What's the Underlying Algorithm for Detail Preserving Upsampling in Photoshop CC? The detail-preserving upsampling algorithm in Photoshop CC is truly amazing. It can upscale any image while preserving details in almost real-time. And I truly wonder how it is implemented.

I've started by searching papers with keywords single image super resolution. And seems the current state-of-art algorithms require an trained external database to guess the missing high frequency information. And I believe it is really hard to train &amp; distribute a complete dictionary, right? Also, I don't think it's possible to train a dictionary with image pyramid in real-time.

After that I've turned to the area of image upsampling, which seems fast enough comparing with super resolution algorithms, but there are so many algorithms, I'm totally lost.

So, does anyone have any guesses or hints on how can that tool is implemented? Thanks!
It's really nothing beyond Bi Cubic Interpolation with "Sharpening".

http://www.lynda.com/Photoshop-tutorials/interpolation-settings/124096/140573-4.html

They haven't updated their interpolation algorithms for ages.