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15th European Conference on Synthetic Aperture Radar, EUSAR 2024

作者： Wu, Yuwei Zhang, Zhe Song, Ruizhen Qiu, Xiaolan Yu, Weidong Department of Space Microwave Remote Sensing System Beijing100090 China Aerospace Information Research Institute Chinese Academy of Sciences Beijing100094 China Key Laboratory of Intelligent Aerospace Big Data Application Technology Suzhou215123 China Suzhou Aerospace Information Research Institute Suzhou215123 China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing100049 China

ISBN: (纸本)9783800762873

Sparse synthetic aperture radar (SAR) imaging allows for a reduction in the azimuth sampling rate based on compressive sensing theory. However, it relies on the sparsity of scenes, which can lead to significant azimuth ambiguity. To address this issue, we introduce a novel network designed to suppress azimuth ambiguity for sparse SAR imaging. Our proposed deep unfolded network is based on the Iterative Thresholding Algorithm Learned (LISTA). We replace the observation matrix with Matched Filter (MF) operators to reduce computational complexity. Experiments with real SAR scene data demonstrate the effectiveness and superiority of our approach in suppressing azimuth ambiguity. © VDE VERLAG GMBH ∙ Berlin ∙ Offenbach.

关键词： Matched filters

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Waterline mapping of inland great lake with subpixel accuracy from GF-3 SAR images 6

Waterline mapping of inland great lake with subpixel accurac...

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6th Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2019

作者： Li, Ning Niu, Shilin Wang, Robert Wu, Lin Guo, Zhengwei College of Computer and Information Engineering Henan University Kaifeng475004 China Henan Key Laboratory of Big Data Analysis and Processing Henan University Kaifeng475004 China Henan Engineering Research Center of Intelligent Technology and Application Kaifeng475004 China Department of Space Microwave Remote Sensing System Institute of Electronics Chinese Academy of Sciences Beijing100190 China

ISBN: (纸本)9781728129129

High-accuracy waterline mapping with Synthetic Aperture Radar (SAR) images is a challenging task because of the inhomogeneities of SAR imagery caused by the speckle noise and complex terrain. This paper presents a novel method for waterline mapping with subpixel accuracy. The proposed method mainly consists of three steps. Firstly, an improved Non-Local filter is adapted to suppress the speckle noise. Secondly, a Fuzzy C-Means (FCM) clustering algorithm is used to extract the pixel-level waterline. Thirdly, along the pixel-level waterline, a novel subpixel-scale waterline extraction method based on bicubic convolution and Geometric Active Contour (GAC) model is presented to further improve the accuracy of the waterline. Without loss of generality, the Danjiangkou reservoir (DJKR), which is the largest artificial freshwater lake in Asia, is selected as a study case. SAR images from Chinese GaoFen-3 (GF-3) satellite working on different modes are processed to demonstrate the effectiveness of the proposed method. © 2019 IEEE.

关键词： Synthetic aperture radar

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AN EFFICIENT AZIMUTH SAMPLING DESIGN NETWORK FOR SPARSE SAR IMAGING

AN EFFICIENT AZIMUTH SAMPLING DESIGN NETWORK FOR SPARSE SAR ...

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IET International Radar Conference 2023, IRC 2023

作者： Wu, Yuwei Zhang, Zhe Qiu, Xiaolan Zhao, Yao Yu, Weidong Song, Ruizhen Department of Space Microwave Remote Sensing System Beijing100090 China Aerospace Information Research Institute Chinese Academy of Sciences Beijing100094 China Key Laboratory of Intelligent Aerospace Big Data Application Technology Suzhou215123 China Suzhou Aerospace Information Research Institute Suzhou215123 China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing100049 China Guangdong University of Technology Guangdong Guangzhou China

ISBN: (纸本)9781839539954

Conventional synthetic aperture radar (SAR) imaging methods based on the Nyquist sampling theorem encounters the dilemma of balancing imaging quality and resource consumption. In order to solve the problem, we propose a novel network to optimize the azimuth sampling pattern for sparse SAR imaging. We harness the impressive information extraction capabilities inherent in deep neural networks to efficiently segregate valuable information from clutter. This empowers us to extract more pertinent data while minimizing pulse utilization. Additionally, we have integrated the nonuniform fast Fourier transform (NUFFT) MF operator into the network-based SAR imaging framework, ensuring both efficiency and viability of the proposed approach. Experiments on real SAR scene data have been conducted, and both visual comparisons and numerical analysis demonstrate the efficiency and superiority of our method in the field of sparse SAR imaging. © The Institution of Engineering & technology 2023.

