EP0856826A2

EP0856826A2 - A security system

Info

Publication number: EP0856826A2
Application number: EP98300802A
Authority: EP
Inventors: Neil James Stevenson; Jonathan Richard Raphael Martin
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-02-04
Filing date: 1998-02-04
Publication date: 1998-08-05
Also published as: EP0856826A3

Abstract

A security system 10 comprises a sensor array 20 which includes, for example, a motion sensor, a thermal sensor and a camera, a control unit 18 which includes a microprocessor arranged to receive data from sensors and to determine whether the data received from the sensors constitutes a threat. The microprocessor can provide an alert to an operator on determination of a threat. The microprocessor includes neural net software which automatically re-defines the threat parameters stored in the memory of the microprocessor if the operator identifies a false threat.

According to another aspect of the invention, a vehicle logging system is provided comprising a camera 114 for recording an image of the registration mark of the vehicle entering an area, and optical camera recognition means, for example, a computer with image processing software, for identifying the vehicle registration mark from the image recorded on the camera 114. A microprocessor stores details of the vehicle registration mark of the vehicle and also details of a transaction conducted by the vehicle within the aforesaid area. The system is especially useful for eliminating fraud at waste disposal sites by keeping a log of vehicle transactions which can be checked against the registration marks of the vehicle that have been on site on a particulat day (Figure 5).

Description

The invention relates to a security system and in particular to a security system connected to one or more units for monitoring by an operator especially for use on a remote site, such as a waste disposal site.

The use of security systems to monitor areas and to sense the presence of an unwanted intruder is known and used in conventional alarm systems. Many alarm systems are now connected to a central control unit and monitored by an operator who can alert the emergency services in the event of an unwanted intruder. Also, the security systems in large buildings often comprise closed circuit cameras for monitoring public areas which are connected to a central unit for monitoring by a security operative. However, those systems suffer the drawback that an operative must pay attention to all of the screens displaying information at any one time and over the course of a shift, an operator may experience lapses of concentration, allowing potential threats to go unnoticed. Alternatively, when alarm systems involve triggering mechanisms, they are vulnerable to an impracticably high level of false alarms, particularly in outdoor locations where animals may trigger the alarm.

It is an object of the present invention to provide a security system which lessens the chance of a threat going unnoticed and which results in a lower level of false alarms.

According to a first aspect of the invention there is provided a security system comprising a sensor for sensing an event, a control unit having at least one threat parameter for determining whether a sensed event constitutes a threat, the control unit being connected to the sensor and switchable to an alert condition from an idle condition on determination of a threat, the control unit having feedback control means whereby the threat parameters can be re-defined by an operator if the operator identifies a false threat.

In that way the system can "learn" to distinguish between a false alarm and a genuine threat. That is advantageous as the system can be left to determine whether an event constitutes a threat without occupying an operator. In that way an operator can monitor systems more effectively and, as the burden on operators is reduced, more sites can be monitored by fewer operators.

The sensor may comprise a camera. The camera may receive images in the visible light band or in the infra-red energy band. Where a camera is provided, the image received by the camera is monitored by the control unit and the control unit determines whether the image constitutes a threat. The control unit processes the data from the sensor and where the sensor is a camera, the control unit preferably includes image processing means, preferably digital image processing software, to perform the evaluation of whether a monitored image constitutes a threat.

Alternatively, the sensor may comprise inter alia a thermal sensor, a sound sensor, a motion sensor or a pressure pad.

Preferably an array of two or more sensors is provided. Where a camera is provided, in addition to another form of sensor, the other sewer may be arranged to activate the camera. In that way, the other sensor can be left monitoring an area permanently and the camera is only activated when the sensor senses something unusual. That provides power saving benefits for remote units which require a self contained power supply.

In one embodiment the sensor is housed in a remote unit at a remote area to be monitored and the control unit is located at a central monitoring location, the sensor being connected to the control unit by any suitable means. In another embodiment, the sensor and control unit are both housed in a remote unit at the remote location and are connected to the central monitoring location by any suitable means. The aforesaid connection may be effected by a hard wire ie analogue or ISDN telephone line. In another embodiment the connection may be a wireless connection, for instance by means of a modem and mobile telephone connection. In the case where the sensor is located at the remote location and the control unit is located at the central monitoring location, the connection is preferably a hard wired connection while in the case where the sensor and control unit are located remote from the central monitoring location the connection is most preferably effected by means of a modem and mobile phone at each location.

