Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
  • G08B13/00—Burglar, theft or intruder alarms
  • G08B13/18—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength
  • G08B13/189—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems
  • G08B13/194—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems using image scanning and comparing systems
  • G08B13/196—Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength using passive radiation detection systems using image scanning and comparing systems using television cameras
  • G08B13/19639—Details of the system layout
  • G08B13/19641—Multiple cameras having overlapping views on a single scene
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N7/00—Television systems
  • H04N7/18—Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
  • H04N7/181—Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast for receiving images from a plurality of remote sources

Definitions

• the present device relates to a device at TV surveil ⁇ lance, comprising TV cameras, a video tape recorder, a switch device for sorting and transmitting the video sig- nals of the different TV cameras to the video tape recor ⁇ der, and a supply device for supplying a synchronizing sig ⁇ nal to each TV camera in the same conduit as the video sig ⁇ nals are transmitted from each TV camera.
• a device at TV surveil ⁇ lance comprising TV cameras, a video tape recorder, a switch device for sorting and transmitting the video sig- nals of the different TV cameras to the video tape recor ⁇ der, and a supply device for supplying a synchronizing sig ⁇ nal to each TV camera in the same conduit as the video sig ⁇ nals are transmitted from each TV camera.
• Such a TV surveillance system may be organized in different ways. Among other things it is important at such systems to provide for a wire laying which is as effective as possible, that a picture quality is attained which is as good as possible, and of course that the security is as good as possible.
• the same conduit in which the video signals are transmitted from each TV camera is used for supplying to the TV camera a drive voltage, for example 35 V, and for a synchronizing signal, so that the right pic ⁇ ture from the right camera enters the tape recorder in the right sequence.
• different units or boxes for the switching function and for the supply and synchronizing function are used.
• the Invention A better, cheaper and more advanced device is accor- ding to the invention attained in that it comprises a video guard against the lack of a video signal from any TV camera or that the lens of any TV camera is covered and a synchro ⁇ nizing device for the video tape recorder for any possibly non-functioning TV camera, the video guard and the synchro ⁇ nizing device being arranged in a recording unit together with the switch device and the supply device.
• This synchronizing device in the recording unit is arranged to substitute every lacking picture on the tape of the video tape recorder due to a non-functioning TV camera having a certain ordinal number with a picture from the functioning TV camera with highest priority, normally with the highest or lowest ordinal number.
• the video tape recorder in the system is analogue (which is preferably the case for the entire system) and operates at a lower, for example eight times lower, speed than if an alarm is activated, which leads to a minimizing of the tape consumption.
• a device for allowing supply of a video signal from at least one TV camera to a video monitor, which is connected directly to the recording unit, is arranged in the recording unit. This supply occurs concurrently with the recording by the video tape recorder.
• the entire TV monitor screen can if desired be filled with the picture from one TV camera, but alternatively pic ⁇ tures from for example four TV cameras can be shown simul ⁇ taneously on the monitor, so called quad show.
• FIG. 1 schematically show a device according to the invention and a modification thereof, respectively.
• the recording unit 9 is connected to a video tape recorder 10, which in turn can be connected to a TV monitor 11.
• the video tape recorder 10 is analogue and operates in a certain recording speed for giving satisfactory pic ⁇ ture quality only if an alarm is activated. In the normal case it operates at a substantially lower speed for conser ⁇ ving tape. For example it can operate at an eight times lo- was speed in the normal case than when an alarm is activa ⁇ ted. In this way a tape can for example give three hours' recording at an activated alarm but 24 hours' recording in the normal case.
• An analogue recording gives the best pos ⁇ sible picture quality and no digital distortion of the pic- ture information.
• a recording "digital signature" can be stored on the video tape, which gives information about which camera the picture emanates from and if an alarm is activated for this camera. This signature is used at play ⁇ back in order to only show pictures from one camera at a time.
• a video signal is transmitted from each operating TV camera 1, 2.
• a drive voltage for example 35 V, is transmitted in the same conduit 1', 2' to the TV camera as well as a synchronizing signal, so that the different cameras operate in phase with each other.
• the recording unit 9 also contains two further functions, namely a video guard and a synchronizing device for the video tape recorder 10.
• the video guard is designed to tell whether video signal is lacking from any TV camera or whether the lens of any TV camera is covered. At for ex ⁇ ample robberies it is namely not unusual that the robber tries to damage a TV camera or to cover its lens.
• the syn- chronizing device has as its purpose to see to it that the synchronization in the video band recorder in a way descri ⁇ bed below is not disturbed in spite of the fact that a cer ⁇ tain TV camera is non-functioning.
• the tape recorder 10 sequencies of pictu- res from the different connected TV cameras are recorded on one single video tape. Singular pictures from all connected cameras are stored on the video tape, and this is done in the following sequence, when for example eight cameras are connected: 8-7-6-5-4-3-2-1-8-7... The number of cameras and the operational speed of the tape recorder determine how often pictures from the different cameras are recorded on the tape. If six cameras are connected to the recording unit 9 it is for example at normal operation possible to obtain one picture per second from each camera, whereas eight pictures per second from each camera can be recorded at an alarm situation.
• the synchronizing device for the video tape recorder functions in such a way that if a camera has been damaged by shooting, damaged in any other way or been covered and accordingly a video signal from this camera is lacking, the camera with the highest ordinal number or the highest prio ⁇ rity is automatically connected instead of the damaged camera. If for example there are six cameras in the sequence 6-5-4-3-2-1-6-5..., camera 4, if this camera has been damaged, will be changed to camera 6, so that the sequence becomes 6-5-6-3-2-1-6-5-6-3-2...
• the camera with the lowest ordinal number or any cho ⁇ sen camera can alternatively be given the highest priority.
• police can survey the video band with a so called digital photo lab by connecting the system to an upgraded PC and can in this way "electronically" enlarge and improve all recorded picture sequences.
• Fig 2 a modified device according to the invention is shown.
• the TV monitor 11 is connected directly to the recording unit 9 (and not via the video tape recorder 10) . Signals from the video tape recorder 10 are accordingly transmitted at play ⁇ back via the unit 9 to the TV monitor 11.
• the drive voltage to the respective TV camera 1, 2 can further be supplied in separate conduits instead of in the conduits 1', 2'.
• this modified device it is pos ⁇ sible in the recording unit 9 to have a device, by means of which concurrently with recording in the way described above and independently thereof a video signal from at least one TV camera 1, 2 is transmitted directly to the TV monitor 11.
• a video signal from at least one TV camera 1, 2 is transmitted directly to the TV monitor 11.
• the analogue signal from the TV camera can preferably be digitalized, before it is sent to the monitor.
• the picture from one TV camera can be shown on the monitor, or alterna ⁇ tively pictures from four, nine or even 16 cameras can be shown on the monitor in a "chess pattern".
• the TV monitor 11 can be used both for the concurrent surveillance described above and for later playback of sequences recorded on the video tape recorder.

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• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Closed-Circuit Television Systems (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20394734

Family Applications (1)

Country Status (3)

Cited By (5)

Citations (3)

• 1994
  • 1994-07-15 SE SE9402486A patent/SE503082C2/sv not_active IP Right Cessation
• 1995
  • 1995-07-14 AU AU29966/95A patent/AU2996695A/en not_active Abandoned
  • 1995-07-14 WO PCT/SE1995/000863 patent/WO1996003005A1/en active Application Filing

Patent Citations (3)

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