GB2231952A - Vehicle length measurement system - Google Patents
Vehicle length measurement system Download PDFInfo
- Publication number
- GB2231952A GB2231952A GB8910079A GB8910079A GB2231952A GB 2231952 A GB2231952 A GB 2231952A GB 8910079 A GB8910079 A GB 8910079A GB 8910079 A GB8910079 A GB 8910079A GB 2231952 A GB2231952 A GB 2231952A
- Authority
- GB
- United Kingdom
- Prior art keywords
- vehicle
- length
- time
- pathway
- light
- 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- Withdrawn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
- G08G1/015—Detecting movement of traffic to be counted or controlled with provision for distinguishing between two or more types of vehicles, e.g. between motor-cars and cycles
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/04—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness specially adapted for measuring length or width of objects while moving
- G01B11/043—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness specially adapted for measuring length or width of objects while moving for measuring length
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/02—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness
- G01B21/06—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness specially adapted for measuring length or width of objects while moving
Abstract
A method for determining the length of a vehicle comprises measuring the time for a fixed point on the vehicle to pass from one location to another so as to determine the vehicle speed, measuring the length of time for which the vehicle, when moving at that speed, impedes the light path between a light source and detector, and calculating the vehicle length from the two time measurements. Apparatus for use in this method comprises at least two pressure-responsive indicators (5, 6, 7) spaced apart along a defined vehicle pathway (1), a first time measurement means for measuring the time interval between a vehicle passing over the indicators in turn, a light source (8) and detector (9, 10) at opposite sides of the pathway, a second time measurement means for measuring the length of time for which the light path between the source and detector is interrupted, and calculator means (12) for calculating the vehicle length from the two time measurements. <IMAGE>
Description
Vehicle Measurement System
The present invention relates to the measurement of the length of a moving vehicle and comprises a method and apparatus for that purpose.
In several situations wherein a charge made to the owner of a vehicle is calculated upon the basis of the length of the vehicle, it is desirable that the overall length of the vehicle and any associated load or trailer should be determined automatically. Thus, for example, if the charge on a toll-road is to be related to the vehicle length, then this length must be measured in some way. Even when a standard charge is made, it ray be necessary to know the overall length, for example when vehicles are to be loaded nose-to-tail in a vehicle transporter such as a car ferry or train.It is highly desirable that the length measurement should be made while the vehicle is in nnt'ion, in order to avoid delays in transit or loading and to make optimm use of available equipment and manpower.
One method which has been proposed for this purpose is to monitor the passage of a vehicle over an inductive detector, which responds to the proximity of a metal and therefore indicates the presence or otherwise of a vehicle chassis above the detector. Unfortunately, this method has proved in practice to be inadequate to give a true measurement of overall length in several situations.For example, chassis length itself may not be an accurate indication of vehicle length when the vehicle has non-metallic bumpers or when the vehicle has a non-metallic body extending beyond one or both ends of the chassis and is a misleading measurement when the vehicle is towing a trailer or carrying a non-metallic over hanging load.
It is therefore an object of the present invention to provide a method and apparatus for determining the overfull length of a moving vehicle, which avoid or reduce at leapt some of the difficulties associated with prior such systems.
The method according to the present invention for determining the length of a moving vehicle comprises measuring the time required for a fixed point on the vehicle to pass from a first location to a second location spaced at a predetermined distance from said first location so as to determine the speed of movement of the vehicle, causing the vehicle to pass at said speed ketr.zeen a light source and a light detector and measuring the time for which the vehicle impedes the detection by said light detector of light emitted by the light source, and calculating from said t.n tire measurerents the overall length f the -ieEcle The invention also includes apparatus for carrying out the foregoing method, which apparatus comprises at least two pressure-responsive indicators disposed at a predetermined distance apart along a defined vehicle pathway, a first time measurement means for measuring the time interval between a vehicle passing over each of said pressure-responsive indicators in turn, a light source located at one side of said pathway, a light detector at the other side of said pathway, a second time measurement means for measuring a length of time for which the light path between the light source and the light detector is interrupted, and calculator means for calculating from said time interval and said length of time the overall length of a said vehicle passing along said pathway.
