Posted under General
So there's this new image upscaling utility at http://waifu2x.udp.jp that apparently involves machine-learning and optimization specifically for anime-style artwork.
Posting this here FYI because it's a pretty good tool, but more importantly because a few upscaled images seem to have been uploaded here already and more will surely follow as this thing gets more popular, so approvers should be extra careful when considering for approval larger versions of existing posts.
Of course, any upscales created with that site and that are uploaded here should be the child of the original. We should treat these as photoshops.
Edit: So basically, this site is an automated vector trace tool. Smaller details (i.e. blush lines) tend to be lost with this.
Updated
Ars said:
Edit: So basically, this site is an automated vector trace tool. Smaller details (i.e. blush lines) tend to be lost with this.
I don't think that's true. I haven't noticed things like that lost in my tests of it. Unless you're counting image artifacts as details; it's designed to get rid of those.
Try it on post #2057491 for example, the blush lines are still there. Although a couple of the dots in the sand at the bottom do disappear, probably because those dots are not in the style it's trained to work with.
And they're not vector images.
Toks said:
I don't think that's true. I haven't noticed things like that lost in my tests of it. Unless you're counting image artifacts as details; it's designed to get rid of those.
Try it on post #2057491 for example, the blush lines are still there. Although a couple of the dots in the sand at the bottom do disappear, probably because those dots are not in the style it's trained to work with.
And they're not vector images.
Well, it seems to depend on how big the original image is. On post #1769742 the blush lines are definitely lost when upscaled(post #2053590) through that site.
Ars said:
Well, it seems to depend on how big the original image is. On post #1769742 the blush lines are definitely lost when upscaled(post #2053590) through that site.
I think it's because of how small and faint the blush lines are in that image. It seems to interpret them as jpeg artifacts and removes them. Unless you disable noise reduction, in which case they stay, and it seems that also applies to the dots in the sand on post #2057491.
tapnek said:
I suggest that any images currently on the database with this upscaling filter be tagged as such. Any future uploads that utilize it should be ignored or deleted.
They're no different from vector images, aren't they? As Ars said, they should be parented to the original, and I think there is meaning in uploading good upscales of smaller images.
CodeKyuubi said:
They're no different from vector images, aren't they? As Ars said, they should be parented to the original, and I think there is meaning in uploading good upscales of smaller images.
What is a "good upscale", and why can't everyone just press the button themselves?
I mean, if we wanted to support that, why not just add a link to the side menu of every post that anyone on danbooru can press which sends a request to that website with the image URL? (like it works with iqdb)
S1eth said:
(like it works with iqdb)
How it used to work with iqdb. For over a year the Find similar buttons that Danbooru provide do not link to http://iqdb.org/, Danbooru processes requests internally with its own iqdb server.
CodeKyuubi said:
They're no different from vector images, aren't they? As Ars said, they should be parented to the original, and I think there is meaning in uploading good upscales of smaller images.
Third-party edits are generally not allowed. Exceptions exist though, such as scan fixes like detexting and removing creases, or colored versions of images, like the colored To Love-Ru manga pages, or pixiv artists coloring other artists' lineart, etc.
Vector traces are mostly crap, but if done properly, they can have some redeeming qualities other than larger image dimensions (e.g. transparent background and gradients) and that may warrant keeping them. An upscaled image on the other hand, is just that. Allowing them might open the floodgates to people upscaling and uploading whatever en masse, and that's just useless clutter when you have the original image and easy access to an automated tool, like S1eth said.
That being said, the tricky thing with waifu2x is that if an image has the usual anime flat colors and no realistic textures and details, the upscaled version can easily pass off as a genuine larger version, especially if the approver isn't familiar with the original and doesn't spend too much time examining minor details.
CodeKyuubi said:
They're no different from vector images, aren't they? As Ars said, they should be parented to the original, and I think there is meaning in uploading good upscales of smaller images.
The problem I see here is that the filter is a computer done thing like the mosaics made out of multiple images. It's an incredibly lazy way of increasing your upload limit since it can be applied to multiple images.
tapnek said:
The problem I see here is that the filter is a computer done thing like the mosaics made out of multiple images. It's an incredibly lazy way of increasing your upload limit since it can be applied to multiple images.
True. Has anyone experimented with upscaling images tagged with lowres?
Lowres images seem to upscale fine, obviously since there's less detail the upscaled can look a little flat in places but lines and strokes scale quite nicely.
I find that jpg artifacts have a bigger effect on the final quality rather than original resolution, the more noise reduction you add, the higher the loss of detail, test this with the kancolle cgs and you'll notice the upscaling fails when it comes to edges against the background and subtle details like shading in the eyes.
Updated
Anyways, as for tagging them, how does waifu2x_upscale sound?
Ars said:
Anyways, as for tagging them, how does waifu2x_upscale sound?
What about images that only had waifu2x's noise reduction applied with no change to resolution?
Ars said:
Of course, any upscales created with that site and that are uploaded here should be the child of the original. We should treat these as photoshops.
Edit: So basically, this site is an automated vector trace tool. Smaller details (i.e. blush lines) tend to be lost with this.
CodeKyuubi said:
They're no different from vector images, aren't they? As Ars said, they should be parented to the original, and I think there is meaning in uploading good upscales of smaller images.
I'm not sure if what the neural network does behind the scenes is anything like vector tracing, but I guess the results are not dissimilar, except more automated and consistent. The Github page has some examples, as well as instructions on how to set it up on your own server: https://github.com/nagadomi/waifu2x
This blog post has more examples, based on historical Japanese woodblock prints: http://ejohn.org/blog/using-waifu2x-to-upscale-japanese-prints/
As for uploads, I don't think we should be too concerned about anyone boosting their stats. But there is a good argument for not flooding the site with waifu2x images when it's easy to use waifu2x on an image yourself.
CodeKyuubi said:
True. Has anyone experimented with upscaling images tagged with lowres?
I've made some tests here: https://imgur.com/a/jWZt7
I like "no noise reduction" best, for most of the images. Sometimes "low noise reduction" helps smooth out curves and make lines pop out more, at the cost of some detail. I guess higher noise reduction may be more useful if the source is not so clean or crisp.
Ars said:
Anyways, as for tagging them, how does waifu2x_upscale sound?
Toks said:
What about images that only had waifu2x's noise reduction applied with no change to resolution?
Perhaps just waifu2x, then?
