Human presence detection is a range of technologies and methods[1] for detecting the presence of a human body in an area of interest (AOI), or verification that computer, smartphone (or other device controlled by software) is operated by human.
Software and hardware technologies are used for human presence detection.
These include software technologies such CAPTCHA and reCAPTCHA, as well as hardware technologies such as: The first robot to successfully demonstrate a static motion detection capability was ROBART I, which was Everett's 1981 thesis project at the Naval Postgraduate School.
[5] In 1997 CAPTCHA ("Completely Automated Public Turing test to tell Computers and Humans Apart") was invented.
This test is used to ensure that computer is operated by a human, preventing spam robots.