关键词： Fast Fourier transforms

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Globally optimal consensus maximization for robust visual inertial localization in point and line map

Globally optimal consensus maximization for robust visual in...

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2020 IEEE/RSJ International Conference on intelligent Robots and systems (IROS)

作者： Yanmei Jiao Yue Wang Bo Fu Qimeng Tan Lei Chen Minhang Wang Shoudong Huang Rong Xiong State Key Laboratory of Industrial Control and Technology Zhejiang University Hangzhou P.R. China Beijing Key Laboratory of Intelligent Space Robotic System Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing P.R. China Minhang Wang is with the Application Lab Huawei Incorporated Company P.R. China Shoudong Huang is with the Center for Autonomous Systems (CAS) the University of Technology Sydney Australia

ISBN: (数字)9781728162126

ISBN: (纸本)9781728162133

Map based visual inertial localization is a crucial step to reduce the drift in state estimation of mobile robots. The underlying problem for localization is to estimate the pose from a set of 3D-2D feature correspondences, of which the main challenge is the presence of outliers, especially in changing environment. In this paper, we propose a robust solution based on efficient global optimization of the consensus maximization problem, which is insensitive to high percentage of outliers. We first introduce translation invariant measurements (TIMs) for both points and lines to decouple the consensus maximization problem into rotation and translation subproblems, allowing for a two-stage solver with reduced search space. Then we show that (i) the rotation can be estimated by minimizing TIMs using only 1-dimensional branch-and-bound (BnB), (ii) the translation can be estimated by running 1-dimensional search for each of the three axes with prioritized progressive voting. Compared with the popular randomized solver, our solver achieves deterministic global convergence without requiring an initial value. Furthermore, ours is exponentially faster compared with existing BnB based methods. Finally, our experiments on both simulation and real-world datasets demonstrate that the proposed method gives accurate pose estimation even in the presence of 90% outliers (only 2 inliers).

关键词： Location awareness Visualization Pose estimation Search problems State estimation Optimization Rotation measurement

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Design of Planar Antenna and space Deployable Mast Based on a New 8r Origami Mechanism

SSRN

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SSRN 2024年

作者： Li, Ruixing Zhou, Guangwu Luo, Pei Zhao, Zhijun School of Aeronautics and Astronautics Sichuan University Chengdu610065 China Sichuan University Chengdu610065 China Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing100092 China

The modular origami mechanism has great application prospect. In this paper, origami based on 8R mechanism is designed, the mechanism can be array. The kinematics of the 8R origami mechanism is analyzed, and the model reconstruction and motion bifurcation of the mechanism are found. There are two kinds of 8R mechanism that can satisfy the array: MMMN mechanism and NNNM mechanism. The motion bifurcation and model reconstruction of the mechanism are avoided in the design of thickness-plate origami. Taking into account the bearing capacity of the mechanism, the 8R mechanism of heavy plate origami is designed. The motion bifurcation and model reconstruction of the mechanism are avoided in the design of thickness-plate origami. The twisting direction of MMMN mechanism and NNNM mechanism is opposite. The planar antenna is designed using multiple MMMN mechanisms. The spread area of the planar antenna reaches 1350〖cm〗^2. NNNM mechanism and MMMN mechanism are used to design space deployable mast. The performance of planar antenna and space deployable mast is tested. The space deployable mast has a self-locking function in the unfolded state. The space deployable mast has a load-carrying capacity of more than 41N and requires only 6N folding force. © 2024, The Authors. All rights reserved.

关键词： Bifurcation (mathematics)

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Dynamic Fluorescent Imaging for robotic Patch Clamp in vivo: Modeling and Control

Dynamic Fluorescent Imaging for Robotic Patch Clamp in vivo:...

