[cdirkx]

A couple of years ago there were news articles that the pentagon has a "lasers that can identify people in a crowd from 200m away based on their heart rate signatures".

No idea if that's true or overblown, but it doesnt seem unlikely that such technology becomes possible in the future.

[johnisgood]

From where did they obtain your or my "heart signature"? What about gait, etc.?

[fasa99]

you can pull a heart rate from color amplification, same basic idea as motion amplification.