The use of the 3D digitizer is the most direct way of obtaining the geometry of faces. The laser illuminated triangulation method [31] involves a laser and camera. With this method, 128,000 range and reflectance samples may be obtained in a few seconds. Cylindrical projection is used for the measurement of faces. Williams [151] created facial models from measured data, and animated it. 120,000 samples are typically too much for rendering and animation use, so they should be represented by a simpler model. Fitting the obtained samples to a generic facial model is efficient for the facial animation. Waters and Terzopoulos [148] proposed a physics-based technique to reduce these samples to coarser, non-uniform meshes (see also [80]). One disadvantage of the laser scanner is that the equipment is relatively expensive.
Another 3D digitizing method uses 3D trackers. With this method, meshes are drawn on a face and the 3D coordinates of vertices are digitized using an electro-magnetic 3D digitizer. This procedure is not automatic and therefore is time consuming. The advantage of the method is that the polygonal mesh is designed according to the topology of the face, and then optimized (few polygons for a good definition of the shape). ``Tony de Peltrie'' from the University of Montreal [41], Marilyn Monroe and Humphrey Bogart from Daniel Thalmann and Nadia Magnenat-Thalmann [87] were created with this method.
CT (Computer Tomography) and MRI (Magnetic Resonance Imaging) are usually used in the field of medicine. These methods can capture not only the facial surface, but also inner structure such as bones or muscles. These additional structures will be useful for more accurate facial modeling and animation, as well as medical applications such as a medical operation simulation.
Geometric modelers may be used for interactive facial design. Facial structure may be modeled using standard computer graphics techniques, except several parts such as hair. Arbitrary facial models (such as imaginary faces or faces of historical person) can be designed. However, it requires time and design skill because faces have very complex structures. Commercial geometric modelers have been used for the face and body design of the figures in ``Little Death'' [40]. [100] has used interactive deformation techniques such as the ``ball and mouse'' metaphor [79] for face and body design.