Research On The Method Of Soft Tissue Deformation Simulation Based On Subspace Aggregation

With the development of virtual reality technology,people pay attention to the virtual surgery technology which applied to medical field.The system of virtual surgery involves the applications such as model reconstruction,collision detection,deformation simulation,cutting simulation,and so on.Among them,the effect of deformation simulation has a direct impact on the operation of virtual surgery,and has an important influence on the cutting step in virtual surgery as well.Therefore,the process of deformation simulation plays an important role in the virtual surgery.In the traditional deformation model,authenticity is always opposed to real-time performance.So this paper proposes a method of subspace agglomeration for deformation simulating,which uses the calculation method of the full space and the subspace to solving the problem of deformation area and no-deformation area individually.Then the authenticity and real-time in deformation process was balanced.The main contents of this paper are as follows:(1)Three-dimensional reconstruction of soft tissue.This paper proposes a region growing method based on threshold to segment soft tissue,draws triangle surface by using partition area to realize the reconstruction of 2D image to 3D model,and uses the OpenGL to render the reconstructed model which is facet model of Soft tissue.(2)Soft tissue deformation in subspace aggregation.This paper analyzes the geometric model of soft tissue from the view of biomechanics according to the requirement,uses the method of AABB bounding box to detect the real-time collision.In addition,a model based on the method of subspace aggregation was built,after the analysis and comparison several kinds of models.Then the three-dimensional model is mapped to a two-dimensional planar circular.The areas can be divided into the full space and subspace according to whether they deformed or not.The areas are parallel computed in order to ensure the authenticity and real-time performance of soft tissue deformation simulation.(3)Optimization of soft tissue deformation based on subspace condensation.This thesis proposes the optimization and improvement methods according to the defects found in the process of collision detection,space mapping during and subspace condensation:optimizes the collision detection by the combination of AABB bounding box and triangles intersect,optimizes space mapping by using kernel,optimizes subspace condensation by generating,selecting and separating the optimal pure subspaces.Finally,the experiment shows that the optimal subspace model has higher veracity which through the simulation and analysis.Finally,this thesis designs and develops a complete experimental system for soft tissue deformation simulation,completes the integration of each module and gives the experimental results and future prospects.The experimental results show that the simulation method of soft tissue deformation based on subspace aggregation has batter effects and takes shorter time,balances the features of authenticity and real-time performance.which plays an important guiding role to virtual deformation simulation in virtual surgery.