[cypherpnks]

That wasn't my point. You can do better than theoretically optimal -- indeed, their results, in many cases, do look better than sinc. Theoretically optimal makes assumptions that the source image is, in some ways, random, in a way that the real world doesn't conform to. If you know there are hard edges, you can do better.

The point is that they should be comparing to sinc. They're comparing to a known-stupid algorithm to make themselves look better than they are.