与三维场景漫游相关的部分技术研究
|
摘要
三维场景漫游是指,用户通过某些设备,与屏幕上显示的真实或虚构的三维场景环境进行交互操作。这种操作能实现在虚拟环境里模拟人在真实场景中的漫游。场景漫游作为虚拟现实领域的一个重要方向,有着广阔的发展空间和应用前景。
以全面了解虚拟现实及场景漫游的相关理论研究,着重分析这个方向上前人的优秀成果为基础,深入研究了三维场景漫游中涉及的几种关键技术,其中包括场景简化的LOD(Level of Detail)技术、漫游时的碰撞检测技术和自动漫游中的路径规划技术等。
因虚拟场景的数据量大,从而导致机器的计算能力不能满足场景实时绘制的要求等问题,本文利用LOD技术对场景的实时显示进行优化。在基于规则网格模型的基础上,提出了一种对四叉树的分割和节点存储结构同时进行改进的LOD算法。它通过减少误差判断次数加快了四叉树的生成速度,同时改变传统的节点存储方式,降低了数据的冗余存储。
另外,为了能尽量真实地模拟现实世界,在三维场景中漫游时,还需解决漫游中可能产生的碰撞问题。采用一种基于混合包围盒的碰撞检测算法,对大量明显不相交的对象进行快速排除,这在一定程度上减小了检测的复杂度。根据所用数据结构的特点,算法中用了插入排序的思想并对其进行了改进,以降低时间上的开销。
最后,针对三维场景中的交互式漫游和自动路径漫游两种方式,在简单分析了交互式漫游的实现方法后,对自动漫游方式进行了仔细研究。根据所研究的三维场景漫游的特点,将三维障碍物以某种规则投影到二维平面后进行路径规划处理,并对前人基于三维空间的规划方法加以改进,成为适合本文三维场景的路径规划方法,同时对路径的合理性方面也做了处理。
3D scene walkthrough means users can interact with real or virtual 3D scene environment which is indicated on the screen by some equipment. This operation can be used to simulate the man's walkthrough in real environment. Scene walkthrough is very important in the field of VR, and has a broad horizonand bright prospect for development.
In this thesis, by having a thorough knowledge of relative theory of VR and scene walkthrough, the former research is dissected in this direction and then several key techniqies involved in 3D scene walkthrough are studied in depth. These techniqies include LOD (Level of Detail) simplifying scene, collision detection when moving and path planning for automated walkthrough.
Virtual environment always means a mass of data. Because of this problem, the computing-power of computers can not meet the needs of real-time rendering scene. In such cases the LOD is used to improve real-time scene display. On the basis of regular net model, a LOD algorithm based on improved quadtree-split and node storage is introduced. In order to expedite the speed of quadtree generation, the times of error judgment is dwindled down. And at the same time, a new node storage structure means much less redundant data can be stored than traditional way.
And besides, in order to simulate the real world best, the problem of collision should be solved at the walkthrough time in 3D scene. A collision detection algorithm based on mixed hierarchical bounding volumes is proposed. And lots of objects which don't collide with each other are excluded quickly. It reduces the complexity of detection to a certain extent. By the characteristic of data structure in this thesis, insertion sort is used and improved in the algorithm. It can reduce the consumptive of time.
Finally, for interactive walkthrough and automated walkthrough these two ways in 3D scene, the implementation method of interactive walkthrough is analysed simply, and after that automated walkthrough is researched in detail. In accordance with the peculiarity of 3D scene walkthrough researched in this thesis, obstacles having three dimensions project some shadows on two-dimensional. Then path planning is implemented on two-dimensional. The method of predecessor basis on three dimensions is improved and used in this thesis. So it is suitable for the 3D scene discussed in this thesis. At the same time the ratio-nality of path also can be thought.
