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Keywords = real-world thermal image

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18 pages, 15953 KiB  
Review
Development of Objective Measurements of Scratching as a Proxy of Atopic Dermatitis—A Review
by Cheuk-Yan Au, Neha Manazir, Huzhaorui Kang and Ali Asgar Saleem Bhagat
Sensors 2025, 25(14), 4316; https://doi.org/10.3390/s25144316 - 10 Jul 2025
Viewed by 413
Abstract
Eczema, or atopic dermatitis (AD), is a chronic inflammatory skin condition characterized by persistent itching and scratching, significantly impacting patients’ quality of life. Effective monitoring of scratching behaviour is crucial for assessing disease severity, treatment efficacy, and understanding the relationship between itch and [...] Read more.
Eczema, or atopic dermatitis (AD), is a chronic inflammatory skin condition characterized by persistent itching and scratching, significantly impacting patients’ quality of life. Effective monitoring of scratching behaviour is crucial for assessing disease severity, treatment efficacy, and understanding the relationship between itch and sleep disturbances. This review explores current technological approaches for detecting and monitoring scratching and itching in AD patients, categorising them into contact-based and non-contact-based methods. Contact-based methods primarily involve wearable sensors, such as accelerometers, electromyography (EMG), and piezoelectric sensors, which track limb movements and muscle activity associated with scratching. Non-contact methods include video-based motion tracking, thermal imaging, and acoustic analysis, commonly employed in sleep clinics and controlled environments to assess nocturnal scratching. Furthermore, emerging artificial intelligence (AI)-driven approaches leveraging machine learning for automated scratch detection are discussed. The advantages, limitations, and validation challenges of these technologies, including accuracy, user comfort, data privacy, and real-world applicability, are critically analysed. Finally, we outline future research directions, emphasizing the integration of multimodal monitoring, real-time data analysis, and patient-centric wearable solutions to improve disease management. This review serves as a comprehensive resource for clinicians, researchers, and technology developers seeking to advance objective itch and scratch monitoring in AD patients. Full article
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20 pages, 7167 KiB  
Article
Drone-Based 3D Thermal Mapping of Urban Buildings for Climate-Responsive Planning
by Haowen Yan, Bo Zhao, Yaxing Du and Jiajia Hua
Sustainability 2025, 17(12), 5600; https://doi.org/10.3390/su17125600 - 18 Jun 2025
Viewed by 428
Abstract
Urban thermal environment is directly linked to the health and comfort of local residents, as well as energy consumption. Drone-based thermal infrared image acquirement provides an efficient and flexible way of assessing urban heat distribution, thereby supporting climate-resilient and sustainable urban development. Here, [...] Read more.
Urban thermal environment is directly linked to the health and comfort of local residents, as well as energy consumption. Drone-based thermal infrared image acquirement provides an efficient and flexible way of assessing urban heat distribution, thereby supporting climate-resilient and sustainable urban development. Here, we present an advanced approach that utilizes the thermal infrared camera mounted on the drone for high-resolution building wall temperature measurement and achieves centimeter accuracy. According to the binocular vision theory, the three-dimensional (3D) reconstruction of thermal infrared images is first conducted, and then the two-dimensional building wall temperature is extracted. Real-world validation shows that our approach can measure the wall temperature within a 5 °C error, which confirms the reliability of this approach. The field measurement of Yuquanting in Xiong’an New Area China during three time periods, i.e., morning (7:00–8:00), noon (13:00–14:00) and evening (18:00–19:00), was used as a case study to demonstrate our approach. The results show that during the heating season, the building wall temperature was the highest at noon time and the lowest in evening time, which were mostly caused by solar radiation. The highest wall temperature at noon time was 55 °C, which was under direct sun radiation. The maximum wall temperature differences were 39 °C, 55 °C, and 20 °C during morning, noon and evening time, respectively. The lighter wall coating color tended to have a lower temperature than the darker wall coating color. Beyond this application, this approach has potential in future autonomous thermal environment measuring systems as a foundational element. Full article
(This article belongs to the Special Issue Air Pollution Control and Sustainable Urban Climate Resilience)
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24 pages, 2351 KiB  
Review
Advancing Object Detection in Transportation with Multimodal Large Language Models (MLLMs): A Comprehensive Review and Empirical Testing
by Huthaifa I. Ashqar, Ahmed Jaber, Taqwa I. Alhadidi and Mohammed Elhenawy
Computation 2025, 13(6), 133; https://doi.org/10.3390/computation13060133 - 3 Jun 2025
Cited by 1 | Viewed by 1492
Abstract
This study aims to comprehensively review and empirically evaluate the application of multimodal large language models (MLLMs) and Large Vision Models (VLMs) in object detection for transportation systems. In the first fold, we provide a background about the potential benefits of MLLMs in [...] Read more.
