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Sensors, Volume 26, Issue 3 (February-1 2026) – 328 articles

Cover Story (view full-size image): We utilize coherent-control quartz-enhanced photoacoustic spectroscopy (COCO-QEPAS) in combination with a widely tunable picosecond near- and mid-infrared laser to detect trace gases such as methane, ethane, ethene, acetylene, among others. The laser system is rapidly tunable so that an entire vibrational–rotational fingerprint of a molecule can be recorded in a few seconds. Limits of detection are on the low ppm and high ppb ranges. Mixtures of gases can be sensed and identified using their spectral infrared fingerprints. We demonstrate and evaluate detection accuracy, detection limits, and mixture decomposition, using different machine learning methods. View this paper
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26 pages, 1206 KB  
Article
ACL-ECG: Anatomy-Aware Contrastive Learning for Multi-Lead Electrocardiograms
by Wenhan Liu, Zhijing Wu and Zhaohui Yuan
Sensors 2026, 26(3), 1080; https://doi.org/10.3390/s26031080 - 6 Feb 2026
Viewed by 666
Abstract
Deep learning has achieved impressive progress in automated electrocardiogram (ECG) analysis, yet its performance still relies heavily on large-scale labeled datasets. As ECG annotation requires cardiologists, this process is costly and time-consuming, limiting its scalability in clinical practice. Contrastive learning offers a promising [...] Read more.
Deep learning has achieved impressive progress in automated electrocardiogram (ECG) analysis, yet its performance still relies heavily on large-scale labeled datasets. As ECG annotation requires cardiologists, this process is costly and time-consuming, limiting its scalability in clinical practice. Contrastive learning offers a promising alternative by enabling the extraction of generalizable representations from unlabeled ECG data. In this study, we propose Anatomy-Aware Contrastive Learning for ECG (ACL-ECG), a self-supervised method that incorporates cardiac anatomical relationships into contrastive learning. ACL-ECG employs a physiology-aware augmentation strategy to generate rhythm-preserving augmented views, including random scale cropping, cardiac-cycle masking, and temporal shifting. Furthermore, ECG leads are grouped into four anatomically meaningful regions—anterior, inferior, septal, and lateral—and region-level contrastive objectives are introduced to promote intra-region consistency while enhancing inter-region discriminability. Extensive evaluations of downstream tasks demonstrate that ACL-ECG consistently outperforms state-of-the-art contrastive baselines under linear probing, achieving improvements of up to 1.29% in the area under the receiver operating characteristic curve (AUROC) and 3.57% in the area under the precision–recall curve (AUPRC). Moreover, when fine-tuned using only 10% of labeled data, ACL-ECG attains a performance comparable to fully supervised training, effectively reducing annotation requirements by approximately 5∼8×. Ablation studies further confirm the contributions of both the physiology-aware augmentation strategy and the anatomy-aware contrastive objective. Overall, ACL-ECG enhances representation quality without increasing annotation burden, and provides a promising and anatomy-informed foundation for self-supervised ECG analysis in label-scarce settings. Full article
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20 pages, 900 KB  
Article
Open-Set Recognition of Human Activities from Head-Mounted Inertial Sensor
by Angela Cortese, Sarah Solbiati, Alice Scandelli, Andrea Giudici, Niccolò Antonello, Diana Trojaniello, Giacomo Boracchi and Enrico Gianluca Caiani
Sensors 2026, 26(3), 1079; https://doi.org/10.3390/s26031079 - 6 Feb 2026
Cited by 1 | Viewed by 899
Abstract
Human activity recognition (HAR) based on inertial measurement units (IMUs) embedded in wearable devices has gained increasing relevance in healthcare, wellness, and fitness monitoring. However, most existing classification methods assume a closed-set setting, where all activity classes need to be defined during training, [...] Read more.
Human activity recognition (HAR) based on inertial measurement units (IMUs) embedded in wearable devices has gained increasing relevance in healthcare, wellness, and fitness monitoring. However, most existing classification methods assume a closed-set setting, where all activity classes need to be defined during training, which limits their applicability in real-world environments where unseen or unexpected activities are present. To overcome this limitation, we adopt an open-set recognition (OSR) framework that requires minimal changes to the HAR classifiers traditionally employed for this purpose. We also provide an extensive empirical evaluation based on a leave-one-activity-out validation protocol applied to two datasets with IMU signals acquired from smart eyewear: a proprietary dataset and the publicly available UCA-EHAR dataset. A lightweight one-dimensional convolutional neural network was trained to classify six-axis IMU data across common activities. We assess open-set HAR performance using several methods requiring limited computational overhead and operating in the logit space, including maximum logit, Gaussian Mixture Models, Kernel Density Estimation, OpenMax, and Nearest Neighbor Distance Ratio. Robust identification of unknown activities was achieved, with area under the ROC curve > 0.8. These findings highlight the potential of low-complexity open-set approaches for real-time HAR on resource-constrained wearable platforms, supporting the development of adaptive and reliable sensor-based recognition systems for real-world use. Full article
(This article belongs to the Special Issue Smart Sensing Technology for Human Activity Recognition)
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19 pages, 24032 KB  
Article
Feature Augmentation-Based Adaptive Neural Network Control for Quadrotors
by Bang Song and Mengxing Huang
Sensors 2026, 26(3), 1078; https://doi.org/10.3390/s26031078 - 6 Feb 2026
Viewed by 479
Abstract
In this article, an adaptive neural network (ANN) controller based on feature augmentation (FA) is designed for quadrotors. The proposed controller consists of two components: a position sub-controller and an attitude sub-controller. We use the ANN to estimate unknown internal and external disturbance [...] Read more.
In this article, an adaptive neural network (ANN) controller based on feature augmentation (FA) is designed for quadrotors. The proposed controller consists of two components: a position sub-controller and an attitude sub-controller. We use the ANN to estimate unknown internal and external disturbance terms within quadrotors. To improve the learning accuracy of the ANN, we design an FA structure, which enables networks to more effectively learn the characteristics in the data. To increase the learning rate of the ANN, a state predictor (SP) is proposed to anticipate the state errors, which subsequently updates the learning rate of the ANN. Based on stability analysis, we prove that the closed-loop system is input-to-state stable (ISS). Finally, the effectiveness of our proposed control algorithm is demonstrated by comparing it with related control algorithms on both the MATLAB R2020a/Simulink simulation platform and a quadrotor experimental platform. Full article
(This article belongs to the Section Sensors and Robotics)
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17 pages, 4523 KB  
Article
Photovoltaic-Related “Black Swan” Hypothesis for Electric Power System: Phenomenology, Simulations, Experiences, and Prevention
by Sasa Sladic and Even Zivic
Sensors 2026, 26(3), 1077; https://doi.org/10.3390/s26031077 - 6 Feb 2026
Viewed by 718
Abstract
Several blackouts have recently occurred in Europe and elsewhere. Blackouts are mostly the consequence of a series of events rather than a single event. Their intensity and frequency could be related to the stronger penetration of renewables into electric power systems. Although many [...] Read more.
