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15th International Conference on Computer Research and Development, ICCRD 2023

作者： Yang, Yang Dai, Shuling Lei, Xiaoyong Beihang University State Key Lab. of Virtual Reality Technology and Systems Beijing China

ISBN: (纸本)9781665487504

Engine aerodynamic noise is a complex component of flight simulation, consisting of multiple groups of harmonics and broadband noise signals based on passing frequency. Harmonic simulation can effectively convey human auditory perception but lacks related study in flight simulation. To accurately simulate the acoustic behavior of harmonic noise, first, a high-order cumulant based pre-filtering method is applied to retrieve harmonic signals from the real engine noise recordings by exploiting the blindness of the third-order cumulants to the harmonic signal. Then, targeting the lower precision of the autoregressive (AR) coefficients in the pre-filtering calculations, a maximum likelihood method is proposed to estimate the ARMA parameters of the high-order cumulants. The simulation results show that the accuracy of AR parameter estimation is significantly improved compared to the moment estimation method. Finally, the exact frequency is verified and obtained based on first-order cyclic statistics, and then the harmonic signal in the time domain is extracted. © 2023 IEEE.

关键词： Aerodynamics

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Multi-attribute complex scene rendering with state clustering and data fusion

Multi-attribute complex scene rendering with state clusterin...

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2nd Workshop on Digital Media and its Application in Museum and Heritage, DMAMH 2007

作者： AiMin, Liang Zhuo, Yu State Key Lab. of Virtual Reality Technology Beihang University

ISBN: (纸本)0769530656

The paper presents a novel rendering method with state clustering and data fusion. It is mainly used to solve the bottleneck in complex scene of real-time rendering. The method improves the application performance through removing the objects outside the view frustum and the occluded objects, it minimizes the number of state changes at the same time. Despite its simplicity, the experiments show the algorithm achieves good efficiency for high depth and multi-attribute complex scene. © 2007 IEEE.

关键词： Data fusion

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Real-time camera tracking using a global localization scheme

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Lecture Notes in Computer Science

作者： Yiming, Yue Xiaohui, Liang Chen, Liu Jie, Liu State Key Lab. of Virtual Reality Technology and Systems Beihang University 100191 Beijing China

ISBN: (纸本)9783642228186

Real-time camera tracking in previously unknown scene is attractive to a wide spectrum of computer vision applications. In Recent years, Simultaneous Localization and Mapping (SLAM) system and its varieties have shown extraordinary camera tracking performance. However, the robustness of these systems to rapid and erratic camera motion is still limited because of the typically used Local Localization scheme. To overcome this limitation, we present an efficient online camera tracking algorithm using a Global Localization scheme which matches features in a global way through two steps: First, coarse matches are obtained through nearest feature descriptor search. Afterwards, a Game Theoretic approach is exploited to eliminate the incorrect matches and the left correct matches can be used to estimate the camera pose. Result shows our camera tracking algorithm has significantly improved the robustness of camera tracking system to rapid and erratic camera motion. © 2011 Springer-Verlag Berlin Heidelberg.

关键词： Tracking (position)

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A novel simplification algorithm based on MLS and splats for point models 09

A novel simplification algorithm based on MLS and splats for...

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CGI 2009 - Computer Graphics International 2009

作者： He, Zhiying Liang, Xiaohui State Key Lab. of Virtual Reality Technology and Systems Beihang University Beijing 100191 China

ISBN: (纸本)9781605586878

The simplification of point models is important in point-based processing technology because of the increasing of data complexity. Many researches focus on getting the subset from the initial point set, which can not represent the whole object properly. In this paper, we present a novel simplification algorithm based on Moving Least Square (MLS) and Splats for point models. The algorithm uses MLS to represent the point models and can get the minimum error point which is used to deputize its neighborhood. This approach can get new proper agent points instead of subset. Then we calculate the error based on the rendering results, which means considering the geometry of splat when calculating the error of simplification. Experiment results show that this algorithm is not only efficient, but also has good quality. Copyright © 2009 by the Association for Computing Machinery, Inc.

关键词： Errors

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Visio-haptic simulation for detection of dental cavity profile

Visio-haptic simulation for detection of dental cavity profi...

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2011 IEEE International Conference on Mechatronics and Automation, ICMA 2011

作者： Yu, Ge Wang, Dangxiao Zhang, Yuru State Key Lab. of Virtual Reality Technology and Systems Beihang University Beijing 100191 China

ISBN: (纸本)9781424481149

In this paper, a feasible approach for cavity profile detection simulation is presented to help dental students learning skills of cavity diagnosis. The cavity profile is modeled as partitioned meshes with different physical properties. To simulate the realistic feeling stem from stiffness, viscosity and friction, several components of force are introduced when dental tool probing the sound portion and carious sites of teeth. In the process of probing, the force vibration may appear around the cavity boundary. To eliminate the vibration, a locking method is proposed to keep the tool's avatar maintaining its collision status. The experiments show that user can clearly identify the prescribed cavity profile and no force vibration occurs around the boundary. The proposed method can also be extended to the other multi-tissues boundary detection for a stable force feedback. © 2011 IEEE.

