检索结果-南通市图书馆

The Data-Reusing MCC-Based Algorithm and Its Performance Analysis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2016年第4期25卷 719-725页

作者： LIU Chunhui QI Yue DING Wenrui Research Institute of Unmanned Aerial Vehicle Beihang University state Key laboratory of virtual reality technology and system Beihang University

Maximum correntropy criterion(MCC)provides a robust optimality criterion for non-Gaussian signal *** this paper,the weight update equation of the conventional MCC-based adaptive filtering algorithm is modified by reusing the past K input vectors,forming a class of data-reusing MCC-based algorithm,called DRMCC *** with the conventional MCCbased algorithm,the DR-MCC algorithm provides a much better convergence performance when the input data is *** mean-square stability bound of the DRMCC algorithm has been studied *** both Gaussian noise case and non-Gaussian noise case,the expressions for the steady-state Excess mean square error(EMSE) of DR-MCC algorithm have been *** relationship between the data-reusing order and the steadystate EMSEs is also *** results are in agreement with the theoretical analysis.

关键词： Adaptive filtering Maximum correntropy criterion(MCC) Data-reusing Mean-square stability Steady-state excess mean square error

A survey on virtual reality

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science in China(Series F) 2009年第3期52卷 348-400页

作者： ZHAO QinPing state Key laboratory of virtual reality technology and system Beihang University Beijing 100083 China

virtual reality （VR） is a scientific method and technology created during the exploration of the nature by human beings to understand, simulate, and better adapt and use the nature. Based on the analysis on the whole process of VR, this paper presents different categories of VR problems and a type of theoretical expression, and abstracts three kinds of scientific and technical problems in VR field. On the basis of foresaid content, this paper also studies current major research objectives, research results and development trend of VR in the aspects of VR modeling method, VR representation technology, human-machine interaction and devices, VR development suites and supporting infrastructure, as well as VR applications. Finally, several theoretical and technical problems that need to be further studied and solved are addressed.

关键词： virtual reality modeling rendering human-machine interaction development suite

GPU-BASED FLUID SIMULATION WITH FAST COLLISION DETECTION ON BOUNDARIES

在线全文

学校读者我要写书评

暂无评论

International Journal of Modeling, Simulation, and Scientific Computing 2012年第1期3卷 137-148页

作者： JIAWEN WU FENGQUAN ZHANG XUKUN SHEN state Key laboratory of virtual reality technology and system Beihang University 100191 BeijingChina

In this paper,we present a method for fluid simulation based on smoothed particle hydrodynamic(SPH)with fast collision detection on boundaries on *** major goal of our algorithm is to get a fast SPH simulation and rendering on ***,our algorithm has the following three features:At first,to make the SPH method GPU-friendly,we introduce a spatial hash method for neighbor *** sorting the particles based on their grid index,neighbor search can be done quickly on ***,we propose a fast particle-boundary collision detection *** precomputing the distance field of scene boundaries,collision detection’s computing cost arrived as O(n),which is much faster than the traditional ***,we propose a pipeline with fine-detail surface reconstruction,and progressive photon mapping working on *** experiment our algorithm on different situations and particle numbers of scenes,and find out that our method gets good *** experimental data shows that we can simulate 100K particles,and up to 1000K particles scene at a rate of approximately 2 times per second.

关键词： SPH simulation fast collision detection GPU progressive photon mapping

Biologically adaptive robust mean shift algorithm with Cauchy predator-prey BBO and space variant resolution for unmanned helicopter formation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2014年第11期57卷 195-207页

作者： WANG XiaoHua DUAN HaiBin state Key laboratory of virtual reality technology and systems Beihang University

