[geeks] silly graphics idea: how to scale an image

[Greg A. Woods]

I was just reading all the whining on the NANOG list about IPv6,
multicast, and cart-horse issues, and in particular about streaming
video in "postage-stamp resolution" when I had an idea about image
scaling.  I'm sure it's not a new idea, but it's certainly new to me and
obviously new to any free image scaling software.  If I'm not mistaken
there are a few computer-graphics nuts on this list, so I thought I'd
ask here to see what y'all think.

Almost all image scaling software I've played with (and read about)
simply makes square pixels bigger, and then possibly smooths them out.
This only works for relatively small amounts of scaling, but soon the
pixelation (square blocky-ness) is unavoidable, even if you do several
steps, smoothing between each (I think XV does this best, though you
still have to save and reload between steps to get it to work best).

However When you optically blow up an image from film (or even a
half-tone'd printed image), it gets grainy, not pixelated, and to my
eyes at least this process much more accurately mimics what happens when
you optically magnify the light coming right off a real object.

Why not make pixels into circles as you expand them, keeping their
centers close enough to not have any spaces in between and "properly"
mixing the overlap (whatever that means in terms of translucency or
whatever)?

Some laser printers fake a higher resolution by using smaller dots
(presumably in order to do anti-aliasing along edges).  I suppose one
could vary the size of the pixels too in order to fill in the holes
between circles, using some kind of averaging to mix colours from
neighbours.

When I visuallize these processes in my mind it seems like the result
will be FAR more visually appealing than a pixelated magnification,
though perhaps I'm dreaming of impossible transformations and imagining
some way to create new information from thin air.....

-- 
								Greg A. Woods

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