I couldn't resist doing a patent search on this technology -- the following is the abstract of the patent (and, thus, is not copyrighted
)
A pencil beam of X-rays is scanned over the surface of the body of a person being examined. X-rays that are scattered or reflected from the subject's body are detected by a detector. The signal produced by this scattered X-ray detector in then used to modulate an image display device to produce an image of the subject and any concealed objects carried by the subject. The detector assembly is constructed in a configuration to automatically and uniformly enhance the image edges of low atomic number (low Z) concealed objects to facilitate their detection. A storage means is provided by which previously acquired images can be compared with the present image for analyzing variances in similarities with the present image, and provides means for creating a generic representation of the body being examined while suppressing anatomical features of the subject to minimize invasion of the subject's privacy.
So, I was on the right track on my last post. This is an interesting technology, taking advantage of a phenomenon (backscatter) that normal X-Ray systems try to minimize or ignore.