最新刊期

    32 7 2024

      Modern Applied Optics

    • 科研人员在星地自由空间光学通信领域取得了重要进展。为了解决该系统中的提前角问题,他们提出了一种基于光强传输的新型波前探测技术——投影光瞳面分布(PPPP)。这一技术利用TIE光强传输公式,通过分析不同传输距离下的光强分布变化,能够反解出大气湍流引起的波前畸变。实验结果显示,PPPP技术采用上行通信激光本身的后向瑞利散射,其测量的大气湍流方向与通信卫星方向一致,因此能够有效解决星地激光通信中的提前角问题。实验模拟了1米口径的地基望远镜作为上行激光发射装置和后向散射光斑成像设备,通过等效高度分别为10公里和17公里的上行激光后向散射光斑图像,实现了对10公里以下大气湍流的波前探测。与传统的夏克-哈特曼波前探测器相比,PPPP技术能够实现相似的波前重构效果,两者重构相位的残差约为初始相位的30%。这一研究成果为星地自由空间光学通信系统中的提前角问题提供了有效的解决方案,为相关领域的研究开辟了新方向,为未来的星地激光通信技术的发展奠定了坚实基础。
      YANG Huizhe,ZHANG Zhenyu,LIU Jin,LIANG Yonghui
      Vol. 32, Issue 7, Pages: 945-955(2024) DOI: 10.37188/OPE.20243207.0945
      摘要:Addressing the challenge of point ahead angle (PAA) in satellite-based free-space optical communication systems, this paper introduces a novel wavefront sensing method, the Projected Pupil Plane Pattern (PPPP), utilizing the transport-of-intensity equation (TIE). Laboratory experiments confirm its viability. The PPPP method, rooted in TIE, can deduce wavefront distortions due to atmospheric turbulence by analyzing variations in light intensity distribution over different transmission distances. Utilizing the back Rayleigh scattering from the communication laser, PPPP's atmospheric turbulence measurements align with the satellite's direction, offering an effective solution to PAA-related issues in satellite-ground laser communications. In our experiments, a 1-m ground telescope simulates an upward laser transmitter and captures the backscattered light for imaging. We measure wavefront distortions caused by atmospheric turbulence up to 10 km using backscattered light from altitudes of 10 km and 17 km. These distortions are simulated using a spatial light modulator or a transparent plastic sheet. The results demonstrate that PPPP and the commonly used Shack-Hartman wavefront sensor provide comparable wavefront reconstructions for various distortions, with the reconstructed phase's residual difference around 30% of the initial phase.  
      关键词:adaptive optics;satellite-ground laser communications;wavefront sensing;Projected Pupil Plane Pattern (PPPP);point ahead angle (PAA)   
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    • 一项针对半导体晶圆厚度高精度非接触测量问题的研究取得了重要进展。该研究提出了一种基于激光共焦技术的晶圆厚度测量方法,实现了晶圆上下表面的高精度瞄准定位,并通过光线追迹算法精确计算每个采样点的物理坐标。实验结果表明,该方法的轴向分辨力优于5nm,扫描范围可达5.7mm,且测量重复性好,单次测量时间小于400ms。这一研究不仅为半导体晶圆厚度的高精度、无损在线测量提供了新技术,也为相关领域的研究和应用提供了新的思路。
      LI Zhaoyu,LIU Zihao,WANG Yaoying,QIU Lirong,YANG Shuai
      Vol. 32, Issue 7, Pages: 956-965(2024) DOI: 10.37188/OPE.20243207.0956
      摘要:Addressing the need for precise non-contact measurement of semiconductor wafer thickness, this study introduces a method based on laser confocal technology that ensures remarkable accuracy. It utilizes a voice coil nanodisplacement platform for high-resolution actuation of a laser confocal optical probe, enabling precise axial scanning. This method relies on identifying the peak points on the confocal laser's axial response curve, which are indicative of the objective lens's focal point, to accurately align and position the wafer's upper and lower surfaces. By accurately calculating the physical coordinates of each sampling point on the wafer surface through ray tracing algorithms, this technique achieves high-precision non-contact measurement of wafer thickness. A specialized laser confocal sensor for semiconductor wafer thickness measurement was developed, showcasing an axial resolution of under 5 nm, an axial scanning range of up to 5.7 mm, and repeatability in thickness measurement of under 100 nm across six wafer types. The process takes less than 400 ms for a single wafer. This research successfully applies confocal focusing technology to semiconductor measurement, offering a novel solution for high-precision, non-destructive, online wafer thickness measurement.  
