Artificial neural networks (ANNs) constitute a class of flexible nonlinear models designed to mimic biological neural systems. In this entry, we introduce ANN using familiar econometric terminology and provide an overview of ANN modeling approach and its implementation methods. † Correspondence: Chung-Ming Kuan, Institute of Economics, Academia Sinica, 128 Academia Road, Sec. 2, Taipei 115, Taiwan; ckuan@econ.sinica.edu.tw. †† I would like to express my sincere gratitude to the editor, Professor Steven Durlauf, for his patience and constructive comments on early drafts of this entry. I also thank Shih-Hsun Hsu and Yu-Lieh Huang for very helpful suggestions. The remaining errors are all mine.

Artificial neural networks

User recognition based on periocular biometrics and touch dynamics

Internet of things for smart factories in industry 4.0, a review

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9755265

A survey on computer vision based human analysis in the COVID-19 era

Combining filtered dictionary representation based deep subspace filter learning with a discriminative classification criterion for facial expression recognition

Fusion of Periocular Deep Features in a Dual-Input CNN for Biometric Recognition

Face identification is one of the most widely adopted approach in several real scenarios. Unfortunately, in presence of occlusions or non-cooperative subjects nontrivial issues arise. This work explores a complementary approach to biometric face recognition, that is the dynamics of facial landmark during phonation while pronouncing sentences. These dynamics (both periocular and labial area) can be seen as a kind of signature that uniquely and unmistakably identifies an individual. The experimental results focus the attention on periocular area, which represents one of the most discriminating physiological characteristics after the whole face. Preliminary experimental results conducted on a public dataset and considering 14 periocular features showed an accuracy slightly below 80%, which confirms the robustness in uncontrolled scenarios.

Biometric Face Recognition Based on Landmark Dynamics

Smart factories are fostered by integrating intelligent systems and ICT technologies. The role they play is crucial in the spread of Industry 4.0 and the economic growth of developed countries. Smart factories can be empowered by using several sensors aimed at making them more and more “smart.” Unfortunately, work accidents are still very common resulting in human losses and permanent injuries. This makes it urgent and key to implementing security and safety measures also in the context of a smart factory. In this article, a novel framework for supporting smart devices in a smart factory, using multiple sensors to monitor different biometric features, both physical and behavioral is proposed. Thanks to the fusion of several biometric traits with the support of machine learning technologies working together with different kinds of sensors, it is possible to guarantee three fundamental aspects within the interaction between an operator of a smart device and the device itself: continuous authentication (i.e., continuous face recognition), drowsiness detection, and liveness detection. With the application of the proposed framework, it is possible to significantly improve the safety of operators avoiding fatal accidents for them. Experiments made using COTS-hardware showed that the authors’ idea is easy to implement in a large-scale smart factory and further improves the spread of Industry 4.0.

On the Impact of Multimodal and Multisensor Biometrics in Smart Factories

Recent regulations to block the widespread transmission of COVID-19 disease among people impose the use of facial masks indoor and outdoor. Such restriction becomes critical in all those scenarios where access controls take benefit from biometric recognition systems. The occlusions due to the presence of a facial mask make a significant portion of human faces unavailable for feature extraction and analysis. This work explores the contribution of the solely periocular region of the face to achieve a robust recognition approach suitable for mobile devices. Rather than working on a static analysis of the facial features, like largely done by work on periocular recognition in the literature, the proposed study focuses the attention on the analysis of face dynamics so that the spatio-temporal features make the recogniser frame-independent and tolerant to user movements during the acquisition. To obtain a lightweight processing, which is compliant with limited computing power of mobile devices, the spatio-temporal representation of the periocular region has analysed and classified through Machine Learning approaches. The experimental discussion has been performed on a new dataset, Mobile Masked Face REcognition Database, specifically designed to analyse the periocular region dynamics in presence of facial masks. For a wider comparative analysis, a publicly available dataset called XM2VTS has been considered as well as Deep Learning solutions have been experimented to discuss the challenging aspects of the recognition problem. Moreover, a summary of the state-of-the-art on periocular recognition driven by COVID pandemic has been presented, showing how the research efforts in this field focused on recognition of still images. Experimental results show promising levels of performance as well as limitations of the proposed approach, creating the premises for future directions.

https://ieeexplore.ieee.org/ielx7/6287639/6514899/09874825.pdf

M2FRED: Mobile Masked Face REcognition Through Periocular Dynamics Analysis

Abstract Facial Expression recognition is a computer vision problem that took relevant benefit from the research in deep learning. Recent deep neural networks achieved superior results, demonstrating the feasibility of recognizing the expression of a user from a single picture or a video recording the face dynamics. Research studies reveal that the most discriminating portions of the face surfaces that contribute to the recognition of facial expressions are located on the mouth and the eyes. The restrictions for COVID pandemic reasons have also revealed that state-of-the-art solutions for the analysis of the face can severely fail due to the occlusions of using the facial masks. This study explores to what extend expression recognition can deal with occluded faces in presence of masks. To a fairer comparison, the analysis is performed in different occluded scenarios to effectively assess if the facial masks can really imply a decrease in the recognition accuracy. The experiments performed on two public datasets show that some famous top deep classifiers expose a significant reduction in accuracy in presence of masks up to half of the accuracy achieved in non-occluded conditions. Moreover, a relevant decrease in performance is also reported also in the case of occluded eyes but the overall drop in performance is not as severe as in presence of the facial masks, thus confirming that, like happens for face biometric recognition, occluded faces by facial mask still represent a challenging limitation for computer vision solutions. 

/pdf/the-limitations-for-expression-recognition-in-computer-2vo3no99.pdf

Lucia Cimmino

Papers

Fusion of Periocular Deep Features in a Dual-Input CNN for Biometric Recognition

Biometric Face Recognition Based on Landmark Dynamics

On the Impact of Multimodal and Multisensor Biometrics in Smart Factories

M2FRED: Mobile Masked Face REcognition Through Periocular Dynamics Analysis

The limitations for expression recognition in computer vision introduced by facial masks