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Three-dimensional intra-rater and inter-rater reliability during a posed smile using a video-based motion analyzing
Katsuaki Mishima1, Hirotsugu Umeda1, Asuka Nakano1
1Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Yamaguchi University. Minami-kogushi 1-1-1, Ube City, Yamaguchi 755-8505, Japan.
Summary
This study found high three-dimensional lip movement reproducibility during posed smiles using a video analysis system. Averaging two measurements ensures reliable results for lip motion analysis.
Area of Science:
- Biomechanical analysis
- Facial dynamics
- Motion capture technology
Background:
- Accurate measurement of facial movements is crucial for understanding expressions and for clinical applications.
- Previous methods for analyzing lip movement lacked precise three-dimensional (3D) quantification.
- Video-based motion analysis offers a promising avenue for detailed facial motion studies.
Purpose of the Study:
- To assess the 3D reproducibility of lip movements during a posed smile.
- To evaluate the reliability of a novel video-based motion analyzing system for facial dynamics.
- To determine the optimal number of measurements for achieving reliable lip motion data.
Main Methods:
- Six volunteers underwent repeated recordings of posed smiles.
- A video-based motion analyzing system generated 3D range images of lip surfaces.
- Virtual grids were used to compute 3D coordinates, and lip motion shifts were quantified.
- Intraclass correlation coefficients (ICC) were calculated for intra-rater and inter-rater reliability.
Main Results:
- Intra-rater ICC (1,1) values ranged from 0.71 to 0.83.
- Inter-rater ICC (2,1) values ranged from 0.77 to 0.99.
- An average of two repeated measurements was sufficient to achieve an ICC level beyond 0.8.
Conclusions:
- The study demonstrated high 3D intra-rater and inter-rater reliability for lip movement analysis during posed smiles.
- Averaging two measurements provides adequate reliability for this motion analysis technique.
- The small sample size necessitates caution when generalizing these findings.