Several blackouts have recently occurred in Europe and elsewhere. Blackouts are mostly the consequence of a series of events rather than a single event. Their intensity and frequency could be related to the stronger penetration of renewables into electric power systems. Although many different renewable power units may be installed, they all have some basic properties: their power is not consistent, and power inverters are used to connect renewables to electric power systems. Photovoltaic systems are the most typical representative of this large group of power sources. These devices have become more sophisticated over the past few years, allowing for the precise control of large photovoltaic fields. In this situation, all power converters act as one. This means that they could be turned on and off during short intervals. Furthermore, their power factor could be independently adjusted. These functions are desirable for small systems; however, their implications for stability at a larger scale are usually not considered. In this study, the stability issues of a system under the high penetration of renewables and a unique control system are investigated. The most prominent case of this influence is a high-impact rare (HR) event, also known as a “black swan”, which could cause a massive blackout in an electric power system. Full article
(This article belongs to the Section Electronic Sensors)
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22 pages, 2929 KB  
Article
Machine Learning-Enhanced Evaluation of Handheld Laser-Induced Breakdown Spectroscopy (LIBS) Analytical Performance for Multi-Element Analysis of Rock Samples
by Giorgio S. Senesi, Olga De Pascale, Ignazio Allegretta, Roberto Terzano and Bruno Marangoni
Sensors 2026, 26(3), 1076; https://doi.org/10.3390/s26031076 - 6 Feb 2026
Cited by 1 | Viewed by 658
Abstract
Handheld laser-induced breakdown spectroscopy (hLIBS) can be considered one of the most recent techniques for rock characterization in situ. Handheld LIBS devices are useful tools for providing “fit for purpose” qualitative and quantitative geochemical data. The analytical performance of hLIBS instruments varies significantly [...] Read more.
Handheld laser-induced breakdown spectroscopy (hLIBS) can be considered one of the most recent techniques for rock characterization in situ. Handheld LIBS devices are useful tools for providing “fit for purpose” qualitative and quantitative geochemical data. The analytical performance of hLIBS instruments varies significantly between similar instruments from different manufacturers. This study employed two commercial hLIBS instruments, both making use of noise reduction and multivariate partial-least-squares (PLS) calibration. Model validation was performed using the Leave-One-Out Cross-Validation (LOOCV) method. The Random Forest (RF) and Artificial Neural Network (ANN) algorithms were also employed as complementary approaches to PLS modeling, with the goal of exploring potential nonlinear relationships between spectral intensities and reference analyte concentrations. A comparison was also made with the most basic and commonly used approach, univariate analysis, demonstrating that multivariate methods achieve superior performances. To evaluate the predictive performance and quantification capability of the acquired LIBS spectra, the Pearson’s coefficient (R2) and root-mean-square error (RMSE) were employed in the analysis of 21 diverse certified geochemical reference materials (CRMs). The results achieved suggested that the spectral resolution was the key factor determining the performance of multivariate LIBS calibrations. The PLS model proved to be satisfactory for analyses performed by the higher-spectral-resolution instrument, whereas complementary algorithms were necessary to achieve better results with the lower-spectral-resolution instrument. Full article
(This article belongs to the Special Issue Novel Sensor Technologies for Civil Infrastructure Monitoring)
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18 pages, 4202 KB  
Article
Scanning Magnetic Microscopy Using a High-Sensitivity Room-Temperature Tunnel Magnetoresistance Sensor for Geological Applications
by Hirokuni Oda, Kosuke Fujiwara, Naoto Fukuyo, Hitoshi Kubota, Tomohiro Ichinose, Mikihiko Oogane, Seiji Kumagai, Hitoshi Matsuzaki, Taizo Uchida, Miki Kawabata and Jun Kawai
Sensors 2026, 26(3), 1075; https://doi.org/10.3390/s26031075 - 6 Feb 2026
Viewed by 930
Abstract
This paper reports magnetic microscopy using high-sensitivity room-temperature tunnel magnetoresistance (TMR) devices for thin geological sections. The sensitivity region of the TMR sensor has dimensions of 178 µm (L) × 0.1 µm (W) × 100 µm (H), consisting of two TMR devices. Magnetic [...] Read more.
This paper reports magnetic microscopy using high-sensitivity room-temperature tunnel magnetoresistance (TMR) devices for thin geological sections. The sensitivity region of the TMR sensor has dimensions of 178 µm (L) × 0.1 µm (W) × 100 µm (H), consisting of two TMR devices. Magnetic images were obtained for a vertically magnetized Hawaii basalt thin section in two sensor configurations, with the sensor length aligned parallel to the X- (lift-off = 174 μm) and Y-axes (lift-off = 200 μm), without introducing anisotropic distortion in the magnetic images. Although the magnetic images obtained with a scanning SQUID microscope (SSM) were similar, slight discrepancies were observed in the high-spatial-resolution region. A magnetic point source (50 μm × 50 μm) with a perpendicular magnetization film was prepared for evaluation. The SSM measurements showed a clear magnetic dipole at an angle of approximately 1° from the vertical direction. The FWHMs for both the SSM and TMR sensors increased linearly with lift-off. However, the peak magnetic fields, magnetic moments, and dipole tilts of the TMR sensor were significantly larger than those of the SSM sensor. This discrepancy may be due to the vertical extent of the active region of the TMR sensor, as well as due to sensor noise and drift. Full article
(This article belongs to the Special Issue Smart Magnetic Sensors and Application)
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17 pages, 944 KB  
Article
Decoding Non-Invasive Electroencephalography Signal via a Two-Discriminator Adversarial Network
by Xuguang Liu, Changyi Yu, Ye Li, Xin Zhang and Xiu Zhang
Sensors 2026, 26(3), 1074; https://doi.org/10.3390/s26031074 - 6 Feb 2026
Viewed by 507
Abstract
Electroencephalography (EEG), as a typical non-invasive biosensing signal, reflects individual emotional changes by recording the brain’s neural activity in response to various external stimuli. However, the significant differences in brain activity among individuals and the complex interrelationships between EEG channels notably hinder the [...] Read more.
Electroencephalography (EEG), as a typical non-invasive biosensing signal, reflects individual emotional changes by recording the brain’s neural activity in response to various external stimuli. However, the significant differences in brain activity among individuals and the complex interrelationships between EEG channels notably hinder the accuracy of emotion decoding in non-invasive biosensing scenarios. To address this challenge, this paper proposes a two-discriminator domain adversarial neural network method (TD-DANN). The proposed method aims to obtain more generalized and individualized emotion feature representations through adversarial learning. Specifically, graph convolution is utilized to extract features from EEG signals. By modeling the EEG channels as graph nodes, the adjacency matrix can be dynamically learned to capture the complex relationships between different channels during emotion generation. Moreover, we design a domain discriminator and an individual discriminator. The domain discriminator is used to minimize the difference in feature distribution between the source and target domains. It is able to obtain discriminative features with universality. The individual discriminator is used to learn discriminative features consistent with the individual’s brain activity. It can enhance the adaptability to the individual’s emotion. The experimental results show that the TD-DANN achieves promising recognition accuracies of (98.45 ± 2.38)% and (89.45 ± 5.87)% for subject-dependent and subject-independent experiments on the SEED dataset, respectively. The proposed method attains recognition accuracies of (84.40 ± 8.70)% and (77.13 ± 7.97)% for subject-dependent and subject-independent experiments on the SEED-IV dataset, respectively. These results validate the effectiveness of the TD-DANN in the emotion decoding problem. Full article
(This article belongs to the Section Biosensors)
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19 pages, 7669 KB  
Article
Experimental Evaluation of Different Optical Fibers for Micro-Invasive Soft-Tissue Ablation with a 1064 nm Diode Laser System
by Danny Di Minno, Cosimo Trono, Lorenzo Capineri, Alessia Blundo and Giovanni Masotti
Sensors 2026, 26(3), 1073; https://doi.org/10.3390/s26031073 - 6 Feb 2026
Viewed by 688
Abstract
This study presents an experimental evaluation of different optical fibers for soft-tissue laser ablation using an Echolaser system, developed by Elesta S.p.A., for minimally invasive therapies. Eight fibers with varying core diameters, numerical apertures, and tip geometries (flat, conical radial, and spherical) were [...] Read more.
