Originally Posted by
cardiomd
RadioGirl, I assumed that the MMW uses a transmission measurement and an inverse radon transform, but I must admit that was biased by the movement that I've seen of the actual device around the person, (looks similar to a CAT scan
) but of course this would not prohibit a backscatter type measurement... are you absolutely sure that it is a raster scan and measurement of reflection/scatter, and not simply shining the beam through to the other side and measuring attenuation, then reconstruction of an "absorbance" index which could produce a nice outline of the person?
I'm
absolutely sure that it's reflection/scatter, not a through transmission. The attenuation by the human body at these frequencies is so great that a transmission system would only generate a silhouette where the beam missed the body completely, and blackout where the beam hit the body. The detailed MMW images we've seen show far more detail than that.
If they had to transmit enough power to get a tomographic image, it would literally cook people in a very obvious (and painful, probably deadly) manner. (Old industry joke: "We sponsor research on RF health effects because it makes us feel all warm inside."
)
Originally Posted by
cardiomd
Yeah, but either way the raw data for postprocessing is there. I'm scared that they will retain the data for hindsight if stuff gets through. In actuality, I'd LIKE them to do this for QC, but I simply don't trust them given the previous inability to divide by n when calculating radiation dose. Too much of a bad history.
I'm
not absolutely sure what they do with data/storage/reconstruction; my previous comments were my conjecture and opinion. To both you and Saulblum, I don't blame anyone for not trusting TSA!