关键词： Tissue

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A physical based meshless method for soft tissue deforming

A physical based meshless method for soft tissue deforming

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2011 IEEE International Symposium on IT in Medicine and Education, ITME 2011

作者： Hao, Aiming Huang, Zhen State Key Lab of Virtual Reality Technology and Systems Beijing China

ISBN: (纸本)9781612847023

This paper concentrated on how to apply meshless method to do physical based soft tissue deformation. First we approximated the deformation field using a Moving Least Squares (MLS) approximation method. Then, a compact force computation was applied to accelerate the physical computation speed. Finally we implemented a surface animation method to simulate the deformation of soft tissue under external forces. We made experiments with real properties of human soft tissue and the results showed that our method successfully made physical based deformation of human soft tissue. © 2011 IEEE.

关键词： Deformation

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Dynamic Characteristics Analysis and Vibration Experiment of Upper-time of Flight Counter (U-ToFC)

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Chinese Journal of Mechanical Engineering 2012年第5期25卷 868-874页

作者： WU Qiong ZHANG Yidu SONG Sunguang State Key Lab of Virtual Reality Technology and Systems Beihang UniversityBeijing 100191China School of Mechanical Engineering andAutomation Beihang UniversityBeijing 100191China

The dynamic characteristic parameters of Up-time of Flight Counter （U-ToFC） are important for research of structure optimization and reliability. However, the current simulation is performed based on homogenous material and simplified constraint model, the correct and reliability of results are difficult to be guaranteed. The finite element method based on identification of material parameters is proposed for this investigation on dynamic analysis, simulation and vibration experiment of the U-ToFC. The structure of the U-ToFC is complicated. Its＇ outside is made of aluminum alloy and inside contains electronic components such as capacitors, resistors, inductors, and integrated circuits. The accurate material parameters of model are identified difficultly. Hence, the parameters identification tests are performed to obtain the material parameters of this structure. On the basis of the above parameters, the experiment and FEA are conducted to the U-ToFC. In terms of the flight acceptance test level, and two kinds of joints condition between the U-ToFC and fixture are considered. The natural frequencies, vibration shapes and the response of the power spectral density of the U-ToFC are obtained. The results show simulation which is based on parameters identification is similar with vibration experiment in natural frequencies and responses. The errors are less than 10%. The vibration modes of simulation and experiment are consistent. The paper provides a more reliable computing method for the dynamic characteristic analysis of large complicated structure.

关键词： random vibration dynamical characteristic parameters finite element analysis identification of material parameters

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Haptic based teleoperation with master-slave motion mapping and haptic rendering for space exploration

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Chinese Journal of Aeronautics 2019年第3期32卷 723-736页

作者： Guanyang LIU Xuda GENG Lingzhi LIU Yan WANG State Key Lab of Virtual Reality Technology and Systems Beihang University School of Mechanical Engineering and Automation Beihang University Key Laboratory of Space Utilization Technology and Engineering Center for Space Utilization Chinese Academy of Sciences

This paper presents a new solution to haptic based teleoperation to control a large-sized slave robot for space exploration, which includes two specially designed haptic joysticks, a hybrid master-slave motion mapping method, and a haptic feedback model rendering the operating resistance and the interactive feedback on the slave side. Two devices using the 3 R and DELTA mechanisms respectively are developed to be manipulated to control the position and orientation of a large-sized slave robot by using both of a user's two hands respectively. The hybrid motion mapping method combines rate control and variable scaled position mapping to realize accurate and efficient master-slave control. Haptic feedback for these two mapping modes is designed with emphasis on ergonomics to improve the immersion of haptic based teleoperation. A stiffness estimation method is used to calculate the contact stiffness on the slave side and play the contact force rendered by using a traditional spring-damping model to a user on the master side stably. Experiments by using virtual environments to simulate the slave side are conducted to validate the effectiveness and efficiency of the proposed solution.

关键词： Teleoperation Haptic device Remote control Haptic rendering Space exploration

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A component-based aircraft instrument rapid modeling tool

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第11期11卷 911-918页

作者： Fang-wen LI Xu-kun SHEN State Key Lab of Virtual Reality Technology and Systems School of Computer Science Beihang University Beijing 100191 China

Component-based software reuse and development is considered to be the best way to improve the efficiency and quality of *** meet the demands of aircraft instrument exhibition in an aviation virtual library,we present a modeling and simulation tool for cockpit instruments on component methods,achieving display functionality and providing a visual interaction platform in the aviation virtual *** the rapid model construction and reuse of virtual library resources,we classify entities in the cockpit into several categories by their behavior,and design a template for each category to describe its *** efficiently reduces the modeling cycle,and thus largely helps users to take advantage of the library resource.

关键词： Components Rapid modeling Simulation

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Quick reconstruction of cameras and quasi-dense geometry from unordered photos

Quick reconstruction of cameras and quasi-dense geometry fro...

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2009 WRI World Congress on Computer Science and Information Engineering, CSIE 2009

作者： Shuang, He Yue, Qi Fei, Hou State Key Lab of Virtual Reality Technology and Systems Beihang University China

ISBN: (纸本)9780769535074

This paper presents a novel approach to quick reconstruction of cameras and quasi-dense geometry from unordered photos of a scene. With three reconstruction goals: reliable camera postures, high-density scene geometry, and a low cost of time, our approach consists of two stages: pairwise relating and two-tier reconstruction. At the first stage, to obtain better putative matches, we impose bidirectional feature matching and disparity constraint;to achieve better normalization, we perform approximate self-calibration using EXIF tag. The second stage includes a sparse and a quasi-dense reconstruction with different pivot respectively, adding selection strategies to avoid degenerate cases and improve time efficiency. © 2008 IEEE.

关键词： Cameras

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