      关键词:laser confocal;thickness measurement;semiconductor wafer;high precision;nondestructive measurement   
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    • 针对烷烃气体浓度的大范围灵活检测问题,科研团队提出了一种基于卡塞格林系统的中红外遥测遥感方法。该研究详细设计了光学系统的发射、接收和探测模块,并采用了透射式非球面准直结构和发射接收同轴技术,解决了光信号丢失和视差问题。实验结果显示,该系统能够在25~100米的范围内准确测量烷烃浓度,发射和接收效率分别高达86%和75.8%。这一创新方法不仅提升了测量效率,还显著降低了测量人员的风险,为烷烃气体浓度的大范围快速检测提供了新的解决方案。
      YIN Liang,XING Zhiming,ZHU Ke,MIAO Yu,JIANG Meng,SHAN Xinzhi,GAO Xiumin
      Vol. 32, Issue 7, Pages: 966-975(2024) DOI: 10.37188/OPE.20243207.0966
      摘要:To enhance the detection of alkane gas concentrations across a broad spectrum, this study introduces a mid-infrared telemetry and remote sensing approach utilizing the Cassegrain system. The design of the optical system's transmitting, receiving, and detecting modules was explored. Utilizing a 3 464 nm mid-infrared light source in conjunction with the Cassegrain system, an optical system for alkane concentration telemetry and remote sensing was developed. To accommodate target measurements within a 25-100 m range, an optical telemetry system was crafted with a 25 cm diameter. To counteract optical signal loss in the Cassegrain system, a transmission aspheric collimation structure was employed, enabling target focusing at varying distances. To address issues arising from the system's large aperture, a co-axial transmission and reception strategy, reducing disparity were implemented. The system can accurately measure targets within the 25-100 m range. Both primary and secondary mirrors were coated with a mid-infrared enhanced gold film, significantly boosting system stability. Testing reveals the system's overall transmission efficiency at 86%, with a reception efficiency of 75.8%. This alkane telemetry and remote sensing system facilitates remote gas concentration measurement over extensive ranges and distances, offering convenience, rapid measurement, and enhanced field safety. It ensures the optical system's stability and operational safety.  
      关键词:telemetry and remote sensing;alkane concentration measurement;mid-infrared light;Cassegrain system   
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    • 一项关于高精度空间六自由度测量系统的研究取得重要进展。针对我国高端制造业对高精度测量技术的迫切需求,研究团队提出了一种基于单目视觉的激光跟踪测量姿态方法。该方法结合了合作靶标的几何特性、EPnP算法和SoftPOSIT算法,通过实时相机成像模型和动态校正技术,实现了大范围内任意动态位姿的自动测量。该研究成果不仅提高了特征点的提取精度,还建立了姿态测量系统的自动监测纠错机制。实验结果显示,在3至10米的测量范围内,方位角/俯仰角为±30°、滚动角为±180°的条件下,该方法能够达到优于0.049°和0.065°的姿态测量精度。这一研究成果为我国高端制造业的激光跟踪测量提供了强有力的技术支持,将有力推动相关领域的精密测量技术发展。
      GAO Doudou,DONG Dengfeng,QIU Qifan,CUI Chengjun,WANG Bo
      Vol. 32, Issue 7, Pages: 976-986(2024) DOI: 10.37188/OPE.20243207.0976
      摘要:Considering the critical need for a high-precision, six-degree-of-freedom measurement system in China's advanced manufacturing sector, this study introduces a novel approach for large-scale, high-accuracy attitude measurement utilizing a monocular vision module for laser tracking. Initially, the paper outlines the hardware configuration of the laser tracking measurement system, encompassing both the attitude measurement system and the cooperative target, and establishes a mathematical model to define spatial attitude angles accurately. It then delves into the adaptive clear imaging features of the attitude measurement module. By leveraging an optical distortion model and Zhengyou Zhang's calibration algorithm, it crafts a real-time camera imaging model that dynamically adjusts the pixel coordinates of feature points, enhancing the precision of feature point extraction. This is further refined by integrating the geometric traits of the cooperative target with the EPnP and SoftPOSIT algorithms, leading to a sophisticated attitude measurement technique complemented by an automatic monitoring and error correction mechanism. This dual approach enables precise automatic measurement across any attitude within the specified distance and measurement range. The system's accuracy was validated through experiments using a two-dimensional precision turntable equipped with a cooperative target, showing an impressive attitude measurement accuracy within a 3-10 m range, with yaw and pitch angles within ±30° and roll angle within ±180°. Specifically, accuracy was better than 0.049° with a 14-feature-point cooperative target and better than 0.065° with a 10-feature-point target. These findings underscore the superiority of this method over other recent laser tracking measurement techniques, highlighting its broad applicability and minimal constraints on the cooperative target's feature point configuration, thus fulfilling the precision measurement demands of high-end manufacturing's laser tracking and measurement.  
