Pub Date : 2026-02-07DOI: 10.1016/j.measurement.2026.120725
Buqin Hu , Jiamei Wang , Haibo Qu , Zhizhen Zhou , Sheng Guo
The positioning accuracy of parallel mechanisms is critical in advanced industrial applications. This paper presents an error avoidance and compensation strategy based on an error model, using a spatial 1T2R type three-degree-of-freedom (3-DOF) kinematically redundant parallel mechanism (KR-PM) as an example. First, a generalized method for establishing a mechanism error model is introduced using matrix differentiation. Error sensitivity evaluation indices that reflect the actual error transmission relationships are also defined. Applying this method, the inverse kinematics and error models of the spatial 3PRR(RR)S-P KR-PM are developed, where P denotes a prismatic joint, R a revolute joint, S a spherical joint, and an underlined letter indicates an actuated joint. Subsequently, an error avoidance strategy is proposed based on error sensitivity indices and static error (i.e., time-invariant manufacturing and assembly errors) to mitigate their impact on positioning accuracy. Furthermore, an error compensation strategy incorporating a spring element is introduced to counteract the influence of joint clearance errors. Theoretical and simulation results demonstrate that the proposed error avoidance and compensation strategies effectively enhance the positioning accuracy of the mechanism when executing task paths.
{"title":"Research on the error avoidance compensation strategy of a kinematically redundant parallel mechanism based on the error model","authors":"Buqin Hu , Jiamei Wang , Haibo Qu , Zhizhen Zhou , Sheng Guo","doi":"10.1016/j.measurement.2026.120725","DOIUrl":"10.1016/j.measurement.2026.120725","url":null,"abstract":"<div><div>The positioning accuracy of parallel mechanisms is critical in advanced industrial applications. This paper presents an error avoidance and compensation strategy based on an error model, using a spatial 1T2R type three-degree-of-freedom (3-DOF) kinematically redundant parallel mechanism (KR-PM) as an example. First, a generalized method for establishing a mechanism error model is introduced using matrix differentiation. Error sensitivity evaluation indices that reflect the actual error transmission relationships are also defined. Applying this method, the inverse kinematics and error models of the spatial 3<u>P</u>RR(RR)S-<u>P</u> KR-PM are developed, where P denotes a prismatic joint, R a revolute joint, S a spherical joint, and an underlined letter indicates an actuated joint. Subsequently, an error avoidance strategy is proposed based on error sensitivity indices and static error (i.e., time-invariant manufacturing and assembly errors) to mitigate their impact on positioning accuracy. Furthermore, an error compensation strategy incorporating a spring element is introduced to counteract the influence of joint clearance errors. Theoretical and simulation results demonstrate that the proposed error avoidance and compensation strategies effectively enhance the positioning accuracy of the mechanism when executing task paths.</div></div>","PeriodicalId":18349,"journal":{"name":"Measurement","volume":"269 ","pages":"Article 120725"},"PeriodicalIF":5.6,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.measurement.2026.120710
Jianwei Li , Meiqi Gao , Jialin Li , Ying Xu , Wanli Tian , Zhongping Zhang , Jiuru Yang
In this paper, we presents a microsphere-based fiber-optic sensor array designed for sitting posture monitoring. The sensor features a hollow-core fiber with silica walls forming an air cavity, enabling high-resolution pressure sensing through intensity demodulation. Encapsulation with polydimethylsiloxane enhances the durability and compatibility of sensors with human interfaces. Comprehensive theoretical analysis and experimental validation identify the optimal cavity length of 48 μm and achieve a wavelength sensitivity of 0.15 nm/N with the range of 0 − 21 N. A six-sensor array is positioned on a chair and precise pressure distribution detection is achieved by the technique of time-division multiplexing. Key pressure areas associated with eight distinct sitting postures are precisely and rapidly captured. Combined with a machine learning model, the system achieves an accuracy of 94.55 % in posture recognition. Testing on previously unseen data achieves an accuracy of 92.25 %, further evaluating the model’s generalization capability.
