最新刊期
卷 32 ， 期 22 ， 2024
- “在应变测量领域，研究人员搭建了基于色散增强的光载微波干涉应变测量系统，验证了色散增强技术可显著提高系统灵敏度，为弱物理量测量提供参考方法。”摘要：In order to measure the strain with high sensitivity and high resolution， an OCMI strain measuring system based on dispersion enhancement was established. Firstly， the transfer function of OCMI strain sensing system was derived based on double-sideband modulation theory， and the mapping relationship between FBG optical wavelength drift and microwave frequency was obtained. Then， a strain sensing system was built， and the sensitivity of the system under different dispersion combinations was compared by monitoring high frequency frequencies. It was shown that reverse access to LCFBG could effectively enhance the sensitivity， and the greater the dispersion of LCFBG， the greater the sensitivity of the system. The experimental results show that the sensitivity of the dispersion-enhanced strain sensing system can reach 43.75 kHz/μɛ， which is 42 times that of the system without LCFBG. The scheme proposed in this paper has high stability and resolution， which provides a reference method for the measurement of weak physical quantities.关键词：fiber Bragg grating;optical carrier microwave interference;linearly chirped fiber bragg grating;strain sensing;high sensitivity73|14|0更新时间：2025-02-20
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Phase-contrast optical coherence tomography method for full-field mechanical measurements of films AI导读
“最新研究突破，采用相衬光学相干层析技术，实现亚毫米级薄膜全场力学性能高灵敏测试，为薄膜材料力学特性研究提供新方法。”摘要：The mechanical properties of polymer films are of great significance for their optimal design， preparation and application， but existing methods generally find it difficult to effectively measure their thickness direction. To this end， this paper proposed a method for characterizing the full-field mechanical properties of films using phase contrast optical coherence tomography. Leveraging the high sensitivity of PC-OCT imaging for full-field displacement， combined with a film stretching and compression loading device， this method achieved full-field tomographic strain measurement in the thickness direction of sub-millimeter films. Furthermore， by integrating principles of elasticity mechanics， the elastic modulus and Poisson's ratio of the material could be calculated from the full-field strain results. By constructing a film tomographic mechanical measurement system based on PC-OCT， the system was first used to quantitatively characterize a single-layer silicone rubber film with a thickness of 0.6 mm under compression and tension loading， yielding an elastic modulus of 2.461 MPa and a Poisson's ratio of 0.470. Subsequently， a three-layer film made of silicone rubber and glass adhesive was subjected to full-field measurements under compression and tension loading， revealing mechanical differences of each layer in the depth direction. The elastic modulus of the glass adhesive film was measured to be 1.005 MPa， with a Poisson's ratio of 0.450. The method described in this paper can measure the full-field strain and local stress in the thickness direction of micro-deformed sub-millimeter films， thereby determining the mechanical parameters of elastic modulus and Poisson's ratio. This enables highly sensitive testing of the mechanical properties in the thickness direction of the films， representing a novel and effective approach for studying the mechanical performance of thin film materials.关键词：phase-contrast optical coherence tomography;strain measurement;elastic modulus;Poisson ratio;mechanical characterization41|13|0更新时间：2025-02-20 - “在无人机导航领域，专家引入偏振光传感器组合导航，构建级联式航姿解算算法，提高了无人机在运动加速度下的姿态解算精度。”摘要：The study examines the accurate establishment of an attitude angle calculation model for UAVs influenced by large motion accelerations. Accelerometer output shows a decreased proportion of effective gravity acceleration information， while polarization sensors exhibit jitter. First， polarization sensor integrated navigation was introduced， along with the orientation principle of polarization navigation. Then， a cascaded attitude solution algorithm was built using the double-vector Gauss-Newton method and the SHKF （Sage-Husa Kalman） algorithm. This algorithm observed UAV attitude information based on multiple sensors. Next， based on analyzing the accuracy of accelerometer measurements under motion acceleration， a trust factor was proposed to mitigate the impact of motion acceleration on attitude calculation. This algorithm could suppress the effects of motion acceleration generated by high-speed UAV bodies. To verify this algorithm's feasibility， experiments were conducted on a polarization/MIMU （Micro Inertial Measurement Unit） integrated navigation platform. Results indicate a 30% improvement over PI and EKF algorithms in static and dynamic environments. The algorithm suppressed attitude deviation caused by non-gravity acceleration under motion acceleration influence. It improved the accuracy of attitude calculation under motion acceleration， ensuring normal UAV flight.关键词：polarized-light sensor;motion acceleration suppression;attitude determination;UAV;integrated navigation23|12|0更新时间：2025-02-20
