ABSTRACT
A wide variety of devices and systems exist whose main function is to generate an image. These devices and systems are used for many different purposes and find applications in many different walks of life. We are all very familiar with some of these systems such as the photographic camera (that can produce a permanent record of a scene on sensitized sheet material) and the television set (that can receive a suitably coded electromagnetic signal broadcast through space and convert it into an image). Less familiar are systems such as an image intensifier sight that is used to amplify the intensity of a very poorly lit scene (e.g. one lit only by starlight) so as to produce a brighter image that is clearly visible to an observer, or a thermal imaging camera that generates a visible image of an object from the infrared radiation that the object emits. Imaging systems find applications in science, medicine, industry, defence, surveillance, space, education, leisure and a host of other areas.