以全面了解虚拟现实及场景漫游的相关理论研究,着重分析这个方向上前人的优秀成果为基础,深入研究了三维场景漫游中涉及的几种关键技术,其中包括场景简化的LOD(Level of Detail)技术、漫游时的碰撞检测技术和自动漫游中的路径规划技术等。
因虚拟场景的数据量大,从而导致机器的计算能力不能满足场景实时绘制的要求等问题,本文利用LOD技术对场景的实时显示进行优化。在基于规则网格模型的基础上,提出了一种对四叉树的分割和节点存储结构同时进行改进的LOD算法。它通过减少误差判断次数加快了四叉树的生成速度,同时改变传统的节点存储方式,降低了数据的冗余存储。
另外,为了能尽量真实地模拟现实世界,在三维场景中漫游时,还需解决漫游中可能产生的碰撞问题。采用一种基于混合包围盒的碰撞检测算法,对大量明显不相交的对象进行快速排除,这在一定程度上减小了检测的复杂度。根据所用数据结构的特点,算法中用了插入排序的思想并对其进行了改进,以降低时间上的开销。
最后,针对三维场景中的交互式漫游和自动路径漫游两种方式,在简单分析了交互式漫游的实现方法后,对自动漫游方式进行了仔细研究。根据所研究的三维场景漫游的特点,将三维障碍物以某种规则投影到二维平面后进行路径规划处理,并对前人基于三维空间的规划方法加以改进,成为适合本文三维场景的路径规划方法,同时对路径的合理性方面也做了处理。
3D scene walkthrough means users can interact with real or virtual 3D scene environment which is indicated on the screen by some equipment. This operation can be used to simulate the man's walkthrough in real environment. Scene walkthrough is very important in the field of VR, and has a broad horizonand bright prospect for development.
In this thesis, by having a thorough knowledge of relative theory of VR and scene walkthrough, the former research is dissected in this direction and then several key techniqies involved in 3D scene walkthrough are studied in depth. These techniqies include LOD (Level of Detail) simplifying scene, collision detection when moving and path planning for automated walkthrough.
Virtual environment always means a mass of data. Because of this problem, the computing-power of computers can not meet the needs of real-time rendering scene. In such cases the LOD is used to improve real-time scene display. On the basis of regular net model, a LOD algorithm based on improved quadtree-split and node storage is introduced. In order to expedite the speed of quadtree generation, the times of error judgment is dwindled down. And at the same time, a new node storage structure means much less redundant data can be stored than traditional way.
And besides, in order to simulate the real world best, the problem of collision should be solved at the walkthrough time in 3D scene. A collision detection algorithm based on mixed hierarchical bounding volumes is proposed. And lots of objects which don't collide with each other are excluded quickly. It reduces the complexity of detection to a certain extent. By the characteristic of data structure in this thesis, insertion sort is used and improved in the algorithm. It can reduce the consumptive of time.
Finally, for interactive walkthrough and automated walkthrough these two ways in 3D scene, the implementation method of interactive walkthrough is analysed simply, and after that automated walkthrough is researched in detail. In accordance with the peculiarity of 3D scene walkthrough researched in this thesis, obstacles having three dimensions project some shadows on two-dimensional. Then path planning is implemented on two-dimensional. The method of predecessor basis on three dimensions is improved and used in this thesis. So it is suitable for the 3D scene discussed in this thesis. At the same time the ratio-nality of path also can be thought.
引文
[1] Cagatay Basdogan, Chih-Hao Ho. Principles of Haptic Rendering for Virtual Environments. http://network.ku.edu.tr/～cbasdogan/Tutorials/haptictutorial.html, last access date: May 2008
[2] Christian Duriez, Frederic Dubois, Abderrahmane Kheddar, Claude Andriot.Realistic Haptic Rendering of Interacting Deformable Objects in Virtual Environments. IEEE Trans. On Visualization and Computer Graphics, 2006, 12(1): 36-47
