Overview of Aliasing in Computer Graphics: Part 1

The images and text in this section are from the 1993 ACM SIGGRAPH Education Slide Set (Rosalee Nerheim-Wolfe, editor) and were produced by the following:

The rendered image differs greatly from the original scene, as does the luminosity signal. Notice that the green leaf has moved to the right in the rendered image.

The errors caused by aliasing are called artefacts. Common aliasing artefacts include jagged profiles, disappearing or improperly rendered fine detail, and disintegrating textures.

The picture on the left shows the sampling grid superimposed on the original scene. The picture on the right

is the rendered image. A jagged profile is quite evident in the rendered image. Also known as "jaggies", jagged silhouettes are probably the most familiar effect caused by aliasing. Jaggies are especially noticeable where there is a high contrast between the interior and the exterior of the silhouette.

The original scene on the left shows a group of small polygons. In the rendered scene, one of the two red rectangles disappears entirely, and the other doubles in width. Two of the orange triangles disappear. Although the two yellow triangles are identical in size, one is larger than the other in the rendered image.

Source: escience.anu.edu.au

Category: Hardware

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