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第42届中国控制会议

作者： Ruimin Li Jinyu Qiu Minghui Li Mingzhu Sun Xin Zhao Qili Zhao Institute of Robotics and Automatic Information System (IRAIS) Nankai University Tianjin Key Laboratory of Intelligent Robotic (tjKLIR) Nankai University Institute of Intelligence Technology and Robotic Systems Shenzhen Research Institute of Nankai University Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of Technology

Fluorescent imaging through fluorescent dye injection is the key technique for lighting the in vivo environment and localizing the target cell in it for patch clamp operation in vivo. At present, manual fluorescent imaging is usually a labor-intensive high-skill requisite work, significantly limiting the application of patch clamp operation in vivo. In this paper, a computational modeling of the diffusion process of the injected fluorescent dye is established using the commercial ANSYS Fluent software. Based on this model, the distribution of the mass fraction, proven to be linearly related to fluorescence intensity,was calculated to simulate the fluorescent field formed by fluorescent dye injection. Further, an ADRC controller was developed to generate feedback-controlled fluorescent fields. With the above model and controller, a mobile fluorescent field, and varying fluorescent field with constant mass fraction at the target position are generated to fulfill the requirement of in vivo environment observation, search and localization of the target cell in patch clamp operation, respectively. The above results prove the feasibility of ADRC-controlled dynamic fluorescent imaging in the patch clamp operation in vivo.

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Near-Zero Thermal Mismatch Flexure Metamaterial with High-Resonant Frequency

SSRN

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SSRN 2022年

作者： Zhou, Hao Yu, Huabin Wang, Zhe Guo, Xiaogang Qi, Junfeng Zhang, Xiaoyu Fang, Daining Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering China Academy of Space Technology No. 104 Youyi Road Beijing100094 China Beijing Key Laboratory of Lightweight Multi-functional Composite Materials and Structures Beijing Institute of Technology No. 5 Zhongguancun South Street Beijing100081 China Beijing Spacecrafts Manufacture Company Beijing100094 China

Heterogeneous mechanical metamaterials, especially fabricated by additive manufacturing techniques, have attracted attention in lightweight multifunctional material engineering. Near-zero thermal expansion materials play an important role in precision equipment. However, undesired thermal mismatch flexure distortion occurs when the precision equipment is mounted on the main load-bearing structures of spacecraft and the environmental temperature changes. The present study presents a near-zero thermal mismatch flexure metamaterial, including the design strategy inspired by plants with axisymmetric distributing anisotropic microstructures , the thermal deformation constitutive relation derived by the flexibility method, and the fabrication of this metamaterial sandwich structure by selective laser melting. Thermal deformation experiments demonstrate that the coefficient of thermal flexure reduces by 92.4% compared with traditional bi-material plates connected by screws. Mechanical vibration experiments demonstrate that the fundamental resonant frequency of this metamaterial sandwich structure can be as high as 956 Hz, which is 5.8 times larger than the common requirements of functional components for spacecraft to avoid mechanical resonance with the main structure during launch. The excellent thermal mismatch shape stability and high-resonant frequency properties make it a potential candidate for thermal geometric stable structures working in variable thermal and mechanical environments. © 2022, The Authors. All rights reserved.

关键词： Metamaterials

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An Approach on Visual Detecting Multi-Targets in the Unstructured and Complex Scenes Based on RGB-D Images

An Approach on Visual Detecting Multi-Targets in the Unstruc...

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Automation, Control and robotics Engineering (CACRE), International Conference on

作者： Qimeng Tan Yikun Sun Pengfei Xin Yimin Lin Chao Ma Xinyu Wang Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Propellant Injection Laboratory Beijing Special Engineering Design and Research Institute Institute of Optical Communication &Optoelectronics Beijing University of Posts &Telecommunications School of Instrument Science and Optoelectronic Engineering Beijing Information Science and Technology University

