Collision Detection And Soft Deformation Based On The Liver In Minimally Invasive Operation

Minimally invasive surgery is an emerging modern medical technology, gradually replace the traditional means of the surgical field with its small wound, less pain, faster recovery, shorter hospital stay, less bleeding, etc.. Minimally invasive surgery is only through a lot of medical practice in order to accumulate experience and improve the technical level.Traditional minimally invasive surgical teaching and training methods costly, and it’s difficult to obtain enough disease timber sources. Virtual minimally invasive surgery can be a good solution to this problem. The development of minimally invasive surgery in virtual significant savings in the cost of the training of medical personnel and training time to achieve the purpose of the rapid increase in the skills of learners surgery and other operations, greatly improving the success rate of surgery and minimally invasive surgery, the training of medical personnel, improve the level of overall health care is important.The main work to be carried out by the development of a complete set of virtual surgery simulation system including data acquisition system, three-dimensional modeling (geometric modeling and physical modeling), the interactive control of the model, collision detection technology, software deformation technology, scalpel soft tissue cutting, stitching, liquid flow simulation, realistic rendering. In the abdominal organs, the liver is the largest organs, the vital organs of the metabolism, but the liver incidence is very high. Therefore, the liver surgery is a relatively common surgery of the virtual minimally invasive surgery. For the entire simulation system, the laboratory has completed the construction of system framework, realizes the interactive control of geometric modeling, geometric modelingof3D model and rough collision detection.The topics selected based on the entire virtual minimally invasive surgery system, for liver, search on the collision detection and soft tissue force deformation in the virtual minimally invasive surgery.Collision detection is a key technology in the virtual minimally invasive surgery. Fast and accurate collision detection is very important to improve the realism and immersion of virtual environments. Collision detection methods contains hierarchical bounding box, space partitioning, and image space. This topic uses hierarchy bounding box to realize collision detection in the virtual surgery. Soft tissue deformation is an important part of virtual surgery, soft tissue deformation effect a direct impact on the visual effects of the virtual surgery system. Mass-spring model and finite element model are normal model of physical modeling of soft tissue, this subject uses mass-spring model for the simulation of soft tissue deformation, and uses mass-spring model based on local dynamic force feedback to speed up the computing speed of deformation, using the local segmentation method to effectively enhance the effect of the deformation of the soft tissue in virtual surgery system.The authenticity is crucial for the virtual operation simulation system, and the real-time of simulating is an important factor to determine the authenticity of the system. The AABB bounding boxes method and local dynamic particle-force feedback spring model which used in collision detection and soft deformation in this system can better meet the needs of real-time.