Collision Detection Based On Virtual Medical Environment And Force Feedback Research

Virtual Medical is a virtual reality technology through visual effects,generate realistic virtual medical scenes,the operator uses a force feedback device to operate the virtual model to generate a force sensing effect,and then use modern medical knowledge to operate the device,it is a cross disciplinary technology combining virtual reality technology and modern medicine.Virtual medical system can be used for surgical training,operation preview,remote operation.Through the virtual system,not only greatly saves manpower,material investment and waste,and can be repeated operation,do the green operation,but also greatly reduces the risk and inevitability of surgery,it plays an important role in the medical field.Collision detection is the key and difficulty of virtual medical system based on force feedback device.In addition to the tight and real-time requirements of the collision,it should also be able to meet the operator’s sense of reality in the sense of vision and force.This article studies on the collision detection and force feedback effect of 3D model in virtual medical system based on force feedback equipment.By improving the construction and updating of bounding box tree based on the data structure of octree tree,the three-dimensional medical model collision detection system based on force feedback device is designed and realized,and the real-time detection and authenticity feedback of collision detection is realized.(1)According to the basic elements of the virtual medical system based on the force feedback device,the article determine the overall structure of the virtual medical system,the program design structure,the system hardware and software components.(2)Modeling.Geometric modeling,we use the visual rendering tool OPENGL to set up and display virtual scene,virtual organ and virtual surgery equipment.In the aspect of physical modeling,the spring mass damper model is used to provide effective physical model for force feedback.(3)This article achives accurate collision detection by optimizing bounding box,octree tree structure.After comparing the establishment and the update of method of several bounding boxes,we use OBB box as main bounding box,spherical box as auxiliary bounding box.And after comparing the spatial segmentation method,we use the method of octree data structure to divide the bounding box tree structure,it reduces the number of layers of the tree and the data redundancy caused by the data structure update calculation of the 3D model in the process of motion,and it improves the accuracy and responsiveness of the collision detection.At the same time,according to the spatial and temporal correlation and the delay characteristic,we optimize the traversal update of the bounding box tree,greatly reduce the amount of useless data calculated,minimize the data storage,improve the data read speed,for improving the fluency of the experiment has a significant effect.(4)Under the action of the force feedback device,the virtual scalpel model is operated to carry out the collision detection,and the friction force and the spring force at the time of the collision are realized,and thefoce is fed to the operator to realize the collision feedback.Experiment results show that the virtual medical system based on force feedback device,not only increase the speed and accuracy of collision detection,but also reduce the data structure redundancy and the movement of the data during the calculation and data updates.The experiment meets the requirements of visual and force sensation by force feedback device.