This study aims to comprehensively review and empirically evaluate the application of multimodal large language models (MLLMs) and Large Vision Models (VLMs) in object detection for transportation systems. In the first fold, we provide a background about the potential benefits of MLLMs in transportation applications and conduct a comprehensive review of current MLLM technologies in previous studies. We highlight their effectiveness and limitations in object detection within various transportation scenarios. The second fold involves providing an overview of the taxonomy of end-to-end object detection in transportation applications and future directions. Building on this, we proposed empirical analysis for testing MLLMs on three real-world transportation problems that include object detection tasks, namely, road safety attribute extraction, safety-critical event detection, and visual reasoning of thermal images. Our findings provide a detailed assessment of MLLM performance, uncovering both strengths and areas for improvement. Finally, we discuss practical limitations and challenges of MLLMs in enhancing object detection in transportation, thereby offering a roadmap for future research and development in this critical area. Full article
(This article belongs to the Special Issue Object Detection Models for Transportation Systems)
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18 pages, 1442 KiB  
Review
Smart Pig Farms: Integration and Application of Digital Technologies in Pig Production
by Katarina Marić, Kristina Gvozdanović, Ivona Djurkin Kušec, Goran Kušec and Vladimir Margeta
Agriculture 2025, 15(9), 937; https://doi.org/10.3390/agriculture15090937 - 25 Apr 2025
Viewed by 2201
Abstract
The prediction that the world population will reach almost 10 billion people by 2050 means an increase in pork production is required. Efforts to meet increased demand have made pig production one of the most technologically advanced branches of production and one which [...] Read more.
The prediction that the world population will reach almost 10 billion people by 2050 means an increase in pork production is required. Efforts to meet increased demand have made pig production one of the most technologically advanced branches of production and one which is growing continuously. Precision Livestock Production (PLF) is an increasingly widespread model in pig farming and describes a management system based on the continuous automatic monitoring and control of production, reproduction, animal health and welfare in real time, as well as the impact of animal husbandry on the environment. Today, a wide range of technologies is available, such as 2D and 3D cameras to assess body weight, behavior and activity, thermal imaging cameras to monitor body temperatures and determine estrus, microphones to monitor vocalizations, various measuring cells to monitor food intake, body weight and weight gain, and many others. By combining and applying the available technologies, it is possible to obtain a variety of data that allow livestock farmers to automatically monitor animals and improve pig health and welfare as well as environmental sustainability. Nevertheless, PLF systems need further research to improve the technologies and create cheap and affordable but accurate models to ensure progress in pig production. Full article
(This article belongs to the Special Issue Modeling of Livestock Breeding Environment and Animal Behavior)
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14 pages, 1539 KiB  
Article
Multimodal Network for Object Detection Using Channel Adjustment and Multi-Scale Attention
by Yihang Ye and Mingxuan Chen
Appl. Sci. 2025, 15(8), 4298; https://doi.org/10.3390/app15084298 - 13 Apr 2025
Viewed by 739
Abstract
Object detection benefits greatly from multimodal image fusion, which integrates complementary data from different modalities like RGB and thermal images. However, existing methods struggle with effective inter-modal fusion, particularly in capturing spatial and contextual information across diverse regions and scales. To address these [...] Read more.
