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An Active Landing Recovery Method for Quadrotor UAV: Localization, Tracking and Buffering Landing

IFAC-PapersOnLine 2023年第2期56卷 3366-3372页

作者： Yongkang Xu Zhihua Chen Shoukun Wang Junzheng Wang National Key Lab of Autonomous Intelligent Unmanned Systems Beijing Institute of Technology Beijing CO 100081 P.R.China Key Laboratory of Jiangxi Province for Image Processing and Pattern Recognition and MOE Key Lab of Nondestructive Testing Technology School of Information Engineering Nanchang Hangkong University Nanchang CO 330063 P.R. China

This paper proposes a principle of fully autonomous ground mobile landing recovery of Unmanned Aerial Vehicles (UAV) for the problems of relatively fixed landing point, passive recovery, poor flexibility, and environmental adaptability, which mainly includes localization, landing point tracking, and buffering landing for quadrotor UAV. Firstly, aiming at the problem that it is difficult to accurately obtain the position of a UAV in dynamic mobile landing recovery, a target location method based on Asynchronous Multisensor Information Fusion(AMIF) and servo turntable focus tracking is proposed. Secondly, to achieve fast and high-precision tracking of UAVs, a tracking control strategy of an independently driven landing recovery system and a Stewart six-degree of freedom platform is proposed. Then, to solve the problems of large impact force and center of gravity instability in the landing process of UAV, a stationarity control algorithm based on model prediction and a compliance control algorithm based on adaptive variable impedance are designed to achieve active compliance control while adjusting the position and attitude of the receiving surface in real-time. Finally, a quadrotor unmanned landing and recovery experimental platform is built to verify the feasibility of the ground mobile landing and recovery strategy proposed in this paper and the effectiveness of the control algorithm.

关键词： Quadrotor UAV Mobile Autonomous recovery Target localization Falling point tracking Buffering landing

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The design of multi-channel signals source with high-speed and high-precision based on FPGA

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Sensors and Transducers 2013年第SPEC.ISS.5期21卷 164-168页

作者： Du, Xiao-Dan Hu, Qing Yan, Tao Liu, Yong-Hong College of Information Science and Technology of Chengdu University Sichuan Chengdu 610106 China College of Electronic and Information Engineering of Chengdu University Sichuan Chengdu 610106 China Key Lab. in Colleges for Pattern Recognition and Intelligent Infor. Processing of Sichuan Province Sichuan Chengdu 610106 China

The multi-channel signals source that the structure is simple and flexible control is proposed in the article, with FPGA and high-speed D/A as its core. The choice of parts of apparatus, hardware constitution and design of software of the signals source are recommended here. Before the hardware designed, detailed theoretical analyses and quantitative description for the key factors on effecting the precision of signal source are given, and when debugging in hardware circuit is completed, on the base of analysis, errors estimation were verified with experimental results. It has provided high-precision signal related to the static and dynamic characteristics test accuracy of measured system for encoder and memory. By experiment and application it can meet the system requirements and has some theoretic and practical value. © 2013 IFSA.

关键词： Field programmable gate arrays (FPGA)

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Network-based VPN architecture using virtual routing

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Wuhan University Journal of Natural Sciences 2005年第1期10卷 161-164页

作者： Zhang, Bao-Liang Hu, Han-Ping Wu, Xiao-Gang Kong, Tao Lab. of Image Info. Wuhan 430074 China Inst. of Pattern Recognition Huazhong Univ. of Sci. and Technol. Wuhan 430074 China 709th Res. Inst. China Shipbuilding Eng. Society Wuhan 430074 China

A network-based Virtual Private Network (VPN) architecture by using fundamental routing mechanism is proposed. This network is a virtual overlay network based on the relay of IP-in-IP tunneling of virtual routing modules. The packet format employs the encapsulation of IPSec ESP (Encapsulating Security Payload), an impact path code and an extended OS (Differentiated Services) code to support multi-path routing and QoS. Comparing with other models of VPN, this network system can be deployed in the current network with little investment, and it is easy to implement. The simulation result shows its performance is better than the traditional VPN system of black box mode.

