A Method For Construction And Interaction Collaboration Of Disaster Scenes Within Mobile Virtual Reality

Disasters often cause a large number of casualties and considerable property losses.Disaster virtual geographic environment(DVGE)can directly display the current,past and future conditions of a disaster area,and can provide intuitive information support and decision-making analysis functions for all kinds of personnel related to disaster emergency.It is of great significance for mitigating the potential adverse effects caused by disasters.Although a large amount of research and practice has been carried out on the DVGE,there are still some problems in the face of disaster emergency response,such as insufficient mobility,weak immersion,and lack of collaborative visualization of scenes.It is difficult to effectively support different users distributed in different places to perceive and recognize the disaster environment faster and better.In response to the above problems,a method for construction and interaction collaboration of disaster scenes within mobile virtual reality(VR)is proposed as a result of this thesis with the support of smartphones,head-mounted displays(HMDs)and Web GL technology.By breaking through the key technologies and methods such as mobile VR disaster scene construction and optimization,gaze interaction and collaborative situation awareness,disaster emergency personnel in different places can perceive and recognize disaster-related information faster and better.The main contents of this thesis are as follows:Firstly,a method for construction and rendering optimization of a disaster scene within mobile VR was proposed.Aiming at the problems of small storage capacity and low rendering efficiency of existing smart phones,we designed a mobile VR disaster scene construction scheme under plugin-free B/S architecture,and established a diversified organization mechanism of disaster scene for smartphones with different performance and diversified display environment.We analyzed the construction technology of terrain,disaster simulation model and representative ground objects,and studied the diverse scene data expression methods of different scene models,and proposed the optimization and adaptive scheduling strategy for mobile VR disaster scene.Those works can realize the optimization organization and adaptive visualization of disaster scene for smartphones,and meets the requirements of high frame rate rendering of mobile VR disaster scenes.Then,an interaction mode for mobile VR disaster scenes was designed based on gaze.Pointing at the issue that conventional touch scene interaction cannot be used in mobile VR,we made compare and analysis on various VR scene interaction modes and various mobile VR device interaction modes,and elaborated the theory of gaze interaction method and mobile VR scene gaze interaction and their application scenarios.Considering the needs of roaming exploration and query analysis of large-scale disaster scenes,we made some researches on multi-level virtual user interface design,coordinate transformation between camera coordinate and world coordinate and user interface dynamic control algorithm.Based on the above researches,we designed a dynamic UI generation method based on gaze and established a mechanism for disaster scene roaming exploration and interactive query of disaster information.These works can realize the effective interaction of large-scale disaster scenes in mobile VR mode.Thirdly,a mobile VR collaborative method for disaster situation awareness was established.In response to the needs of various people distributed in different places for real-time perception of disaster situation information during disaster emergency,we defined the disaster situation awareness and analyzed the ways of disaster situation awareness,and described the necessity of collaborative disaster situation awareness by mobile VR.We established the mobile VR collaborative mode of disaster scenes from the levels of disaster scene construction,scene interaction and scene analysis,and designed the mobile VR collaborative task model and hybrid architecture from the aspects of disaster environment perception,disaster information understanding and future trend prediction analysis.Then,we established a disaster situation collaborative sensing workflow,and proposed a mobile VR collaborative concurrency control method.These results effectively support various users distributed in different places to carry out collaborative operation of disaster scenarios and realize collaborative awareness of disaster situation information.Finally,using the Node.js,Jetty,HTML5,Java Script,Cesium open source framework,AJAX,SQL server and other technologies,a prototype system for mobile VR disaster scene construction,interaction and collaboration was developed based on the above research results.Taking the flood disaster as an example,we used this system to carry out experimental analysis on a selected experimental area.The experimental results show that:the method proposed can achieve high frame rate rendering of mobile VR disaster scene,and the rendering frame rate can be stable above 50fps;the prototype system supports Apple and Android phones,and can run on mainstream browsers such as Chrome and Firefox;It can effectively support roaming exploration of disaster scenes,disaster simulation analysis,disaster information interaction analysis and other visual exploration analysis;it can effectively support multi-user collaborative perception of disaster situation information.