GB2357363A

GB2357363A - Speed bump containing a camera for reading vehicle number plates

Info

Publication number: GB2357363A
Application number: GB9929871A
Authority: GB
Inventors: Graham John St Clair Assinder
Original assignee: Roke Manor Research Ltd
Current assignee: Roke Manor Research Ltd
Priority date: 1999-12-18
Filing date: 1999-12-18
Publication date: 2001-06-20
Also published as: GB9929871D0

Abstract

A speed bump 14 comprising an automatic number plate reading system 10 comprising illumination means (100 fig 3) for illuminating a predetermined field of view 18, imaging means, means for providing output signals indicative of the field of view and processing means to process said output signals. A sensor (10 fig 3) to sense movement of a vehicle over the speed bump may be included. The plate reading system and a power pack may be within pre-fabricated sections (220 fig 3) of the speed bump, the battery may be rechargeable by means of a solar panel (130 fig 3). A transmitter to transmit information relating to the output may be incorporated.

Description

2357363 IMPROVEMENTS IN OR RELATING TO NUMBER-PLATE READING SYSTEMS The

present invention relates to improvements in or relating to number-plate reading systems.

At present, automatic number-plate reading systems comprise cameras and illuminators located by the roadside. Installing such systems is complex and expensive, as it entails the installation of power and signal cabling. A suitable camera lens needs to be chosen for a particular field of view together with the provision of suitable illumination for that field of view.

Due to the complexity of such systems, it is necessary to carry out a thorough site survey prior to installing the system. Moreover, several man hours may be required to physically install the system and to optimise the parameters for the best performance of such a system.

It is therefore an object of the present invention to provide a simplified automatic number-plate reading system which overcomes the problems mentioned above.

In accordance with one aspect of the present invention, there is provided a 'speed bump' comprising a plurality of pre-fabricated sections and including an automatic number-plate reading system mounted in at least one of said pre-fabricated sections, the automatic number-plate reading system comprising: - illumination means for providing illumination for a predetermined field of view beyond the 'speed bump'; imaging means for imaging said predetermined field of view and for providing output signals indicative of said predetermined field of view at a predetermined instant in time; and processing means for processing said output signals and for providing an output indicative of said predetermined field of view.

Advantageously, the system further comprises sensor means for sensing movement of a vehicle over the 'speed bump', said sensor means initiating operation of said illumination means and said imaging means in response to said sensed movement. In a preferred embodiment of the present invention, said sensor means comprises a pressure sensor.

In one embodiment, the processing means initiates operation of said illumination means and said imaging means in response to said sensor means sensing movement of a vehicle over the 'speed bump'.

The system according to the present invention may further comprise energy storage means within one of said pre-fabricated sections for supplying energy to said automatic number-plate reading system. Said energy storage means may comprise a rechargeable battery pack. Additionally, the system further comprises solar panel means associated with one of said prefabricated sections and connected to supply energy to said rechargeable battery pack.

The automatic number-plate reading system may also comprise transmitter means for transmitting information relating to said output indicative of said predetermined field of view. Said transmitter means may comprise a radio transmitter.

In accordance with another aspect of the present invention, there is provided a kit of pre-fabricated sections for constructing a 'speed bump' as descnbed above.

For a better understanding of the present invention, reference will now be made, by way of example only, to the accompanying drawings in which:- 3 Figure 1 is an illustration of an automatic number-plate reading (ANPR) system in accordance with the present invention; Figure 2 is a block diagram of the system of Figure 1; and Figure 3 illustrates pre-fabricated sections which can be used with the system of Figure 1.

In Figure 1, an automatic number-plate reading (ANPR) system 10 in accordance with the present invention is shown. The system 10 is housed in a pre-fabricated section 12 of a 'speed bump' 14. Processing apparatus (not shown) may also be housed in section 12. The processing apparatus may also be housed in another adjoining pre-fabricated section (not shown) of the speed bump' 14. In this case, connectors (not shown) are provided on the adjoining sections for providing connections therebetween. Ideally, the speed bump' 14 can be constructed to be any suitable width across a road 16, that is, the 'speed bump' 14 may extend across the entire road or only a part of the road 16. ('Speed bumps' are currently applied across the whole road where the road does not form part of a bus route. If the road lies on a bus route, the 'speed bumps' only extend across the road in sections leaving regions through which the wheel of a bus can pass without going over the speed bump' section.) The system 10 comprises a camera unit and an illuminator unit (shown in more detail in Figures 2 and 3) which have a field of view 18 which extends a predetermined distance, d, beyond the 'speed bump' 14 and has an angle of elevation, a, which is chosen to encompass at least the height, h, of an average number-plate 20 located on the rear 22 of a car 24 which has passed over the 'speed bump' moving in the direction indicated by arrow 26.

