EP0499177A1 - Eindringmeldealarm - Google Patents

Eindringmeldealarm Download PDF

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Publication number
EP0499177A1
EP0499177A1 EP92102193A EP92102193A EP0499177A1 EP 0499177 A1 EP0499177 A1 EP 0499177A1 EP 92102193 A EP92102193 A EP 92102193A EP 92102193 A EP92102193 A EP 92102193A EP 0499177 A1 EP0499177 A1 EP 0499177A1
Authority
EP
European Patent Office
Prior art keywords
signal
fact
circuit
window
intrusion device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP92102193A
Other languages
English (en)
French (fr)
Inventor
Tommaso Pagoto
Carlo Zelferino
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bitron Video SRL
Original Assignee
Bitron Video SRL
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bitron Video SRL filed Critical Bitron Video SRL
Publication of EP0499177A1 publication Critical patent/EP0499177A1/de
Withdrawn legal-status Critical Current

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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
    • G08B13/19—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 infrared-radiation detection systems
    • G08B13/193—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 infrared-radiation detection systems using focusing means
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/02—Monitoring continuously signalling or alarm systems
    • G08B29/04—Monitoring of the detection circuits
    • G08B29/046—Monitoring of the detection circuits prevention of tampering with detection circuits

Definitions

  • the present invention relates to an anti-intrusion device comprising a container having a window that allows for the entrance of infrared radiation coming from the surroundings and/or an eventual intruder, an infrared radiation focusing system on a first infrared detecting element, an electronic circuit that receives the signal from the infrared detecting element and processes the value with the aims of establishing whether the infrared radiation received is that naturally produced by the surroundings being supervised or whether it is due to the presence of an intruder and in such a case provides for an intrusion alarm signal to be generated and means for assuring that the device not be put out of use, by means of a masking of the window, comprising a source of sample signals situated in the infrared field, but presenting different wave lengths from those typically emitted from the human body, and means that analyse the value of the sample signals with the aims of detecting a variation in their measured value so as to point out any eventual attempts of covering the window.
  • a second solution consists in providing for a signal source having a wave length different from that used for surveilling the area under control, externally mounted with regards the casing containing the infrared sensor and is oriented in such a way so as to irradiate towards the inside of itself, through the window, a control signal, that detected from the self same infrared sensor, reports in the case of a variations with respect the guard value, the attempt of tampering.
  • the first solution results in not being perfectly functional in all practical conditions, as the window could be made opaque with the use of paint or other radiation absorbing material in such a way that the guard signal would not be reflected and therefore the system would be insensitive to such types of masking; furthermore it results in being difficult to put into operation due to the critical assembly and presenting a low level of reliability in the course of time, due to the very fact of its delicate setting.
  • the invention is based on the acknowledgement of these facts.
  • the aims therefore of the present invention is that of obtaining an anti-intrusion device that avoids the above mentioned inconveniences and in particular allows for obtaining an efficient realisation, reliable in all working conditions and being of low costs.
  • an anti-intrusion device comprising a container having a window that allows for the entrance of infrared radiation coming from the surroundings and/or an eventual intruder, an infrared radiation focusing system on a first infrared detecting element, an electronic circuit that receives the signal from the infrared detecting element and processes the value with the aims of establishing whether the infrared radiation received is that naturally produced by the surroundings being supervised or whether it is due to the presence of an intruder and in such a case provides for an intrusion alarm signal to be generated and means for assuring that the device not be put out of use, by means of a masking of the window, comprising a source of sample signals situated in the infrared field, but having different wave lengths from those typically emitted from the human body, and means that analyse the value of the sample signals with the aims of detecting a variation in their measured value so as to point out any eventual attempts of covering the window.
  • the principle characteristic of the anti-intrusion device consists in the fact that said means for analysing the sample signals comprise a second infrared detecting element, apt of detecting variations of said sample signals, due to attempts of tampering with the device by masking said window and that the source of said sample signals and the second detecting element are positioned one inside the other outside of said container and interact through the window.
  • Figure 1 only shows the components having important characteristics from the point of view of their being positioned inside the device, while the remaining parts containing the electronic circuit are not evidenced.