[3] Ming Lin, Kenneth Salisbury. Haptic Rendering-Beyond Visual Computing. IEEE Computer Society, 2004, 3
[4] William A. McNeely, Kevin D. Puterbaugh, James J. Toroy. Voxel-Based 6-DOF Haptic Rendering Improvements. http://www.haptics-e.org, 2006, 3(7)
[5] Herndon, Kenneth P., and Thomas Meyer. 3D Widgets for Exploratory Scientific Visualization. Proceedings of the Seventh Annual ACM User Interface Software and Technology (UIST), 1994, 69-70
[6] Kennedy, R. S., N. E. Lane, K. S. Berbaum, and M. G. Lilienthal. Simulator Sickness Questionnaire; An Enhanced Method for Quantifying Simulator Sickness. International Journal of Aviation Psychology, 1993, 3(3): 203-220
[7] Ouh-young, Ming, David V. Beard, and Frederick P. Brooks, Jr. Force Display Performs Better Than Visual Display in a Simple 6-D Docking Task. Proceedings of the IEEE International Conference on Robotics and Automation, 1999,1466-1562
[8] Bishop, Gary. E-mail correspondence with William Sherman, April 1, 2002
[9] Zeltzer, D., Pioch, N., and Aviles, W. Training the Officer of the Deck. IEEE Computer Graphics and Applications, 1995,15(6): 6-9
[10] Darsa L, Costa B, Varshney A. Navigating Static Environment Using Image-space Simplification and Morphing. ACM Symposium on Interactive 3D Graphics, Providence, RI, 1997, 25-34, 1994, 389-399, Computer Science Technical Report TR, 1998, 98-009
[11] Sillion F, Drettakis G, Bodelet B. Efficient Impostos Manipulation for Real-time Visualization of Urban Scenery. Computer Graphics Forum (Processings of Eurographics'97), 1997, 16(3):207-218
[12] Y. Takase, N. Sho, A. Sone, K. Shimiya. Generation of Digital City Model. Journal of the Visualization Society of Japan, 2003, 23(88):21-27
[13] Witkin A, Kass M., Spacetime constraints. Computer Graphics, 1998, 22(4), 159-168
[14]Benford S.D.,Brown C.C.,Reynard G.T.,Shared Spaces:Transportation,Artificiality and Spatiality.Boston,U.S..ACM Conference on Computer Supported Cooperative Work(CSCW'96),1996,11,77-86
[15]Lee Adams.Visualization and Virtual Reality.McGraw-Hill Publishing 1993
[16]De Haemerjr,Michael J,Michael J.Zyda.Simplification of objects Rendered by Polygonal Approximations Computer&Graphics,1991,15(2):175-184
[17]Sourin,A..Nanyang Technological University Virtual Campus.IEEE Computer Graphics&Applications,2004,24(6),6-8
[18]Prasolova-Forland,E.,Sourin,A.,Sourina,O..Cybercampuses:Design Issues and Future Directions.The Visual Computer,Springer London,2006,22(12),1015-1028
[19]朱英浩,张祖勋.城市尽管实时三维动画的实现.测绘信息与工程,2000,25(1):12-15
[20]邹湘军,孙健,何汉武等.虚拟现实技术的演变发展与展望.系统仿真学报,2004,16(9):1905-1909
[21]王兆其,赵沁平,汪成为.虚拟仿真环境中物体物理特性的表示与处理.计算机研究与发展,1998,35(2):97-101
[22]秦建新,张青年.地图可视化研究.地理研究,2000,19(1):15-21
[23]李清泉,李德仁.三维空间数据模型集成的概念框架研究.测绘学报,1998,27(4):325-330
[24]徐旭明,叶榛,陶品等.基于视觉临场感的机器人遥操作系统[J],高技术通讯,2000,Vol.3:57-60
[25]Fenn,Jackie.The Microsoft System Software Hype Cycle Strikes Again.Gratner Research Report,July 1995
[26]Gayr W.Kmaemna.Laser radar signals the civilian sector[J].Laser Focus Wbrld,April,1996,81-87
[27]Woo M,Neider J,Davis T.OpenGL Programming Guide.Addison Wesley,1999
[28]Clark J H.Hierarchical geometric models for visible surface algorithms.Communication of the ACM,1976,19:547-554
[29]De Floriani,Falcidieno Nagy and Pienovi.Hierarchical structure for surface approximation.Computer Graphics,1984,183-193