It will, of course, be appreciated that the height of a number-plate from the surface of a road may vary from vehicle to vehicle, and ideally, the field of view 18 is chosen to include the maximum number of vehicles.

As the car 24 drives away in the direction of arrow 26, the system 10 will have an excellent view of the number-plate and will be set up to read the number-plate at distance, d, for example. However, any other suitable distance which is less than d can also be employed.

It will be appreciated that the imaging distance in the ANPR system in accordance with the present invention is very short compared to existing ANPR systems. This has the advantage that the illuminators need not be of high power, and an array of light-emitting diodes (LEDs), for example, may meet the illumination requirements of the system when installed in the 'speed bump'. Naturally, the choice of illumination will be made to be compatible with the camera being employed.

Turning now to Figure 2, an ANPR system 10 is shown which comprises an illuminator unit 100 and a camera unit 102. Both the illuminator unit 100 and the camera unit 102 are connected to a processor unit 104 via respective connections 106, 108. Also connected to the processor unit 104 is a sensor unit I 10 via connection 112, and a transmitter unit 114 via connected 116. The illuminator unit 100, camera unit 102, processor unit 104, sensor unit I 10 and transmitter unit 114 are connected to a battery pack 118 via respective electrical connections 120, 122, 124, 126, 128 as shown. Also connected to the battery pack 118 is a solar panel 130 via connection 132.

Processor unit 104 provides signals for the illuminator unit 100 under predetermined conditions so that the illuminator unit 100 illuminates the field of view 18 as shown in Figure 1. In the illustrated embodiment, the sensor unit I 10 operates to detect when a vehicle has passed over a 'speed bump' section (not shown) in which it is housed and to provide a control signal on line 112 for the processor unit 104. Alternatively, the sensor unit I 10 may provide its control signal directly to the illuminator unit 100 as indicated by dotted line connection 134. In the latter case, connection 112 may not be required.

As discussed above, the illuminator unit 100 may comprise an array of LEDs arranged to illuminate the field of view 18 (Figure 1). However, any other suitable low power light source could also be employed.

Camera unit 102 may comprise a digital camera which provides digital signals at its output. Other suitable imaging devices could also be used.

Preferably, processor unit 104 comprises a microprocessor which functions to receive signals from the sensor unit 110 for relaying to the illuminator unit 100, to receive signals from the camera unit 102, to process any signals received and to provide control signals for the illuminator unit 100, the camera unit 102 and the transmitter unit 114. The processing unit 104 may also comprise a memory unit (not shown) for storing the received signals prior to their being accessed or being transmitted.

Sensor unit I 10 may comprise any suitable sensor for determining when a vehicle has crossed the 'speed bump'. For example, the sensor unit may comprise a pressure sensor which detects the pressure of vehicle tyres passing over it.

Transmitter unit 114 may comprise a radio transmitter for transmitting information relating to the vehicle number-plates recorded by the camera unit 102 to a base station (not shown). Alternatively, the transmitter unit 114 can be accessed locally to download the information.

Battery pack 118 may comprise a suitable rechargeable battery which stores energy for powering the units as described above, energy being supplies to the rechargeable battery from the solar panel 130. Alternatively, battery pack 118 may be a long life battery if the ANPR system of the invention is only to be installed for relatively short periods of time. By utilising battery packs, there is no requirement to run power cables to the ANPR system. However, if the location is suitable for running power cables, only a single cable would be required for supplying power into the system and for retrieving information from the system.

Solar panel 130 may be of any suitable construction.

In the illustrated embodiment, connection 106 connects the illuminator unit 100 to the processor unit 104 and transmits control signals from the processor unit 104 to the illuminator unit 100 to active it for illuminating the field of view 18, but as discussed above the control signal for activation of the illuminator unit 100 may be sent directly from the sensor unit 110 on connection 134.

