GB2265243A - Apparatus for determining a vehicle registration code - Google Patents
Apparatus for determining a vehicle registration code Download PDFInfo
- Publication number
- GB2265243A GB2265243A GB9305762A GB9305762A GB2265243A GB 2265243 A GB2265243 A GB 2265243A GB 9305762 A GB9305762 A GB 9305762A GB 9305762 A GB9305762 A GB 9305762A GB 2265243 A GB2265243 A GB 2265243A
- Authority
- GB
- United Kingdom
- Prior art keywords
- image
- registration code
- vehicle
- code
- plaque
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08G—TRAFFIC CONTROL SYSTEMS
- G08G1/00—Traffic control systems for road vehicles
- G08G1/01—Detecting movement of traffic to be counted or controlled
- G08G1/017—Detecting movement of traffic to be counted or controlled identifying vehicles
-
- G—PHYSICS
- G06—COMPUTING OR CALCULATING; COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V10/00—Arrangements for image or video recognition or understanding
- G06V10/20—Image preprocessing
- G06V10/24—Aligning, centring, orientation detection or correction of the image
-
- G—PHYSICS
- G07—CHECKING-DEVICES
- G07B—TICKET-ISSUING APPARATUS; FARE-REGISTERING APPARATUS; FRANKING APPARATUS
- G07B15/00—Arrangements or apparatus for collecting fares, tolls or entrance fees at one or more control points
- G07B15/02—Arrangements or apparatus for collecting fares, tolls or entrance fees at one or more control points taking into account a variable factor such as distance or time, e.g. for passenger transport, parking systems or car rental systems
-
- G—PHYSICS
- G08—SIGNALLING
- G08G—TRAFFIC CONTROL SYSTEMS
- G08G1/00—Traffic control systems for road vehicles
- G08G1/14—Traffic control systems for road vehicles indicating individual free spaces in parking areas
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Theoretical Computer Science (AREA)
- Business, Economics & Management (AREA)
- Finance (AREA)
- Traffic Control Systems (AREA)
Abstract
Apparatus for determining a vehicle registration code extracts and recognises the registration code from the output of a camera (1) to generate a coded representation of the code. An output device (6) outputs the coded representation. The apparatus may be used to monitor vehicles entering and leaving a car park to allow the takings of the car park to be calculated. <IMAGE>
Description
"Apparatus for Determining a Vehicle Registration Code"
The invention relates to apparatus for determining a vehicle registration code and also a system for recording a vehicle registration code.
A common problem which exists with car parks where the parking charge is levied at an exit barrier is ensuring that the takings at the exit barrier correspond to both the number of cars entering and leaving the car park and to the time period each car has spent in the car park.
Conventional methods of trying to confirm the accuracy of the takings have involved security guards recording the vehicle registration number and time at which each vehicle enters and leaves the car park in order to calculate the amount of takings that should have been collected in a given time period. Another method is to use a video recording system to record visual images of cars entering and leaving the car park with the time of entry and the time of exit. These recordings are then manually inspected in order to determine the length of stay of each car in the car park to calculate the takings which should have been collected in a given time period.
Both these conventional methods are time consuming as in each case they require a person to manually identify each vehicle entering and leaving the car park and calculate the time period spent in the car park.
In accordance with a first aspect of the present invention, a system for recording a vehicle registration code comprises image capturing means to capture an image of a portion of a vehicle on which the registration code is located, means to determine the registration code from the captured image and generate a representation of the code, and recording means to record the captured image and the representation of the code.
Preferably, the recording means records the captured image and the representation of the code substantially simultaneously.
In accordance with a second aspect of the present invention, apparatus for determining the registration code of a vehicle comprises detection means which receives an input image and locates the position of a plaque in the input image carrying the registration code, extraction means to extract the registration code from the image generating means to generate a coded representation of the code, and an output device to output the coded representation.
Preferably, the means to determine the registration code from the captured image in the first aspect of the invention comprises the apparatus in accordance with the second aspect of the invention.
Typically, the system further includes a second image capturing means and a second means to determine the registration code, the first image capturing means and the first means to determine the registration code being used to capture an image of a vehicle entering a specified area and the second image capturing means and means to determine the registration code being used to capture an image of a vehicle exiting the specified area and the captured image and the representation of the registration code on both exiting and entering vehicles may be recorded on the same or separate recording media.Typically, where the representation of the code of both exiting and entering vehicles is recorded by the same recording means, a combiner is provided to combine the signals from the first and second means to determine the registration code so that the combined signal is recorded by the recording means.
