Something I do not understand

There is something that I do not understand with regards to the new body scanners used at more and more airports. As I understand it people are upset that the security personnel get to see them in the nude and they feel uncomfortable about that. That I get. What I do not get is why the security personnel needs to see the nude images. I bet that it would be bloody easy to construct a program that analyses the images and looks for suspicious things (hidden blades and plastic explosives and so on) and returns a green or a red light for the person And destroys the image in the process. Hence no-one would ever get so see anyone naked, the check would be faster and more secure than by visual inspection and everyone would be happy campers. Personally I would feel much less violated by such a system. Now if I only had thousands of readers I bet that this idea would quickly find its way to the people in charge and they would have everything sorted within a fortnight.