[30]Hugues Hoppe.Progressive Meshes.SIGGRAPH'96 Proceedings,1996,99-108
[31]William Evans,David Kirkpatrick,Gregg Townsend,Right Triangulated Irregular Networks,Technical Report 97-09,University of Arizona,May
[32]Hoppe,H.Smooth view-dependent level-of-detail control and its application to terrain rendering,IEEE Visualization 1998,October 1998,35-42
[33]Lindstrom,P.and Koller D.and Ribarsky,W.and Hodges,L.F.and Faust,N.and Turner,G.A.Real-Time,Continuous Level of Detail Rendering of Height Fields,Proceedings of ACM SIGGRAPH 96,August 1996,109-118
[34]Duchaineau,M.and Wolinsky,M.and Sigeti,D.E,and Miller,M.C.and Aldrich,C,and Mineev-Weinstein,M.B.ROAMing Terrain:Real-time Optimally Adapting Meshes,Proceedings of Visualization 1997,81-88
[35]Rottger,S.and Heidrich,W.and Slusalleck,P.and Seidel,H.P.Real-Time Generation of Continuous Levels of Detail for Height Fields,V.Skala,editor,Proceedings of WSCG'98,1998,315-322
[36]Jonathan Blow,Terrain Rendering at High Levels of Detail,paper for the Game Developers' Conference 2000,San Jose,California,USA,March 11,2000
[37]王道臣,万旺根,唐经洲,陈华杰.基于限制四叉树LOD大规模地形预处理算.计算机工程与应用,2007,43(24):107-109
[38]芮小平,杨崇俊,张彦敏.一种改进的ROAM算法.武汉大学学报(信息科学版),2004,29(11):1008-1011
[39]芮小平.一种基于不完全四叉树的LOD生成算法[J].中国图象图形学报,2005,10(9):1152-1160
[40]R.Pajarola.Large Scale Terrain Visualization Using The Restricted Quadtree Triangulation.Proceeding of IEEE Visualization'98
[41]C.S.Fahn and S.T.Wu.The View-Dependent Real-Time Rendering of arge-Scale Terrian in Continuous Level of Detail.In Proceeding Ⅱ of NCS99
[42]范昭炜,万华根,高曙明.基于图像的快速碰撞检测算法[J].计算机辅助设计与图形学学报,2002,14(9):805-810
[43]DINGLIANA J,O'SULLIVAN C.Graceful degradation of collision handling in physically based animation[J].Computer Graphics Forum,2000,19(3):239-247
[44]Bradshow G.,Osullivan C.,Sphere-tree construction using dynamic medial axis approximation,In:Proceedings of the ACM SIGGRAPH Symposium on Computer Animation,2002,33-40
[45]Van den Bergen G.,Efficient collision detection of complex deformable models using AABB trees,Journal of Graphics Tools,1999,4(2):1-13
[46]Ar S.,Chazelle B.,Self-customized BSP trees for collision detection. Computational Geometry,Theory and Applications,2000,15(1):91-102
[47]Klosowski J T,Teld M,Mitchell J S B,et al.Efficient Collision Detection Using Bounding Volume Hierarchies of k-DOPs[J].IEEE Trans.on Visualization and Computer Graphics,1998,4(1):21-36
[48]魏迎梅,吴泉涌,石教英.碰撞检测中的固定方向凸包包围盒的研究,软件学报,2001,12(7):1056-1063
[49]Cohen J.D.,Lin M.C.,Manocha D.,et al.I-COLLIDE:An Interactive and Exact Collision Detection System for Large-Scale Environments.In:Proceedings of ACM Interactive 3D Graphics Conference,1995,189-196
[50]Chung K.,Wang.W.Quick Collision Detection of Polytopes in Virtual Environments,ACM Symposium on Virtual Reality Software and Technology,1996,1-4
[51]邹益胜,丁国富,许明恒,何邕.实时碰撞检测算法综述,计算机应用研究,2008,25(1):8-12
[52]Gottschalk S.,Lin M.,Manocha D.OBBTree:A Hierarchical Structure for Rapid Interference Detection.In:Proceedings of SIGGRAPH,1996:171-180
[53]James.T.Klosowski,Martin Held,Joseph S.B.Mitchell:Efficient collision detection using bounding volume hierarchies of k-DOPs.SIGGRAPH'96 Visual Proceedings,1996,26-37
[54]Mezger,S.Kimmerle,O.Etzmub.Hierarchical Techniques in Collision Detection for Cloth Animation.Journal of WSCG 11,2003,11(2):322-329
[55]魏迎梅.虚拟环境中碰撞检测问题的研究[D].长沙:国防科学技术大学,2000
