ABSTRACT
This chapter discusses filtering images in order to enhance certain aspects of the images. Image enhancement is processing which improves the quality of an image in some subjective sense. It is an example of the application of signal processing techniques to a real problem. There are several types of image enhancement; the chapter presents a few much selected examples of image enhancement using filtering. The major examples which will be discussed are smoothing and edge enhancement. Image restoration refers to operations which attempt to correct for distortions caused by an imaging system. The goal of edge enhancement is to make the edges in an image more conspicuous. Unsharp masking also has the effect of compensating for variations in the average intensity in different parts of the image. An unsharp masking operation is performed by making two transparencies. One of the transparencies is a negative; the other transparency is an out-of-focus positive.