This study presents an experimental evaluation of different optical fibers for soft-tissue laser ablation using an Echolaser system, developed by Elesta S.p.A., for minimally invasive therapies. Eight fibers with varying core diameters, numerical apertures, and tip geometries (flat, conical radial, and spherical) were compared to investigate the influence of optical properties on the ablation dimensions and thermal profiles. The experiments were conducted at 1064 nm with powers of 3, 5, and 7 W and delivered energies ranging from 1200 to 3600 J. The results highlight how the fiber characteristics affect tissue ablation, identifying the configurations suitable for minimally invasive prostate applications. These findings provide an experimental reference for the development of laser-based biomedical approaches. Full article
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22 pages, 6824 KB  
Article
Online Multi-Parameter Identification for PMSM Parameter Monitoring Based on a ZOH Model and Dual-Sampling Strategy
by Sidong He, Xuewei Xiang, Hui Li, Shuai Li and Peng Jiang
Sensors 2026, 26(3), 1072; https://doi.org/10.3390/s26031072 - 6 Feb 2026
Viewed by 644
Abstract
The accuracy of online parameter identification for permanent magnet synchronous motors (PMSMs) is constrained by discrete model errors, rank deficiency in the steady-state identification matrix, and voltage deviations resulting from inverter nonlinearities. This paper proposes a multi-parameter identification method acting as a high-precision [...] Read more.
The accuracy of online parameter identification for permanent magnet synchronous motors (PMSMs) is constrained by discrete model errors, rank deficiency in the steady-state identification matrix, and voltage deviations resulting from inverter nonlinearities. This paper proposes a multi-parameter identification method acting as a high-precision virtual sensor, based on Zero-Order Hold (ZOH) discretization and an inverter nonlinear voltage compensation scheme utilizing a dual-sampling strategy. First, a discrete model of the PMSM, accounting for rotor position variations within the control period, is established using the ZOH discretization method. Compared with the forward Euler discretization method, this approach effectively minimizes discretization model errors, especially under high-speed operating conditions where rotor position variations are significant. Second, the rank deficiency problem of the steady-state identification matrix is overcome by combining d-axis small-signal injection with a dual-sampling strategy. Furthermore, the Forgetting Factor Recursive Least Squares (FFRLS) algorithm is introduced to achieve online multi-parameter identification. Finally, the influence mechanisms of the dead-time effect, power switch voltage drop, and turn-on delay on the output voltage are analyzed. Consequently, an inverter nonlinear voltage compensation strategy tailored for the dual-sampling mode is proposed. Experimental results demonstrate that the proposed method significantly enhances parameter identification accuracy across the entire speed range. Specifically, under high-speed conditions, the identification errors for resistance, inductance, and flux linkage are maintained within 5.47%, 4.05%, and 2.46%, respectively. Full article
(This article belongs to the Section Industrial Sensors)
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18 pages, 2891 KB  
Article
DCP-TransUNet: An Approach for Crack Segmentation on Roads
by Yunqing Liu, Xu Du and Weiguang Li
Sensors 2026, 26(3), 1071; https://doi.org/10.3390/s26031071 - 6 Feb 2026
Viewed by 634
Abstract
For cement pavements on vast road networks, cracking has become one of the principal distresses threatening structural integrity and traffic safety. This study introduces DCP-TransUNet, a model featuring a new hybrid encoder that enhances the continuity of crack extraction under complex conditions through [...] Read more.
For cement pavements on vast road networks, cracking has become one of the principal distresses threatening structural integrity and traffic safety. This study introduces DCP-TransUNet, a model featuring a new hybrid encoder that enhances the continuity of crack extraction under complex conditions through a DSE-CNN module and a CLMA-Transformer block. To further strengthen learning and interpretability for challenging crack imagery, a PPA bottleneck module is designed to capture additional discriminative features. Experimental results indicate strong performance: on the public dataset, DCP-TransUNet achieves mIoU 79.12%, Recall 87.96%, F1 87.06%, and Precision 86.21%; on the private dataset, it attains mIoU 68.83%, Recall 74.42%, F1 77.57%, and Precision 81.67%. Compared with other models, these outcomes demonstrate the method’s accuracy and effectiveness for crack segmentation. Full article
(This article belongs to the Special Issue Structural Health Monitoring and Smart Disaster Prevention)
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31 pages, 2850 KB  
Article
Context-Aware Multi-Agent Architecture for Wildfire Insights
by Ashen Sandeep, Sithum Jayarathna, Sunera Sandaruwan, Venura Samarappuli, Dulani Meedeniya and Charith Perera
Sensors 2026, 26(3), 1070; https://doi.org/10.3390/s26031070 - 6 Feb 2026
Cited by 1 | Viewed by 1352
Abstract
Wildfires are environmental hazards with severe ecological, social, and economic impacts. Wildfires devastate ecosystems, communities, and economies worldwide, with rising frequency and intensity driven by climate change, human activity, and environmental shifts. Analyzing wildfire insights such as detection, predictive patterns, and risk assessment [...] Read more.
Wildfires are environmental hazards with severe ecological, social, and economic impacts. Wildfires devastate ecosystems, communities, and economies worldwide, with rising frequency and intensity driven by climate change, human activity, and environmental shifts. Analyzing wildfire insights such as detection, predictive patterns, and risk assessment enables proactive response and long-term prevention. However, most of the existing approaches have been focused on isolated processing of data, making it challenging to orchestrate cross-modal reasoning and transparency. This study proposed a novel orchestrator-based multi-agent system (MAS), with the aim of transforming multimodal environmental data into actionable intelligence for decision making. We designed a framework to utilize Large Multimodal Models (LMMs) augmented by structured prompt engineering and specialized Retrieval-Augmented Generation (RAG) pipelines to enable transparent and context-aware reasoning, providing a cutting-edge Visual Question Answering (VQA) system. It ingests diverse inputs like satellite imagery, sensor readings, weather data, and ground footage and then answers user queries. Validated by several public datasets, the system achieved a precision of 0.797 and an F1-score of 0.736. Thus, powered by Agentic AI, the proposed, human-centric solution for wildfire management, empowers firefighters, governments, and researchers to mitigate threats effectively. Full article
(This article belongs to the Section Internet of Things)
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17 pages, 9291 KB  
Article
A Room-Temperature, High-ppb-Level NO Gas Sensor Based on Pt/WO3 Co-Decorated Carbon Nanofibers Towards Asthma-Relevant Breath Analysis Application
by Shanshan Yu, Xingyu Liu, Jinshun Wang, Qiuxia Li, Yuhao Pang, Lixin Zhang, Chen Yang, Qingkuan Meng, Cao Wang, Qiang Jing, Jingwei Chen and Bo Liu
Sensors 2026, 26(3), 1069; https://doi.org/10.3390/s26031069 - 6 Feb 2026
Cited by 1 | Viewed by 619
Abstract
A chemiresistive nitric oxide (NO) gas sensor based on Pt/WO3 co-decorated carbon nanofibers (CNFs) was fabricated using a simple and scalable electrospinning process. This sensor demonstrates high-ppb-level NO detection at room temperature (25 °C), with an experimentally demonstrated detection limit of 100 [...] Read more.