The remote unit may be powered by battery power, solar power or by mains power or another suitable power source or by a combination of power sources.

The remote unit may include means for illuminating the area to be monitored either by visible light or by infra-red light.

The remote unit is preferably enclosed in a casing. The casing should be sturdy and is preferably vandal proof.

The remote unit may include an anti-tamper device. The anti-tamper device may comprise a sensor for sensing physical interference with the remote unit, for instance a trembler switch. The sensor may alert the central monitoring unit that the remote unit is being tampered with. The anti-tamper device may further include an audible and/or visible alarm and, in a preferred embodiment, means for dispensing a marker substance on to a person who is tampering with the unit. The marker substance may be brightly coloured or may be visible only in UV light. The interior of the casing may include means for maintaining a suitable environment, for instance a heater and a de-humidifier.

Where a camera is provided, the camera may be mounted on a movable mounting to allow the camera to scan a wider area with normal tilt/zoom capability. The movable mounting may be motorised and the movement of the camera is preferably controlled by an operator at the central monitoring location. The camera control may be achieved using a mirrored image and manipulation of the mirrors and/or camera.

The remote unit may include a position indicating device, for instance a GPS device, which indicates the location of the unit to the monitoring centre.

The threat parameters may be altered manually or automatically. Preferably the feedback control means includes a program, most preferably a neural net system implemented either by software or hardware which receives data from the sensor and from the operator to re-define the threat parameters. Neural net software may be extremely useful in this application as it can allow the system to "learn" to recognise a threat without the threat parameters having to be understood by the operator and re-defined manually. Depending upon the intended application of the security system, the program, such as a neural net can operate on different levels of complexity of threat parameters. For instance, in an application to prevent fly-tipping, the threat parameter could simply be the detection of a vehicle which is stationary for a pre-determined period of time. In this, and other situations, the sensor unit could be programmed to distinguish general characteristics, such as humans and animals or to recognise individual characteristics such as a specified vehicle registration number using optical character recognition.

The remote unit may include means for allowing legitimate access to a monitored area, for instance by means of a keypad for keying in a user code or by means of a magnetic swipe card to avoid false atoms. An intercom to the central monitoring unit may also be provided.

The sensor may detect the presence of a vehicle. The threat parameter may be the presence of a vehicle. As mentioned above, the system may be equipped with a camera and optical character recognition means to log the registration mark of the vehicle. The threat parameter may be a particular registration mark. For example, where particular vehicles are known to constitute a threat the system may identify the vehicle and restrict entry or, at least, alert an operative to monitor vehicle activities.

On waste disposal or transfer sites it is usually necessary for a vehicle depositing waste to be weighed at a weighbridge on entry to the site and on leaving the site in order to determine the amount of waste that has been deposited in order to levy a charge. In many waste disposal or transfer sites the entrance to the site is located some distance from the weighbridges which are located within the site. Accordingly, there is usually some time between the vehicle entering the site and the vehicle passing over the weighbridge. Also, the weighbridge can be by-passed by the vehicle driver or the weighbridge operator can allow the vehicle over the weighbridge without logging the weight in order to avoid payment of the charge for depositing the waste. In such a case, the security system can be arranged at the entrance to a waste disposal site and vehicles entering the site can be identified. The threat parameter in that case could be the entry of the vehicle, the identity of the vehicle, or a time limit from entry of the vehicle to its departure. Further threat parameters such as an unexpected difference in vehicle weight between entry and departure or the identity of the vehicle load are also envisaged. Where the system includes a camera and optical character recognition means, the system can be arranged to recognise the load identification signs carried by haulage vehicles and to alert an operator if certain load types, such as noxious chemicals, are detected.

The control unit may also associate details of a transaction conducted in relation to the vehicle within the site with the registration of the vehicle. If an incorrect transaction is noted an operator can be alerted.

