Evaluation of a CCD-based facial measurement system

This paper describes the configuration and evaluation of a CCD-based biostereometric system at the Department of Orthodontics, Kings College Dental Hospital, London. The system has been designed to allow rapid and accurate measurement of facial soft-tissue shape with a minimum of traditional photogrammetric training. This has been achieved by automatic camera calibration and stereo matching, performed on a Sun Microsystem 3/160 workstation. In summary, the characteristics of the system are: (a) non-contract three-dimensional (3D) measurement of soft-tissue; (b) de-skilled, requiring little or no photogrammetric training; (c) rapid data acquisition, combined with slower off-line processing; (d) processing of resulting 3D surface information to yield cross-sections; (e) surface measurement accurate to within 0.5 mm. Accuracy assessment was performed using a manual electromechanical non-contact measurement device with precision exceeding the requirement of the biostereometric system.