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This needs a proper article about anti-aliasing with sampling theory etc. Unfortunately I haven't got time at the moment.
Anti-aliasing is far more general than discussed here: the general outline is:
-- Anon.
I'm a bit confused by the fact it starts by talking about "filters" and frequency-domain stuff but later on just starts averaging multiple samples over each pixel instead. The latter I always thought of as being antialiasing - your pixel's brightness should be the average of what is inside that pixel not just one point within it. The sinc filter, while having the nice property of cutting the high-frequency data off at exactly the Nyquist frequency of the display media, can produce odd fringes either side of sharp edges, it's "nonlocal". —Preceding unsigned comment added by 88.110.208.0 ( talk) 05:42, 21 February 2010 (UTC)
Simple pixel averaging is also a filter having elements of equal value. The image of this filter on frequency domain is the sinc function (surprised :D, they are dual of each other) and it passes the low frequencies well and high frequencies less, so it can also be considered as a non optimal "low pass" filter. Since it eliminates most of the high frequencies, although it will deform the image and leave some aliasing it will work. The reason why it is chosen as a filter is the ease of implementation and low computational cost compared to a sinc like filter. —Preceding unsigned comment added by 24.61.87.72 ( talk) 08:20, 29 June 2010 (UTC)
BTW, what's the exact etymology of the word anti-aliasing ? The fact that two images can be mapped to the same image looks irrelevant to me, as that cannot be avoided (pigeonhole principle tells), and "anti-aliasing" does not specifically try to avoid that either. --FvdP
This article is getting better all the time: but this is a difficult topic which even confuses experts. More work is needed. The Anome 00:11 Jan 25, 2003 (UTC)
I don't think this passage is pertinent to this article. I am moving it here, it can be restored later. If we were to discuss Gamma correction in here, there's no reason why we wouldn't discuss pixel formats, color theory, interlacing and all these other topics, which do not help at all with anti-aliasing.
(Note that the above assumes that the numerical value of a pixel is proportional to its intensity: for systems where this is not the case, gamma correction must be performed to preserve the linearity of the system, for this approach to hold true).
Loisel 05:31 Jan 25, 2003 (UTC)
Please put it back. Gamma correction problems are the #1 cause of poor anti-aliasing in computer graphics -- doing the A-A computation at the wrong gamma, or displaying the A-A'd image at the wrong gamma, will screw everthing up. <Michael Caine>Not a lot of people know that.</Michael Caine> The Anome
Having worked at SGI and NVidia, I'd say that almost all graphics hardware get the gamma wrong. The only place I've ever seen people complain about it is in film or print, and usually not exactly in those terms because they don't dump the images to the screen, and hence don't have a "gamma" in the final product (although they have to deal with more complicated response curves.) The problem of getting gamma right isn't specific to antialiasing, in fact I would say it affects lighting a whole lot more than antialiasing.
With small pixels, edge antialiasing such as FSAA should only be visible on a small fraction of the pixels (those that are on the edge of a triangle), and for in-triangle AA such as mip-mapping, the adjacent texels are of such a similar color that linear interpolation with or without gamma correction gives almost the same result. Hence, I would argue that being careful with gamma is a whole lot more important for lighting (which affects ALL pixels) than it is with anti-aliasing. And you don't really hear people complaining about how the gamma correction screws up their lighting.
To discuss "frequent problems" with antialiasing, we might need to restructure the article somewhat. Perhaps a section near the end summarizing some related issues. Gamma correction only applies to computer monitors in 8 bits or so per components; perhaps a reference to color theory or some comment about the response curve of the display would be more general. The upcoming graphics hardware should have a flat gamma curve when using floating point framebuffers. Loisel 05:31 Jan 27, 2003 (UTC)
The Anome, do you agree with the placement and wording of the Gamma Correction note now? Loisel 03:25 Jan 28, 2003 (UTC)
It sure does matter. The example images are in fact broken. They get dark near the top, as the checkerboard goes off into the distance. This is wrong. AlbertCahalan 00:02, 26 February 2007 (UTC)
Removed "This article certainly needs images!" from Antialiasing article. Created images. Tried to add images. Edit conflict - the new Antialiasing article someone made was merged with this Anti-aliasing article...
