ABSTRACT
We have seen a great many different methods of changing the appearance of an image, and usually our need for the particular change was motivated by a problem: we may need to remove something from an image (noise, for example); we may need to make the image “look better”; we may need to calculate some aspect of the image (size, position, number of components, etc.)
But there is another totally different aspect of image processing, that of adding some sort of special effect to an image. We may want to do this for effect alone, or simply for fun. There are a great many different effects possible, and in this chapter we shall look at a few of them. This is a sort of gray area of image processing; we are encroaching toward the area of computer graphics. However, our algorithms involve the changing either of the value or the position of pixels, and we can achieve many effects with very simple means.
