The generation and manipulation of visual images is one of the most exciting applications of
the computer. We distinguish between different kinds of graphics.
Diagrams, such as numeric charts or maps, are artifacts that convey information to the
viewer. They do not directly depict anything that occurs in the natural world,
but are a tool for visualizing information.
Scenes are computer-generated images that attempt to depict images of the real or an
imagined world. It turns out to be quite a challenge to render light and shadows
accurately. Special effort must be taken so that the images do not look too neat and
simple; clouds, rocks, leaves, and dust in the real world have a complex and somewhat random
appearance. The degree of realism in these images is constantly improving.
Manipulated images are photographs or film footage of actual events that have been converted
to digital form and edited by the computer (see Figure 20). For example, film
sequences of the movie Apollo 13 were produced by starting from actual images and changing
the perspective, showing the launch of the rocket from a more dramatic viewpoint.
Computer graphics is one of the most challenging fields in computer science. It requires
processing of massive amounts of information at very high speed. New algorithms are constantly
invented for this purpose. Viewing overlapping three-dimensional objects with
curved boundaries requires advanced mathematical tools. Realistic modeling of textures and
biological entities requires extensive knowledge of mathematics, physics, and biology.