Preferably, the system also includes reading means to read the representation codes stored on the recording media and a processor which receives the representation codes from the reading means and processes them to identify codes of exiting and entering vehicles which are identical to calculate the time period which a vehicle has spent in the specified area.
Typically, the specified area may be an area in which a fee is charged which is dependent on the period of time a vehicle has been in the specified area and, in this case the specified area may be a car park such as a car park where a fee is charged on exit from the car park.
Preferably, where the specified area is an area in which a fee is charged for the period of time a vehicle has spent in the area, the system further comprises means to calculate the fee each vehicle should have been charged for being in the specified area and may also calculate the total of the fees charged over a given time period.
Preferably, the system may also comprise means to generate an unidentifiable registration code signal if the means to determine the registration code is unable to determine the registration code and preferably, the unidentifiable registration code signal is simultaneously recorded with the captured image by the recording means. Preferably, the processor has means to identify an unidentifiable code signal read from the recording media and in response to this signal the processor displays the captured image recorded on a visual display unit to enable an operator to visually identify the vehicle.
Typically, in the second aspect of the invention, the detection means may locate the boundary of the plaque in response to a predetermined wavelength or wavelength band of light reflected or emitted from the plaque.
Alternatively, if the plaque is of a reflective material, the detection means may identify the boundary of the plaque by comparing an input image of the plaque when it is not illuminated and an input image of the plaque when it is illuminated.
However, preferably, the boundary is located by identifying spatial frequencies of the characters forming the registration code. This is particularly useful where the captured image is a monochrome image.
Typically, the spatial frequencies of the registration code are identified by examining the characteristic frequencies created in a video signal, where a video camera is used as the image capturing means, by the registration code at a given image size.
Preferably, the extraction means includes filtering means to filter out sections of the image within the boundary which do not form part of the registration code.
Typically, the filtering means may comprise a convolution filter and/or analysis of the width and/or height of alpha-numeric characters forming the registration code.
Preferably, the coded representation is digital and may be in the form of an ASCII code file and typically, the generating means optically character reads the registration code extracted from within the boundary to generate the digitised representation.
Typically, the extraction means also includes thresholding means which takes the output from the filtering means and produces a bi-level image, which is typically in a tagged image format (TIF).
Typically, the tagged image format is received by the generating means to generate the digitised representation.
Two examples of an apparatus and system in accordance with the invention will now be described with reference to the accompanying drawings, in which;
Fig. 1 shows a system for determining and recording a
number plate of a vehicle;
Fig. 2 is a schematic representation of a system for
analysing the information recorded using the system
shown in Fig. 1;
Fig. 3 is a flow diagram showing the operation of a
first example of a number plate reader for use in the
system shown in Fig. 1; and
Fig. 4 is a flow diagram showing the operation of a
second example of a number plate reader for use in
the system shown in Fig. 1.
Fig. 1 shows a system for determining and recording the number plate of a vehicle such as a car. The system comprises a colour camera 1 and the output from the camera 1 is coupled via a line 20 to an input 21 on the number plate reader 2. The input 21 on the number plate reader 2 is connected to a frame store 3 which is triggered by the closing of a switch 8 which connects a trigger input line 22 of the frame store 3 to an earthing point 10. The output of the frame store 3 is connected to a microprocessor 4 via a line 23 and the microprocessor 4 is connected via a line 24 to a display 5 and to an output interface 6 via a line 25. The display 5 could be any conventional type of display which can display alpha-numeric characters, such as a liquid crystal display (LCD).
The output interface 6 is connected to an output terminal 26 on the number plate reader 2 via a line 27. A line 28 connects the terminal 26 to an encoder 11 and the encoder 11 is connected to an input of a video cassette recorder (VCR) 12 via a line 29.
The number plate reader system also includes a source of illumination 7 which can be switched on via a switch 9 located in the number plate reader 2 and is connected to a power supply 50.
A flow-diagram illustrating the operation of a first example of the number plate reader 2 is shown in Fig. 3.
