimental results on a self-collected Multi-modal Human Action Dataset, JH-MHAD, show that the M2FM model outperforms other advanced models, with an average recognition accuracy of 99.3% for eight different human actions, and it demonstrates strong adaptability under different conditions.

With the rapid increase in digital technology, most research areas are involved in human activity recognition, which can help to analyze the activities of patients. A novel approach for human activity recognition in egocentric video has been invoked in this research article. Generally, only the objects are identified, but the actions are not recognized. With this motivation and new trends, this paper presents an efficient technique to recognize the activities. In our approach, first the various activity dataset is trained, and the feature vector values are stored for various activities, which are applied to the testing inputs. Here, we use a filtering technique, i.e., a median filter followed by a segmentation method using watershed and feature extraction, such as a Histogram of Oriented Gradient (HOG), Color and GiST and a combination of all Features. Features are reduced using a genetic algorithm, and classification is done using Support Vector Machine (SVM) and a Random Forest classifier. The experimental results demonstrate that the Random Forest classifier outperformed the SVM classifier.

Recognizing human activities is one of the crucial capabilities that a robot needs to have to be useful around people. Although modern robots are equipped with various types of sensors, human activity recognition (HAR) still remains a challenging problem, particularly in the presence of noisy sensor data. In this work, we introduce a multimodal graphical attention-based HAR approach, called Multi-GAT, which hierarchically learns complementary multimodal features. We develop a multimodal mixture-of-experts model to disentangle and extract salient modality-specific features that enable feature interactions. Additionally, we introduce a novel message-passing based graphical attention approach to capture cross-modal relation for extracting complementary multimodal features. The experimental results on two multimodal human activity datasets suggest that Multi-GAT outperformed state-of-the-art HAR algorithms across all datasets and metrics tested. Finally, the experimental results with noisy sensor data indicate that Multi-GAT consistently outperforms all the evaluated baselines. The robust performance suggests that Multi-GAT can enable seamless human-robot collaboration in noisy human environments.

A multi-resolution fusion approach for human activity recognition from video data in tiny edge devices

The emerging research work in human activity recognition is required for smart environment especially in health and home applications. This paper proposed a bio-inspired human visual system model to extract motion features for human activity recognition. The architecture of classical V1-MT model is modified into hierarchical architecture of feedforward model; (1) three-dimensional (3D) Gabor filter in primary visual cortex (V1) layer, (2) new pooling mechanism of active motion map (3) final motion estimation based on confidence mapping in MT layer. The 3D Gabor filter used to model the spatio-temporal direction and speed tuning of the V1 cells. The active mean motion map indicate the most significant feature vector in representing human actions, while the confidence map used to estimate accurate velocity characteristic of neurons in MT layer. The approach is carried out on the Weizmann and KTH action database. The results demonstrate the effectiveness of proposed method and its advantage in terms of recognition performance and computational efficiency compared to other bio-inspired approaches for human action recognition.

This paper presents a new approach for human action recognition around sleeping with the human body parts locations and the positional relationship between human and sleeping environment. Body parts are estimated from the depth image obtained by a time-of-flight (TOF) sensor using oriented 3D normal vector. Issues in action recognition of sleeping situation are the demand of availability in darkness, and hiding of the human body by duvets. Therefore, the extraction of image features is difficult since color and edge features are obscured by covers. Thus, first in our method, positions of four parts of the body (head, torso, thigh, and lower leg) are estimated by using the shape model of bodily surface constructed by oriented 3D normal vector. This shape model can represent the surface shape of rough body, and is effective in robust posture estimation of the body hidden with duvets. Then, action descriptor is extracted from the position of each body part. The descriptor includes temporal variation of each part of the body and spatial vector of position of the parts and the bed. Furthermore, this paper proposes hierarchical action classes and classifiers to improve the indistinct action classification. Classifiers are composed of two layers, and recognize human action by using the action descriptor. First layer focuses on spatial descriptor and classifies action roughly. Second layer focuses on temporal descriptor and classifies action finely. This approach achieves a robust recognition of obscured human by using the posture information and the hierarchical action recognition.

In this work we present an ongoing research which intends to integrate the Block Matching technique into the Human Action Recognition field. We propose a method to create a video descriptor composed of three main steps: Computation of displacement vectors between frames with VSBMA, histogram representation of these vectors, and orientation tensor generation from the histogram. It is a promising approach for human action recognition since it is a simple method with low computational cost which achieves comparable results with state-of-the-art techniques.

Human action recognition (HAR)in videos is a challenging task in computer vision. Conventional methods are prone to explore the spatiotemporal or optical representations for video actions. However, optical representation might be inefficient in some real-life situations, such as object occlusion and dim light. To address this issue, this paper presents a novel approach for human action recognition by jointly exploiting video and Wi-Fi clues. We leverage the fact that Wi-Fi signals carry discriminative information of human actions, which is robust to optical limitations. To validate this innovative thought, we conceive a practical framework for HAR and setup a dataset containing both video clips and Wi-Fi Channel State Information of human actions. The 3D convolutional neural network was used to extract the video features and the statistical algorithms were used to extract radio features. A classical linear support vector machine is employed as the classifier after the video and radio feature fusion. Comprehensive experiments on this dataset achieved desirable results with the maximum improvement in accuracy by 10%. This demonstrates our promising findings: with the aid of Wi-Fi Channel State Information, the performance of the video action recognition methods can be improved significantly, even under the optical limitation.

Human action recognition using genetic algorithms and convolutional neural networks

In this paper we introduce a general probabilistic graphical model for human everyday activity recognition. The proposed model is a discriminative graphical model with hidden variables for modeling body pose and sequential order of them. We use a unified framework for prediction task that is faster and more efficient than structured support vector machine and hidden conditional random fields. We have trained and tested the model on RGB-D videos and the result was comparable to the state of the art.