Geometry Information Processing In The Facial Plastic Simulation System

With the rapid improvement of people's life quality,more and more people are keen on the pursuit of beauty.It has become a common phenomenon to make up for some defects of appearance by plastic surgery in society.However,during the consultation before surgery,most doctors and patients can only communicate by spoken language,which is very easy to cause misunderstanding.In particular,the description of shaping effect is mainly influenced by subjective thinking and often leads to medical disputes.If the desired result of plastic surgery can be presented in the visual way that can be adjusted in real time,it would improve the doctor-patient communication better.In this paper,we study the real-time presentation method of plastic surgery based on the 3d face model,especially the processing of the geometric information of the face model,in order to show the cosmetic results quickly.In addition,we also study the customization of nose prosthesis and volume calculation of filling agent for the rhinoplasty.The main research work is as follows:(1)Selection of local mesh.Due to the complexity of facial contou r,it is necessary to provide methods to select the mesh vertices in the target area precisely,so as to control the deformation result more precisely.By drawing the target area on the screen,we implement the circle,ellipse,fan shape selection tools an d free shape selection tool based on the bezier curve.(2)Local mesh morphing algorithm.In this paper,we propose a deformation algorithm based on the grayscale texture.In the beginning,we need to build a grayscale texture dynamically,and then calculate a set of texture coordinates for the vertices of the model by adopting a linear method based on the line of sight to establish the mapping relationship between vertices and the pixels in the grayscale texture.Otherwise,we also need to deal with the smooth transition problem of mesh deformation.Finally,the deformation of local mesh can be controlled precisely.(3)Generating patient-specific nasal prosthesis models and calculating the facial injection volumes.We mainly study the prosthesis transplant ation and filling operation in the rhinoplasty.For the prosthesis transplantation,we study on the customization method of the nasal prosthesis based on the ray-cast technology.For the filling injection,after the simulation operation,a closed cavity space was formed by the local mesh before and after deformation,so the volume of the filling agent can be solved indirectly by calculating the volume of the closed cavity space,it can provide a reference value of the injection volume to the surgeons.(4)Simulation system for plastic surgery.Based on the studies mentioned above,we have developed a facial plastic surgery simulation system by using Unity3 D.The system can realize the real-time presentation of various facial plastic surgery result,such as filling forehead,epicanthal plastic,nasal root filling,thin face,and small plastic of mouth corner.It can also be used to display the customized model of the nasal prosthesis or the volume of the filling agent.The system has been tested in the market carried out by the Guangzhou shouyuan information technology co.,LTD.,and the customer response good.