In use, the number plate of a vehicle, such as a car, is illuminated by the light source 7 when the switch 9 closes. The actuation of the switch 9 is under the control of a sensor (not shown) which detects the presence of a vehicle and closes the switch 9 in response to the presence. When the switch 9 is closed and the number plate of a vehicle is illuminated the switch 8 closes to trigger the frame store to capture 60 (see Fig. 3) the current image being transmitted by the camera 1 along the line 20 to the frame store 3. The output on the line 20 from the camera is a conventional video signal and the frame store converts 61 this signal to a digitised colour image and stores 62 it in the frame store 3 before passing the digitised colour image to the microprocessor 4.When the digitised colour image is fed into the microprocessor 4 the microprocessor 4 determines 63 the portion of the digitised colour image which includes colours which would be reflected from a number plate. For example, in the
United Kingdom rear number plates are generally yellow and the microprocessor would be instructed to identify areas of the image corresponding to the yellow light reflected from a UK number plate. However, the choice of colour to be detected or identified could be any colour and typically, would be the colour or colours of number plates in the relevant country or geographical region.
Once the microprocessor 4 has determined 63 the region of the digitised colour image corresponding to the number plate, the microprocessor 4 extracts 64 this region and carries out a number of filtering operations on the region in order to filter out extraneous information within the number plate image, such as the heads of rivets or screws holding the number plate onto the vehicle. Typically, these filtering operations may involve convolution filters and can also involve analysis of the width and height of characters on the number plate or indeed any other typical filtering operations for images. After the microprocessor 4 has filtered the number plate image, the microprocessor thresholds 65 the image in order to convert the filtered coloured number plate image into a black and white image which is digitised and this is preferably in a tagged image format (TIF) file.
The TIF file is then decoded 66 by a conventional optical character reading program stored in the microprocessor and this takes the TIF file and generates from the TIF file an
ASCII 67 file which is representative of the registration number of the vehicle. This ASCII file is then output 68 via the interface 6 to an encoder 11 which encodes the
ASCII file representation of the registration number of a vehicle and the time at which the image was captured into a format suitable for recording on a video cassette and storing the encoded information on the top lines of the video signal in a similar manner to the way in which
CEEFAX information is encoded onto the top section of a television signal.The encoded information from the encoder 11 is then passed through the line 29 to the VCR 12 which simultaneously records the encoded information with the video signal of the image of the number plate which has been read.
If, for some reason, the system shown in Fig. 1 is unable to identify the number plate of a vehicle, (for example because the number plate is missing or obscured or is in a format which is unknown to the number plate reader 2) the
TIF file will not be readable 66 by the optical character reading program and an error signal is generated by the microprocessor 4 in the form of an ASCII file 70 which is encoded by the encoder 11 and stored simultaneously with the video image of the vehicle having the unidentifiable number plates.
Typically, the system shown in Fig. 1 may be used to monitor vehicles entering and exiting a specified or restricted area and in particular may be used to monitor the entry and exit of vehicles from a car park.
Typically where the system is used to monitor the entry and exit of vehicles from the car park two such systems as shown in Fig. 1 are used, one system to record the registration number and times of vehicles entering the car park and the second system to record the registration number and time of vehicles exiting from the car park.
Alternatively, it would be possible to store both the information regarding vehicles entering the car park and vehicles exiting the car park on a single video cassette recorder 12 by combining the separate signals from two encoders 11 using a combiner (not shown).
In order to analyse the information recorded on a video cassette using the system shown in Fig. 1, a decoding system, as shown in Fig. 2, is used. The decoding system comprises a VCR 13, the output of which is connected to a decoder 14. The decoder 14 in turn has its output connected to a personal computer 15 which includes a visual display unit 16 and a keyboard 17. A trigger line 30 from the personal computer 15 is connected to a remote control unit 18 of the VCR 13.
In order to analyse the information recorded using the system shown in Fig. 1, a video cassette having the recorded information is inserted into the VCR 13 and played on the VCR 13. The output video signal from the
VCR 13 is then fed to a decoder 14 which decodes the encoded information sections at the top section of the video signal in order to retrieve the ASCII file and time information. The ASCII file and the time information are then fed to the personal computer 15 which stores the registration number and the appropriate time of entry and these can be displayed using the visual display unit (VDU) 16. After the tape of vehicles entering the car park has been decoded and stored on the PC 15, the cassette tape of cars exiting the car park can be played on the VCR 13 and the information or registration numbers exiting and their respective times again stored in the PC 15.The PC 15 can then be used to correlate the entry and exit information so that the time period each vehicle spent in the car park can be calculated and from this information an accurate estimate of the takings of that car park over a given time period can be accurately calculated.
When an error signal is read by the PC 15 the error signal instructs the PC 15 to trigger the remote control unit 18 via the line 30 which in turn displays a visual image on the display (not shown) of the vehicle having the unidentifiable number plate so that an operator may visually identify the vehicle.
