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US 4,382,291 AGranted
Surveillance system in which a reflected signal pattern is compared to a reference pattern
AssigneeSecom Co., Ltd.
InventorShunsaku Nakauchi
Life of this patent
Estimating the term…
Abstract
Radiation energy is emitted intermittently to an area under surveillance and a pattern of reflections is formed. Thereafter, the pattern of reflections is statistically compared with a reference pattern which is prepared in advance. When the two patterns are different, an alarm is activated.
Claims6
A surveillance system for detecting an unauthorized object or person in an area under surveillance, comprising:
- means for transmitting a radiation energy signal, intermittently, to said area under surveillance;
- means for receiving reflections from said area under surveillance and converting analog signals of said reflections into digital signal patterns;
- means, connected to said receiving means, for storing a plurality of said digital signal patterns for a predetermined time;
- means, connected to said storing means, for forming a reference pattern from said plurality of stored digital signal patterns in said storing means;
- and
- means, connected to said receiving means and said reference pattern forming means, for comparing a digital signal pattern from said receiving means with said reference pattern of said reference pattern forming means and for activating an alarm when said digital signal pattern and said reference pattern are different.
3 more elements
Dependencies are inferred from the claim text.