[56]Srikanth Bandi,Daniel Thalmarm.Path finding for human motion in virtual environments[J].Computational Geometry,2000,15:103-127
[57]Petra Jansen-Osmann.Using desktop virtual environments to investigate the role of landmarks[J].Computers in Human Behavior,2002,18:427-436
[58]张惠,傅瑶,PascalHaigrlon,罗立民等.基于场景分析的交互式漫游.东南大学学报(自然科学版),2001,31(2):18-22
[59]Wei G,Kirby J T,Sinha A.Generation of waves in Boussinesq models using a source function method[J].Coastal Engineering,1999,(36):271-299
[60]C.Alexopoulos,P.M.Griffin.Path planning for a mobile robot.IEEE Transactions on Systems,Man and Cybernetics,1992,22(2):318-322
[61]Y.H.Liu,S.Arimoto.Computation of the tangent graph of polygonal obstacles by moving-line processing.IEEE Transaction on Robotics and Automation,1994, 10(6): 823-830
[62] J. F. Canny. A Voronoi method for the piano-movers problem. IEEE International Conference on Robotics and Automation, Mar 1985, Vol.2:530-535
[63] 张钹, 张玲. 无碰撞路径规划的拓扑方法. 计算机学报, 1990,12:881-889
[64] D. Parsons, J. F. Canny. A motion planner for multiple mobile robots. IEEE International Conference on Robotics and Automation, May 1990, vol.1:8-13
[65] D. Z. Chen, R. J. Szczerba, J. J. Uhran. A framed-quadtree approach for determining Euclidean shortest paths in a 2-D environment. IEEE Transactions on Robotics and Automation, Oct. 1997, 13(5): 668-681
[66] Podsedkowski L, Nowakowski J, Idzikowski M et al.A new solution for in partially known or unknown environments for nonholonomic mobile robots [J]. Autonomous Systems, 2001, 34:145-152
[67] Stentz A. Optimal and efficient path planning for unknown and dynamic environments [J]. International Journal of Robotics and Automation, 1995, 10(3): 89-100
[68] J. Borenstein, Y. Koren. Real-time obstacle avoidance for manipulators and mobile robots. IEEE Transactions on Systems, Man and Cybernetics, 1989, 5(19): 1179-1187
[69] A. Howard, H. Seraji. An Intelligent Terrain-Based Navigation System for Planetary Rovers. IEEE Robotics & Automation Magazine, 2001, 8(4):9-17
[70] A. C. Nearchou, Genetic Algorithms in Robot Trajectory Planning. PHD Thesis, University of Patras, School of Engineering, Mechanical Engineering Dept., January 1996
[71] A. C. Nearchou. Path Planning of a Mobile Robot using Genetic Heuristics. ROBOTICA, 1998, Vol. 16:575-588
[72] Yang S, Meng M.Real-time collision-free path planning of robot manipulators using neural network approaches [J] .Autonomous Robots, 2000, 9(1):27-39
[73] S. H. Piao, B. R. Hong. Path planning of robot using genetic annealing algorithm. Proceedings of the 4~(th) World Congrees on Intelligent Control and Automation, 2002, 493-495
[74] B. Bonet. H. Geffner. Planning as Heuristic Search, Artificial Intelligence, Special issue on Heuristic Search, 2001, Vol 129
[75] H. Geffner. Perspectives on Artificial Intelligence Planning. Proceedings Eighteenth National Conference on Artificial Intelligence (AAAI-2002), AAAI/MIT Press,2002,1013-1023
[76]李磊,叶涛,谭民等.移动机器人技术研究现状与未来[J].机器人,2002,24(5):475-480
[77]张起善.智能车辆定位导航系统及应用[M].北京:科学出版社,2002
[78]S.Russell and P.Norvig,Artificial Intelligence:A Modern Approach,Prentice Hall,Englewood Cliffs,NJ,1995,92-117
[79]Korf R.E.Depth-first iterative deepening:an optimal admissible tree search[J].Artificial Intelligence,1985,27(1):97-109
