PRELIMINARY EVALUATION OF AN ELECTROMAGNETIC 3-DIMENSIONAL DIGITIZER IN FACIAL ANTHROPOMETRY

Objective: In this investigation, the precision of a commercial three- dimensional digitizer in the detection of facial landmarks in human ad ults was assessed. Methods: Fifty landmarks were identified and marked on the faces of five men, on five women, and on a stone cast of the f ace of one man. For each subject, the three-dimensional coordinates of the landmarks were obtained twice using an electromagnetic three-dime nsional digitizer, and the duplicate digitizations were superimposed u sing common orientations and centers of gravity. Metric differences be tween homologous landmarks were assessed, and Dahlberg's error was com puted. Results: For both men and women, the error was 1.05% of the nas ion-midtragion distance, while for the cast, it was 0.9%. When the dup licate digitizations were used to mathematically reconstruct the faces , and several distances, angles, volumes, and surfaces were computed, more than 80% of the measurements had coefficients of variation lower than 1%. Conclusions: The digitizer can assess the coordinates of faci al landmarks with sufficient precision, and reliable measurements can be obtained.