Object detection benefits greatly from multimodal image fusion, which integrates complementary data from different modalities like RGB and thermal images. However, existing methods struggle with effective inter-modal fusion, particularly in capturing spatial and contextual information across diverse regions and scales. To address these limitations, we propose the dynamic channel adjustment and multi-scale activated attention mechanism network (MNCM). Our approach incorporates dynamic channel adjustment for precise feature fusion across modalities and a multi-scale attention mechanism to capture both local and global contexts. This design improves robustness while balancing computational efficiency. The model’s scalability is enhanced through its ability to adaptively process multi-scale information without being constrained by fixed-scale designs. To validate our method, we used two multimodal datasets from traffic and industrial scenarios, which consisted of paired thermal infrared and visible light images. The results first demonstrate strong performance in multimodal fusion and then show state-of-the-art results in object detection, proving its effectiveness for real-world applications. Full article
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18 pages, 4347 KiB  
Article
FuzzyH Method for Distance Estimation in Autonomous Train Operation
by Ivan Ćirić, Milan Pavlović, Danijela Ristić-Durrant, Lubomir Dimitrov and Vlastimir Nikolić
Symmetry 2025, 17(4), 509; https://doi.org/10.3390/sym17040509 - 27 Mar 2025
Viewed by 337
Abstract
For reliable autonomous train operation, detecting and classifying obstacles on or near rail tracks, and accurately estimating the distance to these obstacles, is essential. This task is more challenging in low-light conditions, common for freight trains that operate primarily at night. This paper [...] Read more.
For reliable autonomous train operation, detecting and classifying obstacles on or near rail tracks, and accurately estimating the distance to these obstacles, is essential. This task is more challenging in low-light conditions, common for freight trains that operate primarily at night. This paper proposes a novel method, FuzzyH, for estimating the distance between a thermal camera and detected obstacles using image-plane homography. By leveraging the homography between the image and rail track planes, and incorporating a fuzzy logic system, the method improves distance estimation accuracy and eliminates the need for complex calibration. This paper also explores the symmetry and asymmetry of fuzzy membership functions and rules. The system was validated on Serbian railways under simulated real-world conditions, demonstrating reliable performance. A key contribution of this method is the use of fuzzy membership functions tailored to specific distance ranges, based on experimental data and domain knowledge, such as regulatory braking distances. This approach improves over traditional methods by offering reliable distance estimates in low-light environments and simplifying the calibration process, ultimately enhancing system accuracy and robustness. Full article
(This article belongs to the Special Issue Symmetry in Control System Theory and Applications)
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29 pages, 4530 KiB  
Systematic Review
Advances in Deep Learning for Semantic Segmentation of Low-Contrast Images: A Systematic Review of Methods, Challenges, and Future Directions
by Claudio Urrea and Maximiliano Vélez
Sensors 2025, 25(7), 2043; https://doi.org/10.3390/s25072043 - 25 Mar 2025
Viewed by 3193
Abstract
The semantic segmentation (SS) of low-contrast images (LCIs) remains a significant challenge in computer vision, particularly for sensor-driven applications like medical imaging, autonomous navigation, and industrial defect detection, where accurate object delineation is critical. This systematic review develops a comprehensive evaluation of state-of-the-art [...] Read more.
The semantic segmentation (SS) of low-contrast images (LCIs) remains a significant challenge in computer vision, particularly for sensor-driven applications like medical imaging, autonomous navigation, and industrial defect detection, where accurate object delineation is critical. This systematic review develops a comprehensive evaluation of state-of-the-art deep learning (DL) techniques to improve segmentation accuracy in LCI scenarios by addressing key challenges such as diffuse boundaries and regions with similar pixel intensities. It tackles primary challenges, such as diffuse boundaries and regions with similar pixel intensities, which limit conventional methods. Key advancements include attention mechanisms, multi-scale feature extraction, and hybrid architectures combining Convolutional Neural Networks (CNNs) with Vision Transformers (ViTs), which expand the Effective Receptive Field (ERF), improve feature representation, and optimize information flow. We compare the performance of 25 models, evaluating accuracy (e.g., mean Intersection over Union (mIoU), Dice Similarity Coefficient (DSC)), computational efficiency, and robustness across benchmark datasets relevant to automation and robotics. This review identifies limitations, including the scarcity of diverse, annotated LCI datasets and the high computational demands of transformer-based models. Future opportunities emphasize lightweight architectures, advanced data augmentation, integration with multimodal sensor data (e.g., LiDAR, thermal imaging), and ethically transparent AI to build trust in automation systems. This work contributes a practical guide for enhancing LCI segmentation, improving mean accuracy metrics like mIoU by up to 15% in sensor-based applications, as evidenced by benchmark comparisons. It serves as a concise, comprehensive guide for researchers and practitioners advancing DL-based LCI segmentation in real-world sensor applications. Full article
(This article belongs to the Section Sensing and Imaging)
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25 pages, 9497 KiB  
Article
Concealed Weapon Detection Using Thermal Cameras
by Juan D. Muñoz, Jesus Ruiz-Santaquiteria, Oscar Deniz and Gloria Bueno
J. Imaging 2025, 11(3), 72; https://doi.org/10.3390/jimaging11030072 - 26 Feb 2025
Cited by 2 | Viewed by 2893
Abstract
In an era where security concerns are ever-increasing, the need for advanced technology to detect visible and concealed weapons has become critical. This paper introduces a novel two-stage method for concealed handgun detection, leveraging thermal imaging and deep learning, offering a potential real-world [...] Read more.
