Research On Digital Reconstruction And Restoration Of Symmetrical Cultural Relics Combined With Deep Learning

Cultural relics are the precious historical and cultural heritage of mankind,which are of great historical,artistic and scientific value.It is of great significance for the restoration of damaged cultural relics and the reproduction of the original appearance of cultural relics to reconstruct and archive the fine digital preserved cultural relics and permanently record the cultural relics.The beauty of symmetry is deeply rooted in the hearts of the people,and symmetrical cultural relics occupy a large proportion of the existing cultural relics.At present,there are still some problems in digital reconstruction and restoration of symmetrical cultural relics,such as difficulties in digital reconstruction of symmetrical cultural relics based on single data source,low precision of digital reconstruction model,and difficulties in digital restoration due to the lack of damaged information.In view of the above problems,this paper deeply excavates the symmetry characteristics of cultural relics,and realizes the multi-source data fusion and reconstruction of symmetrical cultural relics by studying the registration method of image and laser p oint cloud;a new data acquisition scheme is designed to obtain more complete information of large symmetrical cultural relics,so as to improve the precision of large symmetrical cultural relics reconstruction;the digital restoration method of damaged cultural relics based on symmetric information and the digital restoration method of damaged facial sculptures without symmetric information are studied to restore the original appearance of symmetric cultural relics.The main research contents are as follows:(1)Aiming at the problem that most of the current i mage and laser point cloud registration methods are based on points,lines,surfaces and their combinations,and rarely explore the inherent characteristics of cu ltural relics from a higher level,this paper proposes a registration method of image and lase r point cloud based on symmetric plane from the symmetry of cultural relics.In this method,the mirror symmetry plane of cultural relic image point cloud and las er point cloud are obtained by deep learning netw ork,and the point cloud is projected onto the mirror symmetry plane to generate the projection point cloud set.The scale parameters of image point cloud and laser point cloud are obtained.The invariant four point features of projection point cloud are extracted to realize the initial registration of image projection image point cloud and projection laser point cloud.According to the conversion parameters of projection point cloud,the initial registration of three-dimensional image point cloud and three-dimensional laser point cloud are realized.Finally,the ICP registration method with virtual points is used to optimize the registration results of image point cloud and laser point cloud.(2)Aiming at the problems of the complex structure of large symm etrical cultural relics,the incomplete information obtained by traditional data acquisition scheme and the low precision of digital reconstruction results of cultural relics,a data acquisition scheme of aerial UAV close to photogrammetry and ground laser scanning is designed.UAVs can fly around large cultural relics by setting flight points with three tilt angles of +15°,0° and-30°,and the lens points to the geometric axis of large-scale cultural relics to effectively reduce the impact of self-occlusion of cultural relics.Ground las er scanning the information of large cultural relics in lower position which is UAV missed as a compensation.Finally,the image and laser point cloud registration method proposed in this paper to realize the accurate registration of UAV image point cloud and laser point cloud,and obtain the fine reconstruction model of large cultural re lics.(3)Aiming at the difficulty of digital restoration of damaged symmetrical cultural relics,a digital restoration method of cultural relics based on symmetrical information is proposed.The mirror point cloud is obtained through the symmetrical plane of cultural relics,or the rotation point cloud is obtained through the geometric axis of cultural relics.The damaged point cloud of cultural relics is accurately registered with the mirror point cloud or the rotation point cloud.The hole boundary of the point cloud of cultural relics caused by the damage is accurately obtained by using the BPD algorithm.The mirror point cloud or the rotation point cloud are cut by using the bo undary,so that the point cloud hole of the damaged part of cultural relics i s filled,and the complete point cloud of cultural relics is obtained,so as to realize the digital restoration of the damage of symmetrical cultural relics.This method requires that the symmetry part of the damaged part of cultural relics is complete.(4)Because the digital restoration method of cultural relics based on symmetry information in this paper has a prerequisite that the damaged and symmetrical part of cultural relics is intact,otherwise the ideal restoration effect cannot be achieved.Therefore,this paper takes the facial damaged statues as the research object,proposes a digital restoration method of facial damaged statues combined with deep learning technology.The method uses deep learning network to generate facial point cloud from a single facial historical image,and fuses facial point cloud and laser point cloud to realize digital restoration of facial damaged statues.