{"title":"High accuracy sitting posture monitoring enabled by multiplexing fiber optic microsphere array and deep learning","authors":"Jianwei Li , Meiqi Gao , Jialin Li , Ying Xu , Wanli Tian , Zhongping Zhang , Jiuru Yang","doi":"10.1016/j.measurement.2026.120710","DOIUrl":"10.1016/j.measurement.2026.120710","url":null,"abstract":"<div><div>In this paper, we presents a microsphere-based fiber-optic sensor array designed for sitting posture monitoring. The sensor features a hollow-core fiber with silica walls forming an air cavity, enabling high-resolution pressure sensing through intensity demodulation. Encapsulation with polydimethylsiloxane enhances the durability and compatibility of sensors with human interfaces. Comprehensive theoretical analysis and experimental validation identify the optimal cavity length of 48 μm and achieve a wavelength sensitivity of 0.15 nm/N with the range of 0 − 21 N. A six-sensor array is positioned on a chair and precise pressure distribution detection is achieved by the technique of time-division multiplexing. Key pressure areas associated with eight distinct sitting postures are precisely and rapidly captured. Combined with a machine learning model, the system achieves an accuracy of 94.55 % in posture recognition. Testing on previously unseen data achieves an accuracy of 92.25 %, further evaluating the model’s generalization capability.</div></div>","PeriodicalId":18349,"journal":{"name":"Measurement","volume":"268 ","pages":"Article 120710"},"PeriodicalIF":5.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.measurement.2026.120749
Patrycja Pyzik, Lukasz Ambrozinski
A laser ultrasound (LU) measurement technique is presented for non-contact inspection of metallic structures, addressing the problem of coherent noise that limits the accuracy of conventional ultrasonic measurements. The proposed method introduces a novel compensation procedure based on experimentally acquired data, enabling effective suppression of deterministic wave components originating from multimodal character of laser excitation. Combined with Frequency-domain Synthetic Aperture Focusing Technique (F-SAFT), the method achieved a measurement accuracy of 0.13 mm, the ability to detect 0.6 mm flaws with spatial resolution down to 1.1 mm, and a significant improvement in signal-to-noise ratio compared with raw data. The approach was validated on a real engineering structure — a pre-manufactured tailor welded blank. The result demonstrated that the developed technique enhances the interpretability of LU scans and enables clear flaw detection using automatic gating techniques—a task previously impossible with raw images. The proposed method is general and can be applied to various non-destructive testing (NDT) configurations affected by coherent noise.
{"title":"Signal processing method to coherent noise suppression with application to enhance measurement quality in laser ultrasound","authors":"Patrycja Pyzik, Lukasz Ambrozinski","doi":"10.1016/j.measurement.2026.120749","DOIUrl":"10.1016/j.measurement.2026.120749","url":null,"abstract":"<div><div>A laser ultrasound (LU) measurement technique is presented for non-contact inspection of metallic structures, addressing the problem of coherent noise that limits the accuracy of conventional ultrasonic measurements. The proposed method introduces a novel compensation procedure based on experimentally acquired data, enabling effective suppression of deterministic wave components originating from multimodal character of laser excitation. Combined with Frequency-domain Synthetic Aperture Focusing Technique (F-SAFT), the method achieved a measurement accuracy of 0.13 mm, the ability to detect <span><math><mo>⌀</mo></math></span>0.6 mm flaws with spatial resolution down to 1.1 mm, and a significant improvement in signal-to-noise ratio compared with raw data. The approach was validated on a real engineering structure — a pre-manufactured tailor welded blank. The result demonstrated that the developed technique enhances the interpretability of LU scans and enables clear flaw detection using automatic gating techniques—a task previously impossible with raw images. The proposed method is general and can be applied to various non-destructive testing (NDT) configurations affected by coherent noise.</div></div>","PeriodicalId":18349,"journal":{"name":"Measurement","volume":"269 ","pages":"Article 120749"},"PeriodicalIF":5.