MONITORING SYSTEM

Description

TECHNICAL AREA

[0001] The present invention relates to a monitoring system for monitoring at least a fixed but displaceable object in a volume, which object is provided with at least one marking means in form of a light generating or light reflecting device, which system comprises at least one optical recording unit for recording an image of at least a part of the volume comprising said object provided with the marking means, device for transforming said image to a digital representation of the same image, means for comparison of the digital representation with a stored data-set, and device for generating a signal at the presence of a deviation at comparison of the digital representation with the stored information quantity.

DESCRIPTION OF STATE OF THE ART

[0002] For monitoring of substantially articles of value in spaces such as rooms, stores, museums and so on, fixed alarm connections or so-called border watch are usually used.

[0003] With fixed alarm connections means such systems where each object is provided with an alarm sensor, which via a cable is connected to a central alarm unit. The disadvantage of such systems is that cables must be arranged to each object to be monitored, which makes the system less flexible.

[0004] In border watch system, each object is provided with active or passive sensors, which can alarm when a guarded point is trespassed. The disadvantage of such systems is that damage on an alarmed object cannot be detected immediately, which among others can result in time for manipulation of the alarm sensors.

[0005] There are also systems comprising passive/active transponders attached to the object to be guarded. The transponders are continuously or periodically in radio communication with a controlling unit, which generates an alarm when a boarder is trespassed or an attempt is made to manipulate the transponder. The drawbacks of such systems are that they are usually expensive, for instance because the transponders, complicated monitoring algorithms for several transponders, they do not detect displacements within the controlled area, the need of frequency band for operation and risk of radio interferences.

[0006] In the Swedish patent application No. 9700065-7, a method for calculating the central point for a marker in a motion analysis system is known.

[0007] JP 11 003 474 relates to deciding the changes of the image of a monitored object by means of a reflected laser light from the monitored object and generating an alarm. Accordingly, a pattern corresponded to the incoming image, is compared with a stored pattern.

[0008] In JP 11185175, it is decided whether the image of a marker has been changed or not, whereby an inputted image is compared to a stored image.

[0009] Moreover, EP 393 807 relates to image processing, see for instance claim 1. An image of a marker is compared to a stored image and variations in the image edge are registered.

[0010] According to EP 984 412 signals from an image, or parts of an image, are continuously compared to a stored reference image, whereby correlation analysis is used. When differences are detected in the correlated signal a warning or alarm is generated.

[0011] Also, WO 98/56182, US 4,160,998, US 5,880,775, DE 4417128 and DE 38 42 356 relate to image processing, where alarm is generated when frequent differences in the form of the images are detected.

[0012] The present invention relates to monitoring of a position of a marker, particularly its coordinates in two dimensions, and registering the deviation from a stationary position coordinate. The changes of the form of the marker and the appearance are unimportant, since the coordinates are decided by means of a center of gravity or center point.

[0013] However, FR 2759541 mentions the use of coordinates. Thus, the system relates to motion analysis, in which the motion of the markers are analyzed and if its motion pattern deviates from a motion-determined pattern, an alarm is generated.

BRIEF DESCRIPTION OF THE INVENTION

[0014] The object of the present invention is to provide a system for substantially automatically, contactless and optical monitoring of a volume and/or a number of objects in a volume by means of simple means, substantially in real time without the need for complicated modifications within the volume or the object.

[0015] Another object of the present invention is to provide a simple but yet efficient thief-proof protection system.

[0016] Yet, another object of the invention is to provide a smoke detection system.

[0017] These objects have been achieved by means of the system of claim 1, in which the stored data set comprises at least a two dimensional stationary coordinate value for the initial position of the marking means. The system comprise means for extraction of at least one stationary coordinate value, which is at least a two-dimensional coordinate value, out of the digital representation for the marking means, whereby said comparison means compares said extracted two dimensional coordinate value to the stored stationary coordinate value.

[0018] According to a first embodiment, in which the system is used, for instance as a thief-protection a number of objects are provided with said marking means, where the objects are monitored for uncontrolled displacement.

[0019] Preferably, each object is provided with a reflecting mark. In another embodiment, a part of the object can be used as a marking means. For obtaining a good protection, several marking means are arranged on the same object.

[0020] The digital representation contains coordinate values for the marking means and that the stored data set comprises an initial position for the coordinate values of the marking means.

[0021] In a system for smoke detection, the light intensity of the marking means is measured and the data set stored comprises an initial light intensity.

