The preceding chapter discusses methods for correcting or alleviating the principal defects in as-acquired images. There is a fuzzy area between correcting these defects and going beyond to enhance the images. Enhancement is the subject of this chapter. Methods are available that increase the visibility of one portion, aspect, or component of an image, generally by suppressing others whose visibility is diminished. In this regard, image processing is a bit like word processing or food processing. It is possible to rearrange things to make a product that is more pleasing or interpretable, but the total amount of data does not change.