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[challenge entry] Well...
That's definate then!

From the National Suicide Week challenge. See all 393 entries (closed)

(MAD ADE I feel old all of a sudden, Mon 15 Dec 2003, 18:32, archived)
# mmmm antialiasing
(I helped save b3ta! lemony, Mon 15 Dec 2003, 18:33, archived)
# you know
I've often pondered the word "anti-aliasing". I mean, it's something you turn off if you want it to be the way it was before, which is then anti-anti-aliasing, but you never call it just aliasing anyway.

I mean... come on, from the people who brought us words like "liquify" and "repair", you'd think they'd come up with a better, more self-explanatory fucking word than that!
(I helped save b3ta! zog why change it now?, Mon 15 Dec 2003, 18:36, archived)
# refocus?
(I helped save b3ta! _null_, Mon 15 Dec 2003, 18:38, archived)
# please mail that to adobe.
all though I was thinking something more along the lines of "fluffify".
but whatever.
(I helped save b3ta! zog why change it now?, Mon 15 Dec 2003, 18:39, archived)
# i think it is a term from pre photoshop days
(I helped save b3ta! lemony, Mon 15 Dec 2003, 18:39, archived)
# I can hear the tinkling
of your warm urine spattering off the side of my parade float.
(I helped save b3ta! zog why change it now?, Mon 15 Dec 2003, 18:40, archived)
# haha
(Cockfosters!, Mon 15 Dec 2003, 18:42, archived)
# Like
"unsharp mask", my favourite PhotoShop tool in the world.
(Wong Fei-Hung - now with added flickr.com (see profile), Mon 15 Dec 2003, 19:02, archived)
# I know what aliasing is
in a digital signal sense, but have no idea how it applies to pictures

I know someone who would know though. I can ask if you'd like
(I helped save b3ta! kitty meow meow, Mon 15 Dec 2003, 18:45, archived)
# In 3D projects (videogames etc.)
It refers to polygons whos edges don't appear to be straight, as in the renderer draws them as jagged lines instead, also know as aliasing. The same thing applies to pictures, ie in photoshop when you draw a line with the line tool, it isn't smooth, because photoshop works on a pixel basis, so the line can only be jagged, because the pixels are essentially square. anti-aliasing (in 2 and 3D) refers to filters that make the line appear straight,often meaning it blurs it slightly so the sharp edges fade.

sorry, just spent the like the past 10 hours working with the Halflife engine, trying to make some images appear smoother when they were scaled and partly transparent
(TheTruffleShuffle, Mon 15 Dec 2003, 19:13, archived)
# not seen you in ages!
I was thinking about a more mathematical explanation, not about what it really does.

where've you been?
(I helped save b3ta! kitty meow meow, Mon 15 Dec 2003, 19:16, archived)
# I moved to England
:)

actually, I'm just over here on an exchange program.
(TheTruffleShuffle, Mon 15 Dec 2003, 19:20, archived)
# cool
I'm jealous.
(I helped save b3ta! kitty meow meow, Mon 15 Dec 2003, 19:21, archived)
# It's fantastic,
but I barely have time to lurk, let alone shop anything right now.
(TheTruffleShuffle, Mon 15 Dec 2003, 19:24, archived)
# as long as you're enjoying yourself :)
Everyone I know is over there. I wish I knew how to make freinds in real life
(I helped save b3ta! kitty meow meow, Mon 15 Dec 2003, 19:25, archived)
# Well anti-aliasing is actually a broad term for any process which removes aliasing from an image ...
Like I say below, super-sampling and bi-linear filtering are two of the most common.
In things like font rendering you can calculate for each pixel not just whether it's in or out the glyph (character), but what fraction of the pixel is in or out. For a pixel 30% in the character, you fill it 30% grey.
The human eye will actually perceive a blury line/edge as straighter and finer than an on/off pixel edge when it's diagonal.
In fact recently there's been a more interesting improvement in anti-aliasing for fonts on LCD screens. You now get anti-aliasing routines for fonts which renders little bits of red or blue along the edge of the fonts (which is better than grey because the red cell in the pixel is on the left and the blue cell is on the right*).
Try zooming in on small fonts in XP on a laptop, you might be able to see it - it looks crap close up, but really makes things look sharp when viewed normally.

* - On some LCD's it's BGR etc... but you get the point.
(I helped save b3ta! Hagbard ... it's been a long time., Mon 15 Dec 2003, 19:28, archived)
# hmmm
still doesn't tell me the structure of the filter that it goes through. I understood all that before :)
(I helped save b3ta! kitty meow meow, Mon 15 Dec 2003, 19:31, archived)
# There is no 'the' filter, it can be one of a hundred things.
Photoshop is probably doing something like bi-liinear or bi-cubic filtering whereas 3D graphics cards can also do semi-translucent edges and supersampling when rendering.
(I helped save b3ta! Hagbard ... it's been a long time., Mon 15 Dec 2003, 19:34, archived)
# this is at a much higher level than I understand
I've heard of these, but I'm used to thinking about filters differently, at a very introductory level.

(I helped save b3ta! kitty meow meow, Mon 15 Dec 2003, 19:36, archived)
# Right this is now I see it ...
Aliasing refers to visual artifacts perceived by the eye which are a result of the display technology and not intended to be present. Ie, when a line is nearly horizontal or vertical on a monitor you can see steps along it (commonly called jaggies).
This all started with things like font rendering (which is a highly developed a scary subject in its own right) but applies to any computer graphics.
So, in order to remove the aliasing which has occured, you do 'anti-aliasing'. This is any procedure which reduces the aliasing although these days it's tends to revolve around super-sampling (making the image bigger than you needed and then reducing it) or some form of filtering (bi-linear / cubic etc...).
As a term it pre-dates photoshop by about 20 years and goes back to the first digital typesetting and so on.
(I helped save b3ta! Hagbard ... it's been a long time., Mon 15 Dec 2003, 19:18, archived)
# aliasing in general
is where a signal is distorted by undersampling. Where you haven't taken enough data points to accurately represent the image.

In normal sampling there's a certain rate at which aliasing begins to occur, but I'm not sure about how it applies to images, since I nearly failed DSP so I didn't take image processing
(I helped save b3ta! kitty meow meow, Mon 15 Dec 2003, 19:21, archived)
# I never did DSP stuff ... GC for me.
I hadn't twigged that you were not the original question asker, sorry if my replies have seemed a little dumbed down.
(I helped save b3ta! Hagbard ... it's been a long time., Mon 15 Dec 2003, 19:31, archived)
# It's ok
I'll just have to ask my friend who has a doctorate in image processing :)
(I helped save b3ta! kitty meow meow, Mon 15 Dec 2003, 19:33, archived)
# ask jeeves
"Am I gay?"

1 result returned:
www.cnn.com/session@@~448FD3C588AB67ABBC30/clock/world/03/dec/?1226543
(I helped save b3ta! _null_, Mon 15 Dec 2003, 18:35, archived)
# well, I asked too
and all I got was gay rights and gay porn sites.

so I guess the answer is obvious.

you're not gay.

(I helped save b3ta! zog why change it now?, Mon 15 Dec 2003, 18:38, archived)
# jeeeeeves.
(I helped save b3ta! Sir Sand GOBLIN ^popular page dis, Mon 15 Dec 2003, 18:35, archived)
# jiiiiiives
(I helped save b3ta! lemony, Mon 15 Dec 2003, 18:36, archived)
# jizz
(I helped save b3ta! Blobcat Less Jaffacakes this year, Mon 15 Dec 2003, 18:47, archived)