Research And Implementation Of Cutting Of Soft Tissues Based On Point Model

As an important application of Virtual Reality technique, Virtual Surgery greatly promoted Medical Visualization and Surgical Training, which is of great significance and broad prospects. Cutting simulation of soft tissues is one of the gordian techniques. How to archieve this in a fast and vivid way is a challenging topic in biomedical engineering.Point Based Rendering(PBR) method use the surface points of models obtained by 3 dimension scanning tools to render it directly, which free render pipeline from the dependency of triangular mesh. The aim of we taking advantage of PBR in cutting simulation of soft tissues is to represent the details of models under guaranteeing cutting efficiency. The main research and achievement as follows:1. A Balanced Multi-way Kd Tree(BMKT), which can organize the model data as a balanced space hierarchy through divide the points into several clusters. When new nodes are inserted, the number of children can be kept in the controllable range through split and merge operation.2. A set of algorithms are proposed to implement collision detection, section drawing and topology control. Firstly we use BMKT to detect collision with the front of scalpel quickly. And the section can be got by tracing the cut points. Secondly we resample the parametric surface and insert new points into the BMKT. Lastly we ues the undirected graph composed of phyxels and neighbourhood relationship between them to express the topological relation. A noval heuristic search algorithm based on Minimum Euclidean Distance is proposed to determine whether the topology changed.Besides, a prototypical system based on these algorithms is implemented in this paer, a liver model is used to test our method. The results indicate that our methods are feasible, stable and able to simulate the cutting of soft tissues well with a considerable frame rate.