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Direct absorption spectroscopy (DAS) typically employs sawtooth waveform modulation, which provides a simple baseline that can be approximated using polynomial fitting. However, at high modulation frequencies, sawtooth modulation imposes demanding hardware requirements and may lead to baseline distortion. To address these limitations, we propose a baseline-free DAS method based on sinusoidal modulation. This approach exploits the distinct frequency-domain amplitude characteristics of sinusoidal modulation. By applying a Fourier transform to the logarithm of the transmitted light intensity, the method decouples absorbance from baseline interference. Moreover, tuning the ratio of the modulation signal’s direct current (DC) and alternating current (AC) components provides additional control over baseline influence. For experimental validation, a laser operating at the bandhead region (4.172 um) of the CO2 absorption spectrum was employed. In this spectral range, densely packed absorption lines leave virtually non-absorption intervals, rendering conventional baseline fitting methods inaccurate, particularly for temperature measurements. In contrast, the proposed method demonstrated robust and accurate performance. The accuracy and critical parameters of the method were systematically examined through numerical simulations and experimentally validated in a flat flame established over a Hencken burner.
{"title":"Baseline-free direct laser absorption spectroscopy with sinusoidal modulation: a theoretical and experimental study for combustion diagnostics","authors":"Shaojie Wang, Weifan Hu, Shengming Yin, Liangliang Xu, Mingming Gu, Fei Qi","doi":"10.1016/j.measurement.2026.120756","DOIUrl":"10.1016/j.measurement.2026.120756","url":null,"abstract":"<div><div>Direct absorption spectroscopy (DAS) typically employs sawtooth waveform modulation, which provides a simple baseline that can be approximated using polynomial fitting. However, at high modulation frequencies, sawtooth modulation imposes demanding hardware requirements and may lead to baseline distortion. To address these limitations, we propose a baseline-free DAS method based on sinusoidal modulation. This approach exploits the distinct frequency-domain amplitude characteristics of sinusoidal modulation. By applying a Fourier transform to the logarithm of the transmitted light intensity, the method decouples absorbance from baseline interference. Moreover, tuning the ratio of the modulation signal’s direct current (DC) and alternating current (AC) components provides additional control over baseline influence. For experimental validation, a laser operating at the bandhead region (4.172 um) of the CO<sub>2</sub> absorption spectrum was employed. In this spectral range, densely packed absorption lines leave virtually non-absorption intervals, rendering conventional baseline fitting methods inaccurate, particularly for temperature measurements. In contrast, the proposed method demonstrated robust and accurate performance. The accuracy and critical parameters of the method were systematically examined through numerical simulations and experimentally validated in a flat flame established over a Hencken burner.</div></div>","PeriodicalId":18349,"journal":{"name":"Measurement","volume":"269 ","pages":"Article 120756"},"PeriodicalIF":5.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.measurement.2026.120708
Yi Tian , Xiaoqi Zhou , Juntao Zhu , Mingfu Xiao , Shouyong Xie , Jie Huang , Gang Liu , Yuanyuan Huang
The real-time monitoring of leaf moisture is crucial for understanding the mechanism of physiological activity, breeding crops with drought or flood tolerance, and diagnosing crop physiology status. However, current monitoring methods fail to meet the requirements for in situ, non-destructive monitoring due to limitations in permeability and ductility. Here, we present a biocompatible and wearable sensor to realize real-time monitoring leaf moisture. The sensor incorporates a dual-layer gradient porous structure that forms a vertical export channel, achieving a high moisture evaporation rate (approximately 0.28kg m-2h−1) and enabling the precise recording of moisture signals and long-term wear. Based on the biocompatible and wearable sensor, we utilized a wireless system to enable continuous real-time moisture monitoring. This approach offers a powerful tool for analyzing key physiological signals in plants and holds potential for adaptation to the real-time monitoring of signaling in other crops.