  • 101 indicates a container, normally a moulded plastic box, that has the task of housing the components of the peripheral surveillance device against intrusions and tampering with the same.
  • the container 101 presents an almost rectangular lateral section with a superior projection 102, taking the form of a console apt of housing an infrared radiation transmitter element 103.
  • the container 101 also has a rectangular cavity section 104, that is closed in line with the anterior wall 105 of the container with a focusing element of the external infrared radiation, constituted by a Fresnel lens; the window and the lens that close it are indicated with the reference number 106.
  • a focusing element of the external infrared radiation constituted by a Fresnel lens
  • the window and the lens that close it are indicated with the reference number 106.
  • the infrared radiation focusing system is realised according to known techniques in such a way to comprise a visual field as large as possible.
  • the lines 108 indicate in a schematic way the visual field covered by the sensor 107.
  • the latter may be of a pyroelectric type, as those usually used for such applications, for instance those that contain in the same capsule two adjacent sensors.
  • a second infrared radiation sensor is indicated, for example a photo diode, positioned in such a way so as to receive, through the window 106, the infrared signal emitted from the transmitter 103.
  • the form of the window 106 is realised in such a way so as to allow the second sensor 109 to receive the infrared signal emitted from the transmitter 103.
  • the wave length of the infrared radiation emitted by the transmitter 103 is chosen in such a way as to not interfere with the signals that lie in the infrared field normally emitted from the human body.
  • Reference 111 indicates the course that the infrared radiation normally carries out to directly arrive from the transmitter 103 to the sensor 109, that works as a receiver of the sample signals generated by the transmitter 103.
  • Reference 112 however indicates the course that the infrared radiation carries out to arrive from the transmitter 103 to the sensor 109, in case of placing a screen 110 between peripheral surveillance device against intrusions 101 and the area that has to be placed under surveillance.
  • the sensor 107 is the normal infrared radiation sensor, that through the focusing system constituted by the Fresnel lens 106, detects the human presence within its visual field, starting from the radiation emitted by the human body, being typically that of a wave length of around 10 micron.
  • an electronic circuit (not represented in the figure) that works according to the known art and is able to discriminate real states of alarm from false alarms.
  • the transmitter 103 and the second sensor 109 assure protection against attempts of tampering with the device, followed by the masking in some way of the infrared radiation that reaches the window 106 and from here to the intrusion sensor 107.
  • the electronic circuit that manages this anti-masking function and that will be explained in more detail in reference to figure 2, provides to monitor the sample signal emitted by the transmitter 103 and to compare it with a reference value. If the value of the sample signal received by the sensor 109, through the window 106 (which is the same through which the radiation coming from outside relating to the presence of eventual intruders passes), removed from a range or band of values granted, be it higher, or be it lower, the electronic circuit provides for the generating of an alarm signal due to attempted tampering.
  • the device according to the invention arranged with a pair transmitter elements - autonomous sensors, with respect the sensor used for the anti-intrusion surveillance and dedicated exclusively for anti-masking, and as their mutual positioning does not have bonds with the remaining parts of the device, as demonstrated in figure 1 it is possible to arrange the two elements in the best position for the surveillance of the visual field where attempts of masking could take place, a visual field that never coincides with that of the sensor used for anti-intrusion. In fact the masking takes place in proximity of the surveillance device, while the intrusion usually takes place in a secluded area with respect the device, that is often placed in a high and dominant position.
  • FIG 2 as previously mentioned regards the electronic part relative to the alarm generating system, in the case of attempts of masking the intrusion sensor element.
  • the remaining electronic part of the circuit contained inside the anti-intrusion device is not shown in figure 2 as it refers to a known circuit operating in a conventional way.
  • figure 2 with the reference number 1 indicates an infrared radiation transmitting element (corresponding to 103 in figure 1), typically an infrared LED diode that emits a radiation presenting a wave length of approximately 0,95 m, that transmits pulses, piloted by a circuit generator 2 of synchronising pulses.
  • a circuit generator 2 also supplies the signal to a delay circuit 3, which after having introduced a delay to the signal of a pre-determined value, sends it to a timing circuit 4, that acts on the form of the received wave modifying the duty cycle.
  • the negative signal is present with respect the signal present at the output A; i.e. a signal presenting a complementary duty-cycle with respect to that presented by the signal available at the output terminal A.