[2] Christian Duriez, Frederic Dubois, Abderrahmane Kheddar, Claude Andriot.Realistic Haptic Rendering of Interacting Deformable Objects in Virtual Environments. IEEE Trans. On Visualization and Computer Graphics, 2006, 12(1): 36-47
[3] Ming Lin, Kenneth Salisbury. Haptic Rendering-Beyond Visual Computing. IEEE Computer Society, 2004, 3
[4] William A. McNeely, Kevin D. Puterbaugh, James J. Toroy. Voxel-Based 6-DOF Haptic Rendering Improvements. http://www.haptics-e.org, 2006, 3(7)
[5] Herndon, Kenneth P., and Thomas Meyer. 3D Widgets for Exploratory Scientific Visualization. Proceedings of the Seventh Annual ACM User Interface Software and Technology (UIST), 1994, 69-70
[6] Kennedy, R. S., N. E. Lane, K. S. Berbaum, and M. G. Lilienthal. Simulator Sickness Questionnaire; An Enhanced Method for Quantifying Simulator Sickness. International Journal of Aviation Psychology, 1993, 3(3): 203-220
[7] Ouh-young, Ming, David V. Beard, and Frederick P. Brooks, Jr. Force Display Performs Better Than Visual Display in a Simple 6-D Docking Task. Proceedings of the IEEE International Conference on Robotics and Automation, 1999,1466-1562
[8] Bishop, Gary. E-mail correspondence with William Sherman, April 1, 2002
[9] Zeltzer, D., Pioch, N., and Aviles, W. Training the Officer of the Deck. IEEE Computer Graphics and Applications, 1995,15(6): 6-9
[10] Darsa L, Costa B, Varshney A. Navigating Static Environment Using Image-space Simplification and Morphing. ACM Symposium on Interactive 3D Graphics, Providence, RI, 1997, 25-34, 1994, 389-399, Computer Science Technical Report TR, 1998, 98-009
[11] Sillion F, Drettakis G, Bodelet B. Efficient Impostos Manipulation for Real-time Visualization of Urban Scenery. Computer Graphics Forum (Processings of Eurographics'97), 1997, 16(3):207-218
[12] Y. Takase, N. Sho, A. Sone, K. Shimiya. Generation of Digital City Model. Journal of the Visualization Society of Japan, 2003, 23(88):21-27
[13] Witkin A, Kass M., Spacetime constraints. Computer Graphics, 1998, 22(4), 159-168
[14]Benford S.D.,Brown C.C.,Reynard G.T.,Shared Spaces:Transportation,Artificiality and Spatiality.Boston,U.S..ACM Conference on Computer Supported Cooperative Work(CSCW'96),1996,11,77-86
[15]Lee Adams.Visualization and Virtual Reality.McGraw-Hill Publishing 1993
[16]De Haemerjr,Michael J,Michael J.Zyda.Simplification of objects Rendered by Polygonal Approximations Computer&Graphics,1991,15(2):175-184
[17]Sourin,A..Nanyang Technological University Virtual Campus.IEEE Computer Graphics&Applications,2004,24(6),6-8
[18]Prasolova-Forland,E.,Sourin,A.,Sourina,O..Cybercampuses:Design Issues and Future Directions.The Visual Computer,Springer London,2006,22(12),1015-1028
[19]朱英浩,张祖勋.城市尽管实时三维动画的实现.测绘信息与工程,2000,25(1):12-15
[20]邹湘军,孙健,何汉武等.虚拟现实技术的演变发展与展望.系统仿真学报,2004,16(9):1905-1909
[21]王兆其,赵沁平,汪成为.虚拟仿真环境中物体物理特性的表示与处理.计算机研究与发展,1998,35(2):97-101
[22]秦建新,张青年.地图可视化研究.地理研究,2000,19(1):15-21
[23]李清泉,李德仁.三维空间数据模型集成的概念框架研究.测绘学报,1998,27(4):325-330
[24]徐旭明,叶榛,陶品等.基于视觉临场感的机器人遥操作系统[J],高技术通讯,2000,Vol.3:57-60
[25]Fenn,Jackie.The Microsoft System Software Hype Cycle Strikes Again.Gratner Research Report,July 1995
[26]Gayr W.Kmaemna.Laser radar signals the civilian sector[J].Laser Focus Wbrld,April,1996,81-87
[27]Woo M,Neider J,Davis T.OpenGL Programming Guide.Addison Wesley,1999
[28]Clark J H.Hierarchical geometric models for visible surface algorithms.Communication of the ACM,1976,19:547-554