{"title":"Gradient Pore-Engineered biocompatible and wearable sensor for real-time leaf moisture monitoring","authors":"Yi Tian , Xiaoqi Zhou , Juntao Zhu , Mingfu Xiao , Shouyong Xie , Jie Huang , Gang Liu , Yuanyuan Huang","doi":"10.1016/j.measurement.2026.120708","DOIUrl":"10.1016/j.measurement.2026.120708","url":null,"abstract":"<div><div>The real-time monitoring of leaf moisture is crucial for understanding the mechanism of physiological activity, breeding crops with drought or flood tolerance, and diagnosing crop physiology status. However, current monitoring methods fail to meet the requirements for in situ, non-destructive monitoring due to limitations in permeability and ductility. Here, we present a biocompatible and wearable sensor to realize real-time monitoring leaf moisture. The sensor incorporates a dual-layer gradient porous structure that forms a vertical export channel, achieving a high moisture evaporation rate (approximately 0.28kg m<sup>-2</sup>h<sup>−1</sup>) and enabling the precise recording of moisture signals and long-term wear. Based on the biocompatible and wearable sensor, we utilized a wireless system to enable continuous real-time moisture monitoring. This approach offers a powerful tool for analyzing key physiological signals in plants and holds potential for adaptation to the real-time monitoring of signaling in other crops.</div></div>","PeriodicalId":18349,"journal":{"name":"Measurement","volume":"269 ","pages":"Article 120708"},"PeriodicalIF":5.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.measurement.2026.120748
Jinle Xu, Wang Gao, Shaopeng He, Hong Liu, Hui Jiang, Shuguo Pan
Visual–Inertial Simultaneous Localization and Mapping (VISLAM) has gained widespread adoption owing to its lightweight architecture, particularly in Global Navigation Satellite System (GNSS) denied indoor spaces. However, the indoor environment typically exhibits textureless surfaces and repetitive structure, which results in sparse and ambiguous features. Such visual degradation can lead to failures in tracking and loop closure detection, causing rapidly accumulating SLAM drift without effective correction mechanisms. This paper presents a sign-aided localization method that identifies signs through vision models and extracts key edge points based on geometric shape-based projection. The landmark coordinate system can then be reconstructed for data association, global relocalization, and drift reduction. By incorporating pre-established sign maps which are efficient and consume little memory, we conducted experiments across three collaborative scenarios, relying only on a monocular camera and an inertial measurement unit (IMU). Experimental results demonstrate that our method outperforms several state-of-the-art (SOTA) VISLAM algorithms in terms of localization accuracy and robustness, significantly reducing accumulated drift. Furthermore, compared to marker-based SLAM methods that rely on artificial landmarks such as ArUco tags and texts, our approach can achieve comparable or superior performance by leveraging naturally occurring signs within the scene, without the need for artificial markers.
