One of the traditional surveillance techniques is the human intelligence or otherwise known as HUMINT. This technique involves data or information gathering through human contact rather than using technical means (Espionage Information, 2008). HUMINT activities usually adopt three methods, namely, overt, sensitive, and clandestine activities (Interagency OPSEC Support Staff, 1999). An overt human intelligence is usually performed openly which may include engagement of military attaches, diplomatic personnel, members of official delegations, and debriefers at refugee center (Interagency OPSEC Support Staff, 1999).
It is also undertaken by exploitation of unclassified publications, hearings, and materials in Congressional meetings or conferences. Moreover, overt activities operate by conducting interrogations, and debriefing of travelers to a country which is of interest of the intelligence service. Sensitive human intelligence also involves some of the overt activities but the sponsor of such activity is protected from disclosure (Interagency OPSEC Support Staff, 1999).
This is to avoid the sponsor from being politically embarrassed. Such disclosure also prevents possible compromising of intelligence operation and security threats of other nations (Interagency OPSEC Support Staff, 1999). On the other hand, clandestine human intelligence sources include the use of agents, spies, and undercover officers to provide information or even foreign nationals who have infiltrated an organization to obtain information.
In addition, it employs activities such as interrogating and conversing with persons who have an access to needed information or known to have connections with suspected criminals. Among surveillance techniques, human intelligence is considered as the most difficult because it requires precision as to the sources and the information itself (Espionage Information, 2008). Information gathering from human was found to be difficult. Nevertheless, information taken from human intelligence is considered useful because it is up to date (Espionage Information, 2008).
Imagery Intelligence In imagery intelligence or IMINT, information are gathered through the use of visual photography, satellite, laser, radar sensors, and electro-optics, among others. In turn, the information obtained from imagery intelligence is reproduced electronically on film, electronic display, or other device (U. S. Marine Corps, 2007). Specifically, it uses a long-range photography in order to obtain images, such as places, things, or persons, to which access is impossible (Shulsky & Schmitt, 2002).
IMINT first began as an aerial surveillance but existed also aviation (Shulsky & Schmitt, 2002). During the 1st World War, imagery intelligence was used by the British Royal troops to conduct surveillance against German troops (Shulsky & Schmitt, 2002). Eventually, many countries developed planes for purposes of doing aerial surveillances. The development also led to the use of satellite for a more efficient and effective surveillance (Shulsky & Schmitt, 2002).