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Radiance-based color calibration for image-based modeling with multiple cameras

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Science china(Information Sciences) 2012年第7期55卷 1509-1519页

作者： zhao Xu 1,2 ,zhou zhong 1,2.& WU Wei 1,2.1 state key laboratory of virtual reality technology and systems,beihang university,beijing 100191,china 2 School of Computer Science and Engineering,beihang university,beijing 100191,china state key laboratory of virtual reality technology and systems Beihang University Beijing China School of Computer Science and Engineering Beihang University Beijing China

Photo-consistency estimation is an important part for many image-based modeling *** paper presents a novel radiance-based color calibration method to reduce the uncertainty of photo-consistency estimation across multiple *** idea behind our method is to convert colors into a uniform radiometric color space in which multiple image data are *** results demonstrate that our method can achieve comparable color calibration effect without adjusting camera parameters and is more robust than other existing ***,we obtain an auto-determined threshold for photo-consistency check,which will lead to a better performance than existing photo-consistency based reconstruction algorithms.

关键词： color calibration photo-consistency estimation multi-camera system image-based modeling

A Sensor-Service Collaboration Approach for Target Tracking in Wireless Camera Networks

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china Communications 2017年第7期14卷 44-56页

作者： Shuai zhao le Yu state key laboratory of Networking and Switching technology Beijing University of Posts and Telecommunications china Mobile Information Security Center

Mobile target tracking is a necessary function of some emerging application domains, such as virtual reality, smart home and intelligent healthcare. However, existing portable devices for target tracking are resource intensive and high-cost. Camera tracking is an effective location tracking way for those emerging applications which can reuse the existing ubiquitous video monitoring system. This paper proposes a dynamic community-based camera collaboration(D3C) framework for target location and tracking. The contributions of D3C mainly include that(1) nonlinear perspective projection model is selected as the camera sensing model and sequential Monte Carlo is employed to predict the target location;(2) a dynamic collaboration scheme is proposed, it is based on the local community-detection theory deriving from social network analysis. The performance of proposed approach is validated by both synthetic datasets and real-world application. The experiment results show that D3C meets the versatility, real-time and fault tolerance requirements of target tracking applications.

关键词： service collaboration camera tracking community detection sequential monte carlo

Color liquid crystal grating based color holographic 3D display system with large viewing angle

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light(Science & Applications) 2024年第1期13卷 103-112页

作者： Di Wang Yi-long li Fan Chu Nan-Nan li zhao-Song li Sin-Doo lee zhong-Quan Nie Chao liu Qiong-Hua Wang School of Instrumentation and Optoelectronic Engineering Beihang UniversityBeijing 100191China state key laboratory of virtual reality technology and systems Beihang UniversityBeijing 100191China Display technology Research Center Seoul National UniversityGwanak-ro 1Gwanak-guSeoul 08826Republic of Korea key lab of Advanced Transducers and Intelligent Control System Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China

Holographic 3D display is highly desirable for numerous applications ranging from medical treatments to military ***,it is challenging to simultaneously achieve large viewing angle and high-fidelity color reconstruction due to the intractable constraints of existing ***,we conceptually propose and experimentally demonstrate a simple and feasible pathway of using a well-designed color liquid crystal grating to overcome the inevitable chromatic aberration and enlarge the holographic viewing angle,thus enabling large-viewing-angle and color holographic 3D *** use of color liquid crystal grating allows performing secondary diffraction modulation on red,green and blue reproduced images simultaneously and extending the viewing angle in the holographic 3D display *** principle,a chromatic aberration-free hologram generation mechanism in combination with the color liquid crystal grating is proposed to pave the way for on such a superior holographic 3D *** proposed system shows a color viewing angle of~50.12°,which is about 7 times that of the traditional system with a single spatial light *** work presents a paradigm for achieving desirable holographic 3D display,and is expected to provide a new way for the wide application of holographic display.

