It is impossible (as are those supersharp partial enlargings they do on CSI), to be honest. The pixels of the image are not only shuffled to get the desired effect, their color and lightness has been altered too. Without any memory of their previous live. Actually, they aren't the pixels they were used to be. Theoretically I think it should be possible to analyze the workings of the filter and reverse them, with every possible setting, if you can find someone who is REALLY good at programming and has a lot of time on his hands. The basis would not be the image but the filter, to reverse the process. But then again, the market is probably way to small for an expensive science project like that.