ABSTRACT
A typical optical system contains a number of surfaces separated by media having different optical properties. Optical engineers predict the propagation of radiation through a sequence of optical components by launching a series of rays from an object and calculating the change in direction of each ray at intervening surfaces until they arrive at an image point. This process is termed ray tracing. In general, rays do not arrive perfectly at the desired image point, but fall within some distance from the ideal point. This failure is due to optical aberrations as well as diffraction and is a measure of the performance of the optical system.