- “在三维测量领域，研究者提出了一种改进的高动态范围三维测量方法，有效提升了测量准确性和完整性，实现了高鲁棒、高效率、高精度三维测量。”摘要：Due to the problem of insufficient dynamic range， which may cause image supersaturation and low fringe contrast， traditional fringe projection three-dimensional （3D） measurement technology makes it difficult to obtain complete and effective 3D profiles of objects with non-Lambertian surfaces. To enhance the adaptability of structured light 3D measurement， we proposed an improved high dynamic range （HDR） 3D measurement method using line-shifting strips， which were more robust than sinusoidal fringes， as encoding patterns. A strip contrast model of complementary line-shifting strip sequences was constructed for optimum contrast detection of different color channels responding to light intensity. Subsequently， a color camera could be used to capture a color image sequence in a single exposure time to synthesize new line-shifting strip images， avoiding invalid or error data introduced by insufficient dynamic range. Finally， by using background normalization to unify the background of different channel components of the synthesized image， the line positions could be precisely located through complementary line-shifting strips. This allowed for the accurate demodulation of line encoding information， enabling 3D reconstruction. Experimental results demonstrate that， compared to the multiple exposure method， the image acquisition time is reduced by 82% and the total reconstruction time is reduced by 59%. The proposed method can demodulate the effective line encoding information of metal workpieces with complex surface reflection characteristics to obtain the complete and high-accuracy 3D point cloud， achieving efficient high dynamic range 3D measurement.关键词：non-lambertian surface;high dynamic range;color image synthesis;complementary line-shifting strips;3D measurement35|21|0更新时间：2025-02-20
Modern Applied Optics
- “在磁悬浮高速电机领域，专家提出了并联双输入SOGI-FLL方法，有效抑制谐波电流，为系统稳定运行提供解决方案。”摘要：Rotor mass unbalance and sensor runout are the main disturbances of harmonic current in magnetically suspended rotor system. Accurate and quick speed detection is the premise of harmonic current suppression. In order to suppress harmonic current in high-speed magnetically suspended motor without the speed sensor， a parallel double input second-order generalized integrator frequency-locked loop （SOGI-FLL） method was proposed. Firstly， the rotor dynamics model of the system was established， and mechanism generating harmonic current was analyzed. Afterwards， the double input SOGI-FLL method was introduced to adaptively estimate the speed， enhancing both the accuracy of speed estimation and dynamic performance. On this basis， the double input SOGI modules were connected in parallel and integrated into the original control system to suppress harmonic current. In order to ensure the stability of the system across a wide speed range， a phase compensation was designed based on the closed-loop characteristic equation and the phase frequency characteristics of the system. To verify the effectiveness of the proposed method， simulation analysis was carried out and a magnetically suspended motor platform was used for experimental verification. Experimental results indicate that the proposed method can accurately estimate the speed， with the tracking error kept within ±0.8 Hz. The first， third and fifth harmonic current components are reduced by 86.20%， 86.16% and 83.86% respectively， proving that the proposed method can suppress harmonic current accurately and effectively.关键词：high-speed motor;magnetically suspended rotor;harmonic current suppression;second-order generalized integrator frequency-locked loop;sensor runout;speed estimation25|11|0更新时间：2025-02-20
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Design of robust disturbance observer under load variation for piezoelectric positioning platform AI导读
“在压电定位平台领域，专家提出了一种鲁棒干扰观测器控制策略，有效提高了系统抗扰性能和定位精度。”摘要：The variation in load on the piezoelectric positioning platform significantly limits its accuracy during rapid positioning. To address this， a robust disturbance observer control strategy was proposed， treating load variation as an external disturbance. Firstly， based on the linearization of the MPI hysteresis inverse model， the linear dynamic characteristics of the piezoelectric positioning platform were identified according to experimental data. Next， the system identification error was attributed to model uncertainty， and a less conservative upper bound was established in the frequency domain. Then， considering the impact of model uncertainty and load disturbances on system stability and performance， a robust disturbance observer based on μ-synthesis was designed. Finally， the experimental results show that the proposed method achieves a disturbance rejection bandwidth of 114 Hz， which is 109% higher than that of the traditional DOB method and 86% higher than that of the H∞DOB method. For tracking a 70 Hz sinusoidal trajectory， the proposed method achieves an average relative error change of 0.001 3 under both loaded and no-load conditions， which is a 91.1% reduction compared to the traditional DOB method and a 77.2% reduction compared to the H∞DOB method， demonstrating the effectiveness and superiority of the proposed method.关键词：piezo-positioning platform;load disturbance;model uncertainties;μ-synthesis;disturbance observer47|28|0更新时间：2025-02-20 - “在精密测量领域，专家基于光场式时栅结构特征，提出了辅助装配调校系统，有效降低传感器测量误差至±1.3 μm，为精密测量提供解决方案。”