In an era where security concerns are ever-increasing, the need for advanced technology to detect visible and concealed weapons has become critical. This paper introduces a novel two-stage method for concealed handgun detection, leveraging thermal imaging and deep learning, offering a potential real-world solution for law enforcement and surveillance applications. The approach first detects potential firearms at the frame level and subsequently verifies their association with a detected person, significantly reducing false positives and false negatives. Alarms are triggered only under specific conditions to ensure accurate and reliable detection, with precautionary alerts raised if no person is detected but a firearm is identified. Key contributions include a lightweight algorithm optimized for low-end embedded devices, making it suitable for wearable and mobile applications, and the creation of a tailored thermal dataset for controlled concealment scenarios. The system is implemented on a chest-worn Android smartphone with a miniature thermal camera, enabling hands-free operation. Experimental results validate the method’s effectiveness, achieving an mAP@50-95 of 64.52% on our dataset, improving state-of-the-art methods. By reducing false negatives and improving reliability, this study offers a scalable, practical solution for security applications. Full article
(This article belongs to the Special Issue Object Detection in Video Surveillance Systems)
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21 pages, 10628 KiB  
Article
Thermal Video Enhancement Mamba: A Novel Approach to Thermal Video Enhancement for Real-World Applications
by Sargis Hovhannisyan, Sos Agaian, Karen Panetta and Artyom Grigoryan
Information 2025, 16(2), 125; https://doi.org/10.3390/info16020125 - 9 Feb 2025
Viewed by 1493
Abstract
Object tracking in thermal video is challenging due to noise, blur, and low contrast. We present TVEMamba, a Mamba-based enhancement framework with near-linear complexity that improves tracking in these conditions. Our approach uses a State Space 2D (SS2D) module integrated with Convolutional Neural [...] Read more.
Object tracking in thermal video is challenging due to noise, blur, and low contrast. We present TVEMamba, a Mamba-based enhancement framework with near-linear complexity that improves tracking in these conditions. Our approach uses a State Space 2D (SS2D) module integrated with Convolutional Neural Networks (CNNs) to filter, sharpen, and highlight important details. Key components include (i) a denoising module to reduce background noise and enhance image clarity, (ii) an optical flow attention module to handle complex motion and reduce blur, and (iii) entropy-based labeling to create a fully labeled thermal dataset for training and evaluation. TVEMamba outperforms existing methods (DCRGC, RLBHE, IE-CGAN, BBCNN) across multiple datasets (BIRDSAI, FLIR, CAMEL, Autonomous Vehicles, Solar Panels) and achieves higher scores on standard quality metrics (EME, BDIM, DMTE, MDIMTE, LGTA). Extensive tests, including ablation studies and convergence analysis, confirm its robustness. Real-world examples, such as tracking humans, animals, and moving objects for self-driving vehicles and remote sensing, demonstrate the practical value of TVEMamba. Full article
(This article belongs to the Special Issue Emerging Research in Object Tracking and Image Segmentation)
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17 pages, 40755 KiB  
Article
Data-Driven Clustering of Plantar Thermal Patterns in Healthy Individuals: An Insole-Based Approach to Foot Health Monitoring
by Mark Borg, Stephen Mizzi, Robert Farrugia, Tiziana Mifsud, Anabelle Mizzi, Josef Bajada and Owen Falzon
Bioengineering 2025, 12(2), 143; https://doi.org/10.3390/bioengineering12020143 - 1 Feb 2025
Viewed by 1210
Abstract
Monitoring plantar foot temperatures is essential for assessing foot health, particularly in individuals with diabetes at increased risk of complications. Traditional thermographic imaging measures foot temperatures in unshod individuals lying down, which may not reflect thermal characteristics of feet in shod, active, real-world [...] Read more.
