# 3D Facial Plastic Surgery Simulation: Based on the Structured Light
## 1 Introduction  
Face plastic surgery (PS) is aimed at achieving harmony of facial features by correcting cosmetic deformities. PS enjoys increasing popularity in different countries as well as among various social groups. However, the traditional facial PS only depends on the plastic surgeon's experience and personal esthetics for surgical design, which makes the effect non-predictable, resulting in increased surgical risk. The popularity of PS triggers new studies in face recognition that consider facial differences due to these procedures [1, 2]. Several systems have been proposed for presenting to patients and surgeons the possible outcomes of the surgical procedure [3, 4, 5, 6, 7]. Compared with the acquisition of 2D images, the acquisition efficiency of 3D scanning is higher. Since the 3D model is designed and repaired according to the 3D data of subjects, it has the advantages of visibility, quantitative analysis, and reflection of the 3D structure. They offer an added dimension to the understanding of the presurgical map of a patient's anatomy and provide surgeonswith a lot of preoperative information. As a result, there has been an expansion of the application in facial plastic surgery. When facial data is collected using a 3D camera, the imaging can yield sub-millimeter 3D data [8]. The surgeon can thus perform virtual surgery using these 3D data. Incorporating the behavior of all underlying and surrounding tissues, the surgeon will be reminded which one is at greatest risk. Researchers and practitioners have developed many different systems for cosmetic surgery simulation. They simulated the 3D model in the 3D scene by deforming the mesh patch of the model [9]. [PERSON] evaluated the handling of the 3 dMD system in matters of data acquisition and analysis. They found the system was reliable for the evaluation of the facial surface and could offer new opportunities in PS [10]. [PERSON] through image-guided surgery in the form of intraoperative navigation performed to the idealized virtual image. Finally, the accuracy of the surgical reconstruction could be confirmed using modern portable intraoperative CT scanners [11]. Axis Three's face system applies structured light technology to create 3D data and supply a 3D simulation software on physics-driven tissue typing for use in esthetic surgery [12; 13]. [PERSON] presented a 3D system for the esthetic planning of face PS. The system proposed a \"learning by examples\" approach. It could suggest changes able to approach the shape of similar but more harmonious faces by constructing a database of harmonious faces [14]. [PERSON] presented a rule-based adjustment algorithm and 3D imaging tool to assist rhinoplasty surgeons. The system could assist surgeons by giving them the difference in measurements needed to change the patient's nose [15]. ZBrush, 3D Vectra, e-stetix 3D, and other engraving software present the plastic effect by using mesh deformation on the 3D model and simulating the surgery of the 3D face model. It could simulate body shaping, nose augmentation, breast augmentation, and face shaping. However, the software cannot measure quantitatively and obtain key distance information, such as eye distance, adjusted area, and filling volume. Moreover, 3D reconstruction usually requires the assistance of a large 3D scanner [16; 17]. [PERSON] et al. proposed an optical technique to acquire the dynamical data of face muscle with the colored encoded stripe pattern in order to objectively evaluate the effect of surgery [18]. Although flaps are technically difficult, harvesting and in-setting times of flaps are generally improved with preoperative modeling. Moreover, higher patient satisfaction with preoperative image projections was reported in studies [19; 20]. The models that focused on facial plastic and reconstructive procedures have generally shown significant patient satisfaction and improvements in intraoperative errors [21; 22].