According to a second aspect of the invention there is provided a vehicle logging system comprising a camera for recording an image of the registration mark of a vehicle entering an area, optical character recognition means for identifying the vehicle registration mark from the image recorded by the camera and a control unit which associates details of a transaction conducted by the vehicle within the aforesaid area with the registration mark of the vehicle.

In that way a log of vehicle transactions can be established and mistaken or fraudulent transactions can be identified and associated with a vehicle. This is of particular use to the aforementioned landfill site where a daily log of vehicle entry and exit activity can be compared with a register of transactions to determine whether the transaction is correct. Incorrect or fraudulent transactions can then be associated with a particular vehicle.

A sensor may be provided to activate the camera, the sensor sensing passage of the vehicle through the entry to the area. The sensor may be pressure pad or a light sensor.

The optical character recognition means preferably comprises a computer with image processing software and optical character recognition software. The computer preferably also comprises the control unit.

According to a third aspect of the invention there is provided a security system comprising a sensor for sensing the presence of a vehicle, a camera activated by the sensor when a vehicle is sensed for recording an image of the registration mark of the vehicle, optical character recognition means for identifying the vehicle registration mark from the recorded image and a control unit which associates details of a transaction conducted in relation to the vehicle with the registration mark of the vehicle, the control unit including at least one threat parameter for determining whether an event related to the vehicle constitutes a threat, the control unit being switchable from an idle condition to an alert condition on determination of a threat and the control unit having feedback control means whereby threat parameters can be redefined by an operative if a false threat is identified.

In a preferred embodiment of either of the second or third aspects, the logging system is used in combination with a weighbridge. In that case, the system may comprise a camera at a controlled access point, such as the entry to the site and a camera or cameras at each weighbridge on the site, each camera recording an image of the registration of the vehicle and passing the image to optical character registration means for identifying the vehicle registration mark. In a preferred embodiment the system includes sensors for detecting whether the vehicle is aligned correctly on the weighbridge. The sensors may comprise light sensors or pressure pads. Also, image processing means may be provided to process the image from the camera at the weighbridge to further determine correct alignment of the vehicle on the weighbridge. In some circumstances, it is possible to reduce the charge levied for disposal of waste by incorrectly placing the vehicle on the weighbridge. For example, by leaving the back wheels of the vehicle off the weighbridge a proportion of the weight of the vehicle is not supported on the weighbridge and thus the vehicle weight will be under measured. The sensors and image processing means are intended to prevent such fraudulent activity. In that way fraudulent use or avoidance of the weighbridge altogether can be detected.

Normally, vehicles approach a weighbridge, are aligned on the weighbridge and then the weighbridge operator presses a button on the weighbridge control to cause a weight measurement to be forwarded to a transaction printing system. The operator also enters the vehicle details including the vehicle registration number to identify the vehicle and associate it with a transaction. With the present system, the camera at the weighbridge reads the vehicle registration number and compares it with the details entered by the operator. If any discrepancies occur then the image recorded by the camera, together with the transaction details are transmitted to a remote site and, if necessary, are brought to the attention of the site operator.

In a preferred embodiment two cameras are provided at the weighbridge, the cameras being arranged to view the edges of the weighbridge. In that way the cameras together with appropriate image processing software in the control unit can check for incorrect alignment of the vehicle on the weighbridge, record the vehicle registration information by optical character recognition software and the details of the fraudulent transaction and vehicle details can be passed to an operator at a remote site. The operator can then determine the appropriate action required. Such action might be to require the vehicle to be weighed again or to report the fraudulent transaction to the site operator. The logging system is preferably connected to the remote site via a modem and mobile telephone connection but any appropriate data transfer equipment such as ground telephone line or direct hard-wired connection can be used. One of the cameras or a further camera can be arranged to view the sign on the vehicle which indicates the nature of the goods carried and the control unit can be arranged to recognise that data and make an appropriate log.

A timer may be provided to detect the time a vehicle takes between entering the site and reaching the weighbridge. If a vehicle has not reached the weighbridge a pre-determined time after entering the site then the vehicle may have taken a detour to avoid using the weighbridge. An alarm can be raised by the control unit to alert the site operators of that possibility.

A camera may be provided on the exit to the site, again to determine whether the vehicle has been weighed on exiting the site and to ensure that all vehicles that have entered a site on a particular day have left.