      关键词:laser tracking measurement;monocular vision;adaptive measurement;attitude measurement   
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      Micro/Nano Technology and Fine Mechanics

    • 无线通信领域的研究取得了重要进展。专家们成功提出了一种基于液态金属材质的跨X和Ku波段超宽带极化转换电磁超表面,这一创新设计在电磁波传播和极化方向调控方面展现了显著的优势。该超表面不仅具备宽频带、高极化转换率等优异性能,还具备体积小、无机械疲劳损伤、易共形、成本低等实际应用中的关键优势。实验结果显示,在7.595 GHz到17.712 GHz的超宽带范围内,该超表面能够实现高效的交叉极化转换或宽带圆极化转换功能。特别地,当阶梯状液态金属结构宽度为1.6 mm时,在相对带宽为79.9%的频带上,极化转换率优于90%。而当宽度调整为0.3 mm时,在特定频带上,超表面则展现出线极化向圆极化转换的功能。这一研究成果不仅验证了跨X和Ku波段超宽带极化转换电磁超表面的多功能性和有效性,还为无线通信领域的信号识别与接收提供了新的解决方案,为相关技术的发展和应用奠定了坚实的基础。这一创新性的研究无疑为无线通信领域的未来发展注入了新的活力。
      SHAO Yanan,LI Bowen,GAO Shibo,DENG Yongbo
      Vol. 32, Issue 7, Pages: 987-997(2024) DOI: 10.37188/OPE.20243207.0987
      摘要:In wireless communication, controlling electromagnetic wave propagation and polarization direction is crucial for signal detection and reception. This study introduces a liquid metal-based electromagnetic metasurface for polarization conversion in the X (8-12 GHz) and Ku (12-18 GHz) bands. It offers benefits like ultra-wideband performance, high polarization conversion ratio, compactness, durability against mechanical fatigue, flexibility, and affordability. The metasurface consists of a periodic arrangement with a top step-shaped liquid metal structure, a middle dielectric layer, and a bottom copper foil, capable of ultra-wideband cross-polarization conversion or wideband circular polarization conversion from 7.595 GHz to 17.712 GHz. With a 1.6 mm wide step-shaped liquid metal structure, it achieves over 90% polarization conversion ratio across 7.595-17.712 GHz with a 79.9% relative bandwidth, enabling co-polarization to cross-polarization conversion. At a 0.3mm structure width, it converts linear to circular polarization between 10.864-12.288 GHz with a 12.30% relative bandwidth. Additionally, in the 7.328-7.592 GHz band with a 3.54% relative bandwidth, it maintains over 90% polarization conversion ratio, facilitating co-to cross-polarization conversion. Experimental sample tests reveal a 4.20% relative error between experimental and simulated results, indicating strong theoretical and experimental correlation, thus confirming the metasurface's versatility and effectiveness.  
