Physical surveillance is
|“||comprises watching (visual surveillance) and listening (aural surveillance). Monitoring may be undertaken remotely in space, with the aid of image-amplification devices like field glasses, infrared binoculars, light amplifiers, and satellite cameras, and sound-amplification devices like directional microphones; and remotely in time, with the aid of image- and sound-recording devices.||”|
|“||[a] systematic and deliberate observation of a person by any means on a continuing basis, or the acquisition of a nonpublic communication by a person not a party thereto or visibly present thereat through any means not involving electronic surveillance.||”|
- Roger Clarke, "Introduction to Dataveillance and Information Privacy, and Definitions of Terms" (1997-2006) (full-text).
- Office of Counterintelligence (DXC), Defense CI & HUMINT Center, Defense Intelligence Agency, "Terms and Definitions of Interest for DoD Counterintelligence Professional," at GL-139 (May 2, 2011) (full-text).