- 2D model: we can represent a face with a simple image made of RGB pixels;
- 2.5D model: is an half way representation between 2D and 3D. We can use a Range Image, that is a 2D grid where the values of each pixel represent the distance between the point and the light source. It’s useful to have information about the 3D space without actually building a 3D model.
- 3D model: we can use a shaded model, that models a 3D object by building it with many polygons. Smaller the polygons, the better the 3D reconstruction.