ISBN: (数字)9781728198880

ISBN: (纸本)9781728198897

The technology of detecting and identifying multitarget is of significance for robotic visual navigation within the unknown, unstructured, complex scenes, whose result could be considered as important references of 3 D map building and path planning for mobile robot. Traditional algorithms of target detection can be applied to 2 D images without depth information generally, which is disturbed by few factors such as illumination, view and scale easily. Therefore, an approach on visual detecting multi-target of unstructured and complex scenes based on RGBD images is proposed in this article to solve the above problem, which is composed of extracting descriptor of rotation and scale invariance feature, local encoding of targets, random ferns classifier training, Hough map generation, Hough voting theoretical model and local maximum search. Experimental results have shown that the proposed approach reduce the calculation of extracting and matching local feature, improve the accuracy of object recognition and detection in unknown complex environments, be capable of well robust against few disturbing factors i.e. rotation, scale, illumination, occlusion and non-rigid body deformation.

关键词： robotic Visual Navigation RGB-D Image Target Detection RFC(Random Ferns Classifier) RSI-LBF(Rotation and Scale Invariance-Local Binary Feature)

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Meta-fences: Blocking waves utilizing a layer of identical tiny scatters

arXiv

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arXiv 2021年

作者： Zhang, Yunhao Sha, Zhendong Su, Guangyuan Zhou, Hao Yang, Jiangzhong Jiang, Peng Liu, Yongquan Li, Bing Wang, Tiejun State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace Engineering Xi’an Jiaotong University Xi’an710049 China Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering China Academy of Space Technology Beijing100094 China School of Aeronautics Northwestern Polytechnical University Shaanxi Xi'an710072 China

Wave steering by artificial materials (for example, phononic crystals and acoustic metamaterials) is a fascinating frontier in modern physics and engineering, but suffers from bulky sizes and intractable challenges in fabrication. Here, a sparse layer of identical tiny scatters, which we call meta-fences, is presented with a non-destructive way to omnidirectionally block flexural waves in plates. The underlying mechanism is that the restraining force and moment of the scatter are tuned simultaneously to counter-balance the incident wave. Both our experimental results and numerical analysis have demonstrated that broadband wave sources ranging from 3 to 7 kHz can be segregated from the protected area by the meta-fence. In addition, the meta-fence is further assembled into a waveguide routing with an arbitrary configuration. Compared with previous isolators and waveguides, our meta-fences exhibit absolute advantages in compact size, flexible configuration, and high structural strength. The current scenario sheds light on the design of lightweight-and-strong architectures for vibration control and energy harvesting with a high efficiency, and can be extended to microfluidics, acoustics, seismology and other fields. Copyright © 2021, The Authors. All rights reserved.

关键词： Energy harvesting

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Dynamic Fluorescent Imaging for robotic Patch Clamp in vivo: Modeling and Control

Dynamic Fluorescent Imaging for Robotic Patch Clamp in vivo:...

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Chinese Control Conference (CCC)

作者： Ruimin Li Jinyu Qiu Minghui Li Mingzhu Sun Xin Zhao Qili Zhao Institute of Robotics and Automatic Information System (IRAIS) Nankai University Tianjin China Tianjin Key Laboratory of Intelligent Robotic (tjKLIR) Nankai University Tianjin China Institute of Intelligence Technology and Robotic Systems Shenzhen Research Institute of Nankai University Shenzhen China Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of Technology Beijing China

Fluorescent imaging through fluorescent dye injection is the key technique for lighting the in vivo environment and localizing the target cell in it for patch clamp operation in vivo. At present, manual fluorescent imaging is usually a labor-intensive high-skill requisite work, significantly limiting the application of patch clamp operation in vivo. In this paper, a computational modeling of the diffusion process of the injected fluorescent dye is established using the commercial ANSYS Fluent software. Based on this model, the distribution of the mass fraction, proven to be linearly related to fluorescence intensity, was calculated to simulate the fluorescent field formed by fluorescent dye injection. Further, an ADRC controller was developed to generate feedback-controlled fluorescent fields. With the above model and controller, a mobile fluorescent field, and varying fluorescent field with constant mass fraction at the target position are generated to fulfill the requirement of in vivo environment observation, search and localization of the target cell in patch clamp operation, respectively. The above results prove the feasibility of ADRC-controlled dynamic fluorescent imaging in the patch clamp operation in vivo.

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