Diamond Rough Inclusion Reconstruction

In the process of cutting rough diamonds,workers require a suitable cutting scheme designed based on the location of the rough diamond inclusions,such that the retained part is away from the inclusions.In order to maximize the economic value of the rough diamonds,the cutting scheme is required to maximize the utilization ratio of the original stone.The conventional planning method entirely relies on the skill and experience of workers to design the cutting plan of the original stone,which is both inefficient and difficult to maximize the utilization ratio of the raw stone.In order to improve the utilization ratio of the rough diamonds,people regard the rough diamond cutting planning problem as one optimization problem,whose solution is under the constraints of the position of the diamond inclusions and the surface of the diamond.To solve this optimization problem,we are required to reconstruct the three-dimensional model of the diamond inclusions.In chapter 2,this paper introduces common image-based 3D reconstruction meth-ods.According to the underlying object models,this paper categorizes these methods into three classes and analyzes their respective advantages and limitations.Limited by the shooting condition and the complexity of the structure of the inclusion,conven-tional image-based 3D reconstruction methods face difficulties in the reconstruction of rough inclusion.In chapter 3,this paper analyses the shortcomings of the conventional visual hull method,and with the help of the inverse ray tracing method,we makes an improvement on the visual hull method.By evaluating the light transmittance of the voxels,the voxels with low light transmittance are retained as the voxel model of the inclusion.As a result,the reconstruction quality of the inclusion is improved.Besides,the reconstruction result of the rough diamond surface is also obtained based on the light transmittance of voxels.To reduce the time for reconstruction,this paper parallelize the algorithm based on CUDA.In chapter 4,this paper discusses the effect of light refrac-tion on the reconstruction process,and builds one light refraction model composed of the forward projection process and the backward projection process.Based upon the light refraction model,this paper builds the inverse ray tracing process and the object imaging process,reduces the impact of light refraction on our reconstruction method.In chapter 5,this paper summarizes the reconstruction method and discusses the possible improvement of our method.In this paper,the reconstruction method of rough inclusion gives one reconstruction result consistent well with the rough pictures,which completes the preliminary work for the diamond rough planning job.