Intelligent Sensors for Human Motion Analysis

The book, "Intelligent Sensors for Human Motion Analysis," contains 17 articles published in the Special Issue of the Sensors journal. These articles deal with many aspects related to the analysis of human movement. New techniques and methods for pose estimation, gait recognition, and fall detection have been proposed and verified. Some of them will trigger further research, and some may become the backbone of commercial systems

A Review of Techniques on Gait-Based Person Re-Identification

Copyright (c) 2023 Babak Rahi, Maozhen Li and Man Qi. Person re-identification at a distance across multiple non-overlapping cameras has been an active research area for years. In the past ten years, short-term Person re-identification techniques have made great strides in accuracy using only appearance features in limited environments. However, massive intra-class variations and inter-class confusion limit their ability to be used in practical applications. Moreover, appearance consistency can only be assumed in a short time span from one camera to the other. Since the holistic appearance will change drastically over days and weeks, the technique, as mentioned above, will be ineffective. Practical applications usually require a long-term solution in which the subject's appearance and clothing might have changed after the elapse of a significant period. Facing these problems, soft biometric features such as Gait has stirred much interest in the past years. Nevertheless, even Gait can vary with illness, ageing and emotional states, walking surfaces, shoe types, clothes types, carried objects (by the subject) and even environment clutters. Therefore, Gait is considered as a temporal cue that could provide biometric motion information. On the other hand, the shape of the human body could be viewed as a spatial signal which can produce valuable information. So extracting discriminative features from both spatial and temporal domains would benefit this research. This article examines the main approaches used in gait analysis for re-identification over the past decade. We identify several relevant dimensions of the problem and provide a taxonomic analysis of current research. We conclude by reviewing the performance levels achievable with current technology and providing a perspective on the most challenging and promising research directions.This research received no external funding

View-invariant gait person re-identification with spatial and temporal attention

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonPerson re-identification at a distance across multiple none overlapping cameras has been an active research area for years. In the past ten years, Short term Person Re-Id techniques have made great strides in terms of accuracy using only appearance features in limited environments. However, massive intraclass variations and inter-class confusion limit their ability to be used in practical applications. Moreover, appearance consistency can only be assumed in a short time span from one camera to the other. Since the holistic appearance will change drastically over days and weeks, the technique, as mentioned above, will be ineffective. Practical applications usually require a long-term solution in which the subject appearance and clothing might have changed after a significant period has elapsed. Facing these problems, soft biometric features such as Gait have been proposed in the past. Nevertheless, even Gait can vary with illness, ageing and changes in the emotional state, changes in walking surfaces, shoe type, clothes type, objects carried by the subject and even clutter in the scene. Therefore, Gait is considered a temporal cue that could provide biometric motion information. On the other hand, the shape of the human body could be viewed as a spatial signal which can produce valuable information. So, extracting discriminative features from both spatial and temporal domains would be very beneficial to this research. Therefore, this thesis focuses on finding the best and most robust method to tackle the gait human Re-identification problem and solve it for practical applications. In real-world surveillance scenarios, the human gait cycle is primarily abnormal. These abnormalities include but not limited to temporal and spatial characteristics changes such as walking speed, broken gait phase and most importantly, varied camera angles. Our work performed an extensive literature study on spatial and temporal gait feature extraction methods with a focus on deep learning. Next, we conducted a comparative study and proposed a spatial-temporal approach for gait feature extraction using the fusion of multiple modalities, including optical-flow, raw silhouettes and RGB images. This approach was tested on two of the most challenging publicly available datasets for gait recognition TUM-GAID and CASIA-B, with excellent results presented in chapter 3. Furthermore, a modern spatial-temporal attention mechanism was proposed and tested on CASIA-B and OULP datasets which learns salient features independent of the gait cycle and view variations. The spatial attention layer in the proposed method extracts the spatial feature maps using a two-layered architecture that are fused using late fusion. It can pay attention to the identity-related salient regions in silhouette sequences discriminatively using the spatial feature maps. The temporal attention layer consists of an LSTM that encodes the temporal motion for silhouette sequences. It uses the encoded output vectors in the temporal attention architecture to focus on the most critical timesteps in the gait cycle and discard the rest. Furthermore, we improved the performance of our method by mapping our extracted spatial-temporal gait features to a discriminative null space for use in our Siamese architecture for crossmatching. We also conducted an element removal experiment on each segment of our spatial-temporal attentional network to gain insight into each component’s contribution to the performance. Our method showed outstanding robustness against abnormal gait cycles as well as viewpoint variations on both benchmark datasets