摘要：The assembly precision of the displacement sensor directly determines the measurement accuracy， and an auxiliary calibration system is crucial for achieving precise assembly. This study analyzed the spatial modulation function of the output signal and the assembly relationship based on the structural features and measurement principles of light field time-grid sensors. It proposed an auxiliary assembly calibration system that utilizes the measured signal of the sensor as an installation index. By considering the measurement principle of light field time-grid sensors and studying their influence on installation error， particularly in relation to roll angle calibration， a mathematical model related to the measurement signal was established. Subsequently， an auxiliary assembly calibration system was designed based on this model using original measurement signals to obtain calibration indicators. Experimental results demonstrate that this system provides intuitive roll angle calibration parameters， enabling users to calibrate effectively and reduce original errors in light field time-grid sensors to within ±1.3 μm with simple linkage and easy integration.关键词：time gate;grating;assembly error;roll angle23|10|0更新时间：2025-02-20
Micro/Nano Technology and Fine Mechanics
- “在机器人领域，专家提出了一种低成本、高效率的2D激光雷达手眼标定方法，通过垂直角特征标定装置，优化了标定过程，显著提高了标定精度和收敛速度。”摘要：Existing methods of hand-eye calibration between robot and 2D light detection and ranging （LiDAR） generally have shortcomings such as high cost of calibration instrument manufacture， strict requirement of sampling process， etc. To address these problems， a method using a calibration instrument with orthogonal corner feature was proposed. During the calibration process the calibration instrument was kept a fixed pose in robot base frame. When the robot mounted with the LiDAR was controlled to scan the calibration instrument， there are three intersection lines among the LiDAR’s scanning plane and three calibration planes. Using the geometric constraints among three lines， the transformation between LiDAR and calibration frame was computed. From changing the robot pose and repeptively scanning， a constraint equation with respect to the transformation matrix between LiDAR and robot end-effector frame was built. The transformation matrix estimation was acquired from solving the constraint equation. A hand-eye calibration optimization method based on planar features was also proposed. It is a three-stage iteration process. The optimization method avoids side effects from calibration instrument manufacture errors. The experimental results showed in the condition that the LiDAR scanning error was 2 mm， in 10 iterations the Euler angles error of the estimated rotation matrix was less than 0.01°， and the distance error of the translation vector was less than 1.0 mm. Comparing to another method under the same calibration conditions， the proposed method has an advantage in convergence speed， and is also more objective and reasonable in the choice of initial values.关键词：robot;two dimensional light detection and ranging;hand-eye calibration;corner feature34|21|0更新时间：2025-02-20
- “在高光谱遥感图像解混领域，研究者提出了一种新的空间-光谱重加权的稀疏多层非负矩阵分解算法，有效降低噪声影响，提升解混性能。”摘要：Multilayer non-negative matrix factorization （MLNMF） can not fully use the spatial-spectral features of hyperspectral remote sensing images， and the ubiquitous noise in hyperspectral images. To solve the problem， this paper proposed a new spatial-spectral reweighted sparse MNMF unmixing algorithm. Firstly， the subspace clustering algorithm was used to construct spatial weights according to the spatial characteristics of hyperspectral images. Secondly， the superpixel segmentation algorithm was used to segment the hyperspectral image， and the similarity between superpixels was calculated. The KMEANS++ algorithm was used to cluster the superpixels， and then the pixel-level similarity was calculated in the superpixel to construct the spectral weight. The spatial weight and spectral weight were fused， and the fused spatial-spectral weight was used to characterize the spatial-spectral information of the hyperspectral image. Then， the SUnSAL algorithm was used to calculate the sparse noise reduction weight， which can effectively reduce the influence of noise on the unmixing performance. Finally， the norm was used to constrain the endmembers and abundance of the model to improve the unmixing performance of the model. Compared with the experimental results of five unmixing algorithms， the mean Spectral Angle Distance and Root Mean Square Error of the proposed algorithm on the synthetic dataset were optimal. It also achieves good unmixing results on two real datasets Jasper Ridge and Cuprite. The endmember estimation error of the proposed algorithm is reduced by 1.49% to 4.68%， and the abundance estimation error is reduced by 1.83% to 4.18% on each dataset.关键词：hyperspectral unmixing;multilevel nonnegative matrix factorization;spatial-spectral weight;noise reduction;sparsity constraint24|10|0更新时间：2025-02-20
