Research On Online Inspection Technology Of Hull Components Oriented To Augmented Reality

Automatic inspection and measurement of hull components has always been an important procedure in the process of ship construction.At present,most Chinese ship companies still use traditional technical means in the inspection and measurement of hull components,with poor automation degree and accuracy,which seriously affects the construction cycle.A variety of emerging technologies in recent years also have the disadvantage of poor applicability.If the 3D CAD model of hull components is positioned as the augmented content in real time to enhance the scene image of hull components completed or under construction by using augmented reality technology,the field operator can compare the differences between the design model and the finished result quickly,intuitively and from multiple angles.At the same time,through the process information of the hull components,the field operator can complete a more comprehensive inspection and measurement.In order to achieve this goal,it is important that the composite elements are rendered and aligned in real time in an accurate and acceptable manner both scenically and visually,which is related to registration tracking in virtual-real registration.Considering the complex hull components and the construction site environment,this paper mainly applies the framework of unmarked registration tracking algorithm based on CAD model in VISP library.The real-time,accuracy and robustness of the registration tracking algorithm were improved to meet the requirements of on-line inspection of hull components.Meanwhile,in order to meet the requirements of on-site personnel,the construction process of on-line inspection system software was studied.The main works are following:Firstly,the basic principles and related algorithm modules of how VISP integrates different types of visual features for registration tracking are described in detail.In order to improve the robustness and accuracy of the registered tracking algorithm in the inherent framework,this paper studies the accurate estimation of the initial pose of the camera.SIFT local description detection operator is adopted,and the multi-point matching algorithm combined with the random sample consistency algorithm and the background interference point elimination algorithm is used to accurately solve the initial pose of the camera,and the evaluation results of the algorithm’s adaptability are given.In order to improve the real-time performance of the registration tracking algorithm,a new registration tracking algorithm based on the alternative simplified model was proposed,and the automatic detection and extraction of protrusion edge of complex polygon mesh model was studied.The advantages of the simplified algorithm in the framework of registration tracking algorithm were verified by comparative experiments.Then,based on the improved algorithm framework,the applicability of online inspection of hull components is studied,and six registration tracking schemes under different combinations of three visual features are used to verify different hull components.The results show that the more visual features fused,the more accurate and robust the algorithm is.The reliability of the output results of the optimal algorithm is judged by the correlation index.The results show that the real-time,accuracy and robustness of the algorithm all meet the expected requirements of the online inspection of complex hull components.Finally,the construction process of Augmented Reality(AR)-oriented on-line inspection system software for hull components on PC terminal is studied,mainly including fabrication process information modeling,model interaction module and module design and implementation of the whole system.We verify the feasibility of the technology by using relevant hull component model entities.The simulation results indicate that the operator can visually check whether the geometrical shape,spatial quantity relationship and process attributes of the hull components meet the design requirements through the online inspection system built by the augmented reality,and finally complete the inspection and construction tasks of the hull components faster and more accurately.