title: Evaluation of the Accuracy, Reliability, and Reproducibility of Two Different 3D Face-Scanning Systems.
abstract: OBJECTIVE
  To compare the accuracy, reliability, and reproducibility of a structured light scanning system and a stereophotogrammetry scanning system on human faces.
  
  
  METHODS
  A total of 10 healthy volunteers were included in this study. After marking of facial anatomy points, their faces were scanned by a structured light scanning system and a stereophotogrammetry system, and three-dimensional (3D) images were reconstructed with corresponding software. For each volunteer, scanning was performed twice after calibration. Linear measurements were calculated and compared for the two scanning techniques with direct caliper measurements. Absolute errors (AE), absolute percentage errors (APE), and intraclass correlation coefficients (ICC) were chosen as indices to determine the accuracy, reliability, and reproducibility of the two systems.
  
  
  RESULTS
  There was no statistically significant difference among the three measuring techniques (.891 < P < .999). Both scanning systems demonstrated high accuracy (AE = 0.58 ± 0.37 mm and APE = 1.11 ± 0.73% for the structured light system; AE = 0.62 ± 0.39 mm and APE 1.17 ± 0.71% for the stereophotogrammetry system). The two systems demonstrated extremely high reliability compared to caliper measurement (0.982 < ICC < 0.998 for the structured light system; 0.984 < ICC < 0.999 for the stereophotogrammetry system). In addition, high reproducibility was observed with the two systems (0.981 < ICC < 0.999 for the structured light system; 0.984 < ICC < 1.000 for the stereophotogrammetry system).
  
  
  CONCLUSIONS
  When applied in scanning and measuring human faces, the structured light scanning system and stereophotogrammetry scanning system both demonstrated high accuracy, reliability, and reproducibility.
authors.forename: Hongqiang
authors.initials: H
authors.lastname: Ye
authors.forename: Longwei
authors.initials: L
authors.lastname: Lv
authors.forename: Yunsong
authors.initials: Y
authors.lastname: Liu
authors.forename: Yushu
authors.initials: Y
authors.lastname: Liu
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks / Q000033:anatomy & histology; D002138:Calibration; D003116:Color; D005145:Face / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data*; D008297:Male; D061848:Optical Imaging / Q000706:statistics & numerical data*; D010780:Photogrammetry / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D055815:Young Adult