TABLE OF CONTENTS An imaging system collects radiation emitted by objects to make them visible. The radiation consists of a flow of particles or electromagnetic or acoustic waves. In classical computer vision scenes and illumination are taken and analyzed as they are given, but visual systems used in scientific and industrial applications require a different approach. There, the first task is to establish the quantitative relation between the object feature of interest and the emitted radiation. It is the aim of these efforts to map the object feature of interest with minimum possible distortion of the collected radiance by other parameters.
Figure 6.1 illustrates that both the incident ray and the ray emitted by the object towards the camera may be influenced by additional processes. The position of the object can be shifted by refraction of the emitted ray. Scattering and absorption of the incident and emitted rays lead to an attenuation of the radiant flux that is not caused by the observed object itself but by the environment, which thus falsifies the observation. In a proper setup it is important to ensure that these additional influences are minimized and that the received radiation is directly related to the object feature of interest. In cases where we do not have any influence on the illumination or setup, we can still choose radiation of the most appropriate type and...