  • the electronic circuit of figure 2 also comprises a infrared radiation receiving element 6 (for instance a photodiode) apt at receiving the radiation emitted by the transmitter 1.
  • the receiver 6 (corresponding to reference 109 in figure 1) supplies its output signal to two amplification stages containing high-pass filters, indicated with the reference numbers 7 and 8.
  • the signals present at the output of the amplifying circuit 8 together with those present at output A of the timing circuit 4, are fed to the input terminals of a synchronous discriminator circuit 5, that has the task of giving as an output a signal in proportion to the pulse signal periodically emitted by the transmiting element 1 and picked up by the receiving element 6.
  • the analysis of the signal received by the receiver 6 only takes place in those periods of time corresponding to the transmission pulses, timed by the circuit generator of synchronising pulses 2 and it is for this reason that the synchrone discriminator 5 receives the signal coming from the output A of the timing circuit 4.
  • the delay introduced to the signal coming from the circuit generator of synchronising pulses 2, obtained through the delay circuit 3 serves in compensating the propagation delays of the signal transmitted by the element 1, with respect the signal received by the element 6.
  • the outputting signal from the synchronous discriminator 5, is therefore fed to a compensation circuit 9 of the received signal with respect the slow variations of the infrared radiation of the surroundings picked up by the receiving element 6.
  • the compensation circuit 9 can favourably include a window comparator circuit, i.e. a circuit that works on the principle of commutating the signal present at the output, only when the input signal is not within two pre-determined threshold levels (such comparator can be obtained by a circuit utilising a double differential amplifier).
  • the outputting signal from the compensation circuit 9 is then sent to a masking comparator circuit 10 of the anti-intrusion device and from this to a masking alarm timing circuit 11 and finally to a relay 12 that produces the alarm signal upon attempts of masking.
  • the electronic circuit of figure 2 also comprises a spurious radiation detection circuit 13 that receives at its first input C the signal produced by the receiver 6, through the two amplifying circuits 7 and 8, and at its second input D the outputting signal from the terminal B of the timing circuit 4. The outputting signal of the circuit 13 is then finally adopted to a second port of the comparator circuit 10.
  • the present device functions in the following way.
  • the impulsive signal generated by the generator circuit 2 is irradiated by the infrared radiation transmitter 1 and picked up by the receiver element 6, in accordance with the spaced disposition of the mentioned elements as has been explained in detail with reference to figure 1.
  • the infrared radiation detected by the receiver element 6 generates a signal that is amplified by the amplifiers 7 and 8, that present high-pass filters with frequency values appropriately calculated so as to select signals belonging only to the desired bands of frequency.
  • This signal is adopted by the synchronous discriminator 5 that values it only during the "active" periods, determined by the signal coming from the timing circuit 4.
  • the signal outputting from the discriminator 5 is analysed by the compensation circuit 9 that works in an auto adapting manner, due to the fact that the window comparator varies the value of its threshold in consequence of the medium value of the signal produced by the synchronous discriminator 5. Therefore only if the signal produced by the synchronous discriminator exceeds the range of values granted by the window comparator, due to sudden variations of the signal detected by the receiver element 6, a signal of attempted masking is generated. However this signal is not always adequate, as, before activating the relay 12, it still has to pass the analysis operated by the masking comparator circuit 10.
  • such circuit does not permit the outputting signal from circuit 9 to pass in the case that the threshold has been exceeded for a brief period of time in which the spurious radiation detector 13 has detected a great increase of external radiation, in relation to the surroundings.
  • the exceeding of the threshold could have been produced for a brief period by a source of infrared radiation that has been accidently picked up by the receiver 6; such sources of short duration infrared radiation could be caused by for example by a television remote control unit or a remote control device functioning by means of emitting signals in the infrared field.
  • the masking comparator circuit 10 upon detecting the persistence of a signal that exceeds the pre-determined threshold (high or low), longer than a pre-determined length of time, for instance 2-3 seconds, allows the passing of the alarm signal, as in such a case it means that there is an attempt of obstructing the anti-intrusion device or by means of generating infrared radiation with an autonomous source (the use of an infrared remote control device), or by reflection (by placing a screen in front of the window), or finally because the emission of radiation by the transmitter element has been minimized (spraying of the lens). In each of these cases an alarm signal is generated, through the timer 11, producing the activation of the relay 12 that produces the alarm signal for the complete surveillance system.
  • the pre-determined threshold high or low
  • a pre-determined length of time for instance 2-3 seconds

