[mining____]

This is possibly true, but it's pretty much the only practical way to do this.

If we look at most of the literature around upscaling, this method is used pretty frequently.

For a more comprehensive look at using CNNs for image upscaling, see e.g. http://research.microsoft.com/en-us/um/people/kahe/publicati...

[buymorechuck]

There is a more recent version of this paper published here: http://arxiv.org/abs/1501.00092v3

At Flipboard, we did not have time to do a full comparison of related upscaling research, but we were happy with the low amount of error our CNN achieved.