In the above example the number plate reader 2 detected the region of the number plate in the input image by identifying colour associated with a number plate.
However, as an alternative to this method it would be possible for the frame store to store two images of a vehicle, one image in which a number plate was not illuminated and the second image in which the number plate was illuminated. As number plates are generally reflective the greatest difference in brightness between the two images should occur in the region of the image which represents the number plate and so the microprocessor 4 could identify the number plate in this manner. This would have the advantage of enabling a black and white camera to be used in place of the colour camera 1 shown in Fig. 1.
A flow diagram showing the operation of a second example of the number plate reader 2 is shown in Fig. 4. In the second example a monochrome video camera replaces the camera 1.
The second example works in a similar manner to the first example, but instead of locating the boundary 63 of the image by using a characteristic wavelength of light reflected from the number plate, the boundary is detected 63 by using characteristic spatial frequencies of the characters on the number plate. This is done by examining the characteristic frequencies created in the video signal from the monochrome camera by the plate at a given image size. This can be done in software by examining the frozen data yn or in real time using circuitry, for example, band pass filters.
Once the plate is detected 63, the boundary information is extracted 64 and filtering operations performed 69. The image is then converted from greyscales to a bi-level image over the plate area by using a threshold valve 65.
If the character image is not clean 71 the threshold valve can be changed 72 approximately to cope with shadows and other contamination of the plate.
Connected characters (ligatures) (for example, by bolts fixing the plate to the vehicle) are detected in software by measuring the dimensions of formed characters and the average spacing between charactes. The offending data can then be removed from the image, giving the character recognition 66 a better opportunity to recognise characters accurately.
From the above example it can be seen that the invention has be advantage of providing a system whereby vehicle registration numbers of vehicles entering and leaving a car park or any other specified or restricted area can be read and the information stored on a recording media so that the recording media can be analysed via a computer in order to have the information recorded on the recording media analysed. This has the advantage of reducing the cost and time involved in manually logging each vehicle as it enters and/or leaves the specified or restricted area.
Modifications and improvements may be incorporated without departing from the scope of the invention.
Claims (11)
1. Apparatus for determining a registration code of a vehicle comprising detection means which receives an input image and locates the position of a plaque in the input image carrying the registration code, extraction means to extract the registration code from the image, generating means to generate a coded representation of the code, and an output device to output the coded representation.
2. Apparatus according to Claim 1, wherein the detection means locates the position of the plaque in response to a wavelength or wavelength band of light reflected or emitted from the plaque.
3. Apparatus according to Claim 1, wherein the detection means locates the position of the plaque by identifying characteristic spatial frequencies of the characters of the registration code.
4. Apparatus according to any of Claims 1 to 3, wherein the extraction means includes filtering means to filter out sections of the image of the plaque which do not form part of the registration code.
5. Apparatus according to any of Claims 1 to 4, wherein the coded representation is digital.
6. Apparatus according to any of Claim 1 to 5, wherein the extraction means comprises thresholding means which produced a image of the plaque.
7. A system for recording a vehicle registration code comprising image capturing means to capture an image of a portion of a vehicle on which the registration code is located, means to determine the registration code from the captured image and generate a representation of the code, and recording means to record the captured image and the representation of the code.
8. A system according to Claim 7, wherein the means to determine the registration code comprises apparatus according to any of Claims 1 to 6.
9. A system according to Claim 7 or Claim 9, wherein the recording means records the captured image and the representation of the code substantially simultaneously.
