Artwork image proccessing/enhancement tools?

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Artwork image proccessing/enhancement tools?

Postby RobbieThe1st on Fri Aug 13, 2010 6:33 am

This may not be the best place to ask this sort of question, but...

I'm looking for some sort of (more or less automated) tool that can do some "improvement" on some webcomic pages/artwork.
This artwork I'm talking about has been sampled down for web use, and the originals have gotten lost to insufficient backups.
As such, I'm curious about trying to find ways to "restore" and up-sample these images.
Lets take a look at a good example: http://www.missmab.com/Comics/Vol_141.php
As you can see, there are multiple issues:
1. Jpeg noise. This ought to be able to be dealt with, seeing as its relatively uniform, and we are dealing with limited colors in the origional.
2. Text-quality. In order to do any sort of major resizing, the text will have to be fixed. I know the font that was used(Pasteris), and so in theory it should be possible to use some sort of specialized OCR utility to: A. locate any and all text, B. "delete" each letter by filling the space with color from the surrounding area, and then after resizing, C. add new text in the same location at a much higher resolution.
3. blurred lines and color in the artwork. On some later works, this might be harder, but with the above example, we are only talking about cell-shading, and therefor a tracing program or tracing-stype enhancer could be used without too much difficulty. This should be possible - VectorMagic can do it, but its -too- picky about making things perfect and reduces detail too much even on high settings.

Now, I've heard about this miracle method for improving quality called "l1 minimization", which works by reducing "entropy" in an image. From my understanding of it, such an algorithm would work great on images like these, as we are dealing with a -very- sparse image-source, although it may take some CPU time(which is very cheap these days). However, I haven't seen any practical implementations of it.

Do any of you guys know any tools that could be used for these purposes? Even slightly?

Or, if not, do you guys know a good place to ask about such things?

Thanks,

-Rob
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Re: Artwork image proccessing/enhancement tools?

Postby JasonLG on Fri Aug 13, 2010 8:14 am

GIMP and Inkscape will do all those things and more.
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Re: Artwork image proccessing/enhancement tools?

Postby RobbieThe1st on Sat Aug 14, 2010 12:40 am

JasonLG wrote:GIMP and Inkscape will do all those things and more.

Ah, but -how-, aside from simply manually tracing over each line, etc?

I'm aware of a couple of tools in Gimp that can be used usefully for these purposes, but all require a significant bit of time for each image.

Though, I wasn't aware of there being any text-tracing methods in Gimp at all - Sure, I could manually overlay a template copy of the font, etc... but thats -really- time consuming, and it seems simple enough in concept
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Re: Artwork image proccessing/enhancement tools?

Postby JasonLG on Sat Aug 14, 2010 6:52 am

RobbieThe1st wrote:
JasonLG wrote:GIMP and Inkscape will do all those things and more.

Ah, but -how-, aside from simply manually tracing over each line, etc?

I'm aware of a couple of tools in Gimp that can be used usefully for these purposes, but all require a significant bit of time for each image.

Though, I wasn't aware of there being any text-tracing methods in Gimp at all - Sure, I could manually overlay a template copy of the font, etc... but thats -really- time consuming, and it seems simple enough in concept


If you're talking about simple line drawings like the web comics that you linked to Inkscape has an auto-trace tool that should help, but as far as text goes the best thing to do would probably be to redo it. I don't think you'll find a magic bullet program that will turn a low quality jpeg into an original quality high res/vector image. My advice would be to contact the creator of the original work.
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Re: Artwork image proccessing/enhancement tools?

Postby RobbieThe1st on Sun Aug 15, 2010 12:42 am

JasonLG wrote:If you're talking about simple line drawings like the web comics that you linked to Inkscape has an auto-trace tool that should help, but as far as text goes the best thing to do would probably be to redo it. I don't think you'll find a magic bullet program that will turn a low quality jpeg into an original quality high res/vector image. My advice would be to contact the creator of the original work.

