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Image enlargement software



 
 
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  #1  
Old November 19th 06, 04:42 PM posted to rec.photo.digital
Alfred Molon
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Posts: 80
Default Image enlargement software

I have some old, lower resolution images which occasionally need to be
enlarged (pixel count needs to be increased). A friend recommended
Photozoom, but after giving it a try I'm not that impressed (fail to see
visible improvements over a simple bicubic interpolation enlargement).
What other software would be better? I read Roger's enthusiastic posts
about the Lucy-Richardson stuff - is there a way to try this out?
--

Alfred Molon
------------------------------
Olympus 50X0, 7070, 8080, E300, E330, E400 and E500 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
Olympus E330 resource - http://myolympus.org/E330/
  #2  
Old November 19th 06, 05:18 PM posted to rec.photo.digital
Alfred Molon
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Posts: 80
Default Image enlargement software

In article , Ed Ruf (REPLY
to E-MAIL IN SIG!) says...
On Sun, 19 Nov 2006 16:42:49 +0100, in rec.photo.digital Alfred Molon
wrote:

I have some old, lower resolution images which occasionally need to be
enlarged (pixel count needs to be increased). A friend recommended
Photozoom, but after giving it a try I'm not that impressed (fail to see
visible improvements over a simple bicubic interpolation enlargement).
What other software would be better? I read Roger's enthusiastic posts
about the Lucy-Richardson stuff - is there a way to try this out?


Since it's free, start with Irfanview.


What enlargement tool/method in Irfanview would sou suggest?
--

Alfred Molon
------------------------------
Olympus 50X0, 7070, 8080, E300, E330, E400 and E500 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
Olympus E330 resource - http://myolympus.org/E330/
  #3  
Old November 19th 06, 07:42 PM posted to rec.photo.digital
Marvin
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Posts: 196
Default Image enlargement software

Alfred Molon wrote:
I have some old, lower resolution images which occasionally need to be
enlarged (pixel count needs to be increased). A friend recommended
Photozoom, but after giving it a try I'm not that impressed (fail to see
visible improvements over a simple bicubic interpolation enlargement).
What other software would be better? I read Roger's enthusiastic posts
about the Lucy-Richardson stuff - is there a way to try this out?


I don't know what improvement you expected to see. Adding
pixels doesn't improve resolution. I can't for basic
reasons. All you can really get is interpolated pixels that
make a smooth image. Some methods do a worse job with a
particular image.

Experimenting with different interpolation methods will give
you some experience. You already noted that two methods
didn't give much different results. That may. or may not,
be the case with the next image. I use Paint Shop Pro,
which offers several interpolation methods that I can apply
to an image, and choose the one I like best for that image.
  #4  
Old November 19th 06, 11:10 PM posted to rec.photo.digital
Colin_D
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Posts: 337
Default Image enlargement software

Alfred Molon wrote:
I have some old, lower resolution images which occasionally need to be
enlarged (pixel count needs to be increased). A friend recommended
Photozoom, but after giving it a try I'm not that impressed (fail to see
visible improvements over a simple bicubic interpolation enlargement).
What other software would be better? I read Roger's enthusiastic posts
about the Lucy-Richardson stuff - is there a way to try this out?


Alfred,

Try Qimage, free for a month's trial. All printers have a native
resolution at which they print any file, e.g. 600 ppi for Canons, and
720 ppi for Epsons. Note that is pixels per inch, the printer dpi (dots
per inch) is usually much greater, 4800 x 2400 dpi for my Canon, and
probably similar for Epsons.


Most image-handling software leaves the ppi conversion to the printer
software (if you feed an image at, say, 150 ppi to a native 600 ppi
printer, the printer driver will handle the interpolation) and you are
then at the mercy of however good that driver is at interpolation.

Qimage is different in that it is specifically designed to do the
interpolation before it feeds the image to the printer driver, also it
utilizes the printer profile, doing a much better job than ordinary
printer drivers, and the output is noticeably superior.

http://www.qimage.com

Colin D.

