A
hidden camera or
spy camera is a still or
video camera used to record people without their knowledge. The camera is "hidden" because it is either not visible to the subject being filmed, or is disguised as another object. Hidden cameras can be built into commonly used objects such as
television sets,
smoke detectors,
clock radios,
motion detectors,
ball caps,
plants, and
mobile phones. Hidden cameras may be used for household
surveillance and may also be used commercially or industrially as
security cameras. The proliferation and lower costs of video recording devices has led to an increase in the use of hidden cameras for legitimate surveillance need, as well as for entertainment and other purposes.