The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 30, 1986
Filed:
Feb. 16, 1982
William J Rattman, Bass River, MA (US);
Stephen Marchetti, Norwell, MA (US);
Aaron A Galvin, Lexington, MA (US);
American District Telegraph Company, New York, NY (US);
Abstract
A system for detection of smoke by measuring changes in the contrast of a multi-contrast target disposed remotely from a photoelectric sensor. The obscuration of the detection path causes a reduction in the contrast of the sensed target, and a change of predetermined magnitude is employed to trigger an alarm. The target has one or more relatively darker and one or more relatively lighter areas which are viewed by the sensor. The sensor can be composed of a plurality of photosensors each viewing a respective area of the target. Or, the sensor can be a single scanning sensor such as a video camera. Only a single line or segment of a line of the video frame pattern need be employed to monitor the target. The video camera can be employed on a shared basis for providing smoke monitoring and detection, together with other functions, such as intrusion detection, access control, or visual surveillance of an area.