A chemiresistive nitric oxide (NO) gas sensor based on Pt/WO3 co-decorated carbon nanofibers (CNFs) was fabricated using a simple and scalable electrospinning process. This sensor demonstrates high-ppb-level NO detection at room temperature (25 °C), with an experimentally demonstrated detection limit of 100 ppb. It exhibits rapid response, good signal repeatability, excellent batch-to-batch reproducibility, and high selectivity toward NO. Compared with previously reported NO sensors, this work highlights the integration of Pt and WO3 within a conductive CNF network, enabling room-temperature NO detection down to 100 ppb using a simple chemiresistive architecture. In addition, preliminary sensing tests were conducted using dried simulated breath samples prepared by introducing exogenous NO into exhaled breath from healthy volunteers, demonstrating the sensor’s capability to resolve different NO levels in a complex breath-related background. Owing to its reliable performance and cost-effective fabrication, the sensor holds potential as a NO sensing platform, providing a materials-level basis for future breath NO analysis and other related applications. Full article
(This article belongs to the Section Chemical Sensors)
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14 pages, 1011 KB  
Article
3D TractFormer: 3D Direct Volumetric White Matter Tract Segmentation with Hybrid Channel-Wise Transformer
by Xiang Gao, Hui Tian, Xuefei Yin and Alan Wee-Chung Liew
Sensors 2026, 26(3), 1068; https://doi.org/10.3390/s26031068 - 6 Feb 2026
Viewed by 554
Abstract
Segmenting white matter tracts in diffusion-weighted magnetic resonance imaging (dMRI) is of vital importance for brain health analysis. It remains a challenging task due to the intersection and overlap of tracts (i.e., multiple tracts coexist in one voxel) and the data complexity of [...] Read more.
Segmenting white matter tracts in diffusion-weighted magnetic resonance imaging (dMRI) is of vital importance for brain health analysis. It remains a challenging task due to the intersection and overlap of tracts (i.e., multiple tracts coexist in one voxel) and the data complexity of dMRI images (e.g., 4D high spatial resolution). Existing methods that demonstrate good performance implement direct volumetric tract segmentation by performing on individual 2D slices. However, this ignores 3D contextual information, requires additional post-processing, and struggles with the boundary handling of 3D volumes. Therefore, in this paper, we propose an efficient 3D direct volumetric segmentation method for segmenting white matter tracts. It has three key innovations. First, we propose to deeply interleave convolutions and transformer blocks into a U-shaped network, which effectively integrates their respective strengths to extract spatial contextual features and global long-distance dependencies for enhanced feature extraction. Second, we propose a novel channel-wise transformer, which integrates depth-wise separable convolution and compressed contextual feature-based channel-wise attention, effectively addressing the memory and computational challenges of 4D computing. Moreover, it helps to model global dependencies of contextual features and ensures each hierarchical layer focuses on complementary features. Third, we propose to train a fully symmetric network with gradually sized volumetric patches, which can solve the challenge of few 3D training samples and further reduce memory and computational costs. Experimental results on the largest publicly available tract-specific tractograms dataset demonstrate the superiority of the proposed method over the current state-of-the-art methods. Full article
(This article belongs to the Special Issue Secure AI for Biomedical Sensing and Imaging Applications)
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18 pages, 2041 KB  
Article
Wavelet-CNet: Wavelet Cross Fusion and Detail Enhancement Network for RGB-Thermal Semantic Segmentation
by Wentao Zhang, Qi Zhang and Yue Yan
Sensors 2026, 26(3), 1067; https://doi.org/10.3390/s26031067 - 6 Feb 2026
Cited by 1 | Viewed by 555
Abstract
Leveraging thermal infrared imagery to complement RGB spatial information is a key technology in industrial sensing. This technology enables mobile devices to perform scene understanding through RGB-T semantic segmentation. However, existing networks conduct only limited information interaction between modalities and lack specific designs [...] Read more.
Leveraging thermal infrared imagery to complement RGB spatial information is a key technology in industrial sensing. This technology enables mobile devices to perform scene understanding through RGB-T semantic segmentation. However, existing networks conduct only limited information interaction between modalities and lack specific designs to exploit the thermal aggregation entropy of the thermal modality, resulting in inefficient feature complementarity within bilateral structures. To address these challenges, we propose Wavelet-CNet for RGB-T semantic segmentation. Specifically, we design a Wavelet Cross Fusion Module (WCFM) that applies wavelet transforms to separately extract four types of low- and high-frequency information from RGB and thermal features, which are then fed back into attention mechanisms for dual-modal feature reconstruction. Furthermore, a Cross-Scale Detail Enhancement Module (CSDEM) introduces cross-scale contextual information from the TIR branch into each fusion stage, aligning global localization through contour information from thermal features. Wavelet-CNet achieves competitive mIoU scores of 58.3% and 85.77% on MFNet and PST900, respectively, while ablation studies on MFNet further validate the effectiveness of the proposed WCFM and CSDEM modules. Full article
(This article belongs to the Special Issue AI-Based Computer Vision Sensors & Systems—2nd Edition)
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22 pages, 1042 KB  
Article
Pulse Wave Velocity Estimation in a Controlled In Vitro Vascular Model: Benchmarking Machine Learning Approaches
by Daniel Barvik, Martin Černý, Michal Prochazka and Norbert Noury
Sensors 2026, 26(3), 1066; https://doi.org/10.3390/s26031066 - 6 Feb 2026
Viewed by 580
Abstract
This study evaluates the feasibility of estimating stiffness-related parameters and pulse wave velocity (PWV) in a controlled in vitro circulatory setup using artificial silicone vessels with systematically varied Shore A hardness and wall thickness. From synchronized pressure and capacitive waveforms, fiducial points and [...] Read more.
This study evaluates the feasibility of estimating stiffness-related parameters and pulse wave velocity (PWV) in a controlled in vitro circulatory setup using artificial silicone vessels with systematically varied Shore A hardness and wall thickness. From synchronized pressure and capacitive waveforms, fiducial points and engineered features are extracted, together with pump settings (stroke volume and heart rate). A Sugeno-type adaptive neuro-fuzzy inference system (ANFIS) is used for hardness-level prediction and benchmarked against linear regression and contemporary machine-learning/deep-learning baselines using stratified cross-validation. PWV estimates derived via hardness-to-elasticity conversion models and the Moens–Korteweg formulation are evaluated against a reference PWV obtained within the same experimental configuration. Under these controlled conditions, the proposed pipeline shows strong agreement with reference labels and measurements. The results should be interpreted as an in vitro validation step; translation to biological tissues or in vivo data will require external validation, calibration of material-property mapping, and robustness testing under physiological variability and measurement noise. Full article
(This article belongs to the Section Biomedical Sensors)
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17 pages, 815 KB  
Article
Spatial and Directional Modulation Systems for Near-Field Secure Transmission
by Ji Liu, Yuan Zhong, Yong Wang, Dong Gong and Yue Xiao
Sensors 2026, 26(3), 1065; https://doi.org/10.3390/s26031065 - 6 Feb 2026
Viewed by 346
Abstract
The proliferation of massive antenna arrays and the consequent intensification of near-field effects with 6G necessitate addressing critical security challenges in near-field communication environments. This paper presents a novel artificial noise-aided spatial and directional modulation (SDMN-AN) framework, specifically tailored for secure near-field communications. [...] Read more.
