GB2244581A - System to read barcode signs from or on a moving vehicle - Google Patents

Abstract

A computer based digital video image processing system is configured to read barcode signs, either from or on a moving vehicle or boat. Video cameras, looking to or from either side, are triggered by optical beam scanners, so that an image of each passing barcode sign is obtained. These are processed in the computer, to identify and read the horizontal barcodes. The automatic system can be used to maintain a knowledge of vehicle position, to transfer route information, or to identify passing vehicles or boats.

Description

SPECIFICATION OF AN AUTOMATIC SYSTEM TO READ BARCODE SIGNS FROM OR ON A MOVING VEHICLE This invention concerns an electronic system for reading barcodes from or on a moving vehicle.

The are many potential applications for a system that can measure the forward position of a moving vehicle automatically. Although a single location can be determined using a simple triggering device, this is not sufficient to monitor vehicle position over long distances. Poor accuracy and cumulative errors are inherent in measurements of distance travelled, made from within a moving vehicle. Therefore, regular position fixing is required to maintain an accurate knowledge of vehicle position.

There are also many applications for a system that can identify passing vehicles, to log the time and identification code and possibly other data, and to control access to restricted areas. The system specified here relates to all of these functions This invention concerns a system to read a barcode sign from or on the side of a moving vehicle. It can be used to determine the position of a moving vehicle automatically from within the vehicle. It is suitable for use on road vehicles, channelled boats or railway vehicles. The system can also be used to identify passing vehicles from the roadside, river bank or beside a railway line.

The system reads barcode signs, using sideways looking video cameras.

Either:a) The signs are sited at known positions along the route, eg at both sides of a road. They may contain direct position information (such as distance in meters) or map reference codes; or b) The signs are mounted on the sides of certain vehicles or boats, to be read by cameras sited beside the road, railway or river. These may display vehicle identification codes, which are recognisable to the computer.

The barcodes, which may comprise matt black stripes on a reflective white background, must be horizontal to permit a reasonable scanning time. Even so, the video imaging must be triggered by the proximity of the sign or vehicle.

This can be achieved by an optical scanning system, which sends a light beam across the route. Either, this is received by a sensor on the vehicle to trigger the vehicle mounted imaging system, or the breaking of the beam by the vehicle is monitored from the other side of the route, to trigger the fixed imaging system. By reading from both sides of the vehicle simultaneously, the likelihood of obscuration by other vehicles is reduced.

The video images are digitised and processed using a portable computer system, which also records the time at which the image was triggered. The barcode images are identified and the bar coded information is determined using specialised software in the computer.

There follows a description of an example application, to measure position from within a moving road vehicle.

The system is shown schematically in Figure 1. The vehicle (3) carries a portable computer (4), which contains a video frame grabber and a facility for various analogue signal inputs (A to E). The computer contains software to acquire and process video images, to identify and read barcode signs.

It also records the time when either of the optical receivers is triggered, so that both the location and the exact arrival time are known.

The computer screen can be used to display information including current position, route options obtained from a stored electronic map, or other relevant items.

The computer receives video signals from both the left looking video camera (5) and the right looking video camera (6). The frame grabber and the relevant camera are triggered when an input is received from either of the optical receivers (7,8).

The computer also receives speed information from the gearbox / speedometer (input E) to enable vehicle position to be extrapolated until the next barcode marker.

The barcode signs (1) face across the road and display horizontal painted bars. These are matt black on a reflective white background. An optical beacon (2) is mounted alongside and just before the barcode, pointing across the road. There should be another sign and beacon at the opposite side, so that vehicles could read the information from either side of the carriageway.

The barcode signs should be positioned regularly along the road, and close to road junctions where they could convey route information to the computer.

There follows a description of a second example application, to identify passing river boats. The system is shown schematically in Figure 2.

A portable computer (1), which contains a video frame grabber and a facility for various analogue signal inputs (A to D), is sited in the lock keeper's hut (2). The computer contains software to acquire and process video images, to identify and read barcode signs. It also records the time when the optical receiver is triggered, so that both the boat identification and the exact arrival time are known.

The computer screen can be used to display the identities of recent arrivals, or other relevant items, obtained from an electronic database. It might also be used for automatic tolling for use of the lock.

The computer receives video signals from both the right looking video camera (3) and the left looking video camera (4), which are mounted on either side of the waterway. The frame grabber and both cameras are triggered when the beam from the optical transmitter (5) is broken and an input is received from the optical receiver (6).

The computer also receives and transmits information (signals D) from and to the lock gate control unit (8) to enable automatic tolling and control.

The barcode signs (7) are mounted on the bows of the boat, facing to either side. These are matt black on a reflective white background.

Key to Figure 1: System Configuration to Measure Position from a Moving Vehicle 1 Roadside barcode sign, with horizontal bars, facing across the road.

2 Roadside optical beacon, with beam pointing across the road.

3 Outline of vehicle (with 4 wheels).

4 Portable computer system, with display showing information including vehicle position, route options etc. Inputs to computer are: A Video signal from left camera B Trigger signal from left optical receiver C Trigger signal from right optical receiver D Video signal from right camera E Signal from vehicle speedometer.

5 Left looking video camera.

6 Right looking video camera.

7 Left looking optical receiver.

8 Right looking optical receiver.

Key to Figure 2 System Configuration to Identify Passing River Boats 1 Portable computer system, with display showing boat identification etc. Interfaces to computer are: A Video signal from left camera B Trigger signal from optical receiver C Video signal from right camera D Signals to and from the lock gate control unit.

2 Outline of lock keeper's hut.

3 Right looking video camera.

4 Left looking video camera.

5 Optical beacon, with beam pointing across the river.

6 Optical receiver.

7 Barcode signs, with horizontal bars, on either side of the boat.

8 Lock gate control unit.

Claims (4)

1 A computer based system, with sideways looking video cameras, using digital video image processing to read horizontal barcodes from or on a moving vehicle or boat.

2 The triggering of the system in Claim 1 using optical beam scanners.

3 The use of the system in Claim 1 to determine the position of a moving vehicle or boat.

4 The use of the system in Claim 1 to identify passing vehicles or boats.