Uniscale and multiscale gait recognition in realistic scenario

The performance of a gait recognition method is affected by numerous challenging factors that degrade its reliability as a behavioural biometrics for subject identification in realistic scenario. Thus for effective visual surveillance, this thesis presents five gait recog- nition methods that address various challenging factors to reliably identify a subject in realistic scenario with low computational complexity. It presents a gait recognition method that analyses spatio-temporal motion of a subject with statistical and physical parameters using Procrustes shape analysis and elliptic Fourier descriptors (EFD). It introduces a part- based EFD analysis to achieve invariance to carrying conditions, and the use of physical parameters enables it to achieve invariance to across-day gait variation. Although spatio- temporal deformation of a subject’s shape in gait sequences provides better discriminative power than its kinematics, inclusion of dynamical motion characteristics improves the iden- tification rate. Therefore, the thesis presents a gait recognition method which combines spatio-temporal shape and dynamic motion characteristics of a subject to achieve robust- ness against the maximum number of challenging factors compared to related state-of-the- art methods. A region-based gait recognition method that analyses a subject’s shape in image and feature spaces is presented to achieve invariance to clothing variation and carry- ing conditions. To take into account of arbitrary moving directions of a subject in realistic scenario, a gait recognition method must be robust against variation in view. Hence, the the- sis presents a robust view-invariant multiscale gait recognition method. Finally, the thesis proposes a gait recognition method based on low spatial and low temporal resolution video sequences captured by a CCTV. The computational complexity of each method is analysed. Experimental analyses on public datasets demonstrate the efficacy of the proposed methods

Contributions for the automatic description of multimodal scenes

Tese de doutoramento. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 200

The neuroscience of sadness: A multidisciplinary synthesis and collaborative review

Sadness is typically characterized by raised inner eyebrows, lowered corners of the mouth, reduced walking speed, and slumped posture. Ancient subcortical circuitry provides a neuroanatomical foundation, extending from dorsal periaqueductal grey to subgenual anterior cingulate, the latter of which is now a treatment target in disorders of sadness. Electrophysiological studies further emphasize a role for reduced left relative to right frontal asymmetry in sadness, underpinning interest in the transcranial stimulation of left dorsolateral prefrontal cortex as an antidepressant target. Neuroimaging studies – including meta-analyses – indicate that sadness is associated with reduced cortical activation, which may contribute to reduced parasympathetic inhibitory control over medullary cardioacceleratory circuits. Reduced cardiac control may – in part – contribute to epidemiological reports of reduced life expectancy in affective disorders, effects equivalent to heavy smoking. We suggest that the field may be moving toward a theoretical consensus, in which different models relating to basic emotion theory and psychological constructionism may be considered as complementary, working at different levels of the phylogenetic hierarchy.Fil: Arias, Juan A.. Swansea University; Reino Unido. Universidad de Santiago de Compostela; EspañaFil: Williams, Claire. Swansea University; Reino UnidoFil: Raghvani, Rashmi. Swansea University; Reino UnidoFil: Aghajani, Moji. No especifíca;Fil: Baez, Sandra. Universidad de los Andes; ColombiaFil: Belzung, Catherine. Universite de Tours; FranciaFil: Booij, Linda. Concordia University Montreal; CanadáFil: Busatto, Geraldo. Universidade de Sao Paulo; BrasilFil: Chiarella, Julian. Concordia University Montreal; CanadáFil: Fu, Cynthia. University Of East London; Reino UnidoFil: Ibañez, Agustin Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Instituto de Neurología Cognitiva. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt | Fundación Favaloro. Instituto de Neurociencia Cognitiva y Traslacional. Fundación Ineco Rosario Sede del Incyt; Argentina. Universidad Adolfo Ibañez; Chile. Universidad Autónoma del Caribe; ColombiaFil: Liddell, Belinda J.. University of New South Wales; AustraliaFil: Lowe, Leroy. No especifíca;Fil: Penninx, Brenda W.J.H.. No especifíca;Fil: Rosa, Pedro. Universidade de Sao Paulo; BrasilFil: Kemp, Andrew H.. Universidade de Sao Paulo; Brasil. Swansea University; Reino Unid