{"title":"Enhanced indoor localization with sign-aided visual–inertial odometry","authors":"Jinle Xu, Wang Gao, Shaopeng He, Hong Liu, Hui Jiang, Shuguo Pan","doi":"10.1016/j.measurement.2026.120748","DOIUrl":"10.1016/j.measurement.2026.120748","url":null,"abstract":"<div><div>Visual–Inertial Simultaneous Localization and Mapping (VISLAM) has gained widespread adoption owing to its lightweight architecture, particularly in Global Navigation Satellite System (GNSS) denied indoor spaces. However, the indoor environment typically exhibits textureless surfaces and repetitive structure, which results in sparse and ambiguous features. Such visual degradation can lead to failures in tracking and loop closure detection, causing rapidly accumulating SLAM drift without effective correction mechanisms. This paper presents a sign-aided localization method that identifies signs through vision models and extracts key edge points based on geometric shape-based projection. The landmark coordinate system can then be reconstructed for data association, global relocalization, and drift reduction. By incorporating pre-established sign maps which are efficient and consume little memory, we conducted experiments across three collaborative scenarios, relying only on a monocular camera and an inertial measurement unit (IMU). Experimental results demonstrate that our method outperforms several state-of-the-art (SOTA) VISLAM algorithms in terms of localization accuracy and robustness, significantly reducing accumulated drift. Furthermore, compared to marker-based SLAM methods that rely on artificial landmarks such as ArUco tags and texts, our approach can achieve comparable or superior performance by leveraging naturally occurring signs within the scene, without the need for artificial markers.</div></div>","PeriodicalId":18349,"journal":{"name":"Measurement","volume":"268 ","pages":"Article 120748"},"PeriodicalIF":5.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146172082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.measurement.2026.120623
Yulong Chen, Jiangming Kan, Chunjiang Yu
Human unsafe behavior is the main cause of laboratory accidents; however, existing laboratory monitoring methods perform poorly in the face of unsafe behavior. How to prevent unsafe behavior accurately and in real-time when it occurs is considered a key challenge. In this paper, we propose a Laboratory Unsafe Behavior Detection-YOLO model (LUB-YOLO) based on the improved YOLOv8s, which solves the problems of low detection performance and difficulty in distinguishing unsafe behavior. The model combines the Ghost Conv module with HGNet to optimize the computational complexity of the model to improve the detection performance, incorporates the AIFI multi-head attention mechanism to enhance the feature representation and the ability to combine the contextual features, and the dynamic attention mechanism module of DyHead is applied to the detection head to obtain the scale information of the target. The experimental results show that compared with the original network, the LUB-YOLO model improves the [email protected] by 2.1%, reduces the number of parameters by 18.1% and reduces the amount of computation by 15.5%. The improved model outperforms existing detection models in terms of model performance and accuracy, and is able to complete the recognition task in laboratory scenarios. The LUB-YOLO model is specifically designed for recognizing unsafe behaviors and is more suitable for deployment in laboratory scenarios with limited computational resources. This work provides theoretical insights for enhancing safety monitoring and reducing accidents.
{"title":"LUB-YOLO: A lightweight method for laboratory unsafe behavior detection based on improved YOLOv8s","authors":"Yulong Chen, Jiangming Kan, Chunjiang Yu","doi":"10.1016/j.measurement.2026.120623","DOIUrl":"10.1016/j.measurement.2026.120623","url":null,"abstract":"<div><div>Human unsafe behavior is the main cause of laboratory accidents; however, existing laboratory monitoring methods perform poorly in the face of unsafe behavior. How to prevent unsafe behavior accurately and in real-time when it occurs is considered a key challenge. In this paper, we propose a Laboratory Unsafe Behavior Detection-YOLO model (LUB-YOLO) based on the improved YOLOv8s, which solves the problems of low detection performance and difficulty in distinguishing unsafe behavior. The model combines the Ghost Conv module with HGNet to optimize the computational