      关键词:metasurface;liquid metal;polarization conversion;ultra-wideband   
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    • 航天器供能太阳帆板类柔性薄板结构的振动问题得到了新的解决方案。专家构建了双目视觉系统的振动测控实验平台,利用双目立体视觉技术检测振动,并设计了自回归小波神经网络控制器(SRWNNC)来抑制振动。通过对双目视觉系统的标定和图像处理算法,成功获取了振动信号的三维坐标。实验结果表明,双目视觉传感器对振动信号的检测精度小于0.1 mm,而SRWNNC的抑振效果也优于大增益PD控制器。这一研究不仅验证了双目视觉振动检测和SRWNNC抑制振动的准确性和有效性,也为航天器柔性薄板结构的振动控制提供了新的解决方案。
      QIU Zhicheng,LIU Yihong,LI Min
      Vol. 32, Issue 7, Pages: 998-1010(2024) DOI: 10.37188/OPE.20243207.0998
      摘要:To address the vibration challenges in flexible thin plate structures like solar panels on spacecraft, this study investigates a translational flexible hinged plate system. A binocular vision-based measurement and control experimental platform is developed. This platform employs the binocular stereo vision technique for vibration detection, and introduces a self-recurrent wavelet neural network controller (SRWNNC) to mitigate vibration. The system's binocular vision is precisely calibrated. Utilizing the principles of disparity and advanced image processing algorithms, it calculates the three-dimensional coordinates of specific markers to capture vibration signals. A finite element model of the system is constructed, facilitating the identification of system model parameters. Following this, the SRWNNC is trained within a simulation environment using the identified model parameters, aiming for effective vibration control in the experimental system. Experiments and simulations are conducted on the system, focusing on both fixed base and translational trajectory movements, to evaluate the effectiveness of binocular vision in vibration detection and the SRWNNC in active vibration suppression. The findings confirm that the binocular vision sensor achieves a high accuracy less than 0.1 mm in detecting vibrations, and the SRWNNC outperforms traditional large gain PD controllers in damping vibrations, thus validating the efficiency and accuracy of the proposed vibration detection and suppression methods.  
      关键词:binocular vision;translational flexible hinged plate;self-recurrent wavelet neural network;Vibration suppression   
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    • 滚珠丝杠滚道法向截面检测领域取得了重要突破。专家团队建立了基于光学测微计的滚珠丝杠滚道法向截面测量系统,通过设计检测装置并优化数据处理算法,实现了滚珠丝杠滚道法向截面的快速、精确和无损检测。该系统不仅提升了检测精度,还显著提高了测量结果的稳定性和可靠性。实验验证表明,优化后的检测系统测得的滚道法向截面参数与厂家提供的数据相比,误差大幅缩小,提升率显著。这一研究成果为滚珠丝杠滚道法向截面的精确测量提供了有力工具,对于提高产品质量和推动相关领域的技术进步具有重要意义。
      WU Jian,OU Yi,ZHOU Changguang,FENG Hutian,QIAN Chaoqun
      Vol. 32, Issue 7, Pages: 1011-1022(2024) DOI: 10.37188/OPE.20243207.1011
      摘要:To achieve swift, precise, and non-destructive detection of ball screw raceway's normal section, a measuring system based on an optical micrometer is developed. Initially, the detection device is crafted following the principle of measuring the ball screw raceway's normal section. The original data processing algorithm for the raceway's normal section is then refined, introducing the angle division arc method and arc data homogenization technique. Subsequently, potential errors from sensor installation, the horizontal moving platform's straightness, and sensor inaccuracies within the detection device are examined and compensated for. The detection system's accuracy, comprising the device and the enhanced algorithm, is validated through experimental tests. These tests reveal that with the algorithm's optimization, the normal section parameters of the raceway measured by the system show improved convergence as the divided arc angle increases. Post-optimization, the maximum measured values for arc radius and contact angle, along with the manufacturer's error margins, are 3.6 μm and 19′31″, respectively, marking enhancement rates of 64.36% and 53.46% over pre-optimization. Furthermore, the maximum standard deviation values for the measured arc radius and contact angle are 1.56 μm and 2′41″, respectively, with enhancement rates of 22.77% and 56.67%. Class A uncertainty for measured arc radius and contact angle dropped to 0.63 μm and 1′6″, respectively, a reduction of 56% and 70% compared to before the algorithm's optimization. The detection system's accuracy and repeatability for the raceway's normal cross-section meet the measurement standards.  