关键词： holographic angle crystal

Self-adjustable hyper-graphs for video pose estimation based on spatial-temporal subspace construction

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Science china(Information Sciences) 2022年第3期65卷 260-262页

作者： Jizhou MA Shuai lI Hong QIN Aimin HAO qinping zhao state key laboratory of virtual reality technology and systems Beihang University Department of Computer Science Stony Brook University

Dear editor,In recent years many supervised video pose estimation methods have achieved growing successes based on well-labeled training datasets. Nonetheless, when facing roughly-labeled training data, it still remains challenging to intrinsically encode the video contents’ spatial-temporal coherency for robust video pose *** researches aimed to directly improve and refine the existing confidence maps by combining the spatial-temporal structure models [1, 2]. li et al.

关键词： Video Pose Estimation Self-adjustable Hyper-graph Spatial-temporal Subspace Exploration Maximum Matching Subspace Operator Action Pattern

Designing planar cubic B-spline curves with monotonic curvature for curve interpolation

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Computational Visual Media 2020年第3期6卷 349-354页

作者： Aizeng Wang Chuan He Fei Hou Zhanchuan Cai Gang zhao School of Mechanical Engineering&Automation Beihang UniversityBeijing 100191China state key laboratory of virtual reality technology&systems Beihang UniversityBeijing 100191China state key laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijing 100190China university of Chinese Academy of Sciences Beijing 100049China Faculty of Information technology Macao University of Science and TechnologyMacao 999078China

Monotonic curvature plays an important role in industrial design and styling of curves with aesthetic shapes,e.g.,in automobile and aircraft design[1].Used in conventional parametric CAD/CAM systems,general B-splines are not adequate for aesthetic *** for the straight line and circle,monotonic curvature distribution,associated with pleasing shape,is very difficult to achieve.

关键词： curvature monotonic curves

Orthodontic simulation system with force feedback for training complete bracket placement procedures

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virtual reality & Intelligent Hardware 2021年第4期3卷 261-273页

作者： Fan YE luwei lIU Bin YAN Xiaohan zhao Aimin HAO state key laboratory of virtual reality technology and systems Beihang UniversityBeijing 100083China Jiangsu key laboratory of Oral Diseases Nanjing Medical UniversityNanjing 210029China Department of Orthodontics School of StomatologyNanjing Medical UniversityNanjing 210029China

Background A virtual system that simulates the complete process of orthodontic bracket placement can be used for pre-clinical skill training to help students gain confidence by performing the required tasks on a virtual *** The hardware for the virtual simulation system is built using two force feedback devices to support bi-manual force feedback operation.A 3D mouse is used to adjust the position of the virtual patient.A multi-threaded computational methodology is adopted to satisfy the requirements of the frame *** computation threads mainly consist of the haptic thread running at a frequency of>1000Hz and the graphic thread at>*** graphic thread allows the graphics engine to effectively display the visual effects of biofilm removal and acid erosion through texture *** the haptic thread,the physics engine adopts the hierarchy octree collision-detection algorithm to simulate the multi-point and multi-region interaction between the tools and the virtual *** high efficiency guarantees that the time cost can be controlled within 1 *** physics engine also performs collision detection between the tools and particles,making it possible to simulate paint and removal of *** surface-contact constraints are defined in the system;this ensures that the bracket will not divorce from or embed into the tooth during the adjustment of the ***,the simulated adjustment is more realistic and *** A virtual system to simulate the complete process of orthodontic bracket bonding was *** addition to bracket bonding and adjustment,the system simulates the necessary auxiliary steps such as smearing,acid etching,and ***,the system supports personalized case *** The system provides a new method for students to practice orthodontic skills.