What I was going to add:
This image is not antialiased. | This image is antialiased. | |
File:Nonantialiased line and ellipse.png | File:Antialiased line and ellipse.png |
Unless someone can think of a good use for them, I guess they can be deleted by whoever can delete uploaded files... Cyp 19:08 Feb 12, 2003 (UTC)
Deleted an image from section Full-scene anti-aliasing as it was unprofessional. C Ronald 10:52, 22 March 2007 (UTC)
This was merged in. I think all the information in this stub article is contained in more detail in the current article, so I am moving it to talk. If certain details should be included in the current article, please feel free to integrate them. However, I feel that the language level in the article below is not adequate, and definetly lower than, the language level of the anti-aliasing article. Of course, I am biased, since I wrote most of the anti-aliasing article. Loisel 02:56 Feb 18, 2003 (UTC)
Antialiasing is a graphical effect used to reduce the effect of aliasing (better known as jaggies) in computer graphics.
On a computer lines are drawn in pixels (square dots) the result can look very raw (stairstep-like), depending on the resolution (i.e. the size of the pixels). This stairstep-effect is reduced by surrounding the line with grayscale pixels (black line on white background). You can compare this with a stone stair on which you throw mud and sand as long till you can't see the edges of the steps anymore.
Modern graphic chips like GeForce do this by calculating the gray pixels on their own. See: http://www.nvidia.com/view.asp?IO=feature_hraa
Most modern operating system GUIs (e.g. Windows 2000/XP, Xfree86 on UNIX / GNU) support antialiasing. This is very important for fonts and TFT-Displays. By the way, on TFT-Displays antialiasing is more important since the pixels have a precise square shape. Therefore on TFT subpixel-antialiasing is also used. To increase the optical resolution of a display the color of the neighbour pixels is altered depending on the oriantation of the red, green and blue cells.
I'm coming very late to this discussion, but I just noticed a glaring error/misconception. The statement " ..the term aliasing was used in its radio-engineering sense, related to carrier mixing in a superheterodyne radio: you can hear the same program at two positions on the dial if you don't use prefiltering" is plain wrong. For one thing, this phenomenon in radio is called imaging, not aliasing - I wrote a small article about this under Image response; yes it arises because of mixing within a superheterodyne receiver, but that is not the same thing as sampling/quantization. Whoever wrote that statement either doesn't understand radio receivers, or antialiasing - one of the two! Secondly, the aliasing in graphics is precisely related to the Nyquist sampling theorem - it is in fact a direct example of it, albeit in two dimensions. It arises because the mathematical description of an object - a line, say, has to be rasterised into a pixel grid array, which is effectively sampling it at a lower rate. If the original object contains frequency components higher than the twice the sampling rate, they will be aliased to new lower frequency positions in the frequency spectrum - this manifests itself as jaggies. GRAHAMUK 03:52 10 Jul 2003 (UTC)
I can't fix it, so I'm dropping it here for further discussion.
The term aliasing is used here in its radio-engineering sense, originally used to describe to the phenomenon causing the same transmission to be heard at multiple dial positions on a superheterodyne radio if pre-filtering is not used.
-- Loisel 19:37 14 Jul 2003 (UTC)
What's the difference between figures 1(b) and 1(c)? The article doesn't even hint at the algorithm of figure 1(b), yet the algorithm of figure 1(c) is "considered better". Isidore 21:51, 29 Aug 2004 (UTC)
Speaking of gamma correction, it looks very much like the anti-aliased example images are not gamma-corrected... Anders Kaseorg 03:30, 28 Oct 2004 (UTC)
At present this article has far more information about mip-mapping than does the mip-mapping article itself. I believe the text on mip-mapping should be moved to the mip-mapping article and a summary of it should be kept in this article. What do other people think? MIT Trekkie 04:07, 14 Dec 2004 (UTC)
The mipmapping section here is now just a duplicate of the entire mipmapping article. I am removing it and putting in a summary. Valarauka 10:22, 17 September 2006 (UTC)
I might be reading it wrong, but the sentence "It has been observed that to measure a signal of frequency n, you need at least n sample points, and they need to be well-placed." seems to be slightly misleading. It doesn't specify any sort of time within which the n sample points have to be in. Rspanton 00:03, 24 Dec 2005 (UTC)
how do you pronouce anti aliasing?
