# US 8,786,699 B2 · Suspicious person detection device, suspicious person detection method and suspicious person detection program > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,699 B2 - Document ID: US8786699B2 - Status: Granted - Kind: B2 - Application number: 13/315,770 - Filed: 2011-12-09 - Published: 2012-05-24 - Granted: 2014-07-22 - Earliest claimed: 2009-06-11 - Assignees: Fujitsu Limited - Applicants: Kentaro Tsuji; Eigo Segawa; Takashi Morihara - Inventors: Kentaro Tsuji; Eigo Segawa; Takashi Morihara - Web page: https://patentgrep.com/patent/US8786699B2 ## CPC - G08B 13/19613: {Recognition of a predetermined image pattern or behaviour pattern indicating theft or intrusion} - G06V 20/52: Surveillance or monitoring of activities, e.g. for recognising suspicious objects (recognising microscopic objects G06V20/69) - G08B 21/22: responsive to presence or absence of persons - G08B: SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING ## Abstract A suspicious person detection device is provided with a person detection section capable of detecting the position of persons for each of the persons, a person tracing section for continuously tracing the position of a person detected by the person detection section, and a suspicious person detection section for detecting a suspicious person according to the result of the trace of the person tracing section, wherein the person tracing section determines a person authenticated as a result of the agreement with a predetermined first condition as an authenticated person and determines a person who has agreed with a predetermined second condition associated with the authenticated person as an accompanying person at the time of the authentication, and wherein the suspicious person detection section issues a warning when the accompanying person is away from the authenticated person by a predetermined first distance or more. ## Claims ### Claim 1 A suspicious person detection device comprising: a person detection unit to be capable of detecting a position of a person on a per person basis; a person tracking unit to continuously trace the person's position detected by said person detection unit; and a suspicious person detection unit to detect a suspicious person on the basis of a tracking result of said person tracking unit, wherein said person tracking unit determines, as an already-authenticated person, a person authenticated when coinciding with a predetermined first condition, and determines, as an accompanying person, a person who coincides with a predetermined second condition related to the already-authenticated person when authenticated, said suspicious person detection unit, when the accompanying person is distanced at a predetermined first distance or longer from the already-authenticated person, issues an alarm, 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. ### Claim 2 (depends on 1) A suspicious person detection device according to claim 1, wherein the predetermined second condition is that the distance from the already-authenticated person when authenticated is shorter than a predetermined second distance. ### Claim 3 (depends on 1) A suspicious person detection device according to claim 1, wherein the predetermined first distance is set corresponding to a degree of secrecy of an area where the person is located. ### Claim 4 (depends on 1) A suspicious person detection device according to claim 1, wherein the already-authenticated person opens a door after being authenticated, in which case the predetermined second condition is that the accompanying person is a person who passes through the door till the door is closed since the door has been opened. ### Claim 5 (depends on 1) A suspicious person detection device according to claim 1, wherein the predetermined first condition is that a person, who unlocks a predetermined door, is determined to be the already-authenticated person. ### Claim 6 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. ### Claim 7 (depends on 6) A suspicious person detection method according to claim 6, wherein the predetermined second condition is that the distance from the already-authenticated person when authenticated is shorter than a predetermined second distance. ### Claim 8 (depends on 6) A suspicious person detection method according to claim 6, wherein the predetermined first distance is set corresponding to a degree of secrecy of an area where the person is located. ### Claim 9 (depends on 6) A suspicious person detection method according to claim 6, wherein the already-authenticated person opens a door after being authenticated, in which case the predetermined second condition is that the accompanying person is a person who passes through the door till the door is closed since the door has been opened. ### Claim 10 (depends on 6) A suspicious person detection method according to claim 6, wherein the predetermined first condition is that a person, who unlocks a predetermined door, is determined to be the already-authenticated person. ### Claim 11 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.