EP0273965B1 - Installation for determining the number and the direction of persons staying in a monitored room or pass-through - Google Patents

Abstract

In an installation for determining the number of persons inside a monitored room or so-called pass-through, a sensor field is generated by IR-sensors. An evaluation unit uses as discriminating criterion the detection of moving bodies and generates for an entrance control unit a signal, allowing or barring the entrance of a person.

Description

The invention relates to a device for determining the number of people and their direction of movement within a room to be monitored or a passage gate with at least two infrared sensors and with an evaluation unit, to which the signals of the infrared sensors are fed, and which, taking into account the sensor distance, the number of people passing through the passage gate detected and forwarded to an access control device for further processing.

In the prior art, the so-called "isolation" in the known control systems is attempted in such a way that the so-called lock room is kept structurally narrow or strongly limited, on the other hand the lock room is closed by two mutually locked doors, or by Weight check prevents unwanted simultaneous access by a second person. In the former case, the so-called rotating barrier grids are known, which only function after an identity card has been checked by an identity card reader. Instead of ID, e.g. at major sports events, the admission ticket is inserted in the reader slot. By carrying a second person on your shoulder, such isolation systems are easy to deceive. Estimates indicate that between 14% and 18% of unauthorized persons enter this way.

If the separating device is a closed, narrow lock room, claustrophobia occurs for a large number of visitors, so that a device that works in this way is already rejected by the company personnel supervisor. The situation is similar in the known narrow lock rooms, which are closed off by two doors, the exit door opening automatically after the entrance door is closed. This is aggravated by the fact that the narrow lock room becomes a "prison" in the event of malfunctions, such as those caused by a power failure, etc., and therefore additional emergency call devices, door opening systems which come into operation in the event of a power failure, and the like are required. However, if the lock space is made wider in the aforementioned cases, the simultaneous entry of two people is not a problem and the safety device can be overcome very easily.

In the embodiment, which carries out a separation by means of weight control via running boards, etc., the tricking by two people is also fairly easy, because the specified weight tolerance must be kept very high, so that it is not a problem, for example, that two slim women can enter at the same time or an adult and a teenager. Apart from that, the technical outlay is very considerable in all of the aforementioned cases.

From DE-OS 25 42 594 a device for determining the number of people and direction within a room to be monitored or a passageway, especially the double door of a vehicle, is known in which at least two IR sensors and an evaluation unit for determining the number of those passing through People are used. An active system is used for detection, i.e. a light barrier system with transmitters and receivers. This has the disadvantage that the area to be monitored is precisely defined by the transmission area and is therefore relatively easy to bypass or must be kept small enough by mechanical limitations, which is not a problem in the application area described.

It is also known to arrange a plurality of infrared barriers side by side and one above the other in such a passage lock in order to largely exclude interfering influences such as, for example, moving arms of the person passing through the lock. Such a device is described in GB-A-1 252 253. Although such a device can be used for counting, for example for statistical purposes, it is unsuitable when it comes to largely eliminating manipulations. For example, this facility cannot detect when two people are closely wrapped in each other or walk through the lock while sitting on their shoulders.

The same applies to the device described in US-A-4,528,679, which works with ultrasound.

From US-A-4,009,389 a similar device is known, which works by means of two light barriers arranged closely behind each other within a passage. This device can also be manipulated relatively easily and is therefore not suitable for the purposes described at the beginning.

DE-OS 29 20 333 describes a device for counting people, which works with light sources and associated detectors arranged on the ceiling in a passage lock. The device described there also serves essentially statistical purposes and indeed allows a distinction to be made with regard to the size of the people passing through the light barrier, but not the reliable manipulation-proof detection of the number of people passing through the lock.

DE-OS 30 30 229 discloses a detection device which operates by means of light in the visible range. This device works with sensors which detect the ambient light or the ambient light reflected by a passing object, for example a vehicle, and the resulting light. Compare the electrical signal with pre-entered signal values to determine whether it is an interference signal or an object to be registered. This device is in particular for detecting the speed measurement of vehicles gene provided. For object protection, however, the two-dimensional signal corresponding to the silhouette and the color of the object and generated by only one sensor can be compared with stored patterns.