Visual tracking technology can provide measurement information for unmanned helicopter formation and thus, more attention is being paid to this research area. We propose a novel mean shift(MS) algorithm that is both adaptive and robust for unmanned helicopter formation and apply it to the leading unmanned helicopter tracking. The movement of an unmanned helicopter is very flexible and changeable, which makes the tracking there of more difficulty than for common targets. In creating an algorithm that can adapt to the acceleration of the unmanned helicopter and estimates both the scale and orientation of the movement changes, we combine the traditional MS with the bio-inspired Cauchy predator-prey biogeography-based optimization(CPPBBO)evolutionary algorithm, and also the space variant resolution(SVR) mechanism of the human visual system(MS-CPPBBO-SVR). To demonstrate the effectiveness and robustness of the proposed method and justify the importance of the CPPBBO algorithm and SVR mechanism at the same time, a series of comparative experiments were carried out. The experimental results of the proposed MS-CPPBBO-SVR method are compared with other competitive tracking methods, such as MS, MS with SVR(MS-SVR), MS-SVR with several other optimization algorithms, and the robust particle filter algorithm. The experimental results demonstrate that our proposed tracking approach, MS-CPPBBO-SVR, is more adaptive, robust and efficient in target tracking than the other methods.

关键词： unmanned helicopter formation tracking mean shift biogeography-based optimization(BBO) predator-prey space variant resolution(SVR)

Development of a Hand Exoskeleton system for Index Finger Rehabilitation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2012年第2期25卷 223-233页

作者： LI Jiting WANG Shuang WANG Ju ZHENG Ruoyin ZHANG Yuru CHEN Zhongyuan state Key laboratory of virtual reality technology and systems Beihang UniversityBeijing 100191China

In order to overcome the drawbacks of traditional rehabilitation method,the robot-aided rehabilitation has been widely investigated for the recent *** the hand rehabilitation robot,as one of the hot research fields,remains many challenging issues to be *** paper presents a new hand exoskeleton system with some novel ***,both active and passive rehabilitative motions are ***,the device is elaborately designed and brings advantages in many *** example,joint motion is accomplished by a parallelogram mechanism and high level motion control is therefore made very simple without the need of complicated *** adjustable joint limit design ensures that the actual joint angles don＇t exceed the joint range of motion（ROM） and thus the patient safety is *** design can fit to the different patients with different joint ROM as well as to the dynamically changing ROM for individual *** device can also accommodate to some extent variety of hand ***,the proposed control strategy simultaneously realizes the position control and force control with the motor driver which only works in force control ***,the system resistance compensation is preliminary realized and the resisting force is effectively *** experiments were conducted to verify the proposed *** collected data show that the achieved ROM is close to that of a healthy hand and the range of phalange length（ROPL） covers the size of a typical hand,satisfying the size need of regular hand *** order to evaluate the performance when it works as a haptic device in active mode,the equivalent moment of inertia（MOI） of the device was *** results prove that the device has low inertia which is critical in order to obtain good *** experiments also show that in the active mode the virtual interactive force is successfully feedback to the finger and the resistance i

关键词： exoskeleton hand rehabilitation Bowden-cable transmission active control mode passive control mode

Hierarchical Visual Attention Model for Saliency Detection Inspired by Avian Visual Pathways

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2019年第2期6卷 540-552页

作者： Xiaohua Wang Haibin Duan the state Key laboratory of virtual reality technology and systems School of Automation Science and Electrical Engineering Beihang University the state Key laboratory of virtual reality technology and systems School of Automation Science and Electrical EngineeringBeihang University the Peng Cheng laboratory

Visual attention is a mechanism that enables the visual system to detect potentially important objects in complex environment. Most computational visual attention models are designed with inspirations from mammalian visual ***, electrophysiological and behavioral evidences indicate that avian species are animals with high visual capability that can process complex information accurately in real time. Therefore,the visual system of the avian species, especially the nuclei related to the visual attention mechanism, are investigated in this paper. Afterwards, a hierarchical visual attention model is proposed for saliency detection. The optic tectum neuron responses are computed and the self-information is used to compute primary saliency maps in the first hierarchy. The "winner-takeall" network in the tecto-isthmal projection is simulated and final saliency maps are estimated with the regularized random walks ranking in the second hierarchy. Comparison results verify that the proposed model, which can define the focus of attention accurately, outperforms several state-of-the-art *** study provides insights into the relationship between the visual attention mechanism and the avian visual pathways. The computational visual attention model may reveal the underlying neural mechanism of the nuclei for biological visual attention.