In a preferred embodiment, the system will allow operation of a weighbridge at a site, such as a landfill site, without the need for a weighbridge operator. The type of load carried by the vehicle onto the site in the case of waste disposal, or off the site in the case of a quarry site will, in conjunction with the weight of the load, determine the transaction price. This is best identified by a person at the point of loading or unloading who, with a suitable mobile computer unit may enter the load type identification for inclusion in the transaction record. The entry of the vehicle to the site will be logged as previously described. The correct inbound weight is verified as previously described. The control unit will transmit the initiated transaction to the remote operator at the loading or unloading area of the site. When this operator enters the load type identification, this information is transmitted back to the control unit which, when followed by a verified outbound transaction, will allow the automatic production of a transaction ticket, for collection by the driver before leaving the site.

The control unit may include a memory area for exempted vehicle registrations, such as visitors cars etc.

According to a fourth aspect of the invention there is provided a vehicle logging system comprising a first camera for recording an image of a registration mark of a vehicle on entering an area, optical character recognition means for identifying the vehicle registration mark from the image recorded by the first camera, a second camera for recording an image of a registration mark of a vehicle on exiting the aforesaid area, optical character recognition means for identifying the vehicle registration mark from the image recorded by the second camera and a control unit which records the time between entry of the vehicle to the area and exit of the vehicle from the area.

In that way a ticketless car parking system is provided whereby the exact time that a vehicle has been in a car park can be recorded and charged for, or by the same identifying means, access to an area such as a car park can be restricted to authorised vehicle numbers only, without the need for keys, swipe cards etc.

In a preferred embodiment the control unit can provide an alert where a vehicle has been within the area longer film a predetermined amount of time, say 24 hours. In such a circumstance, the control unit could alert the car park attendant and/or the emergency services.

A security system in accordance with the invention will now be described in detail with reference to the accompanying drawings in which;

Fig 1 is a block diagram of a security system in accordance with the invention,

Fig 2 is a block diagram of a first remote unit for use in the system shown in figure 1,

Fig 3 is a block diagram of a second remote unit for use in the system in figure 1,

Fig 4 is a block diagram of a central monitoring unit in the system of figure 1,

Fig 5 is a schematic diagram of a first vehicle logging system in accordance with the second and third aspects of the invention;

Fig 6 is a schematic diagram of a second vehicle logging system in accordance with the second, third and fourth aspects of the invention; and,

Fig 7 is a plan view of a restricted access point for use with the invention.

In Fig.1 a security system 10 comprises a monitoring centre 12 connected to

remote units

14,16. The remote unit 14 communicates with the monitoring centre 12 via a hard wire, for balance a telephone ground line. The remote unit 16 communicates with the monitoring centre 12 by means of a wireless link, for instance via a modem and mobile telephone connection.

The remote unit 14 is shown in more detail in fig.2. The remote unit 14 comprises a control unit 18, for instance a microprocessor, a sensor array 20 connected to the control unit 18 and to a video camera 22. In another embodiment (not shown) the remote unit 14 could be a portable computer which is in remote communication with the control unit 18. The computer could be carried by an operative at a remote site to log details of the site. For example, where the system is used on a waste disposal site the operative can log details of the loads being dumped by vehicles so that correct charges can be levied.

The camera 22 is connected to the control unit 18 and to a video recorder 24 which is arranged to record the images received by the camera 22. Alternatively, the images may be recorded directly into the control unit 18.

A climate control system 26 is provided comprising a heater/air conditioner 28 and a dehumidifier 30. The climate control 26 is connected to the control unit 18.

An anti-tamper device 32 is connected to the control unit 18.

A position indicator, in this case a global positioning system device 34 (GPS device) is connected to the control unit 18.

The remote unit 14 is surrounded by a strong vandal proof casing 36.

The sensor array 20 comprises a motion sensor, for instance a radar sensor or ultrasound sensor, a noise sensor, for instance a microphone, and a thermal sensor, for instance a passive infrared sensor (PIR). The sensor array 20 is connected to the camera 22 and, on sensing an "event", i.e. something unusual, the array 20 passes sensor data to the control unit 18 which activates the camera 22.

