This is the ‘common man’s’ technique. When we see a number of objects or even a large object, parts that are nearer to the eye appear larger than those that are for away. Thus a matchbox can obscure a building, which is far away. This is the way all humans see and understand things in real life. Thus, the scheme provides very realistic depth information and is best suited for animation and simulation applications. But the draw back is that even though the method provides a feel of depth, it seldom provides the actual information about the depth. (The case of a matchbox obscuring the building clarifies the situation). It also is fairly computation intensive.