Yea, that -was- kind of asking too much.

What about the more practical and doable text-replacement problem? I mean, we have had OCR technology for quite a while now, but I can't find one that actually reads the font correctly - due to it searching too "broadly". However, knowing the exact font in question, and the size used, there ought to be some image-recognition technology that can pick out individual letters, especially if given a bitmap of each letter. The only real issue is that it would have to do fussy/threshold matching, as there -is- Jpeg-artifacts that will prevent exact-color matching from working.
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Re: Artwork image proccessing/enhancement tools?

Postby JasonLG on Sun Aug 15, 2010 1:42 am

RobbieThe1st wrote:
JasonLG wrote:If you're talking about simple line drawings like the web comics that you linked to Inkscape has an auto-trace tool that should help, but as far as text goes the best thing to do would probably be to redo it. I don't think you'll find a magic bullet program that will turn a low quality jpeg into an original quality high res/vector image. My advice would be to contact the creator of the original work.

Yea, that -was- kind of asking too much.

What about the more practical and doable text-replacement problem? I mean, we have had OCR technology for quite a while now, but I can't find one that actually reads the font correctly - due to it searching too "broadly". However, knowing the exact font in question, and the size used, there ought to be some image-recognition technology that can pick out individual letters, especially if given a bitmap of each letter. The only real issue is that it would have to do fussy/threshold matching, as there -is- Jpeg-artifacts that will prevent exact-color matching from working.


Most OCR's only work 100% when the text is very generic i.e. your basic serif and sanserif fonts or very, very good hand writing. They don't do well with stylized or script fonts or sloppy hand writing. Again I don't think that you're going to get a very high quality result from a screen res source image but here's what I'd do.

In Gimp...
1. Convert the image to CYMK and dropout the color channels so you're left with the black channel.

2. upsample that to 300 dpi, sharpen it and jack up the contrast.

3. Remove the text the best you can.

4. Save it as a black and white bitmap.

In Inkscape...
1. Use the auto trace to trace the bitmap.

2. Use a a dropper to get the colors off the original and paint them in.

3. Replace the text the best you can.

I still say asking the artist for a copy of the original is easier.
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Re: Artwork image proccessing/enhancement tools?

Postby RobbieThe1st on Sun Aug 15, 2010 3:44 am

JasonLG wrote:In Gimp...
1. Convert the image to CYMK and dropout the color channels so you're left with the black channel.

2. upsample that to 300 dpi, sharpen it and jack up the contrast.

3. Remove the text the best you can.

4. Save it as a black and white bitmap.

In Inkscape...
1. Use the auto trace to trace the bitmap.

2. Use a a dropper to get the colors off the original and paint them in.

3. Replace the text the best you can.

Hm, this my be useful.


JasonLG wrote:I still say asking the artist for a copy of the original is easier.

You are right, but I happen to know that the originals for the first 600 or so comics in that webcomic have been entirely lost. The web copy is the -only- copy that exists, and the artist in question sold off her black-and-white inked print originals too, and those are scattered... So, the only thing to work with is the web version.

As it is, I was mainly curious if there was a nice tool that could do what I want, but sadly it looks like, between Inkscape, Gimp and the proprietary tool VectorMagic, thats all thats available.
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Re: Artwork image proccessing/enhancement tools?

Postby RobbieThe1st on Mon Aug 16, 2010 7:19 am

Oh, gees. I think I just found exactly what I was looking for.
Its called "GRAYCstoration", and its a plugin for Gimp. (and is encorperated into a stand-alone program called GrayC's Magic Image Converter
I've just started messing with it, but it works excellently at removing JPEG blur and improving things a bit.

Take a look at this 2x resize of the linked example image: http://robbiethe1st.afraid.org/images/Vol141-grayc.png
Compare to the original here.
It may not be perfect, but its quite a bit better, I think.
The text is still an issue, but I'm amazed.


I hope this helps someone else!

-Rob
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