The camera 22 is arranged to monitor a specified area. The camera 22 may operate in the visible or infrared light ranges. Separate illumination (not shown) in the appropriate frequency range may be provided. Alternatively, an image intensifier can be provided to allow the camera to pick up images in low light conditions. The image received by the camera may be recorded by the recorder 24 and is also passed to the control unit 18. The control unit 18 receives the image data, together with the sensor data from the array 20. The control unit 18 applies the image data and sensor data to preset threat parameters to determine whether the "event" constitutes a "threat". If a "threat" is determined then the image and sensor data are transmitted to the central monitoring centre 12 via a telephone line 38. The monitoring centre 12 will be described in more detail in relation to fig.4.
The casing 36 is vandal proof and the interior of the casing is maintained at an appropriate temperature and humidity by the climate control system 26. The control unit 18 may include a humidity sensor and a thermometer to gauge the climatic conditions inside the casing 36 and direct the climate control system 26 accordingly.

The anti-tamper device 32 comprises a trembler switch 40 which signals the control unit 18 when physical interference with the remote unit 14 is sensed. The control unit 18 can then alert the monitoring centre 12 and initiate a local audio and visual alarm 42 and a marking spray 44. The marking spray is arranged to coat the clothes and skin of a vandal with an indelible chemical which is either brightly coloured or visible under UV light.

The remote unit 14 also includes a GPS device 34 so that, in the event that the monitoring centre 12, either due to a sensed threat or to vandalism of the remote unit, the position of the unit is displayed to the operator. That position can be provided in the form of a map grid reference which is helpful for the emergency services when attempting to idendify remote locations. GPS devices can provide accurate location of an object to a range of approximately five metres.

The remote unit 14 is powered by a mains electricity supply 46.

Fig. 3 shows the remote unit 16. The remote unit 16 is substantially similar to the unit 14 shown in fig.2. Parts in fig.3 corresponding to parts in Fig.2 carry the same reference numerals.

The remote unit 16 comprises, as with the unit 14, a control unit 18, a sensor array 20, a video camera 22, a video recorder 24, a climate control system 26, an anti-tamper device 32 and a GPS device 34. However, in the remote unit 16, the control unit 18 communicates with the monitoring centre 12 by means of a modem 48 and mobile telephone 50.

Also, the unit 16 is powered by a combination of solar power via solar cell 52 and battery power via a battery 54. The advantage of that arrangement is that the unit 16 is a "stand alone" system which cannot be prevented from transmitting data by, e.g. cutting telephone wires.

Fig. 4 illustrates the arrangement at the monitoring centre 12. The monitoring centre 12 has incoming direct telephone lines 38 and modems 48 and/or mobile telephones 50 and modems 48 for each remote unit 14 and/or 16. The telephone line 38 and mobile phones 50 transmit and receive data between the

remote units

14,16 and a central control system 56. The central control system 56 processes the data received from the

remote units

14,16 and displays the data to an operator on a display 58. The display 58 is preferably part of a PC, allowing the operator to interface with the control system 56 via the PC. The operator can then identify real and false threats and direct action accordingly.

As the operator only needs to monitor remote locations where a threat has been identified, the workload per remote location is reduced, allowing operator to monitor more sites with less chance of missing a potential threat.

If an operator identifies a genuine threat he can direct the information from the remote location to the appropriate body, e.g. the fire brigade or the police. Also, where a threat is correctly identified then the data associated with a genuine threat is logged by the central control system 56 and retransmitted to the appropriate

remote unit

14,16. That data is recorded in the control unit 18 so that the stored threat parameters in the control unit 18 can be updated.

If the operator identifies a false alarm, the data is passed to the central control system 56 which, in turn notifies the appropriate

remote unit

14, 16. That data, is then logged in the control unit 18, of the

remote unit

14, 16 so that the threat parameters in the control unit 18 can be adjusted accordingly.

By using software such as neural network software in the control units 18, the control units and respective

remote units

14, 16 "learn" the threat parameters appropriate to that location.

