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Aliasing
Antialiasing
(Terms of computer graphics)
When a line in a digital image runs at an angle,
then it will often appear with jagged edges.
This effect is caused by the regular pixel grid
in the image, and is called aliasing.
Example of aliased and antialiased line.
To avoid this effect, the process of antialiasing
paints some nearby pixels in an intermediate color
or brighness. That way, the visuall appearance of the
line (or an edge) is smoothed out.
The problem of aliasing is prevalent in
synthetic images created by methods such as raytracing.
Some programs try to circumvent it by sending more than one
ray per pixel
(oversampling), and interpolating their result. With the
Radiance software,
the same result is reached by rendering an image that is
two or three times as big as the target size with
rpict(1),
and then filtering this intermediate image down to scale with
pfilt(1).
To get even smoother results, the image can also be rendered
with jittered sampling.
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