Monitoring plantar foot temperatures is essential for assessing foot health, particularly in individuals with diabetes at increased risk of complications. Traditional thermographic imaging measures foot temperatures in unshod individuals lying down, which may not reflect thermal characteristics of feet in shod, active, real-world conditions. These controlled settings limit understanding of dynamic foot temperatures during daily activities. Recent advancements in wearable technology, such as insole-based sensors, overcome these limitations by enabling continuous temperature monitoring. This study leverages a data-driven clustering approach, independent of pre-selected foot regions or models like the angiosome concept, to explore normative thermal patterns in shod feet with insole-based sensors. Data were collected from 27 healthy participants using insoles embedded with 21 temperature sensors. The data were analysed using clustering algorithms, including k-means, fuzzy c-means, OPTICS, and hierarchical clustering. The clustering algorithms showed a high degree of similarity, with variations primarily influenced by clustering granularity. Six primary thermal patterns were identified, with the “butterfly pattern” (elevated medial arch temperatures) predominant, representing 51.5% of the dataset, aligning with findings in thermographic studies. Other patterns, like the “medial arch + metatarsal area” pattern, were also observed, highlighting diverse yet consistent thermal distributions. This study shows that while normative thermal patterns observed in thermographic imaging are reflected in insole data, the temperature distribution within the shoe may better represent foot behaviour during everyday activities, particularly when enclosed in a shoe. Unlike thermal imaging, the proposed in-shoe system offers the potential to capture dynamic thermal variations during ambulatory activities, enabling richer insights into foot health in real-world conditions. Full article
(This article belongs to the Special Issue Body-Worn Sensors for Biomedical Applications)
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47 pages, 20555 KiB  
Article
Commissioning an All-Sky Infrared Camera Array for Detection of Airborne Objects
by Laura Domine, Ankit Biswas, Richard Cloete, Alex Delacroix, Andriy Fedorenko, Lucas Jacaruso, Ezra Kelderman, Eric Keto, Sarah Little, Abraham Loeb, Eric Masson, Mike Prior, Forrest Schultz, Matthew Szenher, Wesley Andrés Watters and Abigail White
Sensors 2025, 25(3), 783; https://doi.org/10.3390/s25030783 - 28 Jan 2025
Cited by 2 | Viewed by 3323
Abstract
To date, there is little publicly available scientific data on unidentified aerial phenomena (UAP) whose properties and kinematics purportedly reside outside the performance envelope of known phenomena. To address this deficiency, the Galileo Project is designing, building, and commissioning a multi-modal, multi-spectral ground-based [...] Read more.
To date, there is little publicly available scientific data on unidentified aerial phenomena (UAP) whose properties and kinematics purportedly reside outside the performance envelope of known phenomena. To address this deficiency, the Galileo Project is designing, building, and commissioning a multi-modal, multi-spectral ground-based observatory to continuously monitor the sky and collect data for UAP studies via a rigorous long-term aerial census of all aerial phenomena, including natural and human-made. One of the key instruments is an all-sky infrared camera array using eight uncooled long-wave-infrared FLIR Boson 640 cameras. In addition to performing intrinsic and thermal calibrations, we implement a novel extrinsic calibration method using airplane positions from Automatic Dependent Surveillance–Broadcast (ADS-B) data that we collect synchronously on site. Using a You Only Look Once (YOLO) machine learning model for object detection and the Simple Online and Realtime Tracking (SORT) algorithm for trajectory reconstruction, we establish a first baseline for the performance of the system over five months of field operation. Using an automatically generated real-world dataset derived from ADS-B data, a dataset of synthetic 3D trajectories, and a hand-labeled real-world dataset, we find an acceptance rate (fraction