Three-Dimensional Accuracy of Facial Scan for Facial Deformities in Clinics: A New Evaluation Method for Facial Scanner Accuracy

Abstract

In this study, the practical accuracy (PA) of optical facial scanners for facial deformity patients in oral clinic was evaluated. Ten patients with a variety of facial deformities from oral clinical were included in the study. For each patient, a three-dimensional (3D) face model was acquired, via a high-accuracy industrial “line-laser” scanner (Faro), as the reference model and two test models were obtained, via a “stereophotography” (3dMD) and a “structured light” facial scanner (FaceScan) separately. Registration based on the iterative closest point (ICP) algorithm was executed to overlap the test models to reference models, and “3D error” as a new measurement indicator calculated by reverse engineering software (Geomagic Studio) was used to evaluate the 3D global and partial (upper, middle, and lower parts of face) PA of each facial scanner. The respective 3D accuracy of stereophotography and structured light facial scanners obtained for facial deformities was 0.58±0.11 mm and 0.57±0.07 mm. The 3D accuracy of different facial partitions was inconsistent; the middle face had the best performance. Although the PA of two facial scanners was lower than their nominal accuracy (NA), they all met the requirement for oral clinic use.

The Accuracy of Digital Face Scans Obtained from 3D Scanners: An In Vitro Study

“…The human face not only shows the physical anatomical landmarks of a person's identity, but reveals the psychological make-up or personalization [1]. Facial morphology and analysis are important for various disciplines, such as craniofacial-maxillofacial surgery, orthodontics, prosthodontics, pedodontics, biometrics, and forensic odontologists [2][3][4]. The conventional methods of facial analysis include two-dimensional (2D) photographic, Vernier caliper, and bevel protractor measurements, to measure 2D projection distances and angles [2,5,6].…”

“…Facial morphology and analysis are important for various disciplines, such as craniofacial-maxillofacial surgery, orthodontics, prosthodontics, pedodontics, biometrics, and forensic odontologists [2][3][4]. The conventional methods of facial analysis include two-dimensional (2D) photographic, Vernier caliper, and bevel protractor measurements, to measure 2D projection distances and angles [2,5,6]. Recently, there has been a digital dental era due to the massive advancement and evolution in optical scanning and designing technology that has led a shift from 2D to three-dimensional (3D) technology, with the use of 3D leading to disruption in the treatment modality [7][8][9].…”

Modeling and Calibration of the Galvanometric Laser Scanning Three-Dimensional Measurement System

“…In recent years, the laser scanning systems have been widely applied in many industrial applications, such as medical imaging [1], quality assurance [2], machine vision [3,4] and reverse engineering [5,6]. The fast acquisition speed, the high accuracy, the good stability and the low cost make it one of the most promising techniques to obtain the geometric surface information.…”

Validation of two handheld devices against a non-portable three-dimensional surface scanner and assessment of potential use for intraoperative facial imaging

“…To compare 3D models from each scanner and time-point, images were automatically superimposed in the software by previously described iterative closest point algorithms. 13,27,28 Surface deviation between 3D models was color visualized for the entire face and each facial region, as illustrated in Figure 3 .…”