The proliferation of massive antenna arrays and the consequent intensification of near-field effects with 6G necessitate addressing critical security challenges in near-field communication environments. This paper presents a novel artificial noise-aided spatial and directional modulation (SDMN-AN) framework, specifically tailored for secure near-field communications. The proposed system integrates legitimate receiver indices, modulation symbols, and artificial noise (AN) confined to the null space of legitimate channels, thereby enhancing both spectral efficiency and communication security. Two precoding strategies—maximum-ratio transmission (MRT) and zero-forcing (ZF)—are investigated, offering trade-offs between hardware complexity and detection overhead. Analytical derivations of bit error rate (BER) bounds, corroborated by simulation results, underscore the superiority of the SDMN-AN framework in mitigating eavesdropping threats while significantly improving spectral efficiency, positioning it as a compelling solution for next-generation secure wireless networks. Full article
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19 pages, 2982 KB  
Article
BWD-DETR: A Robust Framework for Bright-Field Wafer Defect Detection
by Ruilou Zhang, Xiangji Guo, Yuankang Xu, Tianyu Zhang and Ming Ming
Sensors 2026, 26(3), 1064; https://doi.org/10.3390/s26031064 - 6 Feb 2026
Viewed by 544
Abstract
Optical defect detection based on bright-field imaging is currently one of the most widely applied inspection techniques in wafer fabrication. However, particle defects on the surface of patterned wafers are often small in size. Under bright-field optical imaging conditions, defect signals are easily [...] Read more.
Optical defect detection based on bright-field imaging is currently one of the most widely applied inspection techniques in wafer fabrication. However, particle defects on the surface of patterned wafers are often small in size. Under bright-field optical imaging conditions, defect signals are easily overwhelmed by complex background textures and noise, seriously affecting the detectability and positioning accuracy of defects. To address this issue, this paper proposes BWD-DETR, a detection framework tailored for wafer surface defects under bright-field imaging. Based on the RT-DETR baseline, this framework integrates a wavelet backbone, an SMFI module, and a CAS-Fusion module, achieving an AP50 of 96.56% and an AP50:95 of 54.94% in bright-field wafer defect detection, with improvements of 1.64% and 2.17% over the baseline, respectively. The proposed method can effectively enhance the detection capability for sub-micron defects on the wafer surface. Full article
(This article belongs to the Section Sensing and Imaging)
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16 pages, 5371 KB  
Article
A Modified Dot-Pattern Moiré Fringe Topography Technique for Efficient Human Body Surface Analysis
by Muhammad Wasim, Syed Talha Ahsan, Lubaid Ahmed and Subhash Sagar
Sensors 2026, 26(3), 1063; https://doi.org/10.3390/s26031063 - 6 Feb 2026
Viewed by 611
Abstract
Raster-stereography and Moiré Fringe Topography are widely recognized as effective techniques for surface screening. Traditionally, these methods have been applied in various medical and clinical contexts, such as assessing human body symmetry, analyzing spinal deformities, evaluating scapular positioning, and predicting trunk-related abnormalities. Both [...] Read more.
Raster-stereography and Moiré Fringe Topography are widely recognized as effective techniques for surface screening. Traditionally, these methods have been applied in various medical and clinical contexts, such as assessing human body symmetry, analyzing spinal deformities, evaluating scapular positioning, and predicting trunk-related abnormalities. Both techniques have proven to be reliable tools for examining the human body surface and identifying health-related issues. However, in these techniques, line grids projected onto non-uniform surfaces often break or distort, complicating curvature detection. Capturing and digitizing these distortions through photographymeans further reducing accuracy due to low contrast between background and projected lines. In this paper, we present a modified, i.e., dotted-based, approach to Moiré Fringe Topography construction, offering a simpler, more accurate, and efficient method for recording human body surface curvatures. The proposed technique significantly reduces the complexity of the data acquisition process while maintaining precision in surface analysis. A Single-Photon Avalanche Diode (SPAD) image sensor was used to capture the Moiré patterns. Full article
(This article belongs to the Section Intelligent Sensors)
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21 pages, 13727 KB  
Article
TSA-Net: Multivariate Time Series Anomaly Detection Based on Two-Stage Temporal Attention
by Hao Wu, Wu Le, Zhen-Hong Jia, Hui Zhao, Sai Zhang and Zhen-Sen Zhang
Sensors 2026, 26(3), 1062; https://doi.org/10.3390/s26031062 - 6 Feb 2026
Viewed by 1084
Abstract
Multivariate time series anomaly detection is a critical technique for industrial intelligent monitoring. However, existing methods often suffer from prohibitively high training costs and slow convergence, making them ill-suited for industrial scenarios that require frequent model retraining due to dynamic operating conditions. To [...] Read more.
Multivariate time series anomaly detection is a critical technique for industrial intelligent monitoring. However, existing methods often suffer from prohibitively high training costs and slow convergence, making them ill-suited for industrial scenarios that require frequent model retraining due to dynamic operating conditions. To this end, an efficient two-stage spatio-temporal attention detection framework, TSA-Net, is proposed. This framework adopts a two-branch architecture utilizing a structurally reparameterized temporal convolutional network (RepVGG-TCN) and a graph attention network (GAT). Crucially, the RepVGG design enhances feature extraction capability during training through a multi-branch structure while collapsing into a compact single-branch architecture for deployment, thereby optimizing structural complexity. At the core of TSA-Net is a cascading feedback mechanism, where preliminary predictions from the first stage serve as guidance signals to augment the input for the second stage, enabling coarse-to-fine iterative refinement. Furthermore, an adaptive gating mechanism dynamically fuses spatio-temporal features, improving the model’s adaptability. Extensive experiments with ten state-of-the-art algorithms on three benchmark datasets demonstrate that TSA-Net achieves significant optimization. Specifically, it improves the F1 score by approximately 7% while reducing the training time by up to 99% compared to complex Transformer-based models, offering a rapid-deployment solution for high-dimensional anomaly detection. Full article
(This article belongs to the Section Internet of Things)
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16 pages, 1100 KB  
Article
Balance Assessments Using Smartphone Sensor Systems and a Clinician-Led Modified BESS Test in Soccer Athletes with Hip-Related Pain: An Exploratory Cross-Sectional Study
by Alexander Puyol, Matthew King, Charlotte Ganderton, Shuwen Hu and Oren Tirosh
Sensors 2026, 26(3), 1061; https://doi.org/10.3390/s26031061 - 6 Feb 2026
Viewed by 774
Abstract
Background: The Balance Error Scoring System (BESS) is the most practiced static postural balance assessment tool, which relies on visual observation, and has been adopted as the gold standard in the clinic and field. However, the BESS can lead to missed and inaccurate [...] Read more.
