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arXiv 2024年

作者： Zheng, Chuanjian Wang, Wenli Ji, Yanfang Hu, Yao Zhang, Shaohui Hao, Qun School of Optics and Photonics Beijing Institute of Technology Beijing100081 China National Key Laboratory on Near-Surface Detection Beijing10012 China Tianjin H-Chip Technology Group Corporation Tianjin300480 China

Large numerical aperture (NA) and large aperture metalenses have shown significant performance and abundant applications in biomedical and astronomical imaging fields. However, the high space-bandwidth product (SBP) requirements for measuring the phase of these metalenses, characterized by small phase periods and large apertures, have resulted in no effective techniques for sufficient characterization. In this paper, we propose a high SBP phase characterization technique using Fourier ptychographic microscopy (FPM), enabling a high spatial resolution and wide field of view simultaneously. To demonstrate the feasibility and effectiveness of this technique, we achieve a high SBP (4.91 megapixels) measurement and characterization for focusing and focusing vortex metalenses, quantitatively displaying the effect of fabrication error on their typical optical performance. Furthermore, we characterize the aberration type and amount of wavefront deviations caused by fabrication. We also analyze compensation methods for different aberrations based on the wavefront characterization results, providing a targeted alignment strategy for optimizing overall optical system performance. We believe that our high SBP characterization technique cannot only help to improve metalens design but also optimize its fabrication processing, which will pave the way for the diversified applications of metalenses. Copyright © 2024, The Authors. All rights reserved.

关键词： Aberrations

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MEMS Accelerometer Stability and Temperature Compensation for Long Term Structure Surveillance System

MEMS Accelerometer Stability and Temperature Compensation fo...

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IEEE International Conference on Robotics and Biomimetics

作者： Yingjiao Rong Zengshuai Qiu Guang Luo Congcong Ma Guangyi Shi Juanhui Zheng The Science and Technology on Near-Surface Detection Laboratory Wuxi China DFH Satellite Co. Ltd. Beijing China Peking University Beijing China BEWIS Sensing Technology LCC Wuxi China School of Software and Microelectronics Peking University Beijing China

ISBN: (纸本)9781665405362

This paper describes the compensation strategy for MEMS accelerometer which needs long time stability and good temperature drift parameter for long time surveillance system. A noise filter for static monitoring environment is designed. The static stability algorithm is designed by studying railway monitoring data. Temperature compensate system is designed, temperature compensation model fitted with a polynomial equation is proposed. Experimental result shows the difference between the heating curve and the cooling curve, a method for judging the heating and cooling according to the readings of the temperature sensor is proposed. Accelerometer array with redundant structure is designed and temperature compensation model is designed to compensate the heating and cooling separately. Through experiments, the errors of the new method and the traditional method are compared. The temperature drift can be compensated less then 80 μg.

关键词： Temperature sensors Accelerometers Heating systems Micromechanical devices Wavelet transforms Cooling Surveillance

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Towards Automatic Operation Motion Tracking Algorithm Based on Inertial Sensors for Multi Joints Machinery

Towards Automatic Operation Motion Tracking Algorithm Based ...

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IEEE International Conference on Robotics and Biomimetics

作者： Yingjiao Rong Zengshuai Qiu Jiayi Liu Zhan Shu Chen Jiao Guangyi Shi Qiang Qin The Science and Technology on Near-Surface Detection Laboratory Wuxi China DFH Satellite Co. Ltd. Beijing China Peking University Beijing China BEWIS Sensing Technology LCC Wuxi China School of Software and Microelectronics Peking University Beijing China

ISBN: (纸本)9781665405362

This paper presents a novel method for multi joints machinery motion tracking, which is useful for automatic operation. Heavy machinery such as excavator bulldozer forklift and grader are with multiple arms for particular tasks. These arms with rotation motion will change the dimensional coordinates accordingly. Thus, the motion tracking will give the feedback for automatic control and realize the unmanned operation in the end. Inertial measurement units (IMUs) are designed with 6D MEMS sensors. Calibration method is studied and the installation error is corrected. Extend Kalman filter is designed for dynamic motion tracking. The acceleration chip structure is also studied for later on ASIC design. Experimental result shows that the dynamic angle error is better than 0.1 degree for every joint of a robot arm, which proves the dynamic tracking method.

关键词： Tracking Robot kinematics Heuristic algorithms Dynamics Arms Robot sensing systems Calibration

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Evaluation of Water Ecological Carrying Capacity Based on Natural Resource Endowment Characteristics: A Case Study of Yicheng City 12

Evaluation of Water Ecological Carrying Capacity Based on Na...

