anti-aliasing

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anti-aliasing

(graphics)
A technique used on a grey-scale or colour bitmap display to make diagonal edges appear smoother by setting pixels near the edge to intermediate colours according to where the edge crosses them.

The most common example is black characters on a white background. Without anti-aliasing, diagonal edges appear jagged, like staircases, which may be noticeable on a low resolution display. If the display can show intermediate greys then anti-aliasing can be applied. A pixel will be black if it is completely within the black area, or white if it is completely outside the black area, or an intermediate shade of grey according to the proportions of it which overlap the black and white areas. The technique works similarly with other foreground and background colours.

"Aliasing" refers to the fact that many points (which would differ in the real image) are mapped or "aliased" to the same pixel (with a single value) in the digital representation.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)

anti-aliasing

(1) Smoothing the jagged appearance of diagonal lines in a bitmapped image. The pixels that surround the edges of the line are changed to varying shades of gray or color in order to blend the sharp edge into the background. This technique is also called "dithering," but is usually known as anti-aliasing when applied to diagonal and curved lines.

(2) Smoothing a distorted signal by applying various techniques that add data or filter out unwanted noise.


Anti-aliasing
This teapot from the University of Utah was a famous first example of anti-aliasing applied to images. (Images courtesy of Computer Sciences Department, University of Utah.)


Anti-aliasing
This teapot from the University of Utah was a famous first example of anti-aliasing applied to images. (Images courtesy of Computer Sciences Department, University of Utah.)
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References in periodicals archive ?
Fluke, ZES Zimmer, and other similar analyzers don't have to apply anti-alias filtering when computing power.
Checking anti-alias keeps the lines smoother, and I usually leave the drawing as 8 bit.
Anti-alias filter: In sampled systems, the bandwidth of the input has to be limited to the folding frequency to avoid aliasing.
On Tuesday, Davao city Representative Karlo Nograles said the use of aliases violates the Revised Penal Code and the Anti-alias law which prohibit the use of pseudonyms in public documents.
This product uses 18-bit, 2-MS/s successive approximation (SAR) ADCs together with analog anti-alias filtering.
Available effects include Anti-Alias, Average, Contrast, Deskew, Emboss, Gamma Correct, Hue, Intensity, Mosaic, Motion Blur, Reverse, Saturation, Sharpen, and more!
They accept [+ or -] 5 V signals and have a 19 kHz three-pole-Bessel low-pass filter for noise and anti-alias filtering.
On Tuesday, Davao City Representative Karlo Nograles said the use of aliases violated the Revised Penal Code and the Anti-alias law which prohibit the use of pseudonyms in public documents.
The implication is that a higher oversampling ratio will create a wider frequency range above the signal bandwidth in which the anti-alias filter stop band can reside.
Images can be processed (Add Noise, Anti-alias, Average, Brightness, Color Resolution, Contrast, Despeckle, Emboss, Gamma Correct, Gaussian Filter, Grayscale, Hue, Intensity Detect, Invert, Median, Mosaic, Motion Blur, Oilify, Posterize, Remove Redeye, Saturation, Sharpen, Shear, Solarize), and the functions can be applied directly from the context menu, offering a very streamlined experience.
Nograles then said the use of aliases violates the Revised Penal Code and the Anti-alias law which prohibit the use of pseudonyms in public documents.
The iDSC 1816 board--a specialized DAP with programmable onboard filter circuits--combines 16-bit resolution on eight simultaneous channels of data acquisition with brick-wall anti-alias filters on each channel.