Research On Mesh Cultural Relic Model Repair Technology With Geometric Feature Constraints

The present unearthed cultural relic models have various holes with different defects.The purpose of the hole restoration technology is to keep the integrity of the models as far as possible and to exhibit the models more realistically in human’s vision,while the existing methods are difficult to recover features of the models precisely.Based on sample filling and advancing front method,we propose two kinds of model restoration algorithms in this paper,and the main work is as follows:First,a shape-constrained sample filling is proposed to solve the problem that the model has serious defect and big hole.The similarity of the projection area between fragment and hole is used to determine the initial matching candidates which can be sewed up perfectly in the hole.Then the energy function of double sparse representation is used to predict the optimal matching model.Feature descriptor is defined according to the inherent attributes between model feature points and their adjacent points,and the existing geometric features of the model are used for registration measurement to fill the fragment in the hole.The algorithm solves the problem that the large defect area results in poor effect in the traditional 3D virtual restoration.Second,a novel mesh reconstruction algorithm based on advancing front method is proposed to repair the small hole.This method can directly generate new nodes in 3D space and construct new cells.The patch mesh is generated preliminarily according to the characteristics around the hole,and then we improve the mesh fine method in order that this algorithm can adjust the triangular density of the initial patch step by step to make triangle density of every zone similar to others.Finally,Poisson surface reconstruction is carried out to smooth the entire surface.The algorithm can preserve the inherent geometric properties of the model and restore the 3D mesh model with irregular hole shape.Third,based on the technique of sample filling and mesh reconstruction,a 3D mesh model restoration system with geometric feature constraints is developed around the digital modeling of cultural relic model.The system can provide necessary guidance for professionals to repair holes and prove the robustness in the process of model repair.