[0022] Preferably, the system comprises a heat detector.

[0023] The invention also relates to a method for monitoring an object in a volume provided with the steps included in claim 10.

[0024] In one embodiment, the data comprises the value of the light intensity for said marking means.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the following the invention will be described with reference to the embodiments according to enclosed drawings, in which:

Fig. 1

shows very schematically a first embodiment of a monitoring system according to the invention, and

Fig. 2

shows very schematically a second embodiment of a monitoring system according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0026] The monitoring system according to the invention consists of a measuring camera system, for instance such a system that can be used for motion analysis. The system 10, which is shown in Fig. 1, comprises at least one camera 11, for monitoring of a number of objects 12 provided with markers 13.

[0027] The camera 11 is provided with means, such as a light flash, a lamp or another light source for sending out light, preferably (but not restricted to) infrared light or the like in form of short light flashes. If required, a continuous illumination can be used. Preferably, the markers 13 comprise a retro reflective tape or a body provided with a reflecting surface, which reflects the light back to the camera. Active or passive markers may comprise illumination devices such as light diodes, which are activated by the camera or another control unit can be used.

[0028] In communication with the camera 11, or integrated therein, there is a computer unit 14 for receiving image data from the camera, which as a rule is arranged with a CCD-unit (CCD: Charge Coupled Device) or another optical sensor. The data from the sensor unit is preferably obtained in form of digital signals. Recording by means of the sensor, and converting the signal to digital or video signals, are assumed to be well known for a man skilled in the art, and will not be described further herein.

[0029] The computer unit 14 evaluates the image of each marker in the field of vision, substantially in real time (image speed 50-240 images/sec) and calculates the coordinates of the markers, preferably to its center (its center of gravity). Preferably, the coordinates are calculated with regard to an interior coordinate system. The coordinate values can have a resolution of 1/50.000 of the field of vision.

[0030] The coordinates are continuously transferred, via for instance a serial interface, to a monitoring computer 15. In a memory unit 16 in the computer, the original positions of the markers are stored. All uncontrolled deviation from the original coordinate value of a marker can initiate an alarm. The original positions are registered, for instance by giving a particular command when the objects and the markers have been located on its correct position. If the position is changed, the new positions can be registered in the computer as new original positions.

[0031] The number of cameras in the room are chosen so that each marker in the monitored volume is seen by at least one camera. The markers are arranged on objects to be protected and other points of interest in the room (doors, windows, etc). At the start of the monitoring, all the coordinates are stored in the memory unit of the computer 16, which then continuously monitors every change of the coordinates.

[0032] Because of the high resolution of the system, a camera having a field of vision of approx 5 m detects a displacement of approx. 0.1 mm. Since the system is passive and has high resolution, it is not possible to interfere the system. Every attempt to manipulate a marker results in that the coordinate values of the marker are changed, which may lead to an alarm. Theoretically, a marker can be displaced from its location in direction towards the camera without the coordinate value is changed, but in practice, this should not be possible to perform. Moreover, several cameras can see a marker and even then, it is not theoretically possible to displace a mark. Of course, the system can be arranged so that it measures the distance between the camera and the mark, such as described in the Swedish patent No. 9700066-5.

[0033] The reliability of the system can be improved by providing a protected object in the system with two or more markers 13a-13c, which allows preventing false alarm if one of the markers is hidden, disturbed or is invisible for a camera, the remaining markers can be discovered.

[0034] The system according to the invention can be made completely self-calibrating and very easy to install. The system can be arranged so that it indicates that if the markers are shown with sufficient intensity in itself. The influence of operation on the measuring values can be easily eliminated in the monitoring computer, since all the markers are moved in the same way.

[0035] The markers are preferably comprised of recessed or punched parts of self-adhering reflex tape to a low cost. However, the markers can be replaced by reflections 13d from the surfaces of the objects if a fixed or defined illumination is arranged.

[0036] If the protected object can be set in motion, for instance through vibration, a tolerance area is defined in the monitoring computer, so that no alarm is generated as long as the object is within the tolerance area.

[0037] "False" markers can eventually appear if there are many bright objects in an image, which the camera apprehends as a reflex mark. False markers can be filtrated in most of the cases by means of that the measuring system contains information concerning the shape of each mark. The false markers. which eventually remain after the filtration, are no problem since they are in fact stationary. Varying strong sunlight may cause problem through dazzling the system, but by means of appropriate camera location, such problems can be eliminated.