Starting from the prior art mentioned in the introduction (DE-OS 25 42 594), the present invention is based on the object of designing a device for ascertaining the number of people and direction within a room to be monitored or a passage gate according to the features specified in the preamble of claim 1 that increased security against fraudulent access by people is achieved without the surveillance area having to be narrowed too much by walls.

This object is achieved in a generic device by the features listed in the characterizing part of claim 1.

The device according to the invention allows reliable monitoring of a room or a passage lock without the usual spatial limitation. Due to the at least two infrared sensors arranged one behind the other in the passage direction, the device is able to detect the movement of one or more people in the passage direction and also take it into account in the evaluation, so that the influence of the speed and the respective distance from the sensor in the evaluation and the comparison with the signal typical for an individual is taken into account. The at least two infrared sensors arranged next to one another transversely to the direction of passage are to be provided in particular if there is a risk that it cannot be reliably determined by means of the infrared sensors arranged one behind the other in the direction of passage whether a person or whether two people are closely intertwined or sitting on top of one another step through. This creates additional security against fraudulent manipulation. However, the infrared sensors arranged one behind the other in the passage direction are essential, with which the movement of people is detected, so that this speed factor can be taken into account in the comparison with the typical limit values stored in the evaluation unit. The use of infrared sensors is of particular advantage for the observation of people, since they cannot be arranged in a visible manner and work reliably without an additional signal source - as is required in active systems - since each adult person emits about 100 watts of heat, which can be measured reliably even in relatively large rooms and is extremely difficult to manipulate.

• Fig. 1a eine Draufsicht auf einen breiten Durchgang, dessen Türe durch einen beiderseits angeordneten Ausweisleser geöffnet wird;
• Fig. 1b eine Draufsicht auf einen breiten Gang, der einen durch zwei Türen verschlossenen Schleusenraum besitzt und jede Türe wird von einem Ausweisleser geöffnet und die jeweilige Eintrittstüre wird automatisch nach Passieren einer Lichtschranke geschlossen;
• Fig. 1c eine schematische Ansicht eines Schleusenraumes mit der vorgeschlagenen Sensorvereinzelung;
• Fig. 2a ein Diagramm eines Sensorausgangssignals von einem IR-Sensor gemäß den beschriebenen Ausführungsbeispielen;
• Fig. 2b ein Diagramm der Ausgangssignale verschiedener Situationen wie sie von sogenannten PID-11-Sensoren gebildet werden;
• Fig. 3 ein Blockschaltbild einer mit der erfindungsgemäßen Vereinzelung versehenen Sicherheitsanlage;
• Fig. 4 ein Blockschaltbild der vorgeschlagenen Vereinzelungseinrichtung mit Anschluß an die vorhandene oder frei wählbare Sicherheitseinrichtung in einem Ausführungsbeispiel.
• Fig. 5 schematisch eine Schleusenanordnung gemäß der Erfindung mit zwei Schiebetüren
• Fig. 6 eine weitere Anordnung der Sensoren
• Fig. 7 eine Auswertungsvorrichtung für den Gegenstand von Fig. 6.

An advantageous development of the invention is given in that the sensors arranged one behind the other in the passage direction are arranged asymmetrically to the passage direction and the sensors with horizontal detection area located on the side walls are arranged at different heights compared to the sensors with vertical detection area. Such an asymmetrical arrangement in particular makes it more difficult to manipulate the device; moreover, with the same number of sensors, a larger room or a larger passage gate can be monitored.

• Fig. 1a is a plan view of a wide passage, the door is opened by a badge reader arranged on both sides;
• Fig. 1b is a plan view of a wide corridor, which has a lock room closed by two doors and each door is opened by an ID card reader and the respective entrance door is automatically closed after passing a light barrier;
• 1c shows a schematic view of a lock room with the proposed sensor separation;
• 2a shows a diagram of a sensor output signal from an IR sensor according to the described exemplary embodiments;
• 2b shows a diagram of the output signals of different situations as they are formed by so-called PID-11 sensors;
• 3 shows a block diagram of a security system provided with the isolation according to the invention;
• Fig. 4 is a block diagram of the proposed separation device with connection to the existing or freely selectable safety device in one embodiment.
• Fig. 5 shows schematically a lock arrangement according to the invention with two sliding doors
• Fig. 6 shows another arrangement of the sensors
• FIG. 7 shows an evaluation device for the object from FIG. 6.