Background: The Balance Error Scoring System (BESS) is the most practiced static postural balance assessment tool, which relies on visual observation, and has been adopted as the gold standard in the clinic and field. However, the BESS can lead to missed and inaccurate diagnoses—because of its low inter-rater reliability and limited sensitivity—by missing subtle balance deficits, particularly in the athletic population. Smartphone technology using motion sensors may act as an alternative option for providing quantitative feedback to healthcare clinicians when performing balance assessments. The primary aim of this study was to explore the discriminative validity of an alternative novel smartphone-based cloud system to measure balance remotely in soccer athletes with and without hip pain. Methods: This is an exploratory cross-sectional study. A total of 64 Australian soccer athletes (128 hips, 28% females) between 18 and 40 years completed single and tandem stance balance tests that were scored using the modified BESS test and quantified using the smartphone device attached to their lower back. An Exploratory Factor Analysis (EFA) and a Clustered Receiver Operating Characteristic (ROC) using an Area Under the Curve (AUC) were used to explore the discriminative validity between the smartphone sensor system and the modified BESS test. A Linear Mixed-Effects Analysis of Covariance (ANCOVA) was used to determine any statistical differences in static balance measures between individuals with and without hip-related pain. Results: EFA revealed that the first factor primarily captured variance related to smartphone measurements, while the second factor was associated with modified BESS test scores. The ROC and the AUC showed that the smartphone sway measurements in the anterior–posterior and mediolateral directions during single-leg stance had an acceptable to excellent level of accuracy in distinguishing between individuals with and without hip-related pain (AUC = 0.72–0.80). Linear Mixed-Effects ANCOVA analysis found that individuals with hip-related pain had significantly less single-leg balance variability and magnitude in the anteroposterior and mediolateral directions compared to individuals without hip-related pain (p < 0.05). Conclusion: Due to the ability of smartphone technology to discriminate between individuals with and without hip-related pain during single-leg static balance tasks, it is recommended to use the technology in addition to the modified BESS test to optimise a clinician-led assessment and to further guide clinical balance decision-making. While the study supports smartphone technology as a method to assess static balance, its use in measuring balance during dynamic movements needs further research. Full article
(This article belongs to the Special Issue Innovative Sensing Methods for Motion and Behavior Analysis)
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20 pages, 3275 KB  
Article
Real-Time Emotion Recognition Performance of Mobile Devices: A Detailed Analysis of Camera and TrueDepth Sensors Using Apple’s ARKit
by Céline Madeleine Aldenhoven, Leon Nissen, Marie Heinemann, Cem Doğdu, Alexander Hanke, Stephan Jonas and Lara Marie Reimer
Sensors 2026, 26(3), 1060; https://doi.org/10.3390/s26031060 - 6 Feb 2026
Cited by 2 | Viewed by 1083
Abstract
Facial features hold information about a person’s emotions, motor function, or genetic defects. Since most current mobile devices are capable of real-time face detection using cameras and depth sensors, real-time facial analysis can be utilized in several mobile use cases. Understanding the real-time [...] Read more.
Facial features hold information about a person’s emotions, motor function, or genetic defects. Since most current mobile devices are capable of real-time face detection using cameras and depth sensors, real-time facial analysis can be utilized in several mobile use cases. Understanding the real-time emotion recognition capabilities of device sensors and frameworks is vital for developing new, valid applications. Therefore, we evaluated on-device emotion recognition using Apple’s ARKit on an iPhone 14 Pro. A native app elicited 36 blend shape-specific movements and 7 discrete emotions from N=31 healthy adults. Per frame, standardized ARKit blend shapes were classified using a prototype-based cosine similarity metric; performance was summarized as accuracy and area under the receiver operating characteristic curves. Cosine similarity achieved an overall accuracy of 68.3%, exceeding the mean of three human raters (58.9%; +9.4 percentage points, ≈16% relative). Per-emotion accuracy was highest for joy, fear, sadness, and surprise, and competitive for anger, disgust, and contempt. AUCs were ≥0.84 for all classes. The method runs in real time on-device using only vector operations, preserving privacy and minimizing compute. These results indicate that a simple, interpretable cosine-similarity classifier over ARKit blend shapes delivers human-comparable, real-time facial emotion recognition on commodity hardware, supporting privacy-preserving mobile applications. Full article
(This article belongs to the Section Optical Sensors)
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17 pages, 7804 KB  
Article
A 3D Camera-Based Approach for Real-Time Hand Configuration Recognition in Italian Sign Language
by Luca Ulrich, Asia De Luca, Riccardo Miraglia, Emma Mulassano, Simone Quattrocchio, Giorgia Marullo, Chiara Innocente, Federico Salerno and Enrico Vezzetti
Sensors 2026, 26(3), 1059; https://doi.org/10.3390/s26031059 - 6 Feb 2026
Cited by 1 | Viewed by 675
Abstract
Deafness poses significant challenges to effective communication, particularly in contexts where access to sign language interpreters is limited. Hand configuration recognition represents a fundamental component of sign language understanding, as configurations constitute a core cheremic element in many sign languages, including Italian Sign [...] Read more.
Deafness poses significant challenges to effective communication, particularly in contexts where access to sign language interpreters is limited. Hand configuration recognition represents a fundamental component of sign language understanding, as configurations constitute a core cheremic element in many sign languages, including Italian Sign Language (LIS). In this work, we address configuration-level recognition as an independent classification task and propose a machine vision framework based on RGB-D sensing. The proposed approach combines MediaPipe-based hand landmark extraction with normalized three-dimensional geometric features and a Support Vector Machine classifier. The first contribution of this study is the formulation of LIS hand configuration recognition as a standalone, configuration-level problem, decoupled from temporal gesture modeling. The second contribution is the integration of sensor-acquired RGB-D depth measurements into the landmark-based feature representation, enabling a direct comparison with estimated depth obtained from monocular data. The third contribution consists of a systematic experimental evaluation on two LIS configuration sets (6 and 16 classes), demonstrating that the use of real depth significantly improves classification performance and class separability, particularly for geometrically similar configurations. The results highlight the critical role of depth quality in configuration-level recognition and provide insights into the design of robust vision-based systems for LIS analysis. Full article
(This article belongs to the Special Issue Sensing and Machine Learning Control: Progress and Applications)
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23 pages, 9109 KB  
Article
Three-Dimensional Mapping-Aided Global Navigation Satellite System in Global Navigation Satellite System-Accessible Indoor Areas
by Hoi-Wah Ng, Hoi-Fung Ng, Li-Ta Hsu and John-Ross Rizzo
Sensors 2026, 26(3), 1058; https://doi.org/10.3390/s26031058 - 6 Feb 2026
Viewed by 591
Abstract
The Global Navigation Satellite System (GNSS) is commonly used for outdoor positioning. However, its effectiveness diminishes in urban canyons and indoor environments attributed to signal blockage. This study aims to explore the potential of GNSS signals penetrating indoor spaces through windows and to [...] Read more.
The Global Navigation Satellite System (GNSS) is commonly used for outdoor positioning. However, its effectiveness diminishes in urban canyons and indoor environments attributed to signal blockage. This study aims to explore the potential of GNSS signals penetrating indoor spaces through windows and to enhance indoor positioning with Three-Dimensional Mapping-Aided (3DMA) GNSS, a concept generally applied outdoors. The research employs a 3D model of a corridor with manually labeled window locations to predict satellite visibility within indoor areas. The study integrates Pedestrian Dead Reckoning (PDR) with an indoor Shadow-matching (I-SM) technique, utilizing an Extended Kalman Filter (EKF) to improve positioning accuracy. One of the findings indicates that the proposed method significantly enhances positioning performance and its availability, achieving a root mean square error (RMSE) that is 2 m better than using PDR alone or single epoch I-SM. The study concludes that integrating GNSS with I-SM technique and PDR can optimize an indoor positioning solution and highlights the potential for improved navigation solutions in complex urban environments. Full article
(This article belongs to the Special Issue INS/GNSS Integrated Navigation Systems)
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16 pages, 6191 KB  
Article
A Hybrid Millimeter-Wave Radar–Ultrasonic Fusion System for Robust Human Activity Recognition with Attention-Enhanced Deep Learning
by Liping Yao, Kwok L. Chung, Luxin Tang, Tao Ye, Shiquan Wang, Pingchuan Xu, Yuhao Bi and Yaowen Wu
Sensors 2026, 26(3), 1057; https://doi.org/10.3390/s26031057 - 6 Feb 2026
Cited by 2 | Viewed by 899
Abstract
To address the tradeoff between environmental robustness and fine-grained accuracy in single-sensor human behavior recognition, this paper proposes a non-contact system fusing 77 GHz SIFT (mmWave) radar and a 40 kHz ultrasonic array. The system leverages radar’s long-range penetration and low-visibility adaptability, paired [...] Read more.