ăn'tī (like antimatter, or antidisestablishmentarianism) ā'lē-əs or āl'yəs (like the tv show
Alias (TV series)) -ing.
The layout of the pictures really needs to be sorted - at the moment the page looks untidy and some pictures are nowhere near the text that references them. Romansanders 17:31, 8 April 2006 (UTC)
I heard theres a ay to turn anti aliasing off in MS paint, can anyone shed some light on that?
I've never seen AA in MSpaint. I just played with it just now, and there is no AA, period (unless I take off my glasses). 206.252.74.48 ( talk) 14:33, 3 January 2008 (UTC)
The 'real time approximations' section and its mipmapping subcomponent don't really fit with the tone of the rest of the article, which is more mathematical/theoretical (as it should be). I was thinking I'd create a new article for AA as used specifically in graphics; mipmapping fits there naturally, as does information about supersampling/multisampling, different sample patterns, coverage masks etc. which again shouldn't really go here, and I haven't seen anywhere else. There's already an article at FSAA but it's pretty scanty. Valarauka 20:49, 17 September 2006 (UTC)
I think this article is better than the (already mentioned as small) FSAA (full screen antialiasing) article, and the content should be merged. They are relatively the same thing. I don't think it would hurt this article to include a mention of the methods used in graphics cards, and fsaa could be one of those subheadings. -- gatoatigrado 05:48, 4 October 2006 (UTC)
Agreed on both counts. I don't really see that mipmapping has a place in the general article on anti-aliasing - it's a very specific technique to avoid having to do antialiasing in real-time rendering, and it's already covered sufficiently in articles on texturing and texture filtering. -
Valarauka(
T/
C)
05:55, 4 October 2006 (UTC)
Since eyes can rotate in their sockets, this must have to do with the fact that we are dealing with data sampled on a square lattice and not with a continuous image.
What does that have to do with anything? I think this sentence should go. User A1 00:14, 15 December 2006 (UTC)
The section "First-principles approach to anti-aliasing" includes this statement:
"By the pigeonhole principle, sometimes two different ideal images f(x,y) and g(x,y) will be converted to the same picture on the screen. This cannot be avoided."
While that is undoubtedly true, it is not clear how it is relevant. The issue is just the opposite, the fact that a single ideal image can be approximated by many alternative reduced images, which creates the challenge of how to select among them.
Steve Wise 04:57, 7 January 2007 (UTC)Steve Wise
I don't agree that the second image is not related. That is a thumbnail, and you can click to view the larger version. Lugiadoom 08:51, 24 January 2007 (UTC)
The section that was added about criticism might have some good points, but criticisms need to backed up by an attribution to a sourced. So I took it out. Put it back when it's ready. Dicklyon 16:10, 24 January 2007 (UTC)
"The idealized image has infinite detail, and is represented by a function f(x,y) where x and y are real numbers defining coordinates."
Infinite or just enough to match the resolution of the human eye? Maybe some elaboration could follow this sentence. -- RITZ 04:03, 7 March 2007 (UTC)
More should be added about different algorithms, for example Xiaoling Wu's work in the early nineties.
"Game consoles and type setting on screen of personal computers employ antialiasing in realtime. Windows Picture and Fax Viewer, Microsoft Powerpoint, Adobe Acrobat Reader, Ghostview, the aqua and aero window managers employ it full screen, while the Gimp and OpenOffice.org Impress are not able to."
That sounds really irrelevant to me. Also like an attempt to discredit and belittle the quality of OpenSource Software, due the wording and the selection of commercial software on one side, the GIMP and OpenOffice on the other side. 217.235.93.78 19:18, 15 July 2007 (UTC)
"The goal of sharply cutting off frequencies above a certain limit, known as the Nyquist frequency, can not be realized exactly, even with Fourier techniques, so it is always approximated, with many different choices of detailed algorithm".
