ABSTRACT
Perspective projections are necessary in computer graphics, as in classical art, in order to render realistic images. Therefore, rigid motions are not sufficient for computer graphics. Here the authors shall show how to use dual quaternions to compute perspective and pseudo-perspective projections. These applications of dual quaternions are relatively new and not available in standard presentations on dual quaternions. In the quaternion algebra they can compute perspective projections by sandwiching a vector between two copies of a unit quaternion. The key trick with quaternions is to use a rotation in the ON-plane to convert some of the distance along the unit normal N to the perspective plane into mass at the origin O.