[29]De Floriani,Falcidieno Nagy and Pienovi.Hierarchical structure for surface approximation.Computer Graphics,1984,183-193
[30]Hugues Hoppe.Progressive Meshes.SIGGRAPH'96 Proceedings,1996,99-108
[31]William Evans,David Kirkpatrick,Gregg Townsend,Right Triangulated Irregular Networks,Technical Report 97-09,University of Arizona,May
[32]Hoppe,H.Smooth view-dependent level-of-detail control and its application to terrain rendering,IEEE Visualization 1998,October 1998,35-42
[33]Lindstrom,P.and Koller D.and Ribarsky,W.and Hodges,L.F.and Faust,N.and Turner,G.A.Real-Time,Continuous Level of Detail Rendering of Height Fields,Proceedings of ACM SIGGRAPH 96,August 1996,109-118
[34]Duchaineau,M.and Wolinsky,M.and Sigeti,D.E,and Miller,M.C.and Aldrich,C,and Mineev-Weinstein,M.B.ROAMing Terrain:Real-time Optimally Adapting Meshes,Proceedings of Visualization 1997,81-88
[35]Rottger,S.and Heidrich,W.and Slusalleck,P.and Seidel,H.P.Real-Time Generation of Continuous Levels of Detail for Height Fields,V.Skala,editor,Proceedings of WSCG'98,1998,315-322
[36]Jonathan Blow,Terrain Rendering at High Levels of Detail,paper for the Game Developers' Conference 2000,San Jose,California,USA,March 11,2000
[37]王道臣,万旺根,唐经洲,陈华杰.基于限制四叉树LOD大规模地形预处理算.计算机工程与应用,2007,43(24):107-109
[38]芮小平,杨崇俊,张彦敏.一种改进的ROAM算法.武汉大学学报(信息科学版),2004,29(11):1008-1011
[39]芮小平.一种基于不完全四叉树的LOD生成算法[J].中国图象图形学报,2005,10(9):1152-1160
[40]R.Pajarola.Large Scale Terrain Visualization Using The Restricted Quadtree Triangulation.Proceeding of IEEE Visualization'98
[41]C.S.Fahn and S.T.Wu.The View-Dependent Real-Time Rendering of arge-Scale Terrian in Continuous Level of Detail.In Proceeding Ⅱ of NCS99
[42]范昭炜,万华根,高曙明.基于图像的快速碰撞检测算法[J].计算机辅助设计与图形学学报,2002,14(9):805-810
[43]DINGLIANA J,O'SULLIVAN C.Graceful degradation of collision handling in physically based animation[J].Computer Graphics Forum,2000,19(3):239-247
[44]Bradshow G.,Osullivan C.,Sphere-tree construction using dynamic medial axis approximation,In:Proceedings of the ACM SIGGRAPH Symposium on Computer Animation,2002,33-40
[45]Van den Bergen G.,Efficient collision detection of complex deformable models using AABB trees,Journal of Graphics Tools,1999,4(2):1-13
[46]Ar S.,Chazelle B.,Self-customized BSP trees for collision detection. Computational Geometry,Theory and Applications,2000,15(1):91-102
[47]Klosowski J T,Teld M,Mitchell J S B,et al.Efficient Collision Detection Using Bounding Volume Hierarchies of k-DOPs[J].IEEE Trans.on Visualization and Computer Graphics,1998,4(1):21-36
[48]魏迎梅,吴泉涌,石教英.碰撞检测中的固定方向凸包包围盒的研究,软件学报,2001,12(7):1056-1063
[49]Cohen J.D.,Lin M.C.,Manocha D.,et al.I-COLLIDE:An Interactive and Exact Collision Detection System for Large-Scale Environments.In:Proceedings of ACM Interactive 3D Graphics Conference,1995,189-196
[50]Chung K.,Wang.W.Quick Collision Detection of Polytopes in Virtual Environments,ACM Symposium on Virtual Reality Software and Technology,1996,1-4
[51]邹益胜,丁国富,许明恒,何邕.实时碰撞检测算法综述,计算机应用研究,2008,25(1):8-12
[52]Gottschalk S.,Lin M.,Manocha D.OBBTree:A Hierarchical Structure for Rapid Interference Detection.In:Proceedings of SIGGRAPH,1996:171-180
[53]James.T.Klosowski,Martin Held,Joseph S.B.Mitchell:Efficient collision detection using bounding volume hierarchies of k-DOPs.SIGGRAPH'96 Visual Proceedings,1996,26-37
[54]Mezger,S.Kimmerle,O.Etzmub.Hierarchical Techniques in Collision Detection for Cloth Animation.Journal of WSCG 11,2003,11(2):322-329