      关键词:optical micrometer;ball screw;raceway normal section;angle division arc method;arc data homogenization method   
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      Information Sciences

    • 针对视觉惯性组合导航系统绝对航向信息缺失与姿态发散的问题,专家们提出并实现了一种自适应视觉惯性地磁紧耦合定位系统。这项创新的设计利用了三轴磁力计内外参数联合标定原理,通过构建地磁信息全局及帧间约束残差,实现了动态调整融合权重,并利用非线性优化方法设计了视觉/惯性/地磁紧耦合系统,有效估计了自身运动状态。在校园环境的户外实验中,该系统在部分建筑及车辆磁场干扰环境下稳定运行,定位精度优于0.8%(RMSE),相较于传统VINS系统,位置误差平均降低了约24%,并展现出良好的实时性。这一突破性的研究不仅改善了现有视觉惯性导航系统的定位性能,还为无人系统提供了高可靠性的实时定位结果,标志着该领域取得了重要的进展。
      FU Peng,WAN Zhenhua,WANG Kunfeng,ZHAO Kaichun
      Vol. 32, Issue 7, Pages: 1023-1033(2024) DOI: 10.37188/OPE.20243207.1023
      摘要:To solve the problem of missing absolute heading data and attitude drift in the visual-inertial navigation system, and to enhance its positioning accuracy, an adaptive visual-inertial-geomagnetic tightly integrated positioning system was developed for environments with unknown magnetic fields. Initially, the calibration process for the internal and external parameters of standard tri-axis magnetometers is detailed. Following this, a strategy for generating global and frame-to-frame constrained residuals from geomagnetic data is outlined. The system dynamically adjusts fusion weights based on variations in magnetic intensity and employs a nonlinear optimization approach for the visual-inertial-geomagnetic integration to estimate its motion state accurately. Outdoor tests conducted on a university campus demonstrated that the system remains stable amidst magnetic disturbances from buildings and vehicles, achieving positioning accuracy better than 0.8% (RMSE). When compared to VINS, this system reduces position error by an average of 24%, showcasing impressive real-time capabilities. Incorporating magnetometers and adaptive fusion techniques significantly boosts the performance of existing visual-inertial navigation systems, offering reliable real-time positioning for autonomous systems.  
      关键词:integrated navigation;geomagnetic field;adaptive system;nonlinear optimization   
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    • 针对远距离非机动单站目标跟踪的难题,研究团队提出了一种基于三维到达角信息且具有渐进无偏特性的目标跟踪算法。这一创新方法以相对运动模型为基础,构建了适用于非机动单站的运动和观测模型,并对系统的可观测性进行了深入分析。研究团队针对伪线性最小二乘算法的有偏性问题,提出了一种具有渐进无偏性能的约束总体最小二乘法,并证明了其无偏性。仿真实验结果显示,在百公里级别的三维到达角跟踪中,该算法在不同角测量标准差和初始距离条件下,均表现出了优异的性能。其收敛速度快、定位精度高,且运行效率与伪线性最小二乘法相当。这一研究成果为远距离场景下的非机动单站三维到达角目标跟踪提供了新的有效方法,具有重要的实际应用价值。它不仅提升了目标跟踪的精度和稳定性,还为相关领域的技术进步提供了新的思路。
      LIN Jianjun,WANG Rangyuhan,BAN Xiaojun,LU Hongqian
      Vol. 32, Issue 7, Pages: 1034-1044(2024) DOI: 10.37188/OPE.20243207.1034
      摘要:To address the challenge of target tracking for non-maneuvering, single-station setups in long-range scenarios, we propose a target tracking algorithm leveraging three-dimensional angle of arrival data, characterized by its asymptotically unbiased nature. Initially, we construct a motion and observation model centered on a non-maneuvering single station, assuming a known rate prior, and examine the system's observability. To tackle the bias inherent in the pseudo linear least squares algorithm, we introduce a constrained total least squares method that demonstrates asymptotically unbiased properties, with its effectiveness validated through simulations. In tests involving three-dimensional angle tracking over distances in the hundred-kilometer range, with angle measurement standard deviations at 0.1°, 0.2°, and 0.3°, the constrained total least squares method achieves a time-average relative distance error of 6%, 12%, and 21% within 50-100 seconds, respectively, and an absolute position error of 9 km, 19 km, and 35 km; at initial distances of 70, 140, and 280 km, the errors are 1%, 6%, and 30% for the same duration, with absolute errors of 0.7 km, 9 km, and 30 km. Notably, the relative distance error can be reduced to below 10% within 100 seconds, marking a significant precision enhancement, while maintaining operational speed comparable to the pseudo linear least squares method. The constrained total least squares approach exhibits rapid convergence, high accuracy, and swift processing, showing resilience against angle measurement errors and initial distance variations. It offers a robust solution for 3D angle of arrival tracking of non-maneuvering single-station targets in distant settings.  
