[pithon]

I wouldn't consider the passive/active distinction the definition for 'invasive.' I'd consider thermal imaging from the outside of the home w/out a warrant 'invasive', but a thermal camera is just picking up the heat radiated by your body.

[dalke]

The article links to the relevant Supreme Court decision. They, in "Kyllo v. United States, 533 U.S. 27 (2001), held that the use of a thermal imaging, or FLIR, device from a public vantage point to monitor the radiation of heat from a person's home was a "search" within the meaning of the Fourth Amendment, and thus required a warrant." -http://en.wikipedia.org/wiki/Kyllo_v._United_States

The article goes on to say the Supreme Court "specifically noted that the rule would apply to radar-based systems that were then being developed."

[scott_karana]

Thank god for that.