[55]魏迎梅.虚拟环境中碰撞检测问题的研究[D].长沙:国防科学技术大学,2000
[56]Srikanth Bandi,Daniel Thalmarm.Path finding for human motion in virtual environments[J].Computational Geometry,2000,15:103-127
[57]Petra Jansen-Osmann.Using desktop virtual environments to investigate the role of landmarks[J].Computers in Human Behavior,2002,18:427-436
[58]张惠,傅瑶,PascalHaigrlon,罗立民等.基于场景分析的交互式漫游.东南大学学报(自然科学版),2001,31(2):18-22
[59]Wei G,Kirby J T,Sinha A.Generation of waves in Boussinesq models using a source function method[J].Coastal Engineering,1999,(36):271-299
[60]C.Alexopoulos,P.M.Griffin.Path planning for a mobile robot.IEEE Transactions on Systems,Man and Cybernetics,1992,22(2):318-322
[61]Y.H.Liu,S.Arimoto.Computation of the tangent graph of polygonal obstacles by moving-line processing.IEEE Transaction on Robotics and Automation,1994, 10(6): 823-830
[62] J. F. Canny. A Voronoi method for the piano-movers problem. IEEE International Conference on Robotics and Automation, Mar 1985, Vol.2:530-535
[63] 张钹, 张玲. 无碰撞路径规划的拓扑方法. 计算机学报, 1990,12:881-889
[64] D. Parsons, J. F. Canny. A motion planner for multiple mobile robots. IEEE International Conference on Robotics and Automation, May 1990, vol.1:8-13
[65] D. Z. Chen, R. J. Szczerba, J. J. Uhran. A framed-quadtree approach for determining Euclidean shortest paths in a 2-D environment. IEEE Transactions on Robotics and Automation, Oct. 1997, 13(5): 668-681
[66] Podsedkowski L, Nowakowski J, Idzikowski M et al.A new solution for in partially known or unknown environments for nonholonomic mobile robots [J]. Autonomous Systems, 2001, 34:145-152
[67] Stentz A. Optimal and efficient path planning for unknown and dynamic environments [J]. International Journal of Robotics and Automation, 1995, 10(3): 89-100
[68] J. Borenstein, Y. Koren. Real-time obstacle avoidance for manipulators and mobile robots. IEEE Transactions on Systems, Man and Cybernetics, 1989, 5(19): 1179-1187
[69] A. Howard, H. Seraji. An Intelligent Terrain-Based Navigation System for Planetary Rovers. IEEE Robotics & Automation Magazine, 2001, 8(4):9-17
[70] A. C. Nearchou, Genetic Algorithms in Robot Trajectory Planning. PHD Thesis, University of Patras, School of Engineering, Mechanical Engineering Dept., January 1996
[71] A. C. Nearchou. Path Planning of a Mobile Robot using Genetic Heuristics. ROBOTICA, 1998, Vol. 16:575-588
[72] Yang S, Meng M.Real-time collision-free path planning of robot manipulators using neural network approaches [J] .Autonomous Robots, 2000, 9(1):27-39
[73] S. H. Piao, B. R. Hong. Path planning of robot using genetic annealing algorithm. Proceedings of the 4~(th) World Congrees on Intelligent Control and Automation, 2002, 493-495
[74] B. Bonet. H. Geffner. Planning as Heuristic Search, Artificial Intelligence, Special issue on Heuristic Search, 2001, Vol 129
[75] H. Geffner. Perspectives on Artificial Intelligence Planning. Proceedings Eighteenth National Conference on Artificial Intelligence (AAAI-2002), AAAI/MIT Press,2002,1013-1023
[76]李磊,叶涛,谭民等.移动机器人技术研究现状与未来[J].机器人,2002,24(5):475-480
[77]张起善.智能车辆定位导航系统及应用[M].北京:科学出版社,2002
[78]S.Russell and P.Norvig,Artificial Intelligence:A Modern Approach,Prentice Hall,Englewood Cliffs,NJ,1995,92-117
[79]Korf R.E.Depth-first iterative deepening:an optimal admissible tree search[J].Artificial Intelligence,1985,27(1):97-109