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Burglar Alarm Systems (AREA)
EP92102193A 1991-02-11 1992-02-10 Eindringmeldealarm Withdrawn EP0499177A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITTO910082 1991-02-11
ITTO910082A IT1245405B (it) 1991-02-11 1991-02-11 Dispositivo anti-intrusione

Publications (1)

Publication Number Publication Date
EP0499177A1 true EP0499177A1 (de) 1992-08-19

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EP92102193A Withdrawn EP0499177A1 (de) 1991-02-11 1992-02-10 Eindringmeldealarm

Country Status (2)

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EP (1) EP0499177A1 (de)
IT (1) IT1245405B (de)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0660284A1 (de) * 1993-12-21 1995-06-28 Optex Co. Ltd. Infrarotes Eindringlings-Detektierungssystem
WO1996006865A1 (en) * 1994-08-28 1996-03-07 Visonic Sicherheitstechnik Gmbh Infrared intrusion detector with obscuring detecting apparatus
WO1997001160A1 (en) * 1995-06-22 1997-01-09 David John Dando Intrusion sensing systems
EP0772171A1 (de) 1995-11-03 1997-05-07 Cerberus Ag Passiver Infrarot-Einbruchdetektor und dessen Verwendung
EP0790590A1 (de) * 1996-02-12 1997-08-20 Siemens Nixdorf Informationssysteme AG Infrarot-Sicherungssystem
GB2317486A (en) * 1995-06-22 1998-03-25 David John Dando Intrusion sensing systems
US5942976A (en) * 1995-11-03 1999-08-24 Cerberus Ag Passive infrared intrusion detector and its use
GB2339614A (en) * 1998-07-14 2000-02-02 Infrared Integrated Syst Ltd Detector array sensor with mask warning
GB2344167A (en) * 1998-11-26 2000-05-31 Infrared Integrated Syst Ltd Optical inactivity sensor
EP1061489A1 (de) * 1999-06-07 2000-12-20 Siemens Building Technologies AG Intrusionsmelder mit einer Einrichtung zur Sabotageüberwachung
EP1093100A1 (de) * 1999-10-14 2001-04-18 Siemens Building Technologies AG Passiv-Infrarotmelder
US6297745B1 (en) 1999-03-08 2001-10-02 Siemens Buildings Technologies Ag Housing for an alarm
CN1075096C (zh) * 1995-03-10 2001-11-21 通用电气公司 高性能聚合物组合物
US6800854B2 (en) 2001-11-05 2004-10-05 Siemens Building Technologies Ag Passive infrared detector
WO2007147322A1 (en) * 2006-06-16 2007-12-27 Hong Kong Applied Science And Technology Research Institute Co. Ltd (Astri) Monitoring devices and surveillance devices
US7875852B2 (en) 2006-07-27 2011-01-25 Visonic Ltd Passive infrared detectors
US9123222B2 (en) 2012-03-15 2015-09-01 Ninve Jr. Inc. Apparatus and method for detecting tampering with an infra-red motion sensor
US9188487B2 (en) 2011-11-16 2015-11-17 Tyco Fire & Security Gmbh Motion detection systems and methodologies

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1439325A (en) * 1972-05-06 1976-06-16 Kgm Electronics Ltd Alarm detectors
EP0005352A1 (de) * 1978-04-27 1979-11-14 B.A. Security Systems Limited Einrichtung zur Meldung von Einbruch durch Strahlungsdetektion
GB2141228A (en) * 1983-06-09 1984-12-12 Shorrock Security Systems Ltd Infra-red intrusion detector
EP0186226A1 (de) * 1984-11-30 1986-07-02 Laboratoires D'electronique Philips Intrusionsdetektoranlage mit Antimaskierungsvorrichtung
DE8609515U1 (de) * 1986-04-08 1986-07-10 Fritz Fuss Gmbh & Co, 72458 Albstadt Vorrichtung zur Sabotageüberwachung an einem IR-Bewegungsmelder
EP0189536A1 (de) * 1985-01-08 1986-08-06 Cerberus Ag Infrarot-Einbruchdetektor
EP0289621A1 (de) * 1986-10-31 1988-11-09 Takenaka Engineering Co. Ltd. Passives infrarot-einbruchmessfühler, ausgerüstet mit sichtfeldunterbrechungsüberwachungsmechanismus