For example, in the case of a system set up to prevent fly tipping, the initial threat parameter could be the presence of a vehicle (which might be indicated by an unusual video image greater than a certain size). Obviously, initially, the system would cause false alarms as cars passed by the monitored location. However, over time, and after repeated false alarms, the system would learn that the parameters for a genuine threat constituted a vehicle stopping for a predetermined period of time. With a sophisticated system the software may learn to distinguish a vehicle stopping for a predetermined period of time without anyone leaving the vehicle and a genuine fly tipping threat where perpetrators leave their vehicle to unload waste or respond to a specified vehicle characteristic (eg the registration number of the vehicle by optical character recognition).

The advantage of the neural net device is that operators who are unskilled in re-programming the security system can operate the system and allow the threat parameter to be re-adjusted automatically. Obviously, that reduces the cost of re-programming the security system to reduce false alarms.

In Fig 5 a vehicle logging system 110 comprises a control unit 112 in the form of a computer. The computer 112 is connected to a video camera 114 which is arranged to film the registration plates of vehicles entering a waste disposal site. The camera 114 is activated by a sensor 116 which detects the passage of vehicles entering the site. The image recorded by the camera 114 is recorded by image processing software in the computer 112 and the vehicle registration number is identified by optical character recognition software. The vehicle registration number is logged in the memory of the computer 112. The computer sets a timer running for that particular vehicle to determine the time taken for the vehicle to reach a weighbridge 118 from the entry. If the vehicle takes longer than a predetermined time to reach the weighbridge 118 then an alarm signal is raised by the computer 112. Alternatively, a barrier may be provided whereby actuation of the barrier initiates the camera 114.

The system 110 further comprises a pair of cameras 120a, 120b arranged at diagonally opposing corners of the weighbridge 118 to film the registration plate of a vehicle at the weighbridge 118 and to confirm that the vehicle is correctly aligned on the weighbridge. Sensors are provided at the weighbridge to check further that the vehicle is correctly aligned on the weighbridge 118. In the embodiment illustrated in Fig 5 the sensors comprises light source and

light detector pairs

122a, 122b, 124a, 124b, 126a, 126b and 128a, 128b. The light source and detector pairs are connected to a common bus 130 which carries the signals from the sensors to the computer 112. In the event that the vehicle is incorrectly aligned on the weighbridge 118, one of the light paths shown in dotted lines in Fig 5 between the respective light source and detector pairs will be broken. That will be registered by the computer 112 which will alert the weighbridge operator or remote site operative to the fact and also log the incorrect alignment in its memory. The weighbridge 118 will not be allowed to provide a measurement of weight until the vehicle is correctly aligned. In the event that the weighbridge provides an incorrect value for the weight of the vehicle for any reason the registration of the vehicle is logged by the camera 120 so that the mistake can be corrected. Mistaken or potentially fraudulent transactions can be notified by the control unit 112 to a remote site (not shown). Operatives at the remote site can then determine the appropriate course of action. The "threat parameter" of the control unit 112 could be the presence of the vehicle, the entry of the vehicle to the site, the time that the vehicle has spent on the site, the weight of the vehicle on entry to the site or on exiting the site or the difference between those two values, or even the type of load carried by the vehicle.

A further camera (not shown) can be provided at the exit of the site to ensure all of the vehicles that have entered the site during the day have left the site when the site closes.

In Fig 6 a vehicle logging system 132 for use in a car park is shown. Parts corresponding to parts in Fig 5 carry the same reference numerals. The vehicle logging system 132 comprises a computer 112 which controls the system. The computer 112 is linked to a video camera 114 which is arranged to film the registration plates of vehicles entering a car park. The camera is linked to a barrier 134 which includes a light sensor (not shown) which detects the presence of a vehicle. The camera 114 films the vehicle and then the barrier is raised to allow the vehicle into the car park.

The system further includes a camera 136 arranged to film the registration of a vehicle approaching an exit barrier 138. A sensor may be provided to activate the camera 136. When the camera 136 is activated, a signal is provided to the computer which logs the registration plate and determines the time between entry and exit of the vehicle. A charge appropriate to the length of stay can be then be displayed on a display screen on the barrier 138 and the barrier 138 can be activated by payment.

The computer 112 preferably also includes the function of providing an alarm signal when a vehicle has entered the car park and has not left the car park after a pre-determined time. This helps to determine whether vehicles have been abandoned and whether there is a security risk due to an abandoned vehicle.

The system can be used in private car parks to allow entry of authorised vehicles only.