To address the tradeoff between environmental robustness and fine-grained accuracy in single-sensor human behavior recognition, this paper proposes a non-contact system fusing 77 GHz SIFT (mmWave) radar and a 40 kHz ultrasonic array. The system leverages radar’s long-range penetration and low-visibility adaptability, paired with ultrasound’s centimeter-level short-range precision and electromagnetic clutter immunity. A synchronized data acquisition platform ensures multi-modal signal consistency, while wavelet transform (for radar) and STFT (for ultrasound) extract complementary time–frequency features. The proposed Attention-CNN-BiLSTM architecture integrates local spatial feature extraction, bidirectional temporal dependency modeling, and salient cue enhancement. Experimental results on 1600 synchronized sequences (four behaviors: standing, sitting, walking, falling) show a 98.6% mean class accuracy with subject-wise generalization, outperforming single-sensor baselines and traditional deep learning models. As a privacy-preserving, lighting-agnostic solution, it offers promising applications in smart homes, healthcare monitoring, and intelligent surveillance, providing a robust technical foundation for contactless behavior recognition. Full article
(This article belongs to the Special Issue Electromagnetic Sensors and Their Applications)
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28 pages, 36503 KB  
Article
Identification of Comorbidities in Obstructive Sleep Apnea Using Diverse Data and a One-Dimensional Convolutional Neural Network
by Kristina Zovko, Ljiljana Šerić, Toni Perković, Ivana Pavlinac Dodig, Renata Pecotić, Zoran Đogaš and Petar Šolić
Sensors 2026, 26(3), 1056; https://doi.org/10.3390/s26031056 - 6 Feb 2026
Viewed by 843
Abstract
Recent advances in deep learning (DL) have enabled the integration of diverse biomedical data for disease prediction and risk stratification. Building on this progress, the overall objective of this study was to develop and evaluate a multimodal DL framework for robust multi-label classification [...] Read more.
Recent advances in deep learning (DL) have enabled the integration of diverse biomedical data for disease prediction and risk stratification. Building on this progress, the overall objective of this study was to develop and evaluate a multimodal DL framework for robust multi-label classification (MLC) of major comorbidities in patients with obstructive sleep apnea (OSA) using physiological time series signals and clinical data. This study proposes a robust framework for multi-label classification (MLC) of comorbidities in patients with OSA using diverse physiological and clinical data sources. We conducted a retrospective observational study including a convenience sample of 144 patients referred for overnight polysomnography at the Sleep Medicine Center (SleepLab Split), University Hospital Centre Split (KBC Split), Split, Croatia. Patients were selected based on predefined inclusion criteria and data availability. A one-dimensional Convolutional Neural Network (1D-CNN) was developed to process and fuse time series signals, oxygen saturation (SpO2), derived SpO2 features, and nasal airflow (FP0), with demographic and physiological parameters, enabling the identification of key comorbidities such as arterial hypertension, diabetes mellitus, and asthma/COPD. The instruments included polysomnography-derived signals (SpO2 and FP0 airflow) and structured demographic/physiological parameters. Signals were preprocessed and used as inputs to the proposed fusion model. The proposed model was trained and fine-tuned using the Optuna hyperparameter optimization framework, addressing class imbalance through weighted loss adjustments. Its performance was comprehensively assessed using multi-label evaluation metrics, including macro/micro F1-score, AUC-ROC, AUC-PR, subset and partial accuracy, Hamming loss, and multi-label confusion matrix (MLCM). The study protocol was approved by the Ethics Committee of the School of Medicine, University of Split (Approval No. 003-08/23-03/0015, Date: 17 October 2023). The 1D-CNN achieved superior predictive performance compared to traditional machine learning (ML) classifiers with macro AUC-ROC = 0.731 and AUC-PR = 0.750. The model demonstrated consistent behavior across age, gender, and BMI groups, indicating strong generalization and minimal demographic bias. In conclusion, the results confirm that SpO2 and airflow signals inherently encode comorbidity-specific physiological patterns, enabling efficient and scalable screening of OSA-related comorbidities without the need for full polysomnography. Although the study is limited by data set size, it provides a methodological basis for the application of multi-label DL models in clinical decision support systems. Future research should focus on the expansion of multi-center datasets, thereby improving model interpretability and potential clinical adoption. Full article
(This article belongs to the Special Issue Sensors-Based Healthcare Diagnostics, Monitoring and Medical Devices)
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23 pages, 14619 KB  
Article
Edge-Distilled and Local–Global Feature Selection Network for Hyperspectral Image Super-Resolution
by Xinzhao Li, Mengzhe Fan, Xiaoqing Zheng and Jiandong Shang
Sensors 2026, 26(3), 1055; https://doi.org/10.3390/s26031055 - 6 Feb 2026
Viewed by 590
Abstract
In recent years, the methods based on convolutional neural networks have achieved significant progress in hyperspectral image super-resolution. However, existing methods still face two key challenges: (1) they fail to fully extract edge detail information from hyperspectral images; (2) they struggle to simultaneously [...] Read more.
In recent years, the methods based on convolutional neural networks have achieved significant progress in hyperspectral image super-resolution. However, existing methods still face two key challenges: (1) they fail to fully extract edge detail information from hyperspectral images; (2) they struggle to simultaneously capture local and global features. To address these issues, we propose an Edge-Distilled and Local–Global Feature Selection network (EDLGFS) for hyperspectral image super-resolution. This network aims to effectively leverage edge details and local–global features, thereby enhancing super-resolution reconstruction quality. Firstly, we design an edge-guided super-resolution network based on knowledge distillation. This network transfers edge knowledge to improve the reconstruction. Secondly, we propose a Local–Global Feature Selection mechanism (LGFS), which integrates convolutions of different sizes with the self-attention mechanism. This design models spatial correlations across features with different receptive fields, achieving efficient feature selection to more effectively capture local and global features. Finally, we propose a dynamic loss mechanism to more effectively balance the contribution of each loss term. Extensive experimental results on three public datasets demonstrate that the proposed EDLGFS achieves superior super-resolution reconstruction quality. Full article
(This article belongs to the Special Issue Intelligent Sensing and Artificial Intelligence for Image Processing)
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25 pages, 20968 KB  
Article
Highly Efficient Deep Learning-Enabled Parameterization and 3D Reconstruction of Traditional Chinese Roof Structures
by Ruisi Ou, Fan Yang, Lili Li, Liyu Cheng, Lile Qian, Ye He, Mingliang Che and Chi Zhang
Sensors 2026, 26(3), 1054; https://doi.org/10.3390/s26031054 - 5 Feb 2026
Viewed by 856
Abstract
Ancient Chinese architecture, with its typical symmetrical structures, curved roofs, and upturned eaves presenting a unique architectural aesthetic, is a treasure of Chinese culture. Recently, unmanned aerial vehicle oblique photogrammetry and laser scanning technology have greatly facilitated the realistic replication of ancient buildings [...] Read more.
