Research On Simulation Methods For Burn Phenomena In Virtual Surgery

Virtual Reality(VR)is an information technology emerging at the beginning of this century.At present,it has been widely used in various fields.Among them,the virtual surgery system is an important application of virtual reality technology in medical education.In addition to providing doctors with a virtual surgical training method,it can also help doctors in real preoperative simulations and other aspects.Therefore,many domestic and foreign researchers have done a lot of research in this field.In various surgical procedures,since cauterization is a common surgical operation for hemostasis and wound treatment,it is very important to simulate its phenomenon.In order to make the simulation effect of burning phenomenon conform to the real-time and authenticity of the virtual surgery system,this paper studies and discusses the following aspects:Firstly,in most virtual surgical systems,the clarity of the texture in the burn area available for simulation is low,which can reduce the user’s immersion.Therefore,this paper proposes a burning texture synthesis algorithm based on particle swarm optimization and variable blocks.This algorithm first divides the neighborhood based on the rule-based texture block synthesis method.Then,it uses the divided neighborhood to search and match the input texture map twice,and introduces particle swarm optimization to improve the efficiency of the matching search and thus speed up the synthesis.Finally,in order to solve the possible local abrupt and unsmooth joint problems,a method of texture block self-increase and texture block self-decrease is designed.Secondly,in order to meet the real-time and accuracy requirements of collision detection in burn simulation in virtual surgery systems,this paper proposes a new collision detection method based on ant colony algorithm.The algorithm divides the collision detection process into fast detection and fine detection stages.Firstly,in the rapid detection stage,a hierarchical bounding box tree is established,and secondly,the collision detection method based on the hierarchical bounding box is used for fast detection,so as to quickly exclude clear disjoint areas.Then,the algorithm enters the phase of fine collision detection.This algorithm uses the triangle faces on the model surface as detection features,and in order to further simplify the calculation and improve efficiency,it combines geometric knowledge and chooses to calculate the distance between the barycenter of triangle faces to determine whether the triangle faces intersect.Therefore,the distance between the particles of the triangular surface is used as the judgment condition,and the collision detection problem is transformed into a nonlinear programming problem of finding the shortest distance between objects with constraints,and then the ant colony optimization algorithm is used to accelerate the solution.In addition,in order to solve the problem of low precision due to the lack of features between models in the fine detection stage,the Gaussian integral method is used to discretize the triangular patches on the model surface.Finally,when re-rendering the local burning area in the simulation of the burning phenomenon in the virtual surgery system,there will be unsmooth boundaries in the edge area,which will lead to the problem of reducing the sense of reality.This paper proposes an edge processing method based on bilinear quadratic interpolation.For the pixels on the burned edge area,the algorithm first extracts two adjacent pixels in the unburned area on the left and two adjacent pixels in the burned area on the right.Then the value of the pixel point at the edge is obtained through weighted calculation to ensure the continuity and smoothness of the obtained pixel point value.