关键词： Network-based Proactive defense Virtual routing VPN

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FVC2002: Second Fingerprint Verification Competition

FVC2002: Second Fingerprint Verification Competition

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International Conference on pattern recognition

作者： D. Maio D. Maltoni R. Cappelli J.L. Wayman A.K. Jain Biometric System Lab-DEIS University of Bologna Cesena Italy Biometric Test Center College of Engineering San Jose State University Foundation San Jose CA USA Pattern Recognition and Image Processing Laboratory Michigan State University East Lansing MI USA

ISBN: (纸本)076951695X

Two years after the first edition, a new Fingerprint Verification Competition (FVC2002) was organized by the authors, with the aim of determining the state-of-the-art in this challenging pattern recognition application. The experience and the feedback received from FVC2000 allowed the authors to improve the organization of FVC2002 and to capture the attention of a significantly higher number of academic and commercial organizations (33 algorithms were submitted). This paper discusses the FVC2002 database, the test protocol and the main differences between FVC2000 and FVC2002. The algorithm performance evaluation will be presented at the 16/sup th/ ICPR.

关键词： Fingerprint recognition Testing Protocols Biometrics image databases pattern recognition Educational institutions image processing Art Feedback

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Gait Planning and Motion Control Based on Vrep Simulation for Quadruped Robot

Gait Planning and Motion Control Based on Vrep Simulation fo...

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WRC Symposium on Advanced Robotics and Automation (WRC SARA)

作者： Linqi Zhou Zhihua Chen Jun Liu Zhi Liu Yumeng Chen Liting Zhang key Laboratory of Jiangxi Province for Image Processing and Pattern Recognition and MOE Key Lab of Nondestructive Testing Technology Nanchang Hangkong University Nanchang China State Key Laboratory of Intelligent Control and Decision of Complex Systems School of Automation Beijing Institute of Technology Beijing China

Gait planning of quadruped robots plays an important role in achieving less walking, including dynamic and static gait. In this article, a static and dynamic gait control method based on center of gravity stability margin is proposed. Firstly, the robot model and kinematics modeling are introduced. Secondly, the robot’s foot static and dynamic gait were planned and the foot trajectory was designed. Finally, two types of gait of the robot were simulated using Vrep simulation software, and the differences in stability and speed between the coordinated gait with speed and stability in the static and dynamic gait of a 12 degree of freedom robot were analyzed, verifying the effectiveness of the gait control method proposed in this paper.

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Application of noise erosion operator to anisotropic diffusion

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Huazhong Keji Daxue Xuebao (Ziran Kexue Ban)/Journal of Huazhong University of Science and Technology (Natural Science Edition) 2004年第11期32卷 48-50页

作者： Cai, Chao Zhou, Chengping Ding, Mingyue Zhang, Tianxu Lab. for Image Proc. Inst. for Pattern Recognition Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

This paper proposed a morphological erosion operator based on partial differential equation (PDE). Its excellent performances on gradient image, noise removal and edge preserving were demonstrated. Based on this operator, an evaluating scheme of diffusion coefficients was introduced: the noise and edge of gradient image was controlled and preserved directly by this morphological erosion operator rather than by pre-smoothing input image with Gaussian function or the conventional morphological operator. The new diffusion coefficient had robustness to noise and better localization of edges. Experiments demonstrated that this anisotropic diffusion scheme could efficiently reduce image noise and sharpen the object boundaries.

关键词： Interference suppression

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Regularized restoration algorithm of astronautical turbulence-degraded images using maximum-likelihood estimation

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Hongwai Yu Haomibo Xuebao/Journal of Infrared and Millimeter Waves 2005年第2期24卷 130-134页

作者： Hong, Han-Yu Zhang, Tian-Xu Yu, Guo-Liang Lab. of Image Proc. Inst. for Pattern Recognition and AI Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

A regularized restoration algorithm based on maximum-likelihood estimation was presented for restoring object images from the noisy turbulence-degraded images. The logarithmic maximum-likelihood function for multi-frame image data based on the model of image random field was built, and some auxiliary terms to smooth noise while preserve the edges of images and the penalized item to avoid trivial solutions were added to the maximum-likelihood function. The iterative formulas of calculating the PSFs and object image were derived so that the PSFs and the object image could be estimated in the iterative manner. A parallel processing scheme for the algorithm is also proposed. The restoration experiments on the simulated turbulence-degraded images in the case of noise show that the proposed algorithm has high ability of noise-resisting and it has some practical applications.