complexity of the model to improve the detection performance, incorporates the AIFI multi-head attention mechanism to enhance the feature representation and the ability to combine the contextual features, and the dynamic attention mechanism module of DyHead is applied to the detection head to obtain the scale information of the target. The experimental results show that compared with the original network, the LUB-YOLO model improves the [email protected] by 2.1%, reduces the number of parameters by 18.1% and reduces the amount of computation by 15.5%. The improved model outperforms existing detection models in terms of model performance and accuracy, and is able to complete the recognition task in laboratory scenarios. The LUB-YOLO model is specifically designed for recognizing unsafe behaviors and is more suitable for deployment in laboratory scenarios with limited computational resources. This work provides theoretical insights for enhancing safety monitoring and reducing accidents.</div></div>","PeriodicalId":18349,"journal":{"name":"Measurement","volume":"269 ","pages":"Article 120623"},"PeriodicalIF":5.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.measurement.2026.120715
Ammar Armghan , Sultan S. Aldkeelalah , Slim Chaoui , Mehtab Singh , Somia A. Abd El-Mottaleb
In this paper, we present a detailed performance analysis of a non-return-to-zero (NRZ) based underwater optical wireless communication (UOWC) system under five standard water types: Pure Sea (PS), Clear Ocean (CO), Coastal Ocean (CS), Harbor I (HI), and Harbor II (HII). The analysis is carried out considering Q Factor, logarithmic bit error rate (log(BER)), received electrical power, and signal-to-noise ratio (SNR) as the key performance metrics. In the baseline system (without compensation), the maximum achievable ranges were limited to 52 m in PS, 30 m in CO, 17 m in CS, 8.6 m in HI, and 5.25 m in HII, with minimum log(BER) values in the range of –4.51 to –6.11 and Q Factors between 4.00 and 4.80 dB. To combat the non-linear response of the photodetector, we propose the deployment of a Square Root module (SRm) at the receiver. The incorporation of SRm demonstrates significant performance improvements, extending the maximum communication ranges to 150 m (PS), 65 m (CO), 32 m (CS), 14.5 m (HI), and 8.2 m (HII). This corresponds to nearly a threefold improvement in PS water and up to 60% enhancement in turbid harbor waters. Additionally, the system demonstrates improved detection quality, with Q Factors increasing to a range of 4.25–5.11 dB and log(BER) as low as –6.81 in PS and –6.65 in HII. Numerical simulations confirm that the proposed SRm-based detection technique effectively compensates for non-linear distortions and significantly enhances UOWC performance across diverse aquatic environments, making it a promising approach for medium to long range underwater optical links.
本文在纯海(PS)、清海(CO)、近海(CS)、海港I (HI)和海港II (HII)五种标准水域类型下,对基于非归零(NRZ)的水下光无线通信(UOWC)系统进行了详细的性能分析。分析考虑了Q因子、对数误码率(log(BER))、接收电功率和信噪比(SNR)作为关键性能指标。在基线系统(无补偿)中,最大可实现范围限制为PS 52 m, CO 30 m, CS 17 m, HI 8.6 m和HII 5.25 m,最小对数(BER)值在-4.51至-6.11范围内,Q因子在4.00至4.80 dB之间。为了对抗光电探测器的非线性响应,我们建议在接收器上部署平方根模块(SRm)。SRm的结合显示了显著的性能改进,将最大通信范围扩展到150米(PS), 65米(CO), 32米(CS), 14.5米(HI)和8.2米(HII)。这相当于PS水的近三倍改善和浑浊港口水域高达60%的改善。此外,该系统显示出更高的检测质量,Q因子增加到4.25-5.11 dB的范围,对数(BER)在PS和HII中低至-6.81和-6.65。数值模拟证实了基于srm的检测技术有效补偿了非线性失真,显著提高了不同水生环境下UOWC的性能,使其成为一种很有前途的中远距离水下光链路检测方法。
{"title":"Performance enhancement of NRZ-based underwater optical wireless communication systems using square root detection under diverse water conditions","authors":"Ammar Armghan , Sultan S. Aldkeelalah , Slim Chaoui , Mehtab Singh , Somia A. Abd El-Mottaleb","doi":"10.1016/j.measurement.2026.120715","DOIUrl":"10.1016/j.measurement.2026.120715","url":null,"abstract":"<div><div>In this paper, we present a detailed performance analysis of a non-return-to-zero (NRZ) based underwater optical wireless communication (UOWC) system under five standard water types: Pure Sea (PS), Clear Ocean (CO), Coastal Ocean (CS), Harbor I (HI), and Harbor II (HII). The analysis is carried out considering Q Factor, logarithmic bit error rate (log(BER)), received electrical power, and signal-to-noise ratio (SNR) as the key performance metrics. In the baseline system (without compensation), the maximum achievable ranges were limited to 52 m in PS, 30 m in CO, 17 m in CS, 8.6 m in HI, and 5.25 m in HII, with minimum log(BER) values in the range of –4.51 to –6.11 and Q Factors between 4.00 and 4.80 