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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
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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
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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
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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
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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
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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
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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
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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
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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
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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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