[0038] The system also provides possibility for protecting encased objects in, for instance in transparent spaces such as display cabinets or the like, without the need for wire laying in the space etcetera.

[0039] In another embodiment of the system 20, as shown in Fig. 2, the camera 21 also measures, in addition to the position of the marker, the light intensity received from the marker 22. In this case a disturbance in the measurement, for instance because of a cloud of smoke 26 can be detected by the computer as the light intensity becomes weaker. When the clouds of smoke are detected, for instance a fire alarm may be generated. The system can use coordinate values for detecting the marker and calculating its light intensity.

[0040] The system may also comprise communication means 15, 25, which in alarm mode sends a message to an alarm central or predetermined receivers. The system can also be connected to a network, such as Internet, for remote control and remote monitoring.

[0041] Moreover, the system according to the invention may be completed with a sensor 30 for heat detection.

[0042] While we have illustrated and described the preferred embodiments of the invention, it is realized that several variations, modifications or combinations of the embodiments within the scope of the appending claims may exist.

Reference Signs

[0043] 

10, 20

System

11, 21

Camera

12

Object

13, 23

Mark

14, 24

Computer unit

15, 25

Communication unit

16

Memory unit

28

Smoke

20

Heat detector

Claims

1. A monitoring system (10, 20) for monitoring at least one fixed but displaceable object in a volume, which object is provided with at least one marking means (13, 13a-13d, 23) in form of a light generating or representing device, which system at least comprises an optical recording unit (11, 21) for recording an image of at least a part of the volume comprising said object provided with the marking means (13, 13a-13d, 23), device for transferring said image to a digital representation of the same image, means (14) for comparison of the digital representation to a stored data-set, and device for generating a signal at the presence of a deviation at the comparison of the digital representation with the stored data set, wherein
said stored data-set is obtained by a self-calibrating process, comprising in a first step storing of a at least two dimensional stationary coordinate value for the initial position of the marking means (13, 13a-13d), that the system comprises means for extracting at least a stationary coordinate value, which is at least a two-dimensional coordinate value, out of the digital representation of the marking means during a monitoring mode, whereby said comparison means (14) compares said extracted two-dimensional coordinate value with the stored stationary coordinate value, and generates an alarm if the comparison result varies.

2. A monitoring system (10) as claimed in claim 1,
characterized in
that said object is monitored for uncontrolled displacement.

3. A monitoring system (10) as claimed in claim 1 and 2,
characterized in
that the object is provided with a reflecting marker.

4. A monitoring system (10) as claimed in claim 2 and 3,
characterized in
that a part of the object is used as marking means.

5. A monitoring system (10) as claimed in claim 1 - 4,
characterized in
that several marking means are arranged on the same object.

6. A monitoring system (20) as claimed in claim 1,
characterized in
that the light intensity of the marking means is also measured.

7. A monitoring system (20) as claimed in claim 6,
characterized in
that the stored data set comprises an initial light intensity.

8. A monitoring system (20) as claimed in claim 6 or 7,
characterized in
that the system is intended as a fire alarm.

9. A monitoring system (20) as claimed in any of the preceding claims,
characterized in
that the system in addition comprises a heat detector.

10. A method for monitoring an object in a volume provided with at least a marking means (13, 13a-13d, 23) in form of a light generating or reflecting device, whereby the method comprises the steps of:

• at least arranging one optical sensor unit (11, 21) for recording an image of at least one part of the volume comprising said marking means (13, 13a-13d, 23),

• transforming said image to a digital representation of the same image,

• comparing the digital representation to a stored data-set,

• at least extracting one coordinate value, which is at least a two-dimensional coordinate value, out of the digital representation of the marking means,

• comparing said extracted two-dimensional coordinate value to a stored stationary coordinate value, obtained by a self-calibrating process comprising a first step of storing of said stationary coordinate value, for said marking means by means of said comparison means (14), and

• generating an alarm at the presence of a deviation at comparison of the extracted coordinate value to the stored coordinate value.

11. A method as claimed in claim 10,
characterized in
that the data comprises a value of the light intensity for said marking means as well.