dB. To combat the non-linear response of the photodetector, we propose the deployment of a Square Root module (SRm) at the receiver. The incorporation of SRm demonstrates significant performance improvements, extending the maximum communication ranges to 150 m (PS), 65 m (CO), 32 m (CS), 14.5 m (HI), and 8.2 m (HII). This corresponds to nearly a threefold improvement in PS water and up to 60% enhancement in turbid harbor waters. Additionally, the system demonstrates improved detection quality, with Q Factors increasing to a range of 4.25–5.11 dB and log(BER) as low as –6.81 in PS and –6.65 in HII. Numerical simulations confirm that the proposed SRm-based detection technique effectively compensates for non-linear distortions and significantly enhances UOWC performance across diverse aquatic environments, making it a promising approach for medium to long range underwater optical links.</div></div>","PeriodicalId":18349,"journal":{"name":"Measurement","volume":"269 ","pages":"Article 120715"},"PeriodicalIF":5.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graininess is a critical perceptual attribute of metallic coatings that strongly affects visual quality, yet its objective measurement remains challenging due to the lack of standardized and perceptually consistent metrics. This study proposes a camera-based image-processing framework for graininess evaluation, incorporating perceptually motivated preprocessing and multiscale analysis to achieve robust agreement with human visual perception while avoiding reliance on proprietary instrumental configurations. The framework is validated using a systematically designed dataset of automotive metallic coatings with controlled pigment characteristics and chromatic variations. Perceptual graininess is established through visual assessments by 32 observers and used as the reference for evaluation. Image-based texture descriptors from spatial and frequency domains are comparatively analyzed, with performance assessed using correlation- and error-based metrics and benchmarked against BYK-mac-i measurements. Results show that multiscale wavelet-based descriptors achieve the highest agreement with visual assessments (r = 0.94), outperforming both Fourier-based methods (r ≈ 0.92) and the industrial gonio-spectrophotometer (r ≈ 0.91). Overall, the proposed framework provides a transparent, computationally efficient, and perceptually consistent solution for reliable graininess quantification in industrial quality control.
{"title":"Quantifying graininess in metallic coatings using spatial and frequency-domain image descriptors: A comparison with visual perception","authors":"Fatemeh Malekpour, Gorji Kandi Saeideh, Mohsen Mohseni","doi":"10.1016/j.measurement.2026.120706","DOIUrl":"10.1016/j.measurement.2026.120706","url":null,"abstract":"<div><div>Graininess is a critical perceptual attribute of metallic coatings that strongly affects visual quality, yet its objective measurement remains challenging due to the lack of standardized and perceptually consistent metrics. This study proposes a camera-based image-processing framework for graininess evaluation, incorporating perceptually motivated preprocessing and multiscale analysis to achieve robust agreement with human visual perception while avoiding reliance on proprietary instrumental configurations. The framework is validated using a systematically designed dataset of automotive metallic coatings with controlled pigment characteristics and chromatic variations. Perceptual graininess is established through visual assessments by 32 observers and used as the reference for evaluation. Image-based texture descriptors from spatial and frequency domains are comparatively analyzed, with performance assessed using correlation- and error-based metrics and benchmarked against BYK-mac-i measurements. Results show that multiscale wavelet-based descriptors achieve the highest agreement with visual assessments (r = 0.94), outperforming both Fourier-based methods (r ≈ 0.92) and the industrial gonio-spectrophotometer (r ≈ 0.91). Overall, the proposed framework provides a transparent, computationally efficient, and perceptually consistent solution for reliable graininess quantification in industrial quality control.</div></div>","PeriodicalId":18349,"journal":{"name":"Measurement","volume":"268 ","pages":"Article 120706"},"PeriodicalIF":5.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146171995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-06DOI: 10.1016/j.measurement.2026.120754