      关键词:target tracking;3d arrival of angle;pseudo-linear;asymptotic unbiased estimation   
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    • 针对传统模糊C均值(FCM)算法在聚类过程中易受噪声、异常值等因素干扰的问题,研究者在聚类分析领域取得了新进展。他们提出了一种基于自适应近邻信息的模糊C均值聚类算法,通过引入样本点和类中心点的近邻信息,增强了算法对数据结构的感知能力,从而提高了聚类的稳定性和性能。这一创新方法不仅丰富了聚类分析的理论体系,还为实际应用中处理复杂数据提供了有效工具。在基准数据集上的实验结果显示,该算法相较于其他先进聚类算法,性能提升了10%以上。同时,研究者还从参数敏感性、收敛性、消融实验等方面对算法进行了全面评价,进一步验证了其可行性与有效性。这一研究成果对于推动聚类分析领域的发展具有重要意义。
      GAO Yunlong,LI Jianpeng,ZHENG Xingshen,SHAO Guifang,ZHU Qingyuan,CAO Chao
      Vol. 32, Issue 7, Pages: 1045-1058(2024) DOI: 10.37188/OPE.20243207.1045
      摘要:Traditional FCM algorithms cluster based on raw data, risking distortion from noise, outliers, or other disruptions, which can degrade clustering outcomes. To bolster FCM's resilience, this study introduces a fuzzy C-means clustering algorithm that leverages adaptive neighbor information. This concept hinges on the similarity between data points, treating each point as a potential neighbor to others, albeit with varying degrees of similarity. By integrating the neighbor information of sample points, labeled GX, and that of cluster centers, labeled GV, into the standard FCM framework, the algorithm gains additional insights into data structure. This aids in steering the clustering process and enhances the algorithm's robustness. Three iterative methods are presented to implement this enhanced clustering model. When compared to leading clustering techniques, our approach demonstrates over a 10% improvement in clustering efficacy on select benchmark datasets. It undergoes thorough evaluation across different dimensions, including parameter sensitivity, convergence rate, and through ablation studies, confirming its practicality and efficiency.  
      关键词:fuzzy C-means clustering;adaptive neighbors;algorithm robustness;iterative algorithm   
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    • 针对水下图像复原领域的研究取得了重要进展。复杂的水下成像环境常常导致图像出现颜色失真、细节模糊和对比度低等问题。为了解决这些问题,研究人员提出了一种结合色彩补偿与双背景光融合的水下图像复原方法。该方法首先分析了光在水中的吸收衰减特性,并据此改进了水下成像模型。通过引入基于Retinex理论与白平衡算法的色彩补偿分量,降低了水体背景颜色对图像质量的影响。同时,根据背景光强度和颜色分布特性,提出了双候选背景光融合方法,从而准确估计了全局背景光。该方法不依赖任何水体环境参数,利用引导-高通滤波优化了各通道透射率,并最终逆求解成像模型以复原水下图像。实验结果表明,与经典及新颖方法相比,该方法在颜色自然度、纹理细节丰富度和清晰度方面均有显著提升,色差值改善幅度达到5.4%,UCIQE及FDUM指标提升幅度分别达到8.3%和4.5%。这一研究成果为水下图像复原领域的发展提供了新的解决方案,有望为水下视觉感知技术的进步奠定坚实基础。
      LIN Sen,ZHA Ziyue
      Vol. 32, Issue 7, Pages: 1059-1074(2024) DOI: 10.37188/OPE.20243207.1059
      摘要:To address the challenges of color distortion, blurred details, and low contrast in underwater images caused by complex imaging environments, a novel restoration method that integrates color compensation with dual background light fusion is introduced. This method begins by enhancing the traditional underwater imaging model to reflect light absorption and attenuation in water more accurately. It incorporates a color compensation technique inspired by Retinex theory and white balance algorithms to mitigate the impact of the water's background color. A novel dual-candidate background light fusion approach is then developed to precisely estimate the global background light, considering the intensity and color distribution of background light. This is followed by the use of guided high-pass filtering to refine and boost the transmission across each channel, leveraging the connection between the water's background color and the scattering coefficient, without relying on specific water environment parameters. The method concludes with the restoration of the underwater image through the reverse application of the imaging model. Testing on four diverse underwater datasets has shown that this approach surpasses several classic and advanced methods, delivering images with more natural colors and enhanced, clearer textures. The color difference value improved by 5.4%, while the UCIQE and FDUM metrics increase by 8.3% and 4.5% respectively, underscoring the method's effectiveness in both qualitative and quantitative evaluations and its significant contribution to enhancing the quality of underwater imagery.  