Ansprüche

1. Überwachungssystem (10, 20) zum Überwachen von wenigstens einem festen, aber verschiebbaren Objekt in einem Volumen, wobei das Objekt mit wenigstens einem Kennzeichnungsmittel (13, 13a - 13d, 23) in Form einer Licht erzeugenden oder darstellenden Vorrichtung versehen ist, wobei das System wenigstens eine optische Aufzeichnungseinheit (11, 21) zum Aufzeichnen eines Bilds von wenigstens einem Teil des Volumens, welches das mit dem Kennzeichnungsmittel (13, 13a - 13d, 23) versehene Objekt umfasst, eine Vorrichtung zum Überführen des Bilds in eine digitale Darstellung des selben Bilds, Mittel (14) zum Vergleichen der digitalen Darstellung mit einem gespeicherten Datensatz, und eine Vorrichtung zum Erzeugen eines Signals bei Vorhandensein einer Abweichung beim Vergleich der digitalen Darstellung mit dem gespeicherten Datensatz umfasst, wobei
der gespeicherte Datensatz durch einen selbstkalibrierenden Prozess erhalten wird, der in einem ersten Schritt das Speichern von einem wenigstens zweidimensionalen stationären Koordinatenwert für die Anfangsposition des Kennzeichnungsmittels (13, 13a - 13d) umfasst, und wobei das System Mittel zum Extrahieren wenigstens eines stationären Koordinatenwerts, der wenigstens ein zweidimensionaler Koordinatenwert ist, aus der digitalen Darstellung des Kennzeichnungsmittels während eines Überwachungsmodus umfasst, wobei das Vergleichsmittel (14) den extrahierten zweidimensionalen Koordinatenwert mit dem gespeicherten stationären Koordinatenwert vergleicht und einen Alarm erzeugt, falls das Vergleichsergebnis abweicht.

2. Überwachungssystem (10) nach Anspruch 1,
dadurch gekennzeichnet,
dass das Objekt auf eine unkontrollierte Verschiebung hin überwacht wird.

3. Überwachungssystem (10) nach Anspruch 1 und 2,
dadurch gekennzeichnet,
dass das Objekt mit einer reflektierenden Kennzeichnung versehen ist.

4. Überwachungssystem (10) nach Anspruch 2 und 3,
dadurch gekennzeichnet,
dass ein Teil des Objekts als Kennzeichnungsmittel verwendet wird.

5. Überwachungssystem (10) nach Ansprüchen 1 - 4,
dadurch gekennzeichnet,
dass mehrere Kennzeichnungsmittel an dem selben Objekt angeordnet sind.

6. Überwachungssystem (20) nach Anspruch 1,
dadurch gekennzeichnet,
dass die Lichtintensität des Kennzeichnungsmittels ebenfalls gemessen wird.

7. Überwachungssystem (20) nach Anspruch 6,
dadurch gekennzeichnet,
dass der gespeicherte Datensatz eine Anfangslichtintensität umfasst.

8. Überwachungssystem (20) nach Anspruch 6 oder 7,
dadurch gekennzeichnet,
dass das System als Feueralarm gedacht ist.

9. Überwachungssystem (20) nach einem der vorhergehenden Ansprüche,
dadurch gekennzeichnet,
dass das System zusätzlich einen Wärmemelder umfasst.

10. Verfahren zum Überwachen eines Objekts in einem Volumen, wobei das Objekt mit wenigstens einem Kennzeichnungsmittel (13, 13a - 13d, 23) in Form einer Licht erzeugenden oder reflektierenden Vorrichtung versehen ist, wobei das Verfahren die Schritte umfasst:

• Anordnen wenigstens einer optischen Sensoreinheit (11, 21) zum Aufzeichnen eines Bilds von mindestens einem Teil des Volumens, das das Kennzeichnungsmittel (13, 13a -13d, 23) umfasst,

• Umwandeln des Bilds in eine digitale Darstellung des selben Bilds,

• Vergleichen der digitalen Darstellung mit einem gespeicherten Datensatz,

• Extrahieren von wenigstens einem Koordinatenwert, der wenigstens ein zweidimensionaler Koordinatenwert ist, aus der digitalen Darstellung des Kennzeichnungsmitteis,

• Vergleichen des extrahierten zweidimensionalen Koordinatenwerts mit einem gespeicherten stationären Koordinatenwert, der durch einen selbstkalibrierenden Prozess erhalten wird, der einen ersten Schritt des Speicherns des stationären Koordinatenwerts für das Kennzeichnungsmittel mittels des Vergleichsmittels (14) umfasst, und

• Erzeugen eines Alarms bei Vorhandensein einer Abweichung beim Vergleich des extrahierten Koordinatenwerts mit dem gespeicherten Koordinatenwert.

