GB2437325A

GB2437325A - Automatic number plate recognition system with velocity sensor adds the number plate and velocity to the photographs in an unambiguous manner

Info

Publication number: GB2437325A
Application number: GB0607679A
Authority: GB
Inventors: John Randolph Vickerstaff; Des Beeson
Original assignee: LIMITED VIDEOFIT
Current assignee: LIMITED VIDEOFIT
Priority date: 2006-04-19
Filing date: 2006-04-19
Publication date: 2007-10-24
Also published as: GB2437325A8; GB0607679D0

Abstract

Disclosed is an automatic number plate recognition system with velocity reporting (speeding) that adds the number plate details and the detected speed of a vehicle, in an unambiguous manner, to the digital report that is sent to the central authorities for entry in a database for further analysis. The speed data may be added as a binary pattern of dark and light pixels or elements in the video. The number plate details may be added to the video in a different style, so as to reduce the possibility of a misread. The system may be able to provide vehicle speed and traffic flow analysis with an accurate audit trail to the individual entries.

Description

Description I

Automatic Number Plate Recognition (ANPR) System To Incorporate Velocity Reporting.

This invention relates to ANPR systems, which may be either portable, temporarily erected or permanent installations.

ANPR systems conventionally combine a video camera together with a computer (sometimes separated by many miles, but connected by electronic means). The latter runs a software program capable of extracting the number plate information only from the video camera image. The automated recognition of number plate information is typically achieved by applying optical character recognition (OCR), pattern analysis or neural network algorithms. Thus the extracted digital information bears none of the attributes of the originating video signal. The digital number plate information may now be presented in such a form to be entered or compared with databases, passed as encoded data or simple ASCII strings over media, or linked by digital means to the originating image or images which may have been previously stored.

ANPR systems may also be used to plot journey times of vehicles, but more than one camera is usually needed for this. Typically, a car passing under ANPR camera I, has their number plate read and an entry is made in a database together with time and date. When the same vehicle passes under ANPR camera 2 (for example; I mile away from ANPR camera 1), a similar reading takes place. The database record may now show a 60 second difference in entries, thus the vehicle may be assumed as having averaged 60 mph over the I mile distance. It is therefore apparent that ANPR may be used for speed checks too.

However, there are major pitfalls in using ANPR for speed enforcement. Firstly more than one camera is needed. The cameras have to be separated by a good distance so that the specific time when a number plate is read (which has a degree of variability), together with the computer processing time, does not significantly detract from overall accuracy. The central and outlying databases have to be time synchronised.

Because of the constraints of necessary camera separation, not all roads are suitable.

A stretch of motorway without exits would be ideal, an urban street with many exits It is an object of the present invention to overcome or obviate many of the aforementioned disadvantages with using ANPR in a speed enforcement or speed advice application and provide significant and useful improvements without necessarily greater cost.

According to the invention there is a provided an ANPR system comprising of a video camera to capture an image(s) of the number plate together with a device which determines the velocity (speed and direction) of the vehicle of interest (this may use technologies which emit electromagnetic waves ie microwaves, light etc. or ultrasonic sound waves). Conveniently the velocity information is combined with the camera image(s) and fed down a common transmission path to the ANPR computer.

Typically, the velocity information would be electronically encoded, forming the basis for a unique binary pattern of light and dark picture elements which would be inserted in part of the camera image or in a part of the overall camera video signal which isn't normally seen on a standard video display device. Thus the combined velocity and image information in the form of a single video transmission passes over the transmission network to be subsequently processed. The remaining component of the system is the ANPR computer which processes the camera image so as to extract the number plate reading. However, in addition to number plate recognition, the computer extracts the velocity information and presents it in a similar digital way as the plate reading, so that database entries can be made or compared, passed as encoded data or simple ASCII strings over communications media, or linked by digital means to the originating image or images which may have been previously stored.

It is considered an important part of the inventive step to send the velocity information in such a distinct form within the camera image, so as to allow the ANPR computer to differentiate between number plate information which is in alpha-numeric form and velocity information which can be encoded as binary light and dark picture elements. The latter featuring a predictable pre-amble pattern (to assist recognition) and constant data element size, thus ensuring the unambiguous separation of number plate characters from velocity data patterns. This allows for the ANPR computer to handle the two visual data types within the one program, but with differing analysis routines. Therefore nothing contained within a number plate can be misconstrued as a velocity reading. This is important to reduce any instance of false alarm by wrongful computer interpretation.

The invention therefore obviates the need for a second ANPR camera and possibly computer where previously this would have been required for speed analysis, plus all the infrastructure this requires. It makes it possible to use ANPR speed enforcement / advice on roads where a two camera solution wouldn't be effective. It provides for near instantaneous speed determination, rather than an average distance / time calculation. It obviates the need for time synchronised databases.

By having the velocity information available from a computer database, it makes it possible to plot trends and averages of vehicle movements on a particular road with audit trail accuracy.

Additionally it allows for a portable ANPR speeding advice system to be rapidly deployed, where following image and velocity capture the ANPR computer could link captured registration numbers with their respective speeds and output this data to a high brightness roadside information sign, effectively naming and shaming.

For speed enforcement applications, the registration and speed data could be forwarded by SMS, GPRS or similar, to awaiting Police Officers.

The invention will now be described by way of example only, with reference to the accompanying diagram.

Block 1 Electronic video camera Block 2 Speed detector (radar, laser etc.) Block 3 Microprocessor data converter. This module receives the raw data from the speed detector, encodes it in a unique binary format then sends the appropriate positional and pixel information to the combining module ( Block 4).

Block 4 Combining module inserts the binary representation of the velocity data on to the video image from the camera in Block I in the form of light and dark patterns.

Block 5 Computer running software to automatically detect number plate and velocity information, which may also include database, graphical user interface, data analysis etc. The computer can also import or export data to extend its functionality.

Block 6 Optional high brightness display Block 7 Digital communication interface to integrate with modern media transmission.

Claims

CLAIMS 5 1. An Automatic Number Plate Recognition (ANPR) System which

incorporates Velocity Reporting so as to use recognition technology to resolve both number plate and velocity information in an unambiguous way and to present such information in a digital form for database entry and further analysis.

2. An Automatic Number Plate Recognition (ANPR) System which incorporates Velocity Reporting where the velocity information as claimed in Claim I to be encoded and inserted in the video camera image at source as a binary pattern of light and dark picture elements.

3. An Automatic Number Plate Recognition (ANPR) System which incorporates Velocity Reporting as claimed in Claim I or Claim 2 to use the same recognition software to resolve in digital form both the number plate information and the vehicle's speed and direction.

4. An Automatic Number Plate Recognition (ANPR) System which incorporates Velocity Reporting as claimed in Claim 1 or Claim 2 or Claim 3 which by virtue of the substantially different style of number plate characters compared with encoded velocity information within the video image, reduces the possibility of recognition software velocity misread.

5. An Automatic Number Plate Recognition (ANPR) System which incorporates Velocity Reporting as claimed in Claim 1 or Claim 2 or Claim 3 or Claim 4 which can provide vehicle speed and traffic flow analysis with an accurate audit trail back to the individual speed / number plate entries.

6. An Automatic Number Plate Recognition (ANPR) System which incorporates Velocity Reporting as claimed in Claim 1 or Claim 2 or Claim 3 to use the same transmission infrastructure in quantity and type as a similar system without Velocity Reporting.

7. An Automatic Number Plate Recognition (ANPR) System which incorporates Velocity Reporting as substantially herein described above and illustrated in the accompanying drawing.