关键词： Avian visual pathways bio-inspired saliency detection visual attention

A guidance law for UAV autonomous aerial refueling based on the iterative computation method

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2014年第4期27卷 875-883页

作者： Luo Delin Xie Rongzeng Duan Haibin Department of Automation Xiamen University state Key laboratory of virtual reality technology and systems Beihang University

The rendezvous and formation problem is a significant part for the unmanned aerial vehicle（UAV） autonomous aerial refueling（AAR） technique. It can be divided into two major phases： the long-range guidance phase and the formation phase. In this paper, an iterative computation guidance law（ICGL） is proposed to compute a series of state variables to get the solution of a control variable for a UAV conducting rendezvous with a tanker in AAR. The proposed method can make the control variable converge to zero when the tanker and the UAV receiver come to a formation flight eventually. For the long-range guidance phase, the ICGL divides it into two sub-phases： the correction sub-phase and the guidance sub-phase. The two sub-phases share the same iterative process. As for the formation phase, a velocity coordinate system is created by which control accelerations are designed to make the speed of the UAV consistent with that of the *** simulation results demonstrate that the proposed ICGL is effective and robust against wind disturbance.

关键词： Autonomous aerial refueling Aerial rendezvous Formation control Guidance law Unmanned aerial vehicle

No-reference synthetic image quality assessment with convolutional neural network and local image saliency

在线全文

学校读者我要写书评

暂无评论

Computational Visual Media 2019年第2期5卷 193-208页

作者： Xiaochuan Wang Xiaohui Liang Bailin Yang Frederick W.B.Li state kay laboratory of virtual reality technology and system Beihang UniversityBeijing 100191China School of Computer Science&Information Engineering Zhejiang Gongshang UniversityHangzhou 310018China Department of Computer Science University of DurhamUnited Kingdom

Depth-image-based rendering(DIBR) is widely used in 3 DTV, free-viewpoint video, and interactive 3 D graphics applications. Typically, synthetic images generated by DIBR-based systems incorporate various distortions, particularly geometric distortions induced by object dis-occlusion. Ensuring the quality of synthetic images is critical to maintaining adequate system service. However, traditional 2 D image quality metrics are ineffective for evaluating synthetic images as they are not sensitive to geometric distortion. In this paper, we propose a novel no-reference image quality assessment method for synthetic images based on convolutional neural networks, introducing local image saliency as prediction weights. Due to the lack of existing training data, we construct a new DIBR synthetic image dataset as part of our contribution. Experiments were conducted on both the public benchmark IRCCyN/IVC DIBR image dataset and our own dataset. Results demonstrate that our proposed metric outperforms traditional 2 D image quality metrics and state-of-the-art DIBR-related metrics.

关键词： image quality assessment synthetic image depth-image-based rendering(DIBR) convolutional neural network local image saliency

AR assistance for efficient dynamic target search

在线全文

学校读者我要写书评

暂无评论

Computational Visual Media 2023年第1期9卷 177-194页

作者： Zixiang Zhao Jian Wu Lili Wang state Key laboratory of virtual reality technology and systems School of Computer Science and EngineeringBeihang UniversityBeijingChina

When searching for a dynamic target in an unknown real world scene,search efficiency is greatly reduced if users lack information about the spatial structure of the *** target search studies,especially in robotics,focus on determining either the shortest path when the target’s position is known,or a strategy to find the target as quickly as possible when the target’s position is ***,the target’s position is often known intermittently in the real world,e.g.,in the case of using surveillance *** goal is to help user find a dynamic target efficiently in the real world when the target’s position is intermittently *** order to achieve this purpose,we have designed an AR guidance assistance system to provide optimal current directional guidance to users,based on searching a prediction *** assume that a certain number of depth cameras are fixed in a real scene to obtain dynamic target’s *** system automatically analyzes all possible meetings between the user and the target,and generates optimal directional guidance to help the user catch up with the target.A user study was used to evaluate our method,and its results showed that compared to free search and a top-view method,our method significantly improves target search efficiency.

关键词： augmented reality(AR) search guidance