Fig 7 shows a restricted access point 140 for use with the invention. The restricted access point 140 comprises an entry 142 defined in, e.g. a fence. The entry 142 has a central reservation 144 and two

barriers

146, 148 extending in opposite directions from the central reservation 144 to close the entry 142. The central reservation 144 includes a housing 150 which has, on each side thereof, a sensor 152 for sensing the presence of a vehicle and a camera 154 for filming the vehicle.

Whilst the system has been described as applied to a waste disposal/transfer sites and car parks, it can be applied to any restricted area where vehicle transactions need to be logged.

The cameras could be video cameras, closed circuit television cameras or digital still cameras.

Claims

A security system comprising a sensor for sensing an event, a control unit having at least one threat parameter for determining whether a sensed event constitutes a threat, the control unit being connected to the sensor and switchable to an alert condition from an idle condition on determination of a threat, the control unit having feedback control means whereby the threat parameters can be re-defined by an operator if the operator identifies a false threat.
A security system according to clam 1 in which the sensor comprises a camera and the image received by the camera is monitored by the control unit to determine whether the image constitutes a threat.
A security system according to claim 2 in which the control unit includes image processing means.
A security system according to claim 3 in which the image processing means includes optical character recognition means.
A security system according to claim 1 in which the sensor comprises one of a thermal sensor, a sound sensor, a motion sensor or a pressure pad.
A security system according to any preceding claim in which an array of two or more sensors is provided.
A security system according to claim 6 in which one of the sensors is a camera, the other sensor or sensors being arranged to activate the camera.
A security system according to any preceding claim in which the sensor or array of sensors is housed in a remote unit at a remote area and the control unit is located at a central monitoring location, the remote unit being connected to the central location by any suitable means.
A security system according to any preceding claim in which the threat parameters are altered automatically.
A security system according to claim 9 in which the feedback control means includes a neural net system which receives data from the sensor or sensors and from the operator to re-define the threat parameters where appropriate.
A security system according to claim 8 in which the remote unit includes means for allowing legitimate access to a monitored area.
A vehicle logging system comprising a camera for recording an image of the registration mark of the vehicle entering an area, optical character recognition means for identifying the vehicle registration mark from the image recorded by the camera and a control unit which associates details of a transaction conducted by the vehicle within the aforesaid area with the registration mark of the vehicle.
A security system comprising a sensor for sensing the presence of a vehicle, a camera activated by the sensor when a vehicle is sensed for recording an image of the registration mark of the vehicle, optical character recognition means for identifying the vehicle registration mark from the recorded image and a control unit which associates details of a transaction conducted in relation to the vehicle with the registration mark of the vehicle, the control unit including at least one threat parameter for determining whether an event related to the vehicle constitutes a threat, the control unit being switchable from an idle condition to an alert condition on determination of a threat and the control unit having feedback control means whereby threat parameters can be re-defined by an operative if a false threat is identified.
A security system according to any of claims 1-11 or 13 in which the threat parameter is one or more of sensing the vehicle entry to a site, the identity of a vehicle, the time the vehicle has spent on the site, the weight of the vehicle on entry to the site, the weight of the vehicle on leaving the site, the difference between the entry weight and the exit weight of the vehicle, the type of load carried by the vehicle, an incorrect transaction logged by the vehicle or incorrect alignment of the vehicle on a weighbridge.
A vehicle logging system according to claim 12 in which a sensor is provided for ensuring correct alignment of a vehicle on a weighbridge located at the entry to an area.
A security system according to claim 13 in which a sensor is provided for ensuring correct alignment of a vehicle on a weighbridge.
A vehicle logging system according to claim 12 in which an operator is located within the area and the operator can input details of the load carried by the vehicle into a mobile computer and the data can be transmitted to the control unit.
A vehicle logging system comprising a first camera for recording an image of a registration mark of a vehicle on entering an area, optical character recognition means for identifying the vehicle registration mark from the image recorded by the first camera, a second camera for recording an image of a registration mark of a vehicle on exiting the aforesaid area, optical character recognition means for identifying the vehicle registration mark from the image recorded by the second camera and a control unit which records the time between entry of the vehicle to the area and exit of the vehicle from the area.