Research And Prototype Design Of Augmented Reality Visualization Of Underground Pipeline On Mobile

Urban underground pipelines are one of the important parts of modern city construction.They have the functions of transmitting information,transmitting energy and reducing floods.With the rapid development of the city,the coverage of underground pipelines has been continuously expanded,and the number of pipelines and related management data have also followed.The rapid growth has accelerated the problems of the traditional pipeline management system,such as the lack of space in the pipeline map,the inflexible construction monitoring and collision detection decisions,and the large workload of ground building model storage and rendering.Therefore,scientific management of underground pipelines is an inevitable requirement for the safe and stable and efficient operation of cities.Augmented Reality(AR)has the characteristics of strong immersion and flexible interaction.Combining AR technology with underground pipeline systems has become a new technical solution for pipeline planning and management in the future.This subject has carried out research on the realization of AR system based on high-precision positioning in the Android mobile terminal.The subject is derived from the management and information service system of underground engineering of Shanghai Zhicheng Pipe Network Co.,Ltd.The design and implementation of the system has significantly improved the efficiency of pipeline information management and decision-making,which has technical practical significance and good social and economic benefits.The content of this topic is as follows:(1)Propose the technical scheme of the mobile terminal's underground pipeline augmented reality prototype system.Requirement analysis,overall architecture and functional module design of the system,detailed design of the system's hardware platform workflow and software platform functional structure,including seven major functions: G-RTK positioning function,pipeline data management analysis function,interactive communication function,ARCore-based environment understanding function,motion tracking function,virtual-real fusion function,pipeline visualization and interaction function.(2)Research and application of G-RTK high-precision positioning,seven-parameter coordinate conversion algorithm,hybrid registration and visual inertial odometry(VIO).This system is a position-based AR system.One of the keys to accurate registration of virtual objects in real scenes is high-precision positioning.RTK and GPS technology is used to design and implement a G-RTK positioning scheme on the Android platform.The positioning accuracy is improved to the centimeter level.The seven-parameter coordinate conversion algorithm was researched and used to transform the pipeline data from latitude and longitude coordinates to the Cartesian coordinate system of the Unity3 D platform,and used My SQL to manage the pipeline attribute database.The hybrid registration technology is used to calculate the position and pose matrix of the virtual object in the real scene,and the anchor point and VIO algorithm are used to reduce the drift error during the movement.The virtual-real fusion process estimates the ambient light of the real scene and renders the virtual model and shadow based on the principle of lighting consistency.Six interaction modes of the pipeline model are designed and implemented according to the concept of human-computer interaction,which can flexibly observe the spatial relationship and attribute information of the pipeline.(3)Perform functional and performance tests on the system separately.The system is tested in combination with actual application scenarios.Among them,the functional test is to verify the availability and stability of the seven major function modules of the system,and the performance test mainly evaluates the drift and tracking error of the pipeline model.The model drift experiment data shows that the drift value of the virtual model within 10 minutes is about 0.1 meters,and the deviation range of the X-axis and Y-axis positions is 0.01 ? 0.02 meters.Analyze according to the system requirements index and test result comparison table,and the test results meet the function and performance indicators proposed in this research topic.