Pixel Art Scaling Comparison Part 2

I’ve been playing with a few other scaling algorithms in the 2dimagefilter project. They produce even more impressive results than the previous batch…

Part 1 showcased the Eagle, SuperEagle, SaI and SuperSaI algorithms. I will continue here with EPX/Scale, HQx, xBR and xBRZ.

EPX/Scale#

The EPX algorithm was originally developed by Eric Johnston at LucasArts around 1992.

Nine years later, while working on the AdvanceMAME project, Andrea Mazzoleni developed the Scale algorithm, which produced exactly the same results as EPX, even though Andrea didn’t know of its existence. Great minds think alike, I guess.

Here you can see an image scaled using Scale, compared to the nearest-neighbor algorithm:

Image on the left Image on the right

And here you can see the details:

Zoomable image

Great results. I can see why so many emulators include it.

HQx#

The HQx family of algorithms (HQ2x, HQ3x, HQ4x) was created by Maxim Stepin around 2003. They are all based on pattern recognition using a pregenerated lookup table.

Here you can see an image scaled using HQx, compared to nearest-neighbor:

Image on the left Image on the right

And here you can see the details:

Zoomable image

Excluding the blurriness of the roof pattern, it does a great job with this image.

xBR#

The xBR algorithm was created by Hyllian in 2011. It is also based on pattern recognition, but uses a multi-stage set of interpolation rules.

Here you can see an image scaled using xBR, compared to nearest-neighbor:

Image on the left Image on the right

And here you can see the details:

Zoomable image

The results are much sharper than what HQx produced for this image. Extremely impressive.

xBRZ#

The xBRZ algorithm was created by Zenju in 2012, as an enhanced and optimized version of xBR. It equals the performance of HQx, and on certain architectures it even surpasses it.

Here you can see an image scaled using xBRZ, compared to nearest-neighbor:

Image on the left Image on the right

And here you can see the details:

Zoomable image

I can’t tell it apart from xBR. Everything looks super sharp.

That’s all for now, I guess. If you enjoyed this, be sure to check out the paper Depixelizing Pixel Art by Johannes Kopf and Dani Lischinski. The supplementary material also contains a ton of interesting comparisons between algorithms.

Posted on by Daniel Perez Alvarez. Got any comments or suggestions? Send me a tweet or an email.