WIPO logo
Mobile | Deutsch | Español | Français | 日本語 | 한국어 | Português | Русский | 中文 | العربية |

Search International and National Patent Collections
World Intellectual Property Organization
Machine translation
Latest bibliographic data on file with the International Bureau   

Pub. No.:    WO/1980/002096    International Application No.:    PCT/US1980/000302
Publication Date: 02.10.1980 International Filing Date: 21.03.1980
G08B 13/194 (2006.01), G08B 13/196 (2006.01)
Priority Data:
23032 23.03.1979 US
Abstract: front page image
(EN)A television system and method for monitoring and indicating changes in a scene from which electromagnetic radiation, such as visible light, emanates. A television system including a televison camera (10) scans the scene in known raster fashion in a series of image frames, producing an amplitude modulated video signal describing the energy intensity distribution of the scene. Clocking and gating circuitry (42, 44) triggered in synchronism with television camera synchronization signals defines a set of predetermined discrete spaced locations of the raster during each image frame and samples video signal amplitude at each of the defined locations. The same discrete locations a re sampled during each frame. Video selection circuitry (20) during a succession of sampling periods, inputs in real time a representation of each video amplitude sample to one of several storage channels (24, 26, 28) of a multi-channel memory system including a multi-channel counter. The video amplitude samples are allocated among the channels as a function of their amplitude values. The collection of stored amplitude samples in the multi-channel memory system thus constitutes a profile of the amplitude distribution of the video samples made during the frame. This first amplitude profile is then stored. The scanning, allocating and counting operation is repeated. Subsequently, comparison circuitry, (114, 116) in response to the development of a subsequent amplitude distribution profile, corresponding to a selected later frame, actuates an alarm (30) in response to the occurrence of a predetermined threshold difference between (1) the earlier and (2) a succession of later developed amplitude distribution profiles. Circuitry (132) is also provided for modifying characteristics of the threshold difference required to trigger the alarm. It has been found that even a single channel counter, responsive to video count samples in only a single amplitude range, can often provide enough information for a workable and inexpensive surveillance system.
(FR)Un systeme et un procede de television servent a controler et indiquer des changements de scenes d"ou emanent des rayonnements electromagnetiques, tels que de la lumiere visible. Un systeme de television comprenant une camera de television (10) explore ou analyse la scene par le procede connu du canevas dans une serie de cadres d"images, produisant un signal video a amplitude modulee decrivant la distribution de l"intensite d"energie de la scene. Des circuits d"horloge et de debloquage (42, 44) declenches en synchronisation avec des signaux de synchronisation de la camera de television definissent un ensemble de points ou emplacements a espacements discrets, predetermines du canevas pendant chaque cadre d"image et echantillonnent l"amplitude du signal video a chacun des points ou emplacements definis. Les memes points discrets sont echantillonnes pendant chaque cadre. Un circuit de selection video (20), pendant une succession de periodes d"echantillonnage, effectue l"entree en temps reel d"une representation de chaque echantillon d"amplitude video dans l"un des plusieurs canaux de stockage (24, 26, 28) d"un systeme memoire a multi-canaux comprenant un compteur multi-canaux. Les echantillons d"amplitude video sont affectes aux canaux en fonction de leur valeur d"amplitude. Une collection ou ensemble d"echantillons d"amplitude stockes dans le systeme de memoire a multi-canaux constitue ainsi un profil de la distribution d"amplitude des echantillons video effectues pendant le cadre. Ce premier profil d"amplitude est alors stocke. Le balayage ou analyse, l"affectation et le comptage sont repetes. Par la suite, un circuit de comparaison (74, 116), en reponse au developpement d"un profil ulterieur de distribution d"amplitude, correspondant a un cadre ulterieur selectionne, actionne une alarme (30) en reponse a une difference de seuil predeterminee entre le premier profil (1) et une succession de profils ulterieurs (2) de distribution d"amplitudes developpees. Un circuit (132) modifie les caracteristiques de la difference de seuil requise pour declencher l"alarme. Il s"est revele que meme un compteur d"un seul canal, en reponse a des echantillons de comptage video dans une seule portee d"amplitude, peut souvent procurer assez d"informations a un systeme de surveillance operationnel et peu couteux.
Designated States:
Publication Language: English (EN)
Filing Language: English (EN)