I believe the above statement is wrong and should be removed or rephrased. Could you please justify why can you not achieve a sharp cut-off on a discrete signal of finite length such as a computer image. Maybe you are referring to the ringing artifacts (Gibbs phenomenon) which are a consequence of a sharp cut-off? -- xerm ( talk) 11:59, 15 February 2008 (UTC)
You can resample a digital image with filters. But in computer graphics, the initial rendering operation involves sampling what I called a "symbolic image" represented by some scene description, and in general there is no way to pre-filter that symbolic scene representation before it is sampled (e.g. by rasteriztion or ray tracing). Take a look at a tutorial I wrote for SIGGRAPH '90: http://www.mentallandscape.com/Papers_siggraph90tutorial.pdf DonPMitchell ( talk) 20:13, 5 July 2008 (UTC)
I'm suggesting merging the small amount of content at Temporal anti-aliasing into this article, as the underlying principles are identical. Whilst it's the case that this article is currently dedicated solely to spatial anti-aliasing in the context of computer graphics, there's no reason it should be limited to just this. A wider exposition of the field is needed. Alternatively, this article should be renamed to Spatial anti-aliasing in computer graphics or similar. Oli Filth( talk| contribs) 17:54, 31 May 2009 (UTC)
(outdent) Per the discussions above, I've now moved the article to Spatial anti-aliasing, as that is the only correct title given the article's content. Oli Filth( talk| contribs) 17:38, 16 May 2010 (UTC)
Pictures are in some strange non-linear color space, instead of sRGB. 83.4.200.31 ( talk) 20:34, 4 January 2010 (UTC)
In the FSAA section "jaggies" are considered to be the only aliasing effect which is NOT correct. In fact there are effects like "moire" or loosing edges, curves(some high frequency geometry) altogether rather then having "jagged" edges. Unfortunately people have a false perception of "aliasing = jagged edges" because of this false treatment of the subject. Please correct it. —Preceding unsigned comment added by 24.61.87.72 ( talk) 21:10, 29 June 2010 (UTC)
How about Morphological anti-aliasing which is coming into effect as the new Radeon 6000 series releases? Some of it is discussed in this article: http://www.tomshardware.com/reviews/radeon-hd-6870-radeon-hd-6850-barts,2776-4.html IOA94 ( talk) 20:32, 1 November 2010 (UTC)
Is the line "The ear is predominantly sensitive to lower frequencies. And so, in signal processing, we choose to eliminate all high frequencies from the signal, keeping only the frequencies that are low enough to be sampled correctly by our sample rate." strictly necessary and in context? Evn2-NJITWILL ( talk) 20:22, 23 November 2010 (UTC)
I have not been able to find any information anywhere on the internet about FSAA, it is "sourced" with only one link, but the article in that link NEVER mentions the term FSAA, meaning it has no sourcing at all. -- Taltamir ( talk) 22:17, 10 January 2011 (UTC) Note, that while unable to find information about what it means or what it is, I have found mention of the term. For example here: http://www.nvidia.com/object/quadro_sli_fsaa.html nvidia clearly uses the term FSAA, just not in the one source given for that portion of the article. So if anyone could find better sources for it, please do.-- Taltamir ( talk) 22:21, 10 January 2011 (UTC)
Is this article supposed to be only about anti-aliasing in graphical display systems? Anti-alias (low pass) spatial filters are a part of many digital cameras, needed to prevent aliasing due to the spatial sampling of the image sensor. There is a little in the anti-aliasing filter page, but not so much. Given the title of this page, it should include optical (spatial) low-pass anti-alias filters, too. Gah4 ( talk) 21:20, 17 August 2017 (UTC)
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A few TV station articles, e.g.
TV Land refer to downscaling: "Picture Format:
1080i
HDTV (
downscaled to
letterboxed
480i for the
SDTV feed)". By "downscaling" do they mean spatial anti-aliasing? I would like to add have added a
WP:HATNOTE to
Downscaling - directing readers to this article if they are interested in image downscaling - but I want to be sure I have got it right.
On a related note, this article is linked to from the dab page Downsizing, with the (uncited) comment "Downsizing the image : resizing the image to lower pixel resolution for reduce the file size or Spatial_anti-aliasing". If downsizing and downscaling are alternative terms for spatial anti-aliasing, this article should say so. Adpete Adpete ( talk) 23:12, 22 December 2021 (UTC)
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This needs a proper article about anti-aliasing with sampling theory etc. Unfortunately I haven't got time at the moment.