Connection 108 is shown as a two-way connection. Naturally, this connection may comprise two separate connections. Connection 108 transmits a control signal from the processor unit 104 to the camera unit 102 to initiate its operation at a suitable time after a vehicle has triggered the sensor unit 110. The operation of the camera unit 102 may be timed in relation to the operation of the illumination unit 100 or in relation to triggering: of the sensor unit 110. The operation of the camera unit 102 may also be controlled directly by the illuminator unit 100 via a further connection (not. shown).

Connection 108 also transfers signals from the camera unit 102 corresponding to the image of a vehicle number-plate to the processor unit 104. The signals may comprise digital signals.

Although a separate processor unit 104 is shown, it will readily be appreciated that the illuminator unit 100, camera unit 102, sensor unit 110 and transmitter unit 114 may each have its own dedicated processor unit. In this: case, processor unit 104 may not be required.

It may also be possible to combine the battery pack 118 with the processor unit 104 to reduce the number of connections required.

Figure 3 shows three pre-fabricated 'speed bump' sections 200, 2 10, 220 which when assembled forin 'speed bump' 14 (Figure 1). Components which have previously been described bear the same reference numerals.

Section 200 comprises the section housing the illuminator unit 100 and camera unit 102. In this embodiment, the illuminator unit 100 comprises two rows 202, 204 of LEDs. Section 210 houses the solar panel 130 and is connected to section 200 by connectors (not shown). Section 220 is a plain section which does not house any components. This section is the one which is used to extend the 'speed bump' to the desired width.

The ANPR system in accordance with the present invention has the advantage that the specification for the system is much simplified over known ANPR systems. The width of the road and the number of traffic lanes can readily be specified and the 'speed bump' constructed from any suitable combination of pre-fabricated sections 200, 210, 220 described above.

Installation of an ANPR system according to the present invention is also simplified. The pre-fabricated sections can be bolted together to the desired width and then fixed to the road as a complete unit.

The system could be made to have a 'standby' mode in which it consumes very little power, only powering up into an operational mode when a vehicle drives over the 'speed bump'. A system having a 'standby' mode could readily be adapted for operation under battery-power as described above with reference to Figure 2.

As the sections are pre-fabricated, manufacturing costs can be substantially reduced enabling an ANPR system according to the invention to be supplied relatively cheaply.

Claims

CLAIMS:

1. A 'speed bump' comprising a plurality of pre-fabricated sections and including an automatic number-plate reading system mounted in at least one of said pre-fabricated sections, the automatic number-plate reading system comprising:- illumination means for providing illumination for a predetennined field of view beyond the 'speed bump'; imaging means for imaging said predetennined field of view and for providing output signals indicative of said predetermined field of view at a predeten-nined instant in time; and processing means for processing said output signals and for providing an output indicative of said predetermined field of view.

2. A 'speed bump' according to claim 1, further comprising sensor means for sensing movement of a vehicle over the 'speed bump', said sensor means initiating operation of said illumination means and said imaging means in response to said sensed movement.

3. A 'speed bump' according to claim 2, wherein said sensor means comprises a pressure sensor.

4. A 'speed bump' according to claim 2 or 3, wherein said processing means initiates operation of said illumination means and said imaging means in response to said sensor means sensing movement of a vehicle over the speed bump'.

5. A 'speed bump' according to any one of the preceding claims, further comprising energy storage means within one of said pre-fabricated sections for supplying energy to said automatic number-plate reading system.

6. A 'speed bump' according to claim 5, wherein said energy storage means comprises a rechargeable battery pack.

7. A 'speed bump' according to claim 6, further comprising solar panel means associated with one of said pre-fabricated sections and connected to supply energy to said rechargeable battery pack.

8. A 'speed bump' according to any one of the preceding claims, further comprising transmitter means for transmitting information relating to said output indicative of said predetermined field of view.

9. A 'speed bump' according to claim 8, wherein said transmitter means comprises a radio transmitter.

10. A kit of pre-fabricated sections for constructing a 'speed bump' according to any one of the preceding claims.

11. A 'speed bump' substantially as hereinbefore described with reference to the accompanying drawings.

12. A kit of pre-fabricated sections substantially as hereinbefore described with reference to the accompanying drawings.