A basic element of a machine vision system is the corresponding illumination system. The price or even the feasibility of a machine vision system depends siginuicantly on the quality of the image and the image itself is directly Influenced by the illumination quality of the object (intensity, Intensity distribution, size, etc.). Fiber optic illumination components are very suitable as illumination elements because they are flexible, robust, they need only few adjusting elements and provide therefore easy means for well defined and controlled illumination situations. The very first step in a machine vision project is the image creation process. A good knowledge of the illumination problems and the properties of illumination components helps to create an optimal image and this in turn gives the opportunity to keep the image analysis system (hardand software) as simple as possible. While the classical way to create a good image is the illumination experiment, there are methods to do a simulation of fiber optic components and to calculate the influence of design parameters on the illumination distributions. This helps to predefine illumination parameters before creating any hardware for illumination.