Steve wrote his article tongue-in-cheek, of course, but he bases it on a very real article that appeared in 1985 (!) in the journal Perception: "On the plausibility of superman's x-ray vision" by J.B. Pittenger.
There are three basic conditions that a superman x-ray system must meet to be plausible.
1. Transparency:The rays must be such that all objects but lead are entirely or almost entirely transparent to them. Lead is always entirely opaque to the rays.
2. Color:The rays and processor must result in Superman perceiving the same colors as would an Earthling viewing the scene in ordinary sunlight.
3. Exclusivity:The rays must permit Superman, but not Earthling standing in line with the reflected rays, to see through normally opaque surfaces.
And they wonder why everybody thinks scientists are a bunch of nerds...