The general idea of the invention is to create a safe working isolation for existing passage security systems, which is no longer tied to confined spaces. The detection and evaluation should be able to be carried out reliably with commercially available components. Integration into existing access control systems is effortlessly possible and can be adapted to the relevant security relevance and user frequency. It is also essential here that the passage clearance is made dependent on the evaluation of the sensor signals proposed here.

For this purpose, it is proposed that two or more infrared sensors S ₁ to S _" detect the deviations from the ambient temperature to a body temperature and the determined values are entered into an evaluation unit 10. This evaluation unit now adjusts according to the temporal course of the temperature changes that are caused by the running or The walking speed of the person passing through and the absorbed energy of the IR sensors S ₁ -S _n , taking into account the sensor distance, determine the number of people in the lock or in the passage, etc. This is determined by the evaluation unit 10 values formed are now forwarded to the access control unit, which may already be present, for further processing.

Various arrangements and exemplary embodiments are shown in FIGS. 1a to 1c. In Fig. 1a, a passage space 100 is closed by a door. This door can be opened from both directions by a so-called badge reader 23a. As far as access control is given according to the state of the art. Now this wide passage can of course be used by a larger number of people at the same time, only one person needs to insert their ID into the reader and the door that has been released and opened in this way must be kept open for subsequent people, which is generally done at the start of work. There is no effective control here. An effective control is also possible for such a system by means of the separating device according to the invention, because now each person who enters the sensor field 101 generated by them is registered by the IR sensors. Now the access control device, which opens the door after the identification card has been read out, can be easily programmed so that the door is not opened if two people are detected within the sensor field 101. The illumination by the IR sensors S ₁ , S ......, ie the sensor field, can now be carried out by a corresponding number of the same commercially available IR sensors, and their position can also be arranged differently from one another. In Fig. 1a, the sensors are attached in pairs one behind the other and transversely to each other (seen in the direction of passage) on the ceiling.

In Fig. 1 b, a closed lock room is illuminated by two pairs of sensors arranged one behind the other. FIG. 1c shows a schematic view which illustrates the passage of a person through a sensor field illuminated by IR sensor lobes. These or similar sensor arrangements now also determine the direction of movement of the person passing through. The arrangement of the sensors lying next to one another or laterally to one another prevents the heat radiation from being outwitted and provides redundancy.

3 and 4 illustrate in block diagrams the structure and circuitry of the device according to the invention with the existing access control systems. The sensor separation or its evaluation unit 10 transmits its signal to the exit control unit 20, which - in the given example - is activated by an identification reader 23a, 23b. This unit 20 inquires at the access control center 21 whether the badge holder is authorized to pass through and, after confirmation by the sensor separator 10 that it is only one person, gives the opening signal to the door control 22. If the badge reader is not actuated now present in the sensor field 101, the sensors indicate this to the access control 20, which reports this to the access control center 21, which in turn communicates this fact to the security center or issues an alarm. The circuit diagram in FIG. 4 should be so understandable that no further explanation is required, in particular also for the reason that all the components shown are freely available commercially.

To evaluate the sensor signals, it should also be mentioned that the course of the sensor signal is dependent on the change in temperature over time. This means that the speed and the energy given off are detected due to the deviation of the body temperature from its surroundings. The operating voltage and the distance to the sensor have an influence as further variables and are to be regarded as constant variables.

In order to keep the effect of the speed on the signal width small, a minimum speed can be set or used as the basis for the evaluation. For control purposes, the speed v can be determined from the distance between the maxima and the distance between the sensors. The ambient temperature is continuously monitored and used for the calculation. An absolutely reliable signal can thus be obtained from the spatial conditions, the ambient temperature, the lock temperature, the body temperature and the speed, which largely makes it impossible for a second person to be introduced.

• Die Sensorenausgangssignalspannung U_A = der fest eingestellten Referenzspannung U_R, wenn niemand detektiert wird.

