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Depixelizing Pixel Art

research.microsoft.com

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Re: Depixelizing Pixel Art

#81

Post by jpatokal »

chongli wrote: post #66
josh-wrale wrote: post #53

Earlier quoted context omitted.

Here's a video: https://research.microsoft.com/en-us/um/people/kopf/pixelart...

Am I crazy for preferring the one on the left (nearest-neighbour)? The other two really mess up certain details such as the point numbers, the stem of the fruits and pokey's eyes. They also tend to cause a very subtle distortion of the outlines of foreground sprites as they move over the background.

The one on the left is effectively Super Mario in its original pixelated glory, so it'll certainly look the most familiar.

Re: Depixelizing Pixel Art

#82

Post by araes »

lloeki wrote: post #73
Camillo wrote: post #59

Earlier quoted context omitted.

No, hq4x is still better on almost all of them. Microsoft's makes everything too round and blobby. It pretty much only works really well when everything is round, like in Boo. But look at what it does to the Golden Axe characters' faces.

hq4x keeps angles when it should not, degrading many features in the process, and that bothers me much more than the overall change to a bit more blobbiness. Look at the outline of Bowser's horns and mouth, Toad's cap outline, Fake Sage's moustache, or Axe Battler 2 sword. The mouths of invaders are also faithfully reproduced. In the Ports icon, the cable is correctly represented, and the port itself has volume inste…

I noted the same issue with round vs sharp sections. Honestly, what this needs is a blending function, kind of like how they do intense shocks in fluid dynamics, where it would use MS's algo in areas where it detected significant roundness, and then blend into the hq4x algo in areas where there's more angular sections, like in the treasure box.

Re: Depixelizing Pixel Art

#84

Post by GhotiFish »

frik wrote: post #17

hq4x looks better (IMHO), sadly the website is offline (default blank wordpress site): http://hiend3d.com/hq4x.html backup on archive.org: https://web.archive.org/web/20120630044334/http://www.hiend3... http://en.wikipedia.org/wiki/Hqx Source: https://code.google.com/p/hqx/source/browse/trunk/src/hq4x.c

even so. I suspect a live rendering of the vector process would be fairly attractive. I'd love to see this technique used on the textures for n64 games. The rendering times wouldn't be such an issue in that case.

Re: Depixelizing Pixel Art

#85

Post by vanderZwan »

rsiqueira wrote: post #30

The authors of this paper also have other amazing image processing/optimization algorithms. Eg: Deblurring, Optimizing Color Consistency, Content-aware Automatic Photo Enhancement, Object Discovery and Segmentation in Internet Images and more: Dani Lischinski's page: http://www.cs.huji.ac.il/~danix/ Johannes Kopf page: http://johanneskopf.de/

Wow, the content-aware downscaling seems very useful!

http://research.microsoft.com/en-us/um/people/kopf/downscali...

> This paper introduces a novel content-adaptive image downscaling method. The key idea is to optimize the shape and locations of the downsampling kernels to better align with local image features. [...] Besides natural images, our algorithm is also effective for creating pixel art images from vector graphics inputs, due to its ability to keep linear features sharp and connected.

IIRC, this is one of the major reasons that vector graphics based icons have not taken off.

Re: Depixelizing Pixel Art

#86

Post by Camillo »

lloeki wrote: post #73
Camillo wrote: post #59

Earlier quoted context omitted.

No, hq4x is still better on almost all of them. Microsoft's makes everything too round and blobby. It pretty much only works really well when everything is round, like in Boo. But look at what it does to the Golden Axe characters' faces.

hq4x keeps angles when it should not, degrading many features in the process, and that bothers me much more than the overall change to a bit more blobbiness. Look at the outline of Bowser's horns and mouth, Toad's cap outline, Fake Sage's moustache, or Axe Battler 2 sword. The mouths of invaders are also faithfully reproduced. In the Ports icon, the cable is correctly represented, and the port itself has volume inste…

I think we're trying to optimize different functions.

For Bowser, I think hq4x is fine (the mouth needs not have a smooth contour like a human's - compare with a dinosaur or a crocodile), but you are giving more weight to the fact that the shaded part on the bottom right of the mouth is broken in several pieces, instead of being a single piece like in ours.

For Fake Sage, I think hq4x does better. A pointy moustache is fine. The "ours" version is practically melted, and hardly recognizable as an old man - it looks more like some sort of fish shaman.

For Axe Battler 2, the shaded part of the sword is jagged in hq4x, but that doesn't bother me. Same thing for the broken black outline in the leg. I am much more bothered by how "ours" messes up his face.

In general, I would say that "ours" is better at putting together some parts that are supposed to be a single line, while hq4x separates them (especially with thin shadows). But graphically, hq4x's result is much more faithful to what the sprite is supposed to represent. With "ours", everything looks like melted ink, or like it's been seen through a wet pane of glass in the rain.

It would be nice to see if it's possible to combine "ours"'s better detection of continuous shades with hq4x's better preservation of straight lines and details.

Re: Depixelizing Pixel Art

#87

Post by Drexl »

lloeki wrote: post #73
Camillo wrote: post #59

Earlier quoted context omitted.

No, hq4x is still better on almost all of them. Microsoft's makes everything too round and blobby. It pretty much only works really well when everything is round, like in Boo. But look at what it does to the Golden Axe characters' faces.

hq4x keeps angles when it should not, degrading many features in the process, and that bothers me much more than the overall change to a bit more blobbiness. Look at the outline of Bowser's horns and mouth, Toad's cap outline, Fake Sage's moustache, or Axe Battler 2 sword. The mouths of invaders are also faithfully reproduced. In the Ports icon, the cable is correctly represented, and the port itself has volume inste…

I think the lesson here is that it is subjective and the ability to use multiple such tools together would be best.

Re: Depixelizing Pixel Art

#90

Post by brianpgordon »

bri3d wrote: post #29
rkuykendall-com wrote: post #24

Earlier quoted context omitted.

Do you know if MS is working on Mac-Style resolution independence for W9? I'm currently running a Retina MBP, at 2x res I think, and it works _perfectly_. The first few months some apps didn't work well, but the community adapted very quickly.

Windows has had support for resolution independence where DPI is configurable across a continuum (rather than only available as 1x or 2x scale like on the Mac) for quite some time - the issue is that with a huge legacy application base, a giant morass of drawing technologies, and no shipped "HiDPI" or "Retina" Windows hardware until recently, there's been no real incentive for app developers to support it. In Windows…

It's not just the "legacy application base" or "app developers" which are at fault; even most of Windows itself is still using the old drawing libraries. As soon as you start digging into system properties, MMC, etc, everything is horribly blurry.

But yes, apps are also broken, even very popular ones like Chrome and Steam.

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