关键词： Orthodontic treatment Complete procedures Force feedback Simulation system

Visual object tracking- classical and contemporary approaches

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Frontiers of Computer Science 2016年第1期10卷 167-188页

作者： Ahmad AlI Abdul JAlIl Jianwei NIU Xiaoke zhao Saima RATHORE Javed AHMED Muhammad AKSAM IFTIKHAR Department of Computer and Information Sciences Pakistan Institute of Engineering & Applied Sciences Islamabad 44000 Pakistan state key laboratory of virtual reality technology and systems School of Computer Science and Engineering Beihang University Beijing 100191 China Department of Electrical (Telecom) Engineering NUST Military College of Signals Islamabad 44000 Pakistan COMSATS Institute of Information technology Lahore 54000 Pakistan

Visual object tracking （VOT） is an important sub- field of computer vision. It has widespread application do- mains, and has been considered as an important part of surveillance and security system. VOA facilitates finding the position of target in image coordinates of video frames. While doing this, VOA also faces many challenges such as noise, clutter, occlusion, rapid change in object appearances, highly maneuvered （complex） object motion, illumination changes. In recent years, VOT has made significant progress due to availability of low-cost high-quality video cameras as well as fast computational resources, and many modern techniques have been proposed to handle the challenges faced by VOT. This article introduces the readers to 1） VOT and its applica- tions in other domains, 2） different issues which arise in it, 3） various classical as well as contemporary approaches for object tracking, 4） evaluation methodologies for VOT, and 5） online resources, i.e., annotated datasets and source code available for various tracking techniques.

关键词： visual object tracking computer vision imageprocessing point tracking kernel tracking silhouette track-ing

Typical curve with G1 constraints for curve completion

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Visual Computing for Industry,Biomedicine,and Art 2021年第1期4卷 283-294页

作者： Chuan He Gang zhao Aizeng Wang Fei Hou Zhanchuan Cai Shaolin li School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China state key laboratory of lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China state key laboratory of virtual reality technology and systems Beihang UniversityBeijing 100191China state key laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijing 100190China state key laboratory of Computer Science Institute of SoftwareUniversity of Chinese Academy of SciencesBeijing 100049China Faculty of Information technology Macao University of Science and TechnologyMacao 999078China

This paper presents a novel algorithm for planar G1 interpolation using typical curves with monotonic *** G1 interpolation problem is converted into a system of nonlinear equations and sufficient conditions are provided to check whether there is a *** proposed algorithm was applied to a curve completion *** main advantages of the proposed method are its simple construction,compatibility with NURBS,and monotonic curvature.

关键词： Typical curves Monotonic curvature G1 interpolation Curve completion Euler spiral

面向月球科研站任务的地月准实时遥操作模拟验证系统设计与关键技术研究

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上海航天（中英文） 2024年第1期41卷 11-23页

作者：王镓胡国林罗益鸿梁家林万文辉赵迪薄正北京航天飞行控制中心北京100094 中国科学院空天信息创新研究院/遥感科学国家重点实验室北京100101 华中科技大学机械工程学院湖北武汉430074 中国科学院空间应用工程与技术中心北京100094

针对月球科研站任务地月遥操作需求和特点,设计地月准实时遥操作模拟验证系统,对其中的关键技术海量多尺度遥感数据环境感知、空地协同高精度定位、基于混合现实的预测仿真等进行了研究。提出了基于海量多尺度遥感数据的联合处理方法,... 详细信息

针对月球科研站任务地月遥操作需求和特点,设计地月准实时遥操作模拟验证系统,对其中的关键技术海量多尺度遥感数据环境感知、空地协同高精度定位、基于混合现实的预测仿真等进行了研究。提出了基于海量多尺度遥感数据的联合处理方法,环境感知数据融合可处理米级至厘米级环境感知结果;设计基于空地多运动平台协同定位的原型软件,空地协同地标约束下,定位精度不低于轨道器影像1个像素;开发了带有力觉反馈的预测仿真验证平台,在2~3 s变时延约束下可在仿真环境下协同演示遥操作过程,真实还原从端的遥操作作业场景,提高遥操作的执行效率和安全性。为地面人员的方案设计、操作手训练、故障处置等提供实时支持,为我国未来实施月球科研站任务筑牢基础。

关键词：月球科研站遥操作遥感制图任务规划空地协同定位预测仿真