of in-range airplanes passing through the effective field of view of at least one camera that are recorded) of 41% for ADS-B-equipped aircraft, and a mean frame-by-frame aircraft detection efficiency (fraction of recorded airplanes in individual frames which are successfully detected) of 36%. The detection efficiency is heavily dependent on weather conditions, range, and aircraft size. Approximately 500,000 trajectories of various aerial objects are reconstructed from this five-month commissioning period. These trajectories are analyzed with a toy outlier search focused on the large sinuosity of apparent 2D reconstructed object trajectories. About 16% of the trajectories are flagged as outliers and manually examined in the IR images. From these ∼80,000 outliers and 144 trajectories remain ambiguous, which are likely mundane objects but cannot be further elucidated at this stage of development without information about distance and kinematics or other sensor modalities. We demonstrate the application of a likelihood-based statistical test to evaluate the significance of this toy outlier analysis. Our observed count of ambiguous outliers combined with systematic uncertainties yields an upper limit of 18,271 outliers for the five-month interval at a 95% confidence level. This test is applicable to all of our future outlier searches. Full article
(This article belongs to the Section Sensors and Robotics)
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20 pages, 9636 KiB  
Article
Optimization of Ultra Lightweight Mirror and Opto-Mechanical–Thermal Coupling Analysis Based on Solar Thermal Radiation
by Quanliang Dong, Jinhe Yang, Tong Zhang and Xiaoming Wang
Sensors 2025, 25(2), 483; https://doi.org/10.3390/s25020483 - 16 Jan 2025
Viewed by 937
Abstract
To improve maneuverability, the focus of photoelectric theodolites is on reducing the weight of the primary mirror and enhancing its optical performance. This study uses MOAT and Sobol methods to identify key parameters that affect design. Using the high-sensitivity part as the optimization [...] Read more.
To improve maneuverability, the focus of photoelectric theodolites is on reducing the weight of the primary mirror and enhancing its optical performance. This study uses MOAT and Sobol methods to identify key parameters that affect design. Using the high-sensitivity part as the optimization domain, six optimization results were obtained based on the multi-objective SIMP topology optimization method and synthesized into a compromise optimization structure. The performance of the mirror before and after optimization was compared on the opto-mechanical–thermal level. Modal analysis shows the optimized structure has a first natural frequency of 716.84 Hz, indicating excellent stiffness and avoiding low-frequency resonance, with a 30.37% weight reduction. Optical performance is also improved, with a 6 μm reduction in the spot diagram radius and an 8.95 nm decrease in RMS. Simulations under real-world conditions show that the lightweight mirror performs better in resisting gravity deformation and maintaining imaging quality. At maximum thermal deformation, the spot diagram radius of the optimized mirror is 1521.819 μm, with only a 0.145% difference in imaging quality compared to the original. In conclusion, the optimized structure shows comprehensive advantages. Constructing the optical system components and the real physical environment of the site provides a valuable reference for the optimization and analysis of the mirror. Full article
(This article belongs to the Section Optical Sensors)
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22 pages, 8466 KiB  
Article
A Comparative Study of Convolutional Neural Network and Transformer Architectures for Drone Detection in Thermal Images
by Gian Gutierrez, Juan P. Llerena, Luis Usero and Miguel A. Patricio
Appl. Sci. 2025, 15(1), 109; https://doi.org/10.3390/app15010109 - 27 Dec 2024
Cited by 6 | Viewed by 2024
Abstract
The widespread growth of drone technology is generating new security paradigms, especially with regard to the unauthorized activities of UAVs in restricted or sensitive areas, as well as illegal and illicit activities or attacks. Among the various UAV detection technologies, vision systems in [...] Read more.