Anti-aliasing is far more general than discussed here: the general outline is:
-- Anon.
I'm a bit confused by the fact it starts by talking about "filters" and frequency-domain stuff but later on just starts averaging multiple samples over each pixel instead. The latter I always thought of as being antialiasing - your pixel's brightness should be the average of what is inside that pixel not just one point within it. The sinc filter, while having the nice property of cutting the high-frequency data off at exactly the Nyquist frequency of the display media, can produce odd fringes either side of sharp edges, it's "nonlocal". —Preceding unsigned comment added by 88.110.208.0 ( talk) 05:42, 21 February 2010 (UTC)
Simple pixel averaging is also a filter having elements of equal value. The image of this filter on frequency domain is the sinc function (surprised :D, they are dual of each other) and it passes the low frequencies well and high frequencies less, so it can also be considered as a non optimal "low pass" filter. Since it eliminates most of the high frequencies, although it will deform the image and leave some aliasing it will work. The reason why it is chosen as a filter is the ease of implementation and low computational cost compared to a sinc like filter. —Preceding unsigned comment added by 24.61.87.72 ( talk) 08:20, 29 June 2010 (UTC)
BTW, what's the exact etymology of the word anti-aliasing ? The fact that two images can be mapped to the same image looks irrelevant to me, as that cannot be avoided (pigeonhole principle tells), and "anti-aliasing" does not specifically try to avoid that either. --FvdP
This article is getting better all the time: but this is a difficult topic which even confuses experts. More work is needed. The Anome 00:11 Jan 25, 2003 (UTC)
I don't think this passage is pertinent to this article. I am moving it here, it can be restored later. If we were to discuss Gamma correction in here, there's no reason why we wouldn't discuss pixel formats, color theory, interlacing and all these other topics, which do not help at all with anti-aliasing.
(Note that the above assumes that the numerical value of a pixel is proportional to its intensity: for systems where this is not the case, gamma correction must be performed to preserve the linearity of the system, for this approach to hold true).
Loisel 05:31 Jan 25, 2003 (UTC)
Please put it back. Gamma correction problems are the #1 cause of poor anti-aliasing in computer graphics -- doing the A-A computation at the wrong gamma, or displaying the A-A'd image at the wrong gamma, will screw everthing up. <Michael Caine>Not a lot of people know that.</Michael Caine> The Anome
Having worked at SGI and NVidia, I'd say that almost all graphics hardware get the gamma wrong. The only place I've ever seen people complain about it is in film or print, and usually not exactly in those terms because they don't dump the images to the screen, and hence don't have a "gamma" in the final product (although they have to deal with more complicated response curves.) The problem of getting gamma right isn't specific to antialiasing, in fact I would say it affects lighting a whole lot more than antialiasing.
With small pixels, edge antialiasing such as FSAA should only be visible on a small fraction of the pixels (those that are on the edge of a triangle), and for in-triangle AA such as mip-mapping, the adjacent texels are of such a similar color that linear interpolation with or without gamma correction gives almost the same result. Hence, I would argue that being careful with gamma is a whole lot more important for lighting (which affects ALL pixels) than it is with anti-aliasing. And you don't really hear people complaining about how the gamma correction screws up their lighting.
To discuss "frequent problems" with antialiasing, we might need to restructure the article somewhat. Perhaps a section near the end summarizing some related issues. Gamma correction only applies to computer monitors in 8 bits or so per components; perhaps a reference to color theory or some comment about the response curve of the display would be more general. The upcoming graphics hardware should have a flat gamma curve when using floating point framebuffers. Loisel 05:31 Jan 27, 2003 (UTC)
The Anome, do you agree with the placement and wording of the Gamma Correction note now? Loisel 03:25 Jan 28, 2003 (UTC)
It sure does matter. The example images are in fact broken. They get dark near the top, as the checkerboard goes off into the distance. This is wrong. AlbertCahalan 00:02, 26 February 2007 (UTC)
Removed "This article certainly needs images!" from Antialiasing article. Created images. Tried to add images. Edit conflict - the new Antialiasing article someone made was merged with this Anti-aliasing article...
