ABSTRACT
The enhancement may be interpreted as ad hoc compensation of imperfections in the imaging process providing the image; however, on the difference from image restoration, the imaging properties, distortion, or noise parameters usually need not be identified for enhancement, or only roughly. The enhancement of images is the most frequently treated topic in literature on image processing and computer vision. The appearance of an image, as well as possibilities of recognizing the diagnostic features, depends crucially on the image contrast. Modern image processing systems often allow determination of the mentioned limits by a suitable interface device such as a joystick, mouse, or tablet pen; as the global contrast transforms can be realized in real time, changes in the image’s appearance may be evaluated immediately. A special type of nonlinear contrast transform deserves mention—the gamma correction. Originally, as the name suggests, it was intended to compensate for exponential characteristics of image sensors and displays.
