21. Machine vision
There are a surprising number of machine vision applications out there these days- 2D barcodes, out-of-lane detection in cars, and manufacturing. This is a result of the dramatic increase in available computing power- as data transfer rates go up, image sensor integration gets cheaper and more complete, and processing cycles get cheaper, the number of applications will go up as well.
Which begs the question- why does the TSA need to people to look at my naked body on the scanner? Presumably, any thing a person would see could be seen by a computer; if the area of interest were cropped and presented to a human for follow-up, then a more thorough search could be ordered.
I suspect it's for the same reason voting machine companies have told us it's "impossible" to issue a paper receipt- failure of imagination coupled with hidebound ways of doing business. And money, of course. Lots and lots of money.