Optical Capture Based Development Of Virtual Interaction System

Virtual reality system, which can achieve multi-channel information transferthrough sound, video, and tactual sensation, provides probability and methods forefficient flexible Human-Computer Interaction. Since Motion capture technology canobtain the object’s motion state in real environment, it provides technical guarantee forcommunication between virtual environments and real ones. For these reasons, theresearch onthe technology and realization of Human-Computer Interaction in virtualreality system by means of passive optical motion capture system is conducted indissertation.To establish the virtual interaction system based on optical motion capture, thefunctional structures and performance requirements, and key technology of virtualinteraction system are discussed. On this basis, generalframework of the system isconstructed, and constitutions and structures of the software and hardware modulesareformulated. Additionally, the software layers are related classes are designed.In this thesis,interactive environment of virtual interaction system is created,including analysis of human body structure and establishment of geometric model ofhuman body. The development of data interface for geometric model makes datatransfer possible between commercial CAD model and virtual interaction system.Meanwhile, it analyzes movement characteristics of human hands andbuilds hierarchicalstructure model for the movement of human hands. The motion parameter of handmodel is also determined. Based on detection precision and efficiencyanalysisofcollision detection algorithm, suitable collision detection methods for this research isselected, and real-time collision detection by means of bounding volume hierarchies isachieved.According to human motion model, placing position of markers are identified. Thecalibration of cameras is conducted, and real-time motion capture is applied tomovement of human hands. In addition, communication protocol and data structure ofVicon Real-Time Energy are analyzed, motion data interface is developed based on theSoftware Development Kit (SDK) of Vicon and data communication between Vicon andvirtual interactive system is implemented. Moreover, motion control is applied togeometric model of human body as well as mapping image from human hand’s motionto virtual hand motion model is established. Furthermore, itstudieshuman handsgrabbing motion and defines grabbing rulesof virtual hands for grabbing motion ofobjects in VR Environment.Finally, development and test of virtual interaction system are accomplished. Thedevelopment of environment is conducted by Visual Studio2008, working as a development tool, in combination with Vicon optical motion capture system andOpenGL (Open graphics library). The model database is set up through the employmentof SQL Server2005, which makes the management of model data possible.Variousmotions, such as grabbing, moving and release are demonstratedin the virtualinteraction system for the aimingmanipulations tasks.