关键词： image processing

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3D terrain matching algorithm based on iso-elevation-contour map and normalized wavelet description

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Yuhang Xuebao/Journal of Astronautics 2004年第3期25卷 262-268页

作者： Yu, Qiu-Ze Tian, Jin-Wen Liu, Jian Lab. of Image proc. and Intelligence Inst. for pattern recognition Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

A contour-based 3D terrain matching method is presented. In the method, Iso-Elevation Contour Map (IECM), a compact feature-based representation is proposed to represent the reference DEM and recovered DEM (REM) from real-time data to convert 3-D terrain matching to contour-based matching. In the contour-based matching, a normalized wavelet descriptor, which is invariant to 2-D rigid transformation and insensitive to noise, is employed to describe contours. A very fast contour-matching algorithm based on normalized wavelet descriptor is presented and the computation cost is analyzed. Control points based on matched contour pairs are located. 2-D rigid image transformation model and parameter estimation using the rule of least root mean square error (RMSE) are discussed. The proposed matching method is robust and computing efficiency is very high, and can obtain high location accuracy;all these are demonstrated by experimental results using real terrain data.

关键词： 3D terrain matching DEM IECM Normalized contour distance Normalized wavelet descriptor REM

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Novel all-sky autonomous triangle-based star map recognition algorithm

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Guangdian Gongcheng/Opto-Electronic Engineering 2004年第3期31卷 4-7页

作者： Zheng, Sheng Wu, Wei-Ren Tian, Jin-Wen Liu, Jian Tian, Yan Inst. of Image Recognition Huazhong Univ. of Sci. and Technol. Wuhan 430074 China Lab. for Image Processing Education Commission Wuhan 430074 China

A star map recognition algorithm is proposed. According to the observation accuracy of star sensor, the algorithm eliminates observation error of star triangle before recognition and codes the error-free star triangle to form characteristics quantity. The recognition for navigation triangle can only be carried out on the matching of single characteristics quantity. The combination of multi-triangle improves correct recognition ratio. Simulation experiments show that compared with the traditional triangle algorithm, the proposed algorithm has better timeliness and robustness.

关键词： Algorithm Navigation star database Star map recognition Star sensor

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Evaluating deformation patterns of the thoracic aorta in gated CTA sequences

Evaluating deformation patterns of the thoracic aorta in gat...

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IEEE International Symposium on Biomedical Imaging

作者： Ernst Schwartz Roman Gottardi Johannes Holfeld Christian Loewe Martin Czerny Georg Langs Computational Image Analysis and Radiology Lab (CIR) Medical University of Vienna Austria Pattern Recognition and Image Processing Group University of Technology Vienna Austria Division of Cardiothoracic Surgery Department of Surgery Medical University of Vienna Austria Division of Interventional Radiology Department of Radiology Medical University of Vienna Austria Computer Science and Artificial Intelligence Laboratory Massachusetts Institute of Technology USA

ISBN: (纸本)9781424441259;9781424441266

Cardiovascular interventions in the region of the aortic isthmus such as stent-grafting and vessel transposition introduce substantial changes in the deformation properties of the affected vessels. The changes play a fundamental role in the long-term prognosis for any such treatment, but are only poorly understood to date. We explore a fully automated method to quantify the deformation patterns of the thoracic aorta in gated computed tomography sequences. The aorta is segmented by a level set approach that accurately identifies the vessel lumen in each frame of the sequence. Consequently, landmarks on the vessel wall in each frame are registered using a probabilistic method. This allows for the measurement of global and local deformation properties. We evaluate our method on synthetic datasets and report first results of its application on real world data.

关键词： Biomedical imaging image segmentation Radiology Cardiology Surgery Computed tomography Level set Electrocardiography Pathology Deformable models

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