--
Posted via a free Usenet account from http://www.teranews.com

  #5  
Old November 20th 06, 01:14 AM posted to rec.photo.digital
[email protected]
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Posts: 1,311
Default Image enlargement software

Alfred Molon wrote:
I have some old, lower resolution images which occasionally need to be
enlarged (pixel count needs to be increased). A friend recommended
Photozoom, but after giving it a try I'm not that impressed (fail to see
visible improvements over a simple bicubic interpolation enlargement).
What other software would be better? I read Roger's enthusiastic posts
about the Lucy-Richardson stuff - is there a way to try this out?


Another vote for QImage. I've never seen anything better it. The R-L
(or L-R) stuff is out there but can be a bit non-user friendly, and I
haven't seen it do better than the QImage pyramid or vector algorithms.

In Irfanview, try Lanczos. It's a tiny bit better than bicubic, but
the differences are subtle and sadly, image dependent, which makes this
stuff all very subjective.. There's no free lunch with enlargement -
once anything starts guessing pixels, the image content often
determines how good the result might be!

Try these for some comparisons - give the second one plenty of time to
load and read the instructions..

http://hannemyr.com/photo/interpolation.html
http://www.general-cathexis.com/interpolation.html
http://www.americaswonderlands.com/d...erpolation.htm

  #6  
Old November 20th 06, 02:01 AM posted to rec.photo.digital
Alfred Molon
external usenet poster
 
Posts: 80
Default Image enlargement software

In article , Colin_D
says...

Try Qimage, free for a month's trial. All printers have a native
resolution at which they print any file, e.g. 600 ppi for Canons, and
720 ppi for Epsons. Note that is pixels per inch, the printer dpi (dots
per inch) is usually much greater, 4800 x 2400 dpi for my Canon, and
probably similar for Epsons.


Hi Colin, are you perhaps confusing something? I've never heard of any
printer with 720 ppi. Even the Lightjet printers, which are the best
currently available on the professional market, print at 300-400 ppi.
300 ppi is the industry standard.
By the way, are you sure that your Canon is capable of 4800 dpi? Sounds
a bit on the high side.
--

Alfred Molon
------------------------------
Olympus 50X0, 7070, 8080, E300, E330, E400 and E500 forum at
http://tech.groups.yahoo.com/group/MyOlympus/
Olympus E330 resource - http://myolympus.org/E330/
  #7  
Old November 20th 06, 06:31 AM posted to rec.photo.digital
Roger N. Clark (change username to rnclark)
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Posts: 1,818
Default Image enlargement software

Alfred Molon wrote:

I have some old, lower resolution images which occasionally need to be
enlarged (pixel count needs to be increased). A friend recommended
Photozoom, but after giving it a try I'm not that impressed (fail to see
visible improvements over a simple bicubic interpolation enlargement).
What other software would be better? I read Roger's enthusiastic posts
about the Lucy-Richardson stuff - is there a way to try this out?


Alfred,
Richardson-Lucy is not an interpolation method; it is an
image restoration (image sharpening) method. I use
an interpolation method then R-L. In general, I've not
seen an interpolation algorithm I liked. Every one
I've used (both commercial image editing and research
image processing systems) create artifacts. One may
do well with a certain type of image detail only
to do poorly on another type. If there were a great
solution, I would sure like to know about it.

Roger

  #8  
Old November 22nd 06, 01:20 AM posted to rec.photo.digital
Bart van der Wolf
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Posts: 314
Default Image enlargement software


"Alfred Molon" wrote in message
...
I have some old, lower resolution images which occasionally need to
be
enlarged (pixel count needs to be increased). A friend recommended
Photozoom, but after giving it a try I'm not that impressed (fail to
see
visible improvements over a simple bicubic interpolation
enlargement).


Photozoom does a reasonably good job on enlarging without creating
pixelization/jagged edges. Qimage does a very realistic, edge
preserving,
interpolation.

I give Qimage my vote, especially for printing, since it also adds a
superior
workflow. Do note that these programs do not improve resolution, but
they
deliver superior (without resampling artifacts) upscaled images.

What other software would be better? I read Roger's enthusiastic
posts
about the Lucy-Richardson stuff - is there a way to try this out?