2a shows, as already mentioned, a sensor output signal U _" which has an unchanged value when no people are detected. It can also be said:

• The sensor output signal voltage U _A = the fixed reference voltage U _R if no one is detected.

In the diagram, 6U _A means the differential voltage between the ambient temperature and the detected person temperature. To this end, it must also be stated that an object with the same radiation as the temperature of the surroundings can only be detected if the sensor is artificially kept at a temperature which deviates by at least 5 ° C.

2b shows the parameters for various situations, these being achieved by means of two PID-11 sensors which were arranged at a distance of 0.5 m from one another. The distance from the sensors to the person was also about 0.5m.

5 schematically shows a lock arrangement with two sliding doors T1 and T2. For normal operation, these doors only open to a certain width, so that additional protection against unauthorized passage is given.

In order to be able to use the doors as an escape route, they have to be opened to their full width at the same time using an appropriate switch. The full opening also allows the transport of bulky items.

FIG. 6 shows a further advantageous possibility for the IR sensors, namely an asymmetrical arrangement. The distance between the lateral sensors 204 and 205 from the floor is selected so that when walking only the body parts head and shoulder that are moved uniformly compared to the arms and legs are detected by the sensors. This makes it possible to clearly delimit the signal curve of two people from one person with the help of the detected person speed. This also applies in the event that the people walking behind each other are closely entwined.

In this constellation, the sensors 201, 202 and 203 likewise asymmetrically arranged above the head enable a clear statement to be made as to whether a second person, from the perspective of the sensors 204 and 205, is passing the lock hidden by the first person.

This is done by distributing the sensible body heat. The signal profiles of 201, 202 and 203 result in a uniform distribution in one person, which is characterized by the amplitudes of the sensor output signals. A second person inevitably produces a significantly different amplitude distribution in the sensors 201, 202 and 203 arranged overhead.

For this type of evaluation, the evaluation unit 10 must ensure a uniform sensor supply voltage. Likewise, the sensor groups, as shown in FIG. 6 and FIG. 7, must be selected with the same component scatter values.

Figure 7 also relates to the sensor arrangement shown in Figure 6. It shows a simple possibility of variation as to how the evaluation unit 10 can be connected to known access control units and lock control units. This has the advantage that the evaluation unit can be used universally.

By means of the invention, a device for separating has now been created which, in addition to fulfilling all the functions of conventional devices, can not only be manufactured much more cost-effectively, has greater functional reliability and can be easily combined with almost all existing safety devices and structural conditions, but also by the risk that the unauthorized person and their necessarily authorized helper cannot be calculated when trying to overcome them, a significantly higher deterrent compared to the easily calculable conventional locks and thus more security against unauthorized entry.

Furthermore, the indispensable escape route or a widened transport route can be integrated without further effort.

Claims (2)

1. Equipment for ascertaining the number of persons and direction inside a room that is to be monitored or a transit gate with at least two infra-red sensors (S1 to Sn), and with an evaluation unit (10) to which the signals of the infra-red sensors (S1 to Sn) are fed and which, taking into account the sensor spacing, ascertains the number of persons passing through the transit gate and passes it on to an access controlling device (20) for further processing, characterised in that the infra-red sensors (S1 to Sn) ascertain the deviation of the ambient temperature with regard to the body-heat of the persons passing through, and in that at least two infra-red sensors (S1 to Sn) are arranged one after the other in the direction of passage and at least two infra-red sensors (S1 to Sn) are arranged side-by-side transversely to the passage direction, and in that, to detect a deceptive simultaneous access of more than one person, the temporal course, dependent upon the speed of the person or persons and the energy of the infra-red radiation, of the sensor signals is compared in an evaluation unit (10) with limiting values which are typical of a single person, with respect to amplitude course, duration of the signal and detected speed of the person.

2. Equipment according to claim 1, characterised in that the sensors (201 ... 205) are arranged asymmetrically to the passage direction, in which respect the sensors (204, 205) present on the side walls with a horizontal detection region have different spacings from the floor relative to the ceiling sensors (201 ... 203) with a vertical detection region.

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