A method for constructing three-dimensional face symmetry reference plane based on weighted shape analysis algorithm.
- Author:
Yu Jia ZHU
1
;
Yi Jiao ZHAO
1
;
Sheng Wen ZHENG
2
;
Ao Nan WEN
1
;
Xiang Ling FU
2
;
Yong WANG
1
Author Information
1. Center of Digital Dentistry, Peking University School and Hospital of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Laboratory for Digital and Material Technology of Stomatology & Beijing Key Laboratory of Digital Stomatology, Beijing 100081, China.
2. School of Computer Science, Beijing University of Posts and Telecommunications (National Pilot Software Engineering School), Beijing 100876, China.
- Publication Type:Journal Article
- Keywords:
Euclidean distance matrix analysis;
Facial asymmetry;
Procrustes analysis;
Symmetry reference plane
- MeSH:
Algorithms;
Cephalometry;
Face;
Facial Asymmetry;
Humans;
Imaging, Three-Dimensional
- From:
Journal of Peking University(Health Sciences)
2020;53(1):220-226
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE:To establish a novel method based on three-dimensional (3D) shape analysis and weighted Procrustes analysis (WPA) algorithm to construct a 3D facial symmetry reference plane (SRP), automatically assigning weight to facial anatomical landmarks. The WPA algorithm suitability for commonly observed clinical cases of mandibular deviation were analysed and evaluated.
METHODS:Thirty patients with mandibular deviation were recruited for this study. The 3D facial SRPs were extracted independently based on original-mirror alignment method. Thirty-two anatomical landmarks were selected from the overall region by three times to obtain the mean coordinate. The SRP of experimental groups 1 and 2 were using the standard Procrustes analysis (PA) algorithm and WPA algorithm, respectively. A reference plane defined by experts based on regional iterative closest point (ICP) algorithm, served as the ground truth. Three experts manually selecting facial regions with good symmetry for original model, and common region was included in the study. The angle error values between the SRP of WPA algorithm in the experimental group 1 and the truth plane were evaluated in this study, and the SRP of PA algorithm of experimental group 2 was calculated in the same way. Statistics and measurement analysis were used to comprehensively evaluate the clinical suitability of the WPA algorithm to calculate the SRP. A paired t-test analysis (two-tailed) was conducted to compare the angles.
RESULTS:The average angle error between the SRP of WPA algorithm and the ground truth was 1.53°±0.84°, which was smaller than that between the SRP of PA and the ground truth (2.06°±0.86°). There were significant differences in the angle errors among the groups (P < 0.05). For the patients with severe mandibular deviation that the distance between pogonion and facial midline greater than 12 mm, the average angle error of the WPA algorithm was 0.86° smaller than that of the PA algorithm.
CONCLUSION:The WPA algorithm, based on weighted shape analysis, can provide a more adaptable SRP than the standard PA algorithm when applied to mandibular deviation patients and preliminarily simulate the diagnosis strategies of clinical experts.
