The Research On Virtual Repair Technology For Bronze Deformation Fragments

Due to the long history,most bronze cultural relics have been damaged to varying degrees when they are unearthed.Among them,the deformation of fragments caused by collapse and extrusion have a greater impact on the subsequent splicing and restoration.Computer-aided virtual restoration of deformed fragments of bronze can not only provide data closer to the original state of cultural relics for subsequent virtual restoration,such as fragment splicing,hole filling and three-dimensional mapping,but also provide a reference for the deformation restoration of similar objects.Therefore,this paper takes the bronze fragments collected in the museum as the research object,and classifies the fragments according to their deformation degree.The main work is as follows:(1)The idea of classifying and repairing deformed fragments of bronze is proposed.Based on the analysis of the deformation characteristics of bronze fragments,they can be divided into slight deformation and severe deformation according to the degree of deformation,which lay a foundation for the subsequent classification and repair.(2)For slightly deformed bronze fragments,a multi-constraint deformation repair algorithm for non-rigid objects is proposed.Firstly,the fragments are rasterized to extract the cross-section curves.Secondly,the mean value of the normal vector of the point in the three section curves passing through the deformation point is calculated to obtain the direction constraint of the deformation point.Thirdly,the position constraint is worked out with the point set curvature and Voronoi diagram.Then move deformation points to get initial repair result by the means of directional constraint and position constraint.In order to avoid local optimization,finally,the local repaired point set is globally fine-tuned to obtain the final repair result under least squares method.(3)A non-rigid deformation repair algorithm based on skeleton and contour feature linesis proposed for severely deformed bronze fragments.Firstly,the contours and the feature lines of point cloud are extracted based on neighborhood geometric properties.Secondly,the connected domains are marked by combining the Gaussian curvature and Morse function of point cloud,and the contraction direction of point cloud is defined to get point cloud skeleton points.Then fit surface with skeleton points and contour feature lines to get the initial repair result by the means of least square.In order to get final repair result,the loop surface subdivison is used to find repair positions of all point sets.(4)A virtual restoration system for deformed fragments of bronze is designed and implemented.The whole restoration system is designed and developed based on matlab.It realizes the functions of classification of deformed fragments,virtual repair of slight deformation fragments and severe deformation fragments.