Research On Key Technologies Of Real-time Deformation Interaction Of Soft Tissues For Lung Surgery Simulation

As an important application of virtual reality technology in the field of modern medicine,virtual surgery is a multidisciplinary technology combining computer graphics,material mechanics and biomedicine to provide doctors and learners with a surgical simulation training scene that integrates audio-visual and tactile multidimensional perception.Although the existing virtual surgery simulation training system has provided good surgical model performance,there is still room for improvement in the deformation realism and real-time interactivity of soft tissue models.This article mainly focuses on the two key technologies of mass-spring model based soft tissue modeling and collision detection in virtual lung surgery,aiming to effectively improve the realism of soft tissue modeling and the real-time interactivity and stability of collision detection.The specific research content is as follows.(1)An improved method of soft tissue modeling based on hexahedral point spring is proposed,aiming to enhance and improve the accuracy of model deformation simulation.Firstly,the modeling method adopts the hexahedral particle spring structure,introduces the virtual body spring and damping spring,and represents the nonlinearity of soft tissue in segments,so that the model can effectively simulate the biomechanical characteristics of soft tissue.Then,the relationship between the elastic coefficient of the spring,Young’s modulus and Poisson’s ratio is established through the Lagrange equation,and the corresponding correction force is introduced for each node while establishing the model coefficient,so as to improve the accuracy of the model.Experiments show that the improved soft tissue modeling method is more accurate and stable than the general particle spring model,and can well simulate the biomechanical properties of soft tissue.(2)A method for collision detection using OBB sphere bounding box fusion with BLS is proposed,aiming to enhance and improve the real-time.Assuming the end of the surgical instrument as a small ball,an OBB bounding box is used to surround the soft tissue,and a hierarchical bounding tree is established to achieve rapid interactive positioning between the surgical instrument and the soft tissue.This method involves two stages: rapid detection and precise detection.In the rapid detection stage,continuous space hash algorithm is used to quickly exclude soft tissues that are unlikely to collide,improving the detection speed.In the precise verification stage,the spatial collision position feature extraction between surgical instruments and soft tissue hexahedral models was achieved,and the detection speed was increased through BLS.The experimental results show that the proposed collision detection algorithm has real-time and accurate collision detection.(3)A virtual surgical simulation system for lung surgery was designed,and the proposed soft tissue modeling method and collision detection algorithm were integrated into the system to verify the effectiveness of the proposed method.The experimental results show that the designed lung surgery simulation system has good visual realism and real-time interaction performance.