What I was going to add:
This image is not antialiased. | This image is antialiased. | |
File:Nonantialiased line and ellipse.png | File:Antialiased line and ellipse.png |
Unless someone can think of a good use for them, I guess they can be deleted by whoever can delete uploaded files... Cyp 19:08 Feb 12, 2003 (UTC)
Deleted an image from section Full-scene anti-aliasing as it was unprofessional. C Ronald 10:52, 22 March 2007 (UTC)
This was merged in. I think all the information in this stub article is contained in more detail in the current article, so I am moving it to talk. If certain details should be included in the current article, please feel free to integrate them. However, I feel that the language level in the article below is not adequate, and definetly lower than, the language level of the anti-aliasing article. Of course, I am biased, since I wrote most of the anti-aliasing article. Loisel 02:56 Feb 18, 2003 (UTC)
Antialiasing is a graphical effect used to reduce the effect of aliasing (better known as jaggies) in computer graphics.
On a computer lines are drawn in pixels (square dots) the result can look very raw (stairstep-like), depending on the resolution (i.e. the size of the pixels). This stairstep-effect is reduced by surrounding the line with grayscale pixels (black line on white background). You can compare this with a stone stair on which you throw mud and sand as long till you can't see the edges of the steps anymore.
Modern graphic chips like GeForce do this by calculating the gray pixels on their own. See: http://www.nvidia.com/view.asp?IO=feature_hraa
Most modern operating system GUIs (e.g. Windows 2000/XP, Xfree86 on UNIX / GNU) support antialiasing. This is very important for fonts and TFT-Displays. By the way, on TFT-Displays antialiasing is more important since the pixels have a precise square shape. Therefore on TFT subpixel-antialiasing is also used. To increase the optical resolution of a display the color of the neighbour pixels is altered depending on the oriantation of the red, green and blue cells.
I'm coming very late to this discussion, but I just noticed a glaring error/misconception. The statement " ..the term aliasing was used in its radio-engineering sense, related to carrier mixing in a superheterodyne radio: you can hear the same program at two positions on the dial if you don't use prefiltering" is plain wrong. For one thing, this phenomenon in radio is called imaging, not aliasing - I wrote a small article about this under Image response; yes it arises because of mixing within a superheterodyne receiver, but that is not the same thing as sampling/quantization. Whoever wrote that statement either doesn't understand radio receivers, or antialiasing - one of the two! Secondly, the aliasing in graphics is precisely related to the Nyquist sampling theorem - it is in fact a direct example of it, albeit in two dimensions. It arises because the mathematical description of an object - a line, say, has to be rasterised into a pixel grid array, which is effectively sampling it at a lower rate. If the original object contains frequency components higher than the twice the sampling rate, they will be aliased to new lower frequency positions in the frequency spectrum - this manifests itself as jaggies. GRAHAMUK 03:52 10 Jul 2003 (UTC)
I can't fix it, so I'm dropping it here for further discussion.
The term aliasing is used here in its radio-engineering sense, originally used to describe to the phenomenon causing the same transmission to be heard at multiple dial positions on a superheterodyne radio if pre-filtering is not used.
-- Loisel 19:37 14 Jul 2003 (UTC)
What's the difference between figures 1(b) and 1(c)? The article doesn't even hint at the algorithm of figure 1(b), yet the algorithm of figure 1(c) is "considered better". Isidore 21:51, 29 Aug 2004 (UTC)
Speaking of gamma correction, it looks very much like the anti-aliased example images are not gamma-corrected... Anders Kaseorg 03:30, 28 Oct 2004 (UTC)
At present this article has far more information about mip-mapping than does the mip-mapping article itself. I believe the text on mip-mapping should be moved to the mip-mapping article and a summary of it should be kept in this article. What do other people think? MIT Trekkie 04:07, 14 Dec 2004 (UTC)
The mipmapping section here is now just a duplicate of the entire mipmapping article. I am removing it and putting in a summary. Valarauka 10:22, 17 September 2006 (UTC)
I might be reading it wrong, but the sentence "It has been observed that to measure a signal of frequency n, you need at least n sample points, and they need to be well-placed." seems to be slightly misleading. It doesn't specify any sort of time within which the n sample points have to be in. Rspanton 00:03, 24 Dec 2005 (UTC)
how do you pronouce anti aliasing?