ImagesPlus, is the program Roger uses for both its capabilities in
processing
astronomical imagery and for its implementation of the Richardson-Lucy
restoration algorithm. There is a time-limited Demo version available
at:
http://www.mlunsold.com/ .

In general, these (RL and similar) restoration methods work best if
you already have a good model of the lens+sensor unsharpness, a
so-called Point-Spread-Function (PSF). It might be useful to prepare
something like a PSF determination and study the website, because
ImagesPlus may have a bit of a learning curve, and it would allow to
make the best use of the time offered for testing.

--
Bart

  #9  
Old November 22nd 06, 02:08 AM posted to rec.photo.digital
Bart van der Wolf
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Posts: 314
Default Image enlargement software


"Roger N. Clark (change username to rnclark)"
wrote in message ...
SNIP
Richardson-Lucy is not an interpolation method; it is an
image restoration (image sharpening) method.


Indeed.

I use an interpolation method then R-L.


For understandable reasons, because one doesn't want to enlarge
sharpening artifacts. However, 'restoration' of up-sampling artifacts
is not an attractive proposition either.

I've been experimenting with this as well, and think the best approach
(although a bit more involved than I state here) is an R-L of the
original image, followed by an up-sample (e.g. factor 2x like you do,
which can possibly be characterized and losses restored with a PSF
based R-L). A good up-sampling method should already reduce artifacts,
so the second R-L run(s) will only attempt to restore losses, not
artifacts.

In general, I've not seen an interpolation algorithm I liked. Every
one I've used (both commercial image editing and research image
processing systems) create artifacts. One may do well with a
certain type of image detail only
to do poorly on another type. If there were a great
solution, I would sure like to know about it.


I'm quite pleased with the recent 'Hybrid SE' method from Qimage
Studio Edition. It preserves edges without stair-stepping, but unlike
other methods it doesn't create any halo along edges. I know your
reservations towards Qimage since it produces 8-bit/channel images
(targeted at printer drivers) and post-processing 8-b/ch images bears
the risk of posterizing in smooth gradients, like in skies. However,
already applying R-L at the original size (in 16-b/ch) will reduce the
amount of substantial sharpening needed after re-sampling (which has a
large diameter PSF).

--
Bart

  #10  
Old November 22nd 06, 05:49 AM posted to rec.photo.digital
Roger N. Clark (change username to rnclark)
external usenet poster
 
Posts: 1,818
Default Image enlargement software

Bart van der Wolf wrote:


"Roger N. Clark (change username to rnclark)" wrote
in message ...
SNIP

Richardson-Lucy is not an interpolation method; it is an
image restoration (image sharpening) method.



Indeed.

I use an interpolation method then R-L.



For understandable reasons, because one doesn't want to enlarge
sharpening artifacts. However, 'restoration' of up-sampling artifacts is
not an attractive proposition either.

I've been experimenting with this as well, and think the best approach
(although a bit more involved than I state here) is an R-L of the
original image, followed by an up-sample (e.g. factor 2x like you do,
which can possibly be characterized and losses restored with a PSF based
R-L). A good up-sampling method should already reduce artifacts, so the
second R-L run(s) will only attempt to restore losses, not artifacts.

In general, I've not seen an interpolation algorithm I liked. Every
one I've used (both commercial image editing and research image
processing systems) create artifacts. One may do well with a certain
type of image detail only
to do poorly on another type. If there were a great
solution, I would sure like to know about it.



I'm quite pleased with the recent 'Hybrid SE' method from Qimage Studio
Edition. It preserves edges without stair-stepping, but unlike other
methods it doesn't create any halo along edges. I know your reservations
towards Qimage since it produces 8-bit/channel images (targeted at
printer drivers) and post-processing 8-b/ch images bears the risk of
posterizing in smooth gradients, like in skies. However, already
applying R-L at the original size (in 16-b/ch) will reduce the amount of
substantial sharpening needed after re-sampling (which has a large
diameter PSF).

Bart,
Thanks for the info. I'll have to try this too (R-L first).
I've been working out a new interpolation algorithm for work
on imaging spectroscopy data. It will be compute intensive
but will avoid many artifacts I see now.

Roger
 




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