11. Verfahren nach Anspruch 10,
dadurch gekennzeichnet,
dass die Daten auch einen Wert der Lichtintensität für das Kennzeichnungsmittel umfassen.

Revendications

1. Système de surveillance (10, 20) pour surveiller au moins un objet fixe mais déplaçable dans un volume, lequel objet est muni d'au moins un moyen de marquage (13, 13a-13d, 23) sous la forme d'un dispositif de génération ou de représentation de lumière, lequel système comprend au moins une unité d'enregistrement optique (11, 21) pour enregistrer une image d'au moins une partie du volume comprenant ledit objet muni du moyen de marquage (13, 13a-13d, 23), dispositif pour transférer ladite image vers une représentation numérique de la même image, des moyens (14) pour la comparaison de la représentation numérique avec un ensemble de données enregistré, et dispositif pour générer un signal en présence d'un écart à la comparaison de la représentation numérique avec un ensemble de données enregistré, où
ledit ensemble de données enregistré est obtenu par un processus d'auto-étalonnage, comprenant, dans une première étape, l'enregistrement d'une valeur de coordonnées stationnaires au moins bidimensionnelle pour la position du moyen de marquage (13, 13a-13d, 23), le système comprend des moyens pour extraire au moins une valeur de coordonnées stationnaires, qui est au moins une valeur de coordonnées bidimensionnelle, à partir de la représentation numérique du moyen de marquage pendant un mode de surveillance, à l'occasion de quoi lesdits moyens de comparaison (14) comparent ladite valeur de coordonnées bidimensionnelle extraite avec la valeur de coordonnées stationnaires enregistrée, et génère une alarme si le résultat de la comparaison varie.

2. Système de surveillance (10) selon la revendication 1,
caractérisé en ce que
ledit objet fait l'objet d'une surveillance de déplacement incontrôlé.

3. Système de surveillance (10) selon la revendication 1 et 2,
caractérisé en ce que
l'objet est muni d'un marqueur réfléchissant.

4. Système de surveillance (10) selon la revendication 2 et 3,
caractérisé en ce
qu'une partie de l'objet est utilisée comme moyen de marquage.

5. Système de surveillance (10) selon les revendications 1 - 4,
caractérisé en ce
que plusieurs moyens de marquage sont agencés sur le même objet.

6. Système de surveillance (20) selon la revendication 1,
caractérisé en ce
que l'intensité lumineuse du moyen de marquage est également mesurée.

7. Système de surveillance (20) selon la revendication 6,
caractérisé en ce
que l'ensemble de données enregistré comprend une intensité lumineuse initiale.

8. Système de surveillance (20) selon la revendication 6 ou 7,
caractérisé en ce
que le système est prévu comme une alarme incendie.

9. Système de surveillance (20) selon l'une quelconque des revendications précédentes,
caractérisé en ce
que le système comprend en plus un détecteur de chaleur.

10. Procédé de surveillance d'un objet dans un volume, muni d'au moins un moyen de marquage (13, 13a-13d, 23) sous forme d'un dispositif de génération ou de réflexion de lumière, à l'occasion de quoi le procédé comprend les étapes consistant à :

• agencer au moins une unité de capteur optique (11, 21) pour enregistrer une image d'au moins une partie du volume comprenant ledit moyen de marquage (13, 13a-13d, 23),

• transformer ladite image en une représentation numérique de la même image,

• comparer la représentation numérique avec un ensemble de données enregistré,

• extraire au moins une valeur de coordonnées, qui est au moins une valeur de coordonnées bidimensionnelle à partir de la représentation numérique du moyen de marquage,

• comparer ladite valeur de coordonnées bidimensionnelle extraite avec une valeur de coordonnées stationnaires enregistrée obtenue par un processus d'auto-étalonnage comprenant une première étape consistant à enregistrer ladite valeur de coordonnées stationnaire pour ledit moyen de marquage au moyen desdits moyens de comparaison (14), et

• générer une alarme en présence d'un écart à la comparaison de la valeur de coordonnées extraite avec la valeur de coordonnées enregistrée.

11. Procédé selon la revendication 10,
caractérisé en ce que
les données comprennent une valeur d'intensité lumineuse pour ledit moyen de marquage également.

Drawing