ăn'tī (like antimatter, or antidisestablishmentarianism) ā'lē-əs or āl'yəs (like the tv show
Alias (TV series)) -ing.
The layout of the pictures really needs to be sorted - at the moment the page looks untidy and some pictures are nowhere near the text that references them. Romansanders 17:31, 8 April 2006 (UTC)
I heard theres a ay to turn anti aliasing off in MS paint, can anyone shed some light on that?
I've never seen AA in MSpaint. I just played with it just now, and there is no AA, period (unless I take off my glasses). 206.252.74.48 ( talk) 14:33, 3 January 2008 (UTC)
The 'real time approximations' section and its mipmapping subcomponent don't really fit with the tone of the rest of the article, which is more mathematical/theoretical (as it should be). I was thinking I'd create a new article for AA as used specifically in graphics; mipmapping fits there naturally, as does information about supersampling/multisampling, different sample patterns, coverage masks etc. which again shouldn't really go here, and I haven't seen anywhere else. There's already an article at FSAA but it's pretty scanty. Valarauka 20:49, 17 September 2006 (UTC)
I think this article is better than the (already mentioned as small) FSAA (full screen antialiasing) article, and the content should be merged. They are relatively the same thing. I don't think it would hurt this article to include a mention of the methods used in graphics cards, and fsaa could be one of those subheadings. -- gatoatigrado 05:48, 4 October 2006 (UTC)
Agreed on both counts. I don't really see that mipmapping has a place in the general article on anti-aliasing - it's a very specific technique to avoid having to do antialiasing in real-time rendering, and it's already covered sufficiently in articles on texturing and texture filtering. -
Valarauka(
T/
C)
05:55, 4 October 2006 (UTC)
Since eyes can rotate in their sockets, this must have to do with the fact that we are dealing with data sampled on a square lattice and not with a continuous image.
What does that have to do with anything? I think this sentence should go. User A1 00:14, 15 December 2006 (UTC)
The section "First-principles approach to anti-aliasing" includes this statement:
"By the pigeonhole principle, sometimes two different ideal images f(x,y) and g(x,y) will be converted to the same picture on the screen. This cannot be avoided."
While that is undoubtedly true, it is not clear how it is relevant. The issue is just the opposite, the fact that a single ideal image can be approximated by many alternative reduced images, which creates the challenge of how to select among them.
Steve Wise 04:57, 7 January 2007 (UTC)Steve Wise
I don't agree that the second image is not related. That is a thumbnail, and you can click to view the larger version. Lugiadoom 08:51, 24 January 2007 (UTC)
The section that was added about criticism might have some good points, but criticisms need to backed up by an attribution to a sourced. So I took it out. Put it back when it's ready. Dicklyon 16:10, 24 January 2007 (UTC)
"The idealized image has infinite detail, and is represented by a function f(x,y) where x and y are real numbers defining coordinates."
Infinite or just enough to match the resolution of the human eye? Maybe some elaboration could follow this sentence. -- RITZ 04:03, 7 March 2007 (UTC)
More should be added about different algorithms, for example Xiaoling Wu's work in the early nineties.
"Game consoles and type setting on screen of personal computers employ antialiasing in realtime. Windows Picture and Fax Viewer, Microsoft Powerpoint, Adobe Acrobat Reader, Ghostview, the aqua and aero window managers employ it full screen, while the Gimp and OpenOffice.org Impress are not able to."
That sounds really irrelevant to me. Also like an attempt to discredit and belittle the quality of OpenSource Software, due the wording and the selection of commercial software on one side, the GIMP and OpenOffice on the other side. 217.235.93.78 19:18, 15 July 2007 (UTC)
"The goal of sharply cutting off frequencies above a certain limit, known as the Nyquist frequency, can not be realized exactly, even with Fourier techniques, so it is always approximated, with many different choices of detailed algorithm".
