Suspicious person detection device, suspicious person detection method and suspicious person detection program

A suspicious person detection method by which a computer executes:

• detecting a position of a person on a per person basis;
• and
• tracking continuously the detected position of the person;
• and
• wherein a person authenticated by coinciding with the predetermined first condition is determined to be an already-authenticated person, while a person, who coincides with a predetermined second condition related to the already-authenticated person when authenticated is determined to be an accompanying person, and
• an alarm is issued when the accompanying person is distanced at a predetermined first distance or longer from the already-authenticated person, and
• the predetermined first distance is set based on a difference in velocity vector between the accompanying person and the already-authenticated person, the difference in the velocity vector being defined by a difference in moving velocity and an angular difference in moving direction.

A non-transitory computer readable storage medium storing a suspicious person detection program to be executed by a computer, the program executing:

• detecting a position of a person on a per person basis;
• and
• tracking continuously the detected position of the person;
• and
• wherein a person authenticated by coinciding with the predetermined first condition is determined to be an already-authenticated person, while a person, who coincides with a predetermined second condition related to the already-authenticated person when authenticated is determined to be an accompanying person,
• an alarm is issued when the accompanying person is distanced at a predetermined first distance or longer from the already-authenticated person, and
• the predetermined first distance is set based on a difference in velocity vector between the accompanying person and the already-authenticated person, the difference in the velocity vector being defined by a difference in moving velocity and an angular difference in moving direction.