Slashdot Mirror
Upscaling Retro 8-Bit Pixel Art To Vector Graphics
An anonymous reader writes "Two researchers — Johannes Kopf from Microsoft, and Dani Lischinski from The Hebrew University — have successfully created an algorithm that depixelizes and upscales low-resolution 8-bit 'pixel art' into lush vector graphics. The algorithm identifies pixel-level details (original paper — PDF) to accurately shade the new image — but more importantly, the algorithm can create smooth, curved contour lines from only-connected-on-the-diagonal single pixels. At long last, we might be able to play Super Mario Bros. on a big screen without stretching our beloved plumber's pixels to breaking point. You really must look at the sample images." Scroll down in the paper to see how their technique stacks up against some others, including Adobe's Live Trace.
http://johanneskopf.de.nyud.net/publications/pixelart/paper/pixel.pdf
Don't tell me people have never heard of the coral cache
EvilHom3r over on Reddit seems to have mirrored the paper (as images) here.
My verdict: Yeah, it looks all nice and smooth, but with all upscaling, it's basically interpolating data. The original just didn't have that much detail, so you can only get so much out of it. Sometimes it works, sometimes it doesn't.
(Oh, and it makes all text look pretty bad. Kinda Comic Sans-y, if I can say that without invoking instant hate.)
EvilHom3r over on Reddit seems to have mirrored the paper (as images) here.
My verdict: Yeah, it looks all nice and smooth, but with all upscaling, it's basically interpolating data. The original just didn't have that much detail, so you can only get so much out of it. Sometimes it works, sometimes it doesn't.
(Oh, and it makes all text look pretty bad. Kinda Comic Sans-y, if I can say that without invoking instant hate.)
I know what you mean but it's pretty impressive nonetheless. The flaw I found interesting was in the keyboard image. I'm sure the intention here is square keys, but their algorithm made all the keys round. Some things in a pixelated image should not be smoothed but without human context that's a very hard call to make.
These posts express my own personal views, not those of my employer
RTFP - they list the various existing upscaling algorithms, and why they're not perfect:
Several later algorithms are based on the same idea, but use more sophisticated logic to determine the colors of the 2x2 block. The best known ones are Eagle [Unknown 1997], 2xSaI [Ohannessian 1999], and Scale2x [Mazzoleni 2001], which use larger causal neighborhoods and blend colors. Several slightly different implementations exist under different names, such as SuperEagle and Super2xSaI. An inherent limitation of all these algorithms is that they only allow upscaling by a factor of two. Larger magnication canbe achieved by applying the algorithm multiple times, each time doubling the resolution. This strategy, however, signicantly reduces quality at larger upscaling factors, because the methods assume non-antialiased input, while producing antialiased output.
The latest and most sophisticated evolution of this type of algorithms is the hqx family [Stepin 2003]. This algorithm examines 3x3 pixel blocks at a time and compares the center pixel to its 8 neighbors. Each neighbor is classied as being either similar or dissimilar in color, which leads to 256 possible combinations. The algorithm uses a lookup table to apply a custom interpolation scheme for each combination. This enables it to produce various shapes, such as sharp corners, etc. The quality of the results is high. However, due to its strictly local nature, the algorithm cannot resolve certain ambiguous patterns and is still prone to produce staircasing artifacts. Lookup tables exist only for 2, 3, and 4 magnication factors.
whereas what they did here is:
Our goal in this work is to convert pixel art images to a resolution-independent vector representation, where regions with smoothly
varying shading are crisply separated by piecewise-smooth contour curves.
Seriously, just look at the whale image linked from TFS.
I'm going to steal it. Next time I see something I'm both apprehensive, and tired of, I shall be /we?ary/ of it.
You're kidding, right? This is allowing us to play all those games from our youth without them looking like blocks at 1080 HD. If anything this is helping the past, no longer will they need to release a "remake", they can re-release the original with this algorithm attached and they're done.
Besides, do you think 1080 HD will be the resolution of choice 20-40 years from now? I imagine we'll be looking at wall-sized TVs at some point and 1080 pixels will look awfully blocky on a 10 foot wall. Sharp has already released a 7x680 x 4,320 pixel 85-inch screen, how long before 4320 is the new 1080?
my karma will be here long after I'm gone
Last time I checked, these filters you speak of in Zsnes and other emulators simply extrapolate the pixels without paying any special attention to shapes and colors. TFA picture looks quite a bit more advanced.
Those are all post-processing up-scaling effects. But they do have limitations in that even the pixels themselves can still be made out. Obfuscating them only goes so far. But with this new technique, they're pure vectors. They will scale infinitely with splines to match your screen resolution, much like fonts.
Life is not for the lazy.
Mirror: http://easy-iphone-unlocking.com/download/pixel.pdf
It looked like it was on the verge of a Slashdotting, so I CORALized it.
http://johanneskopf.de.nyud.net/publications/pixelart/paper/pixel.pdf
Very interesting, and quite effective.
Willie...
It is. This has nothing to do with that, but is about giving a nicer representation to information that is there. All this does is removes jagged corners that result from up-scaling.
Sorry, but that's just plain not going to work.
Forget magic. Any technology distinguishable from divine power is insufficiently advanced.