Jiawen Sun , Wenzhong Yang , Yabo Yin , Jinhai Sa , Xinjun Pei , Fuyuan Wei , Danni Chen , Jianli Zhou
Accurate geometric measurement of steel surface defects is essential for quantitative quality assessment and process control in photovoltaic polysilicon production. Traditional methods primarily rely on fixed camera setups for qualitative inspection, with few studies exploring the use of unmanned aerial vehicles (UAVs). Existing deep learning-based detection approaches lack an intrinsic, calibrated metrology framework to establish traceable mapping from pixel-level outputs to physical dimensions. To address this challenge, this paper proposes a complete traceable visual metrology system. First, we established a calibrated UAV dynamic imaging platform. By establishing a known ground sampling distance (GSD = 1.2 mm/pixel), we constructed a deterministic mapping function from pixel coordinates to physical world coordinates. This function ensures each pixel corresponds to a clear and traceable physical scale. Second, we propose a specialized neural network architecture tailored for measurement tasks, serving as the core computational unit for quantitative measurement. Addressing the challenges of extreme defect size variations and complex background interference in industrial settings, we designed the measurement-driven DFA-Net. The Multi-scale Pyramid Pooling and Feature Processing (MSPP) module dynamically fuses cross-scale information to preserve complete defect features ranging from microcracks to macroscopic patches. The Omni-Dimensional Attention-Guided Selective Enhancement (ODESE) module improves spatial localization robustness under reflections, oil stains, and other interferences. The Wise-IoU v3 (WIoUv3) loss function ensures measurement consistency through dynamic gradient optimization based on defect difficulty and scale. Experimental results demonstrate that our method is effective in achieving traceable measurement outputs for physical parameters such as defect location and size range.
{"title":"DFA-Net: Dynamic multi-scale feature fusion and attention mechanism for surface defect detection in polysilicon production","authors":"Jiawen Sun , Wenzhong Yang , Yabo Yin , Jinhai Sa , Xinjun Pei , Fuyuan Wei , Danni Chen , Jianli Zhou","doi":"10.1016/j.measurement.2026.120754","DOIUrl":"10.1016/j.measurement.2026.120754","url":null,"abstract":"<div><div>Accurate geometric measurement of steel surface defects is essential for quantitative quality assessment and process control in photovoltaic polysilicon production. Traditional methods primarily rely on fixed camera setups for qualitative inspection, with few studies exploring the use of unmanned aerial vehicles (UAVs). Existing deep learning-based detection approaches lack an intrinsic, calibrated metrology framework to establish traceable mapping from pixel-level outputs to physical dimensions. To address this challenge, this paper proposes a complete traceable visual metrology system. First, we established a calibrated UAV dynamic imaging platform. By establishing a known ground sampling distance (GSD = 1.2 mm/pixel), we constructed a deterministic mapping function from pixel coordinates to physical world coordinates. This function ensures each pixel corresponds to a clear and traceable physical scale. Second, we propose a specialized neural network architecture tailored for measurement tasks, serving as the core computational unit for quantitative measurement. Addressing the challenges of extreme defect size variations and complex background interference in industrial settings, we designed the measurement-driven DFA-Net. The Multi-scale Pyramid Pooling and Feature Processing (MSPP) module dynamically fuses cross-scale information to preserve complete defect features ranging from microcracks to macroscopic patches. The Omni-Dimensional Attention-Guided Selective Enhancement (ODESE) module improves spatial localization robustness under reflections, oil stains, and other interferences. The Wise-IoU v3 (WIoUv3) loss function ensures measurement consistency through dynamic gradient optimization based on defect difficulty and scale. Experimental results demonstrate that our method is effective in achieving traceable measurement outputs for physical parameters such as defect location and size range.</div></div>","PeriodicalId":18349,"journal":{"name":"Measurement","volume":"269 ","pages":"Article 120754"},"PeriodicalIF":5.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}