As far as I am aware pixelation occurs where information has been lost in the digital picture information. This is either through noise, zooming in or bandwidth limiting in motion sequences.

As it is due to information missing it is not possible to get the original information back. The only possible solution I can imagine is to pass it through a filter to soften the picture to reduce the visibility of the problem, but all you are really doing then is removing more information from the picture.

Scanner software "interpolates", which basically meaning it makes up information based on a good guess from the surrounding pixels, it might be possible to get video interpolators. Certainly HDTVs can "up convert" - ie add in "fake" pixels but this is not quite the same thing