      关键词:underwater image restoration;color compensation;background light fusion;transmission estimation   
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    • 针对轻量级目标检测算法在钢表面缺陷检测任务中识别精度低的问题,科研人员提出了一种多尺度增强特征融合的钢表面缺陷目标检测算法。该算法创新性地采用了自适应加权融合模块,实现了深层语义与浅层细节的加权融合,有效提升了特征表示能力。同时,算法还引入了空间特征增强模块,从三个独立方向强化融合特征,增强了网络结构的稳定性,挖掘了更多的关键信息。实验结果表明,该算法的检测精度达到了80.47%,相比原始算法提升了6.81%。此外,算法的参数量和计算量也相对较小,能够快速且高精度地检测钢材表面的缺陷信息,具有很高的应用价值。这一研究成果为钢材表面缺陷检测提供了新的解决方案,也为相关领域的研究开辟了新的方向。
      LIN Shanling,PENG Xueling,WANG Dong,LIN Zhixian,LIN Jianpu,GUO Tailiang
      Vol. 32, Issue 7, Pages: 1075-1086(2024) DOI: 10.37188/OPE.20243207.1075
      摘要:To address the issue of low recognition accuracy in lightweight algorithms for steel surface defect detection, this paper introduces a Multi-scale Enhanced Feature Fusion (EFF) technique. Initially, an Adaptive Weighted Fusion (AWF) module calculates fusion weights adaptively for different feature levels. This allows shallow features to enrich with deep semantics without compromising detail. Subsequently, the Spatial Feature Enhancement (SFE) module boosts the fused features from three distinct directions and improves network stability by integrating residual pathways, enabling the convolution process to extract more critical information. The model then selects better training samples based on the overlap between the prior box and the ground truth. Experimental outcomes show that the proposed method achieves a detection accuracy of 80.47%, marking a 6.81% increase over the baseline algorithm. Moreover, with 2.36 M parameters and 952.67 MFLOPs, this algorithm efficiently and accurately identifies steel surface defects, demonstrating significant practical utility.  
