A photographic system for the three-dimensional study of facial morphology : preliminary study and validation in healthy adults

Objectives: To test whether digital photographs supported by three-dimensional (3D) software are suitable for measuring the facial soft tissues of healthy subjects as compared with data obtained by a certified 3D computerized electromagnetic digitizer. Materials and Methods: Three-dimensional soft tissue facial landmarks were obtained from the faces of 15 healthy young adults, using a 3D computerized electromagnetic digitizer and a new low-cost photogrammetry system. Twelve linear and 18 angular measurements were computed. Errors between methods and repeatability of the new method were calculated. Results: Systematic errors between methods were found for only two distances and three angles (paired t-test, P < .05). The mean absolute differences between methods were always lower than 3 mm and 3 degrees. Repeated digitization of photographs showed that the method was repeatable (no systematic differences; random errors lower than 1.6 mm and 3 degrees). Repeated sets of photographs showed random errors of up to 5.3 mm and 5.6 degrees, without systematic biases. Conclusion: The 3D photogrammetry system can provide reliable facial measurements. The method is relatively fast and requires only inexpensive equipment. It is simple to use for private practice, research, or other practice.