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12th Academic Conference of Geology Resource Management and Sustainable Development, GRMSD 2024

作者： Jiang, Xingzheng Liu, Xiaojing Li, Xuanhui Zeng, Guanzhong Center for Geophysical Survey China Geological Survey Lang Fang065000 China Technology Innovation Center for Earth Near Surface Detection China Geological Survey Lang Fang065000 China Key Laboratory of Coupling Process and Effect of Natural Resources Elements MNR Beijing100055 China Comprehensive Observation and Research Station for Hubei Xiangyang Natural Resource Elements Xiangyang441000 China

ISBN: (纸本)9798331314545

Water is the source of life, the foundation of ecology and the key to production. In Yicheng City, a typical county city in China's watersheds, the concept of water ecological carrying capacity and the assessment method are proposed by combining the general situation of the study area and the relevant research bases at home and abroad, taking into account the whole elements of natural resources. Determination of factor weights using a combined hierarchical analysis-entropy weighting approach. Deriving water ecological carrying capacity evaluation results suitable for adoption in rural China. Results and analysis of water ecological carrying capacity zoning and grading in Yicheng City. There are 223 village units in Yicheng City, and considering the spatial scarcity of the indicator factors, the study area is divided into four categories of village-level evaluation units, namely, the ideal carrying, preferable carrying, critical overloading and overloading. The proportion of the area is 9.56%, 25.24%, 46.65% and 18.55% respectively, providing scientific reference and data support for the construction of the "Thousand Villages Demonstration and Ten Thousand Villages Improvement" project and the realization of rural revitalization and sustainable development. © 2024 Proceedings of the 12th Academic Conference of Geology Resource Management and Sustainable Development, GRMSD 2024. All rights reserved.

关键词： Sustainable city

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Dilution of precision for time difference of arrival with station deployment

arXiv

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arXiv 2021年

作者： Zhang, Fengyun Li, Hao Ding, Yulong Yang, Shuang-Hua Yang, Li Department of Computer Science and Engineering Southern University of Science and Technology Guangdong Shenzhen China Science and Technology on Near-surface Detection Laboratory Jiangsu Wuxi China Academy for Advanced Interdisciplinary Studies Southern University of Science and Technology Guangdong Shenzhen China Department of Mathematics Southern University of Science and Technology Guangdong Shenzhen China Army Engineering University of Pla Jiangsu Nanjing China

A study is conducted with the aim to reveal the relationship between the performance of moving object tracking algorithms and tracking anchor (station) deployment. The dilution of precision (DoP) for the time difference of arrival (TDoA) technique with respect to anchor deployment is studied. Linear and non-linear estimators are used for TDoA algorithms. The research findings for the linear estimator indicate that the DoP attains a lower value when other anchors are scattered around a central anchor;for the non-linear estimator, the DoP is optimal when the anchors are scattered around the target tag. Experiments on both algorithms are conducted that target location precision related to anchor deployment in practical situations for tracking moving objects integrated with a Kalman filter in an ultra-wideband (UWB)-based real-time localization system. The work provides a guideline for deploying anchors in UWB-based tracking systems. Copyright © 2021, The Authors. All rights reserved.

关键词： Time difference of arrival

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Study on the Spatiotemporal Pattern of Land Use Change in Han River Basin 12

Study on the Spatiotemporal Pattern of Land Use Change in Ha...

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12th Academic Conference of Geology Resource Management and Sustainable Development, GRMSD 2024

作者： Yu, Peng Zeng, Guanzhong Liu, Xiaojing Li, Xuanhui Center for Geophysical Survey China Geological Survey Lang Fang065000 China Technology Innovation Center for Earth Near Surface Detection China Geological Survey Lang Fang065000 China Key Laboratory of Coupling Process and Effect of Natural Resources Elements MNR Beijing100055 China Comprehensive Observation and Research Station for Hubei Xiangyang Natural Resource Elements Xiangyang441000 China

ISBN: (纸本)9798331314545

In response to the frequent changes in land use and prominent conflicts between people and land in the Han River Basin, this study takes the Han River Basin as the research area, based on GIS technology, and uses the land use dataset from 2000 to 2022 to comprehensively utilize the land transfer matrix and standard deviation ellipse analysis to study the spatiotemporal characteristics of land use changes in the research area. The results show that from 2000 to 2022, the cropland area in the study area decreased the most, while the construction land area increased significantly;The spatial change of land use is inclined with the northwest to Dingnan direction as the main axis, concentrated in the southeast and central regions. The research results can provide scientific basis for the national spatial planning and sustainable development of central cities in the Han River Basin. © 2024 Proceedings of the 12th Academic Conference of Geology Resource Management and Sustainable Development, GRMSD 2024. All rights reserved.

关键词： Abiotic

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A Dual-band Broadband Conical Beam Antenna Based on TM₀₁ and TM₀₂ mode

A Dual-band Broadband Conical Beam Antenna Based on TM₀₁ a...

