Sanki Eng., Co., Ltd.

Toshihiro Nozawa

Shinya Ishi

Norihiko Shibata

Fumiaki Tsuchiya

Intrusion by climbing or jumping over a fence can be detected, and intrusion is detected in a wide area without large-scale equipment. FBGs (grating sections) of different types having different refractive indexes of fiber glass are arranged at predetermined intervals in a longitudinal direction of optical fibersA, andB, the optical fibers are laid down between poles on the top of a fence or a side thereof, reflected waves from the FBGs are issued by photodetection devicesA, andB in response to an optical input to the optical fibers, and a wavelength shift detection devicedetects a position of an FBG which exhibits a wavelength shift by swinging of the optical fibers by a stress acting on the fence. A pattern recognition devicefetches positions of the wavelength-shifted FBGs as differences between timings of the pulse signals and discriminates swinging of the fence caused by intrusion from swinging of the fence caused by other factors on the basis of output patterns of the pulse signals.

Break-in detection sensor

A break-in detection system includes a detection sensor of an FBG type for detecting an intruder trying to climb over a fence around a premises, and a detection sensor of an OTDR type for detecting an intruder trying to demolish the fence. A fiber optic cable used as a detection sensor has a sensor core wire and a LAN transmission core wire arranged in parallel to form a LAN transmission channel. The LAN transmission core wire transmits videotaped image signals from ITV cameras and image control signals two ways between a monitoring room and an ITV control device. The LAN transmission channel is available for connection by IP telephone sets, a LAN terminal, a wireless LAN terminal, and an IP-BOX for internet communication. The system has excellent reliability and maintenance-free characteristics.

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Hitachi, Japan

Toshihiro Nozawa