UBC Theses and Dissertations
Validation of the Apple i-Phone© combined with the Bellus© three-dimensional photogrammetry application for facial imaging Andrews, James Robert McNair
Introduction: This study was designed to compare two three-dimensional facial imaging systems in a sample of adult participants: the smartphone iPhone 11 Pro using Bellus3D Face Application and the widely used and extensively tested stationary 3dMDface system. The goal was to determine the concordance between these two systems, one new, cheap, portable, and widely accessible and the other well-established and validated. Methods: The sample comprised 29 adult participants from the UBC Dental School. Exclusion criteria in this study included facial hair and craniofacial anomalies. Eighteen soft-tissue landmarks were marked on each participant’s face prior to imaging. Three-dimensional facial images were captured using a 3dMDface system and the Apple iPhone “True Depth” camera combined with the Bellus3D application. Data analysis was done using Geomagic Control X processing software. Accuracy of the Apple iPhone smartphone compared to the 3dMD face system was assessed by calculating the mean absolute difference between the systems. The reliability of the smartphone was also tested by taking consecutive scans of the same subject and comparing those to the reference scan. The intraclass correlation coefficient (ICC) assessed data reproducibility and inter-observer reliability. Results: Accuracy: Relative to the 3dMDface system, the root mean square (RMS) difference of the iPhone/Bellus3D app was 0.86 ± 0.4 mm. 97% of all the landmarked points were within 2 mm of error of our reference data. Intraobserver reproducibility/Precision: Relative to the 3dMDface system, the intra-rater reliability (ICC) of the iPhone/Bellus3D app was 0.7, which is classified as good. Interobserver reliability: The ICC between the two operators was 0.75, classified as good. Conclusions: These results suggest that 3D facial images acquired with the True Depth camera technology in the iPhone are accurate and precise. However, care should be taken when using an Apple iPhone in clinical situations that require high degrees of detail due to a lack of image resolution. Further technological advancements to improve the camera's resolution combined and higher-powered processor capabilities will improve the iPhone potential for clinical use due to its accessibility and ease of use.
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