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Asia-Pacific Conference on Microwave

作者： Chuchu Shan Shuai Zhang Hui Xue Li Wu Yingjiao Rong School of Electronic and Optical Engineering Nanjing University of Science and Technology Nanjing P. R. China Shanghai Radio Equipment Research Institute Shanghai P. R. China Science and Technology on Near Surface Detection Laboratory Wuxi P. R. China

A dual-band broadband conical beam antenna operating at Ku-/ Ka-band is presented in this paper. The proposed antenna adopts a novel across-layer folded structure which consists of two substrates. A circular patch with coupling slot is printed on the lower substrate as a monopole at Ku-band, and a circular patch and a loop patch are printed on the upper substrate to achieve operating at Ka-band. A wideband performance is obtained by introducing shorting vias to excite TM 01 and TM 02 mode in both bands. The simulation results show that the proposed antenna operates at 11.74 GHz-14.47 GHz in Ku-band and 32.20 GHz-35.63 GHz in Ka-band with 10 dB impedance bandwidth of 20.8% and 10.1%. And conical beam radiation patterns are achieved within the two bands, the peak gains in the lower and upper bands are 5.4 dBi and 9.9 dBi respectively.

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Ground penetrating radar target detection method based on optimized faster RCNN and k-means clustering

Ground penetrating radar target detection method based on op...

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IET International Radar Conference (IRC 2023)

作者： Changle Xin Wentai Lei Chaopeng Luo Wei Xue School of Computer Science and Engineering Central South University Changsha People's Republic of China School of Electronic Information Central South University Changsha People's Republic of China Science and Technology on Near-Surface Detection Laboratory Wuxi People's Republic of China

ISBN: (数字)9781837240982

Ground Penetrating Radar (GPR) technology is a widely used detection technology for underground target objects, which can perform non-destructive detection of underground targets. Due to the complexity of the underground environment and the interference of clutter, manual processing of GPR data is a time-consuming and laborious task. Therefore, an accurate and fast automatic underground target detection method is urgently needed. We propose a method that can achieve fast goals in complex multi-goal situations. The simplified ResNet-50 network is used to detect dense intersecting hyperbolic curves and reduce the computation of the network. At the same time, we use k-means clustering algorithm to optimize the anchor in faster-Rcnn based on the characteristics of GPR hyperbola. In addition, this method is also suitable for target detection on GPR images under random media.

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Exploiting More Information in Sparse Point Cloud for 3D Single Object Tracking

arXiv

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arXiv 2022年

作者： Cui, Yubo Shan, Jiayao Gu, Zuoxu Li, Zhiheng Fang, Zheng The Faculty of Robot Science and Engineering Northeastern University Shenyang110819 China The Science and Technology Near-Surface Detection Laboratory Wuxi214000 China The National Frontiers Science Center for Industrial Intelligence and Systems Optimization Shenyang110819 China The The Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern University Ministry of Education Shenyang110819 China

3D single object tracking is a key task in 3D computer vision. However, the sparsity of point clouds makes it difficult to compute the similarity and locate the object, posing big challenges to the 3D tracker. Previous works tried to solve the problem and improved the tracking performance in some common scenarios, but they usually failed in some extreme sparse scenarios, such as for tracking objects at long distances or partially occluded. To address the above problems, in this paper, we propose a sparse-to-dense and transformer-based framework for 3D single object tracking. First, we transform the 3D sparse points into 3D pillars and then compress them into 2D bird's eye view (BEV) features to have a dense representation. Then, we propose an attention-based encoder to achieve global similarity computation between template and search branches, which could alleviate the influence of sparsity. Meanwhile, the encoder applies the attention on multi-scale features to compensate for the lack of information caused by the sparsity of point cloud and the single scale of features. Finally, we use set-prediction to track the object through a two-stage decoder which also utilizes attention. Extensive experiments show that our method achieves very promising results on the KITTI and NuScenes datasets. Code is available at https://***/3bobo/smat. © 2022, CC BY.

关键词： Signal encoding

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A Co-offset GPR Data Inversion Based on Ray Theory

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IOP Conference Series: Earth and Environmental science 2021年第1期660卷

作者： Meiqi Xue Sixin Liu Qi Lu Hongqing Li Yuanxin Wang School of Earth Exploration Science and Technology Jilin University Changchun China Science and Technology on Near-Surface Detection Laboratory Wuxi

We use Monte Carlo method to establish a randomly undulating homogeneous layered medium model. Then the co-offset GPR data for the built geological model is simulated by FDTD. The ray-tracing based inversion is applied for interval velocity estimation. During the inversion, the offset between antennas, the velocity value of the first layer, the picked amplitudes values of each reflection layer and reference amplitude are the input data. The thickness and velocity of each layer are calculated by this recursive method. It is proved that this inversion method is feasible for the layered geological model with random undulation, and the fact that undulation, i.e. RMS height and correlation length, influences the inversion results is discussed.

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