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1439325A (en) * 1972-05-06 1976-06-16 Kgm Electronics Ltd Alarm detectors
EP0005352A1 (de) * 1978-04-27 1979-11-14 B.A. Security Systems Limited Einrichtung zur Meldung von Einbruch durch Strahlungsdetektion
GB2141228A (en) * 1983-06-09 1984-12-12 Shorrock Security Systems Ltd Infra-red intrusion detector
EP0186226A1 (de) * 1984-11-30 1986-07-02 Laboratoires D'electronique Philips Intrusionsdetektoranlage mit Antimaskierungsvorrichtung
EP0189536A1 (de) * 1985-01-08 1986-08-06 Cerberus Ag Infrarot-Einbruchdetektor
DE8609515U1 (de) * 1986-04-08 1986-07-10 Fritz Fuss Gmbh & Co, 72458 Albstadt Vorrichtung zur Sabotageüberwachung an einem IR-Bewegungsmelder
EP0289621A1 (de) * 1986-10-31 1988-11-09 Takenaka Engineering Co. Ltd. Passives infrarot-einbruchmessfühler, ausgerüstet mit sichtfeldunterbrechungsüberwachungsmechanismus

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0660284A1 (de) * 1993-12-21 1995-06-28 Optex Co. Ltd. Infrarotes Eindringlings-Detektierungssystem
WO1996006865A1 (en) * 1994-08-28 1996-03-07 Visonic Sicherheitstechnik Gmbh Infrared intrusion detector with obscuring detecting apparatus
CN1075096C (zh) * 1995-03-10 2001-11-21 通用电气公司 高性能聚合物组合物
GB2317486B (en) * 1995-06-22 2000-01-12 David John Dando Intrusion sensing systems
WO1997001160A1 (en) * 1995-06-22 1997-01-09 David John Dando Intrusion sensing systems
US6127926A (en) * 1995-06-22 2000-10-03 Dando; David John Intrusion sensing systems
GB2317486A (en) * 1995-06-22 1998-03-25 David John Dando Intrusion sensing systems
US5942976A (en) * 1995-11-03 1999-08-24 Cerberus Ag Passive infrared intrusion detector and its use
EP0772171A1 (de) 1995-11-03 1997-05-07 Cerberus Ag Passiver Infrarot-Einbruchdetektor und dessen Verwendung
EP0790590A1 (de) * 1996-02-12 1997-08-20 Siemens Nixdorf Informationssysteme AG Infrarot-Sicherungssystem
GB2339614A (en) * 1998-07-14 2000-02-02 Infrared Integrated Syst Ltd Detector array sensor with mask warning
GB2339614B (en) * 1998-07-14 2000-06-21 Infrared Integrated Syst Ltd Detector-array sensor with mask warning
GB2344167A (en) * 1998-11-26 2000-05-31 Infrared Integrated Syst Ltd Optical inactivity sensor
GB2344167B (en) * 1998-11-26 2000-09-06 Infrared Integrated Syst Ltd Use of detector arrays to detect cessation of motion
US6297745B1 (en) 1999-03-08 2001-10-02 Siemens Buildings Technologies Ag Housing for an alarm
EP1061489A1 (de) * 1999-06-07 2000-12-20 Siemens Building Technologies AG Intrusionsmelder mit einer Einrichtung zur Sabotageüberwachung
US6377174B1 (en) 1999-06-07 2002-04-23 Siemens Technologies Ag, Cerberus Division Intrusion detector having a sabotage surveillance device
US6262661B1 (en) 1999-10-14 2001-07-17 Siemens Building Technologies, Ag Cerberus Division Passive infrared detector
EP1093100A1 (de) * 1999-10-14 2001-04-18 Siemens Building Technologies AG Passiv-Infrarotmelder
US6800854B2 (en) 2001-11-05 2004-10-05 Siemens Building Technologies Ag Passive infrared detector
WO2007147322A1 (en) * 2006-06-16 2007-12-27 Hong Kong Applied Science And Technology Research Institute Co. Ltd (Astri) Monitoring devices and surveillance devices
US7414236B2 (en) 2006-06-16 2008-08-19 Hong Kong Applied Science And Technology Research Institute Co., Ltd. Monitoring devices and intrusion surveillance devices
US7875852B2 (en) 2006-07-27 2011-01-25 Visonic Ltd Passive infrared detectors
US8017913B2 (en) 2006-07-27 2011-09-13 Visonic Ltd. Passive infrared detectors
US9188487B2 (en) 2011-11-16 2015-11-17 Tyco Fire & Security Gmbh Motion detection systems and methodologies
US9123222B2 (en) 2012-03-15 2015-09-01 Ninve Jr. Inc. Apparatus and method for detecting tampering with an infra-red motion sensor

Also Published As

Publication number Publication date
IT1245405B (it) 1994-09-20
ITTO910082A0 (it) 1991-02-11
ITTO910082A1 (it) 1992-08-11

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