Chapter 8 Low Cost 3D Face Scanning Based on Landmarks and Photogrammetry A New Tool for a Surface Diagnosis in Orthodontics

Anthropometry is an objective tool serving to evaluate the shape of the face and reveal changes observed in the subject over time, or among different sub- jects, analyzing quantitative and qualitative differences. It also permits the study of normal and abnormal growth, diagnosis of genetic or acquired malformations, plan- ning and evaluation of surgical and/or orthodontic therapy, and verification of the treatment results by analyzing, measuring and comparing the face shape. Among 3D digitization technologies, photogrammetry shows great promise because it is a low cost, biocompatible, safe and non-invasive methodology, but it still suffers from a need for considerable human intervention. In previous research, the Authors illus- trated a new approach based on a 3-Cameras photogrammetric system. After several tests, conducted to verify the validity of this methodology, the present experimen- tal study was carried out using a re-engineered photogrammetric scanning system to obtain landmark-models of human faces, and comparing these results with those achieved with laser scanning, applied to a dummy face (in order to eliminate errors caused by breathing movements in a living subject). Two different, specifically de- signed experimental 3D photogrammetric setups have been developed and tested to enhance the performance. This research demonstrates the potential of low-cost pho- togrammetry for medical digitization; further research will be addressed to testing the use of the scanning system on humans to validate its clinical performance.