The Neuroscience of Sadness: A Multidisciplinary Synthesis and Collaborative Review for the Human Affectome Project

Sadness is typically characterized by raised inner eyebrows, lowered corners of the mouth, reduced walking speed, and slumped posture. Ancient subcortical circuitry provides a neuroanatomical foundation, extending from dorsal periaqueductal grey to subgenual anterior cingulate, the latter of which is now a treatment target in disorders of sadness. Electrophysiological studies further emphasize a role for reduced left relative to right frontal asymmetry in sadness, underpinning interest in the transcranial stimulation of left dorsolateral prefrontal cortex as an antidepressant target. Neuroimaging studies – including meta-analyses – indicate that sadness is associated with reduced cortical activation, which may contribute to reduced parasympathetic inhibitory control over medullary cardioacceleratory circuits. Reduced cardiac control may – in part – contribute to epidemiological reports of reduced life expectancy in affective disorders, effects equivalent to heavy smoking. We suggest that the field may be moving toward a theoretical consensus, in which different models relating to basic emotion theory and psychological constructionism may be considered as complementary, working at different levels of the phylogenetic hierarchy

[¹⁸F]fluorination of biorelevant arylboronic acid pinacol ester scaffolds synthesized by convergence techniques

Aim: The development of small molecules through convergent multicomponent reactions (MCR) has been boosted during the last decade due to the ability to synthesize, virtually without any side-products, numerous small drug-like molecules with several degrees of structural diversity.(1) The association of positron emission tomography (PET) labeling techniques in line with the “one-pot” development of biologically active compounds has the potential to become relevant not only for the evaluation and characterization of those MCR products through molecular imaging, but also to increase the library of radiotracers available. Therefore, since the [18F]fluorination of arylboronic acid pinacol ester derivatives tolerates electron-poor and electro-rich arenes and various functional groups,(2) the main goal of this research work was to achieve the 18F-radiolabeling of several different molecules synthesized through MCR. Materials and Methods: [18F]Fluorination of boronic acid pinacol esters was first extensively optimized using a benzaldehyde derivative in relation to the ideal amount of Cu(II) catalyst and precursor to be used, as well as the reaction solvent. Radiochemical conversion (RCC) yields were assessed by TLC-SG. The optimized radiolabeling conditions were subsequently applied to several structurally different MCR scaffolds comprising biologically relevant pharmacophores (e.g. β-lactam, morpholine, tetrazole, oxazole) that were synthesized to specifically contain a boronic acid pinacol ester group. Results: Radiolabeling with fluorine-18 was achieved with volumes (800 μl) and activities (≤ 2 GBq) compatible with most radiochemistry techniques and modules. In summary, an increase in the quantities of precursor or Cu(II) catalyst lead to higher conversion yields. An optimal amount of precursor (0.06 mmol) and Cu(OTf)2(py)4 (0.04 mmol) was defined for further reactions, with DMA being a preferential solvent over DMF. RCC yields from 15% to 76%, depending on the scaffold, were reproducibly achieved. Interestingly, it was noticed that the structure of the scaffolds, beyond the arylboronic acid, exerts some influence in the final RCC, with electron-withdrawing groups in the para position apparently enhancing the radiolabeling yield. Conclusion: The developed method with high RCC and reproducibility has the potential to be applied in line with MCR and also has a possibility to be incorporated in a later stage of this convergent “one-pot” synthesis strategy. Further studies are currently ongoing to apply this radiolabeling concept to fluorine-containing approved drugs whose boronic acid pinacol ester precursors can be synthesized through MCR (e.g. atorvastatin)