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Depixelizing Pixel Art

research.microsoft.com

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Re: Depixelizing Pixel Art

#91

Post by Spittie »

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.

No, you aren't. I prefer nearest-neighbor too, I think it preserves the "spirit" of the game. Generally speaking, I prefer it for any kind of "pixel art".

That said, those algorithms are impressive, and I can see why someone could prefer them over a simple nn.

Re: Depixelizing Pixel Art

#92

Post by dublinben »

jjcm wrote: post #43
jrockway wrote: post #14

I wish they would use this in Windows 8. As far as I can tell, their scaling algorithm for 4k displays is: scale up 2x using nearest neighbor, then randomly drop pixels to get back to 125% or 150%. The result is horrifyingly bad. Not just kind of bad, but unusably bad. (Adding insult to injury, they ClearType the text before scaling.)

While something similar would probably be better, this is heavily optimized for pixel artwork. Lots of curves, shading, and most importantly - limited colors. UI is generally much straighter, less shaded, with far more colors. Here's an example of UI that's scaled with potrace (a similar algorithm): http://i.imgur.com/jDq4M7e.png (left side is the converted side, right side is nearest-neighbor. Top is 3x, bottom is 2…

1. That looks awful.

2. We just need vector-based icons already.

Re: Depixelizing Pixel Art

#94

Post by joosters »

josh-wrale wrote: post #53
glhaynes wrote: post #47

Earlier quoted context omitted.

A problem with this algorithm is that it's pretty slow. It would be hard to use it for real time scaling. Even if it's too slow for realtime on today's hardware, I'd love to see some prerendered sample videos.

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

Is the video based on applying the algorithm to the entire screen, or is it applied to the sprites individually, then they are plotted to the screen?

Just wondering, because the samples in the paper are all lone objects against a clear background. If the same object is drawn in front of a detailed background and then the upscaling is applied, this would affect the patterning. It's a little tricky to tell from the video, since the graphics (especially the backgrounds) use large blocks of plain colours.

Worst case, you could imagine Mario walking in front of the background and his shape shifting madly with every step he took?

(Edit: From freeze-framing the video, I'm guessing that the algorithm is being applied to the whole screen. The scaling works great when Mario is in front of the pale background. There are small artifacts when he crosses the black outline of the green bushes. Very minor in this video, I wonder how it would affect more intricate backgrounds or those that aren't such contrasting colours to the foreground?)

Re: Depixelizing Pixel Art

#97

Post by archagon »

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.

As interesting as these smoothing algorithms are, they can't add any information to the sprites that wasn't already there. Why make everything look smooth and plasticky when the original game was carefully hand-drawn, pixel by pixel?

Re: Depixelizing Pixel Art

#98

Post by arrrg »

ahassan wrote: post #65
bluedino wrote: post #34

Earlier quoted context omitted.

It works perfect on the Mac but I wonder if that would be the case if you could still run old 'classic' apps. You'd think Microsoft of all companies would work in compatibilty fixes for at least the major apps. Like how they worked in so many fixes to make them compatible from 98-XP and such.

"Classic" apps will be scaled (using the normal bicubic filter) to twice their resolution on Mac. If they were implemented using Apple APIs, there's a good chance that text will be at a higher resolution and will appear clear.

I don’t think there is any interpolation happening, actually. The display just uses four pixels to display one pixel, that’s all.

Re: Depixelizing Pixel Art

#100

Post by josh-wrale »

joosters wrote: post #94
josh-wrale wrote: post #53

Earlier quoted context omitted.

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

Is the video based on applying the algorithm to the entire screen, or is it applied to the sprites individually, then they are plotted to the screen? Just wondering, because the samples in the paper are all lone objects against a clear background. If the same object is drawn in front of a detailed background and then the upscaling is applied, this would affect the patterning. It's a little tricky to tell from the vid…

> Worst case, you could imagine Mario walking in front of the background and his shape shifting madly with every step he took?

This brings up something interesting: In terms of media containing sprites and minimal layering (e.g. NES-like games), wouldn't it be computationally cheaper to perform the scaling on the sprites and textures independently of one another, instead of post-processing? I wonder if there is any emulator that does this. I'm thinking not, as the NES wouldn't be capable of layering such detail (large sprites + textures). Upsampling emulators.. Hmm...

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