      关键词:defect detection;Single Shot multibox Detector (SSD);enhanced feature fusion;adaptive weighted fusion;spatial feature enhancement   
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    • 多模态分类任务在遥感图像处理领域取得了新突破。针对高光谱图像(HSI)与LiDAR数据融合处理的挑战,研究者提出了一种基于对比学习的CNN-Transformer协同分类网络——CLCT-Net。该网络通过创新的共有特征提取模块,实现了不同传感器数据间的语义对齐,解决了跨模态信息表达和特征对齐的难题。研究者设计了包含空间-通道分支和光谱上下文分支的双分支HSI编码器,以及结合频域自注意力机制的LiDAR编码器,从而充分提取并整合了两种数据的丰富特征。同时,他们巧妙地集成了对比学习方法,进一步提高了多模态数据协同分类的精度。在Houston 2013和Trento数据集上的实验验证,CLCT-Net模型的地物分类精度分别高达92.01%和98.90%,显著超越了其他同类模型。这一成果不仅为跨模态数据特征的深度挖掘和协同提取提供了有力工具,也为遥感图像处理领域的多模态分类任务研究开辟了新的方向。
      WU Haibin,DAI Shiyu,WANG Aili,YUJI Iwahori,YU Xiaoyu
      Vol. 32, Issue 7, Pages: 1087-1100(2024) DOI: 10.37188/OPE.20243207.1087
      摘要:To tackle the challenges in multimodal classification tasks involving hyperspectral images (HSI) and LiDAR data, such as cross-modal information expression and feature alignment, this paper introduces a contrastive learning-based multi-branch CNN-Transformer network (CLCT-Net) for the joint classification of hyperspectral and LiDAR data. Initially, CLCT-Net employs a feature extraction module with a ConvNeXt V2 Block to capture shared features across different modalities, addressing the semantic alignment issue between data from heterogeneous sensors. It then develops a dual-branch HSI encoder with spatial channel and spectral context branches, alongside a LiDAR encoder enhanced by a frequency domain self-attention mechanism, to secure more comprehensive feature representations. Lastly, it leverages ensemble contrastive learning for classification to further refine the accuracy of multimodal collaborative classification. Experimental evaluations on the Houston 2013 and Trento datasets demonstrate that the proposed model excels in extracting and integrating cross-modal data features, achieving superior ground object classification accuracies of 92.01% and 98.90%, respectively, when compared to existing models for classifying hyperspectral images and LiDAR data.  
      关键词:hyperspectral image;LiDAR data;transformer;convolutional neural network;contrastive Learning   
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    • 针对弱光环境下红外与可见光图像融合面临的挑战,某研究团队提出了一种创新的多尺度结构化融合方法。这一方法首先利用动态范围压缩算法增强弱光下的可见光图像,然后通过多尺度结构化分解将增强后的图像与红外图像分解为低频和高频信息。在融合过程中,研究团队创新性地采用均方根误差系数融合低频信息,并通过信息熵自适应调整权重策略对高频信息进行二次优化。最后,通过灰度分类的区域像素增强算法提升融合图像的对比度。实验结果显示,该方法在TNO和CVC-14数据集上表现出色,不仅在平均梯度、交叉熵、边缘强度、标准差和空间频率等指标上取得了更好的客观评价结果,而且整体视觉效果也显著优于其他对比方法。这一突破性的研究成果不仅丰富了图像融合技术的细节纹理和清晰度,还显著缩短了融合耗时,为弱光环境下的图像融合提供了新的解决方案。
      LONG Zhiliang,DENG Yueming,XIE Jing,WANG Runmin
      Vol. 32, Issue 7, Pages: 1101-1110(2024) DOI: 10.37188/OPE.20243207.1101
      摘要:Under low-light conditions, the fusion of infrared and visible images often results in images with poor contrast, lacking in detail, and requiring a lengthy processing time. To address these issues, this paper introduces an enhanced multi-scale structural fusion approach. Initially, it improves the low-light visible image using a dynamic range compression enhancement algorithm. Subsequently, through a multi-scale structural image decomposition method, it separates the enhanced visible and infrared images into their low-frequency and high-frequency components. For image fusion, the low-frequency components of both image types are merged using a technique based on the root mean square error coefficient. The high-frequency components are initially fused in a straightforward manner, followed by an optimized fusion using a self-adaptive weight adjustment based on image information entropy. Afterward, by reversing the multi-scale structural decomposition, the fused low and high-frequency components are combined to form a complete image. To further enhance the image contrast, a regional pixel enhancement algorithm based on gray level classification is introduced. The effectiveness of this method is compared with nine conventional infrared and visible image fusion techniques, both qualitatively and quantitatively, using TNO and CVC-14 datasets. The proposed method demonstrates superior performance in terms of average gradient, cross entropy, edge intensity, standard deviation, and spatial frequency, along with an improved overall visual quality. This confirms that the images produced by the proposed method exhibit enhanced detail, clarity, contrast, and are processed more quickly.  
      关键词:image processing;multi-scale structural fusion;dynamic range compression;root mean square error;information entropy;Contrast   
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