I believe the above statement is wrong and should be removed or rephrased. Could you please justify why can you not achieve a sharp cut-off on a discrete signal of finite length such as a computer image. Maybe you are referring to the ringing artifacts (Gibbs phenomenon) which are a consequence of a sharp cut-off? -- xerm ( talk) 11:59, 15 February 2008 (UTC)
You can resample a digital image with filters. But in computer graphics, the initial rendering operation involves sampling what I called a "symbolic image" represented by some scene description, and in general there is no way to pre-filter that symbolic scene representation before it is sampled (e.g. by rasteriztion or ray tracing). Take a look at a tutorial I wrote for SIGGRAPH '90: http://www.mentallandscape.com/Papers_siggraph90tutorial.pdf DonPMitchell ( talk) 20:13, 5 July 2008 (UTC)
I'm suggesting merging the small amount of content at Temporal anti-aliasing into this article, as the underlying principles are identical. Whilst it's the case that this article is currently dedicated solely to spatial anti-aliasing in the context of computer graphics, there's no reason it should be limited to just this. A wider exposition of the field is needed. Alternatively, this article should be renamed to Spatial anti-aliasing in computer graphics or similar. Oli Filth( talk| contribs) 17:54, 31 May 2009 (UTC)
(outdent) Per the discussions above, I've now moved the article to Spatial anti-aliasing, as that is the only correct title given the article's content. Oli Filth( talk| contribs) 17:38, 16 May 2010 (UTC)
Pictures are in some strange non-linear color space, instead of sRGB. 83.4.200.31 ( talk) 20:34, 4 January 2010 (UTC)
In the FSAA section "jaggies" are considered to be the only aliasing effect which is NOT correct. In fact there are effects like "moire" or loosing edges, curves(some high frequency geometry) altogether rather then having "jagged" edges. Unfortunately people have a false perception of "aliasing = jagged edges" because of this false treatment of the subject. Please correct it. —Preceding unsigned comment added by 24.61.87.72 ( talk) 21:10, 29 June 2010 (UTC)
How about Morphological anti-aliasing which is coming into effect as the new Radeon 6000 series releases? Some of it is discussed in this article: http://www.tomshardware.com/reviews/radeon-hd-6870-radeon-hd-6850-barts,2776-4.html IOA94 ( talk) 20:32, 1 November 2010 (UTC)
Is the line "The ear is predominantly sensitive to lower frequencies. And so, in signal processing, we choose to eliminate all high frequencies from the signal, keeping only the frequencies that are low enough to be sampled correctly by our sample rate." strictly necessary and in context? Evn2-NJITWILL ( talk) 20:22, 23 November 2010 (UTC)
I have not been able to find any information anywhere on the internet about FSAA, it is "sourced" with only one link, but the article in that link NEVER mentions the term FSAA, meaning it has no sourcing at all. -- Taltamir ( talk) 22:17, 10 January 2011 (UTC) Note, that while unable to find information about what it means or what it is, I have found mention of the term. For example here: http://www.nvidia.com/object/quadro_sli_fsaa.html nvidia clearly uses the term FSAA, just not in the one source given for that portion of the article. So if anyone could find better sources for it, please do.-- Taltamir ( talk) 22:21, 10 January 2011 (UTC)
Is this article supposed to be only about anti-aliasing in graphical display systems? Anti-alias (low pass) spatial filters are a part of many digital cameras, needed to prevent aliasing due to the spatial sampling of the image sensor. There is a little in the anti-aliasing filter page, but not so much. Given the title of this page, it should include optical (spatial) low-pass anti-alias filters, too. Gah4 ( talk) 21:20, 17 August 2017 (UTC)
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A few TV station articles, e.g.
TV Land refer to downscaling: "Picture Format:
1080i
HDTV (
downscaled to
letterboxed
480i for the
SDTV feed)". By "downscaling" do they mean spatial anti-aliasing? I would like to add have added a
WP:HATNOTE to
Downscaling - directing readers to this article if they are interested in image downscaling - but I want to be sure I have got it right.
On a related note, this article is linked to from the dab page Downsizing, with the (uncited) comment "Downsizing the image : resizing the image to lower pixel resolution for reduce the file size or Spatial_anti-aliasing". If downsizing and downscaling are alternative terms for spatial anti-aliasing, this article should say so. Adpete Adpete ( talk) 23:12, 22 December 2021 (UTC)