The widespread growth of drone technology is generating new security paradigms, especially with regard to the unauthorized activities of UAVs in restricted or sensitive areas, as well as illegal and illicit activities or attacks. Among the various UAV detection technologies, vision systems in different spectra are postulated as outstanding technologies due to their peculiarities compared to other technologies. However, drone detection in thermal imaging is a challenging task due to specific factors such as thermal noise, temperature variability, or cluttered environments. This study addresses these challenges through a comparative evaluation of contemporary neural network architectures—specifically, convolutional neural networks (CNNs) and transformer-based models—for UAV detection in infrared imagery. The research focuses on real-world conditions and examines the performance of YOLOv9, GELAN, DETR, and ViTDet in different scenarios of the Anti-UAV Challenge 2023 dataset. The results show that YOLOv9 stands out for its real-time detection speed, while GELAN provides the highest accuracy in varying conditions and DETR performs reliably in thermally complex environments. The study contributes to the advancement of state-of-the-art UAV detection techniques and highlights the need for the further development of specialized models for specific detection scenarios. Full article
(This article belongs to the Special Issue Convolutional Neural Networks and Computer Vision)
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24 pages, 27231 KiB  
Article
Bentayga-I: Development of a Low-Cost and Open-Source Multispectral CubeSat for Marine Environment Monitoring and Prevention
by Adrián Rodríguez-Molina, Alejandro Santana, Felipe Machado, Yubal Barrios, Emma Hernández-Suárez, Ámbar Pérez-García, María Díaz, Raúl Santana, Antonio J. Sánchez and José F. López
Sensors 2024, 24(23), 7648; https://doi.org/10.3390/s24237648 - 29 Nov 2024
Viewed by 1904
Abstract
CubeSats have emerged as a promising alternative to satellite missions for studying remote areas where satellite data are scarce and insufficient, such as coastal and marine environments. However, their standard size and weight limitations make integrating remote sensing optical instruments challenging. This work [...] Read more.
CubeSats have emerged as a promising alternative to satellite missions for studying remote areas where satellite data are scarce and insufficient, such as coastal and marine environments. However, their standard size and weight limitations make integrating remote sensing optical instruments challenging. This work presents the development of Bentayga-I, a CubeSat designed to validate PANDORA, a self-made, lightweight, cost-effective multispectral camera with interchangeable spectral optical filters, in near-space conditions. Its four selected spectral bands are relevant for ocean studies. Alongside the camera, Bentayga-I integrates a power system for short-time operation capacity; a thermal subsystem to maintain battery function; environmental sensors to monitor the CubeSat’s internal and external conditions; and a communication subsystem to transmit acquired data to a ground station. The first helium balloon launch with B2Space proved that Bentayga-I electronics worked correctly in near-space environments. During this launch, the spectral capabilities of PANDORA alongside the spectrum were validated using a hyperspectral camera. Its scientific applicability was also tested by capturing images of coastal areas. A second launch is planned to further validate the multispectral camera in a real-world scenario. The integration of Bentayga-I and PANDORA presents promising results for future low-cost CubeSats missions. Full article
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29 pages, 61165 KiB  
Article
LiDAR-360 RGB Camera-360 Thermal Camera Targetless Calibration for Dynamic Situations
by Khanh Bao Tran, Alexander Carballo and Kazuya Takeda
Sensors 2024, 24(22), 7199; https://doi.org/10.3390/s24227199 - 10 Nov 2024
Viewed by 2146
Abstract
Integrating multiple types of sensors into autonomous systems, such as cars and robots, has become a widely adopted approach in modern technology. Among these sensors, RGB cameras, thermal cameras, and LiDAR are particularly valued for their ability to provide comprehensive environmental data. However, [...] Read more.
Integrating multiple types of sensors into autonomous systems, such as cars and robots, has become a widely adopted approach in modern technology. Among these sensors, RGB cameras, thermal cameras, and LiDAR are particularly valued for their ability to provide comprehensive environmental data. However, despite their advantages, current research primarily focuses on the one or combination of two sensors at a time. The full potential of utilizing all three sensors is often neglected. One key challenge is the ego-motion compensation of data in dynamic situations, which results from the rotational nature of the LiDAR sensor, and the blind spots of standard cameras due to their limited field of view. To resolve this problem, this paper proposes a novel method for the simultaneous registration of LiDAR, panoramic RGB cameras, and panoramic thermal cameras in dynamic environments without the need for calibration targets. Initially, essential features from RGB images, thermal data, and LiDAR point clouds are extracted through a novel method, designed to capture significant raw data characteristics. These extracted features then serve as a foundation for ego-motion compensation, optimizing the initial dataset. Subsequently, the raw features can be further refined to enhance calibration accuracy, achieving more precise alignment results. The results of the paper demonstrate the effectiveness of this approach in enhancing multiple sensor calibration compared to other ways. In the case of a high speed of around 9 m/s, some situations can improve the accuracy about 30 percent higher for LiDAR and Camera calibration. The proposed method has the potential to significantly improve the reliability and accuracy of autonomous systems in real-world scenarios, particularly under challenging environmental conditions. Full article
(This article belongs to the Section Radar Sensors)
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