Ancient Chinese architecture, with its typical symmetrical structures, curved roofs, and upturned eaves presenting a unique architectural aesthetic, is a treasure of Chinese culture. Recently, unmanned aerial vehicle oblique photogrammetry and laser scanning technology have greatly facilitated the realistic replication of ancient buildings and have become crucial data sources for the HBIM of ancient buildings. However, parameter extraction and geometric model representation are more difficult because of the curved surfaces and upturned eaves of traditional Chinese roofs. As symmetrical features are typical of ancient Chinese architecture, the parameter quantity and modelling difficulty of the model representation can be effectively reduced by recognizing the symmetrical structure of traditional Chinese roofs and using “mirror replication” to quickly generate the other half of the model. Accurate symmetry detection and highly efficient parameter extraction are crucial for the HBIM of traditional Chinese roofs. Therefore, in this study, a deep learning network, namely, TCRSym-Net, is proposed to identify the symmetry from point clouds of traditional Chinese roofs. Each roof point cloud is then relocated and reoriented to obtain longitudinal and cross sections, and parametric modelling scripts are coded in Dynamo to model traditional Chinese roofs via curve lofting and solid Boolean operations. The experimental results reveal that the symmetry detection network is effective for symmetry detection, and five different types of traditional Chinese roofs are successfully recreated, which confirms the dependability of the method. Full article
(This article belongs to the Topic 3D Documentation of Natural and Cultural Heritage)
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24 pages, 1673 KB  
Article
Music Performance Improvement Support System Using a Semi-Automated Instrument-Playing Robot with Real-Time Acoustic Analysis and Habit Visualization
by Kouki Tomiyoshi, Hiroaki Sonoda, Hikari Kuriyama and Gou Koutaki
Sensors 2026, 26(3), 1053; https://doi.org/10.3390/s26031053 - 5 Feb 2026
Viewed by 644
Abstract
This paper proposes an acoustic analysis system to help improve saxophone performance skills. The system combines direct support for performance movements by a robot with indirect support by presenting performance information. By sensing the performance audio and performing real-time acoustic analysis, the system [...] Read more.
This paper proposes an acoustic analysis system to help improve saxophone performance skills. The system combines direct support for performance movements by a robot with indirect support by presenting performance information. By sensing the performance audio and performing real-time acoustic analysis, the system presents the learner with information about their performance and their playing habits. The performance information presented to the learner includes pitch, volume, and playing timing. For performance habit analysis, a Markov model with pitch as the state and an internal probability parameter that indicates the quality of the performance evaluation as the pitch transitions are defined. In the experiment, we conducted a pilot study targeting experienced saxophone players and a beginner saxophone player to verify the effectiveness of the proposed system. The experiment showed that the MAE of the played pitch was significantly reduced by using the proposed system. Full article
(This article belongs to the Special Issue Acoustic Sensing for Musical Instrument Study and Vocal Analysis)
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23 pages, 4617 KB  
Article
Application and Comparison of FPGA-Based Carry Chain TDC and DDMTD Schemes in High-Precision Time Synchronization
by Yuzhen Huang, Jiajie Yu, Wenlong Xia, Qinggong Guo and Linyu Huang
Sensors 2026, 26(3), 1052; https://doi.org/10.3390/s26031052 - 5 Feb 2026
Cited by 1 | Viewed by 766
Abstract
High-precision phase difference measurement based on field-programmable gate arrays (FPGA) has important application requirements in fields such as high-stability time-frequency transmission, signal synchronization, and precision testing. Addressing the limitations of traditional methods in terms of temperature stability and measurement accuracy, this paper proposes [...] Read more.
High-precision phase difference measurement based on field-programmable gate arrays (FPGA) has important application requirements in fields such as high-stability time-frequency transmission, signal synchronization, and precision testing. Addressing the limitations of traditional methods in terms of temperature stability and measurement accuracy, this paper proposes two high-precision phase difference measurement schemes based on the FPGA platform. An eight-parallel-multi-carry chain time-to-digital converter (TDC) and digital dual-mixer time difference (DDMTD) measurement modules are constructed to perform high-precision phase difference measurements on the phase-shifted output signal of the MMCM dynamic phase-shifted module. Results show that at room temperature (25 °C), the single-carry chain TDC exhibits better measurement accuracy than the DDMTD, and the single-carry chain TDC’s measurement error range of 4.7–6.0 ps is superior to the DDMTD’s 20–75 ps error range. Under different temperature conditions, the eight-parallel-multi-carry chain TDC consistently demonstrates superior measurement accuracy, resolution, and temperature stability compared to the single-carry chain TDC. In terms of measurement accuracy, under room temperature conditions, in three sets of phase difference tests (178.5714 ps, 357.1428 ps, and 535.7142 ps), the measurement error of the eight-parallel-multi-carry chain TDC was controlled within 4.6 ps, which is better than the 4.7–6.0 ps error range of the single-carry chain TDC. Average resolution: The average resolution of the single-carry chain TDC was 6.329 ps, while the average resolution of the eight-parallel-multi-carry chain TDC improved to 0.833 ps. Temperature stability: Within the temperature range of 10 °C to 100 °C, the temperature coefficient of the single-carry chain TDC was 0.002127 ps/°C, while the temperature coefficient of the eight-parallel-multi-carry chain TDC decreased to 0.000564 ps/°C. This paper also summarizes the advantages and limitations of the above methods in terms of implementation complexity and robustness, providing a reference for the optimized design of high-precision phase difference measurement technology for FPGA platforms. Full article
(This article belongs to the Section Electronic Sensors)
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25 pages, 5939 KB  
Article
The Impact of Maximum Power Point Tracking Algorithms on Properties of On-Chip PV-Based Energy Harvester for IoT Devices
by Adam Hudec, Viera Stopjakova, Robert Ondica, Miroslav Potocny and Lukas Nagy
Sensors 2026, 26(3), 1051; https://doi.org/10.3390/s26031051 - 5 Feb 2026
Cited by 1 | Viewed by 637
Abstract
This article presents the analysis of selected maximum power point tracking (MPPT) algorithms and their influence on developed energy harvester (EH) systems under uniform conditions. The energy harvester is an electronic system that converts available ambient energy to electrical energy and regulates its [...] Read more.
This article presents the analysis of selected maximum power point tracking (MPPT) algorithms and their influence on developed energy harvester (EH) systems under uniform conditions. The energy harvester is an electronic system that converts available ambient energy to electrical energy and regulates its distribution to the output. The aim is to design an energy harvester with the highest integration rate possible with consideration of area requirements and low power consumption. To improve the overall energy conversion of the developed harvester, we implemented several MPPT algorithms (Pilot Cell, Constant Voltage, Perturb and Observe) into a dedicated MPPT controller that controls the DC-DC converter. Consequently, we experimentally analyzed their impact on the harvester system. Findings show that even simple algorithms with smaller chip areas and lower power consumption can achieve results comparable to more complex ones. The proposed, manufactured and experimentally evaluated EH chip prototype has proven its expected functionality and is therefore fully capable of supplying energy for low-power electronics and battery-operated devices. Full article
(This article belongs to the Section Internet of Things)
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