- “在点云配准领域，研究者设计了一种重叠点云配准网络，有效提高了配准性能和抗噪能力。”摘要：The current partial overlapping point cloud registration algorithms have limitations in detecting overlapping boundary areas and eliminating non-overlapping points， which hinders the further enhancement of their performance. In order to address these issues， this study proposed a partially overlapping point cloud registration network driven by two-stage overlap scores and matching matrix. Firstly， the pose estimation module utilized neighborhood consistent features to estimate the initial pose for improved alignment accuracy. Secondly， a channel space perception Transformer module was designed to perceive two-point cloud overlapping regions to maintain accurate perception of overlapping boundary regions. Then， a feature encoder based on Transformer was proposed to encode the features of the point cloud after initial alignment， so as to excavate the feature map global and significant channel features. Finally， the cosine similarity matrix was transformed into a matching matrix using outlier removal method to correctly match corresponding points while removing overlapping points. The effectiveness of the proposed algorithm was validated on ModelNet40， ShapeNetCore.v2 and Stanford Bunny datasets. On ModelNet40 dataset， compared with sub-optimal algorithm GeoTransformer， MIE（R） and MAE（R） decrease by 12.79% and 9.78% respectively. On ShapeNetCore.v2 dataset， compared with sub-optimal algorithm MGFPCR， RMSE（R） and MAE（R） of the proposed algorithm decreased by 42.00% and 61.66%， respectively. On Stanford Bunny dataset， compared with sub-optimal algorithm ROPNet， RMSE（R） and MAE（R） of the proposed algorithm decreased by 25.53% and 5.58%， respectively. Experimental results demonstrate that the proposed algorithm outperforms other algorithms in terms of generalization performance and noise resistance.关键词：image processing;point cloud registration;overlap score prediction;channel space perception;slack variable26|10|0更新时间：2025-02-20
- “在地基实况测量望远镜领域，专家提出了支持场景切换感知的电子稳像技术，有效提升了目标稳定性和观测质量。”摘要：Ground based real-time measurement telescopes typically include two sets of optical systems for capture and imaging. When a telescope uses a capture system to track an object in a closed-loop manner， due to the large field of view and low tracking accuracy， the video jitter of the imaging system can be clearly felt， which is not conducive to real-time observation of the object and related scientific experiments. To address the aforementioned issues， this article proposed an electronic image stabilization technology that supports scene switching perception. Firstly， when the object did not appear， the maximum connected region method was used to attempt to extract the object feature region for each frame until it was successfully extracted. Then， for each image， a kernel correlation filter was used to match the features of the previous frame's training model， and the training model was updated. Next， the least squares method was used to fit the object motion trajectory and determine the authenticity of the object through error analysis. Finally， determined whether to use jitter compensation for cropping the current image based on the authenticity of the object. Experimental results indicate that the video processed by this technology has a significant improvement in object stability， the maximum jitter amplitude of adjacent image feature regions decreases from ± 10 pixels to approximately ± 1 pixel， the peak signal-to-noise ratio of reference frames within 50 frames is increased by an average of 4.62 dB； Simultaneously， the algorithm can perceive the object entering and leaving the field of view； The algorithm processing time is less than 2 ms， meeting the online processing requirements. Realize the automation of the image stabilization process for continuous observation of multiple objects， and improve the quality and success rate of related scientific experiments.关键词：closed loop tracking;electronic image stabilization;kernel correlation filter;Least squares method;error analysis33|21|0更新时间：2025-02-20
- “在人群计数领域，提出了一种新方法，有效提高了计数性能，降低了误差。”摘要：Aiming at the problems of background interference and drastic change of crowd scale in crowd counting， which leads to poor counting effect， a crowd counting method enhanced by dense connected attention and scale perception recombination was proposed. First， a feature extraction network with dense connected attention mechanism was designed to enhance the crowd counting features and suppress the background interference by using the inflated convolutionally improved VGG19 network as the model coarse feature extraction network and embedding the dense connected dual-channel attention mechanism. Then， the scale-aware reorganized upsampling and soft mask feature enhancement and delivery structures were designed to achieve the full utilization of crowd feature information at different scales from shallow to deep， and overcome the problem of poor counting performance due to drastic changes in crowd scales. Secondly， a multi-resolution fusion module was proposed to enhance the interaction between multi-resolution information， reduce the semantic gap between different resolutions， and improve the accuracy of crowd counting. Finally， comparison experiments were conducted on ShanghaiTech， UCF-QNRF， JHU_CROWD++ and other crowd counting datasets， and the results show that the proposed method outperforms the comparison algorithms. For instance， compared with DM-Count crowd counting algorithm， the MAE and MSE error values of proposed method are reduced by 15.98% and 14.52%， respectively， and the proposed method has higher counting performance in crowd counting.关键词：crowd counting;dense connected attention;scale perception recombination;multi-scale enhancement;multi-resolution fusion30|19|0更新时间：2025-02-20
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