10. Apparatus for determining a registration code of a vehicle with reference to the accompanying drawings.
11. A system for recording a vehicle registration code, substantially as hereinbefore described with reference to the accompanying drawings.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9305762A GB2265243A (en) | 1992-03-21 | 1993-03-22 | Apparatus for determining a vehicle registration code |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB929206196A GB9206196D0 (en) | 1992-03-21 | 1992-03-21 | Apparatus for determining a vehicle registration code |
GB9305762A GB2265243A (en) | 1992-03-21 | 1993-03-22 | Apparatus for determining a vehicle registration code |
Publications (2)
Publication Number | Publication Date |
---|---|
GB9305762D0 GB9305762D0 (en) | 1993-05-05 |
GB2265243A true GB2265243A (en) | 1993-09-22 |
Family
ID=26300567
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9305762A Withdrawn GB2265243A (en) | 1992-03-21 | 1993-03-22 | Apparatus for determining a vehicle registration code |
Country Status (1)
Country | Link |
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GB (1) | GB2265243A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2280027A (en) * | 1993-06-23 | 1995-01-18 | Knott James | Automatic reading of vehicle number plates |
WO1998041953A1 (en) * | 1997-03-14 | 1998-09-24 | Kielland Peter J | Parking regulation enforcement system |
USRE38626E1 (en) * | 1997-03-14 | 2004-10-19 | Visionary Technology, Inc. | Parking regulation enforcement system |
FR2863807A1 (en) * | 2003-12-15 | 2005-06-17 | Marie France Pissardy | ASSEMBLIES AND METHODS FOR AUDIOVISUAL AND COMPUTER MANAGEMENT OF PARKING CARS, WITH THEIR EROM COMPUTERS, CALCULATORS OF THE PERIOD OF PAYABLE PARKING OR NOT |
US7504965B1 (en) | 2005-08-05 | 2009-03-17 | Elsag North America, Llc | Portable covert license plate reader |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1987007057A1 (en) * | 1986-05-05 | 1987-11-19 | Perceptics Corporation | Apparatus for reading a license plate |
GB2217498A (en) * | 1988-04-18 | 1989-10-25 | Ind Tech Res Inst | Automatic recognition of licence plate characters |
GB2219881A (en) * | 1988-06-15 | 1989-12-20 | English Electric Valve Co Ltd | Vehicle monitoring system |
US4908500A (en) * | 1987-06-29 | 1990-03-13 | Campagnie Generale D'Automatisme CGa-HBS | System for automatically reading indentification data disposed on a vehicle |
GB2227866A (en) * | 1988-12-13 | 1990-08-08 | Matsushita Electric Ind Co Ltd | Vehicle identification |
US5081685A (en) * | 1988-11-29 | 1992-01-14 | Westinghouse Electric Corp. | Apparatus and method for reading a license plate |
GB2246894A (en) * | 1990-06-13 | 1992-02-12 | Matsushita Electric Ind Co Ltd | Licence plate recognition system |
-
1993
- 1993-03-22 GB GB9305762A patent/GB2265243A/en not_active Withdrawn
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1987007057A1 (en) * | 1986-05-05 | 1987-11-19 | Perceptics Corporation | Apparatus for reading a license plate |
US4908500A (en) * | 1987-06-29 | 1990-03-13 | Campagnie Generale D'Automatisme CGa-HBS | System for automatically reading indentification data disposed on a vehicle |
GB2217498A (en) * | 1988-04-18 | 1989-10-25 | Ind Tech Res Inst | Automatic recognition of licence plate characters |
GB2219881A (en) * | 1988-06-15 | 1989-12-20 | English Electric Valve Co Ltd | Vehicle monitoring system |
US5081685A (en) * | 1988-11-29 | 1992-01-14 | Westinghouse Electric Corp. | Apparatus and method for reading a license plate |
GB2227866A (en) * | 1988-12-13 | 1990-08-08 | Matsushita Electric Ind Co Ltd | Vehicle identification |
GB2246894A (en) * | 1990-06-13 | 1992-02-12 | Matsushita Electric Ind Co Ltd | Licence plate recognition system |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2280027A (en) * | 1993-06-23 | 1995-01-18 | Knott James | Automatic reading of vehicle number plates |
GB2280027B (en) * | 1993-06-23 | 1996-12-11 | Knott James | Object recognition and identification |
WO1998041953A1 (en) * | 1997-03-14 | 1998-09-24 | Kielland Peter J | Parking regulation enforcement system |
US6081206A (en) * | 1997-03-14 | 2000-06-27 | Visionary Technology Inc. | Parking regulation enforcement system |
USRE38626E1 (en) * | 1997-03-14 | 2004-10-19 | Visionary Technology, Inc. | Parking regulation enforcement system |
FR2863807A1 (en) * | 2003-12-15 | 2005-06-17 | Marie France Pissardy | ASSEMBLIES AND METHODS FOR AUDIOVISUAL AND COMPUTER MANAGEMENT OF PARKING CARS, WITH THEIR EROM COMPUTERS, CALCULATORS OF THE PERIOD OF PAYABLE PARKING OR NOT |
US7504965B1 (en) | 2005-08-05 | 2009-03-17 | Elsag North America, Llc | Portable covert license plate reader |
Also Published As
Publication number | Publication date |
---|---|
GB9305762D0 (en) | 1993-05-05 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |