Validation of a low-cost portable 3-dimensional face scanner

Abstract

Purpose The goal of this study was to assess the accuracy and reliability of a low-cost portable scanner (Scanify) for imaging facial casts compared to a previously validated portable digital stereophotogrammetry device (Vectra H1). This in vitro study was performed using 2 facial casts obtained by recording impressions of the authors, at King's College London Academic Centre of Reconstructive Science. Materials and Methods The casts were marked with anthropometric landmarks, then digitised using Scanify and Vectra H1. Computed tomography (CT) scans of the same casts were performed to verify the validation of Vectra H1. The 3-dimensional (3D) images acquired with each device were compared using linear measurements and 3D surface analysis software. Results Overall, 91% of the linear Scanify measurements were within 1 mm of the corresponding reference values. The mean overall surface difference between the Scanify and Vectra images was <0.3 mm. Significant differences were detected in depth measurements. Merging multiple Scanify images produced significantly greater registration error. Conclusion Scanify is a very low-cost device that could have clinical applications for facial imaging if imaging errors could be corrected by a future software update or hardware revision.

Accuracy of Mobile Device–Compatible 3D Scanners for Facial Digitization: Systematic Review and Meta-Analysis

“…There were 2 studies [ 41 , 42 ] showing some risk of bias, and there were 2 studies [ 40 , 42 ] for which there were some concerns for applicability. The patient selection and index test had a higher risk of bias than those of other domains in some studies because of unclear statements regarding the methods employed for random sampling [ 28 , 43 ] or the small number of participants included [ 5 , 15 ]. For applicability, the major concerns arose in the index test domain because several studies did not describe the scanning procedures in detail or did not provide sufficient information about the scanning devices [ 27 , 28 , 40 , 41 ].…”

“…The number of participants in these studies ranged from 8 to 34, with 2 to 15 male and 4 to 15 female participants. The other 5 studies were conducted using inanimate objects such as impression casts of the face [ 5 , 15 , 43 ] or mannequin heads [ 28 , 44 ], and 1 study [ 40 ] was conducted on human cadaver heads. Stereophotogrammetry [ 29 , 41 , 42 , 44 ], computed tomography [ 5 , 15 , 43 ], and high-resolution structured-light handheld scanning [ 40 , 45 ] were used as the reference measurements for comparison, and 2 studies [ 27 , 28 ] used manual interlandmark distance as the reference measurement.…”

Accuracy of Portable Face-Scanning Devices for Obtaining Three-Dimensional Face Models: A Systematic Review and Meta-Analysis

“…Among 21 articles, 15 papers had a low risk of bias [ 1 , 6 , 11 , 13 , 18 , 25 , 29 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ], four articles displayed some level of unclear risk of bias [ 12 , 17 , 28 , 42 ], and two articles had a high risk of bias [ 15 , 43 ]. Considering applicability concerns, 13 articles exhibited a low level of concern [ 1 , 6 , 11 , 12 , 13 , 25 , 34 , 35 , 36 , 38 , 39 , 40 , 41 ], two articles showed an unclear level of concern [ 17 , 28 ], and six articles showed a high level of concern [ 15 , 18 , 29 , 37 , 42 , 43 ]. Major bias was found in the patient selection domain because some studies were not clear in method to provide random samples or used a small number of included volunteers/patients [ 11 , 15 , 18 , 34 , 41 , 42 , 43 ].…”

“…Considering applicability concerns, 13 articles exhibited a low level of concern [ 1 , 6 , 11 , 12 , 13 , 25 , 34 , 35 , 36 , 38 , 39 , 40 , 41 ], two articles showed an unclear level of concern [ 17 , 28 ], and six articles showed a high level of concern [ 15 , 18 , 29 , 37 , 42 , 43 ]. Major bias was found in the patient selection domain because some studies were not clear in method to provide random samples or used a small number of included volunteers/patients [ 11 , 15 , 18 , 34 , 41 , 42 , 43 ]. As for the index test domain, most studies provided adequate manufacturer information and parameter setups for the tested scanning systems.…”

“…The mean discrepancy values of the face models obtained by portable facial scanners were below 1.0 mm, which is considered acceptable for clinical use [ 1 , 40 , 44 ]. Portable face scanners relying on laser or structured light technology showed more diversity than those that rely on stereophotogrammetry technology [ 11 , 12 , 13 , 18 , 25 , 28 , 29 , 42 , 43 ].…”