The foregoing method and apparatus represent a minimum requirement for determining approximately the length of a vehicle moving at a constant speed, or for obtaining a very rough vehicle length measurement when the vehicle speed is only roughly constant. In most situations a higher level of accuracy is necessary or desirable and indeed is readily achievable. For example, it is much preferred to use at least three pressureresponsive indicators, spaced apart at predetermined intervals which are accurately known but need not bie equal to each other.
In this way, t or three time intervals may be iteasured, each of which may be used to calculate a value for the vehicle speed. The different speed values may then be averaged, or they may be used to calculate the acceleration of the vehicle so as to determine its speed at a particular mint alsr,g the ':ehicle pathway, or they may be used in t' D or more different calculations of vehicle length, the answers arising from the different calculations being averaged and/or unlikely answers being discarded.
The time measurement upon which the velocity calculation is based may be made when the front wheels of the vehicle pass over the selected pressure-responsive indicators, or when the rear wheels pass over them, or again both measurements may be made, to give two or more velocity determinations for use in subsequently determining the vehicle length. When the velocity value or values have been calculated, the resulting figures are then preferably extrapolated to give calculated values of the velocity of the vehicle at the point in time when the front of the vehicle and the rear of the vehicle respectively pass the light path and/or to calculate an average value of the car speed during the passage of the vehicle through the light path.
This extrapolation may be based simply on a notional approximate figure representing the length of an average car bend the wheel-base but is preferably achieved by inter-relating the actual times at which, say, the front wheels pass over a pressure pad and the front of the vehicle interrupts the light path. This may be achieved by synchronising the various times in a microcontroller, which then performs the numerous calculations leading to a value for the vehicle length.
It has been determined that a high degree of accuracy is ?.chlQveble if the overall length of a standard zour-t.4aeeled vehicle on .e axles is reasured in three parts, n:ly the length from the front of the vehicle body to the front wheels, the length f=n front wheels to rear wheels, and the length from the rear wheels to the rear of the vehicle body, the three calculated lengths then being added together.
When the velocity of the vehicle is calculated from times determined by means of pressure-responsive indicators, these latter most conveniently and preferably are in the form of strips of cable laid parallel to each other at spaced intervals transverse to the vehicle pathway. Such cable may comprise a piezoelectric material sandwiched between a pair of electrodes, for example a metal core and a metal sheath, suitably enclosed in a robust protective jacket. Typically the spacing between adjacent strips may lie within the range from 0.5 to 1.0 m, preferably from 60 to 90 cm.
The light source and detector are aligned on opposite sides of the vehicle pathway at any position along that pathway.
When the vehicle-wheel times and the body times are to be synchronised as mentioned above, then the position of the light path in relation to that of the pressure-iesponsive indicators needs to be known accurately. Preferably the light path coincides with the position of a pressure-cable strip, most preferably with that of the last strip to be traversed by the vehicle.
It has been found to be particularly advantageous to employ as the light source an elongated source, such as a fluorescent strip light, extending generally vertically and to lìse tn light detectors, which Ire spaced prt in n generally vertical direction with overlapping fields of detection. Preferably one such detector is located close to the ground and directed upwardly and the other is located above an average vehicle height and directed downwardly. It is particularly preferred that the detectors used be video cameras.
The invention will now be further described and illustrated with reference to the accompanying drawing, which is a schematic perspective view of one embodiment of the apparatus according to the present invention, given by way of example.
The illustrated system comprises a defined vehicle pathway 1, along which a vehicle of which the overall length is to be determined is driven in the direction of the arrow 2. Access to and from the measurement section is controlled by barrier units 3 and 4 respectively.
Across the pathway 1, at spacings of the order of 80 cm, are extended three pressure-responsive detectors in the form of parallel piezoelectric cables 5, 6 and 7. A vertical fluorescent light 8 stands at the side of the vehicle pathway 1 in alignment with the cable 7 and a pair of linescan video cameras 9, 10 are supported opposite to the light 8 on a column 11. The carrera 9 points generally downwards and the camera 10 generally upwards so that their fields of view overlap in an area above the cable 7. The output of each camera is a signal directly proportional to the intensity of incident light upon the camera.
Thus any interruption of the light path from the light 8 to either camera is indicated by a change in this output signal anS t length ngFh of fte for which the light pzth is interrupted is related to the length of the vehicle, including any caravan or trailer being towed by it or any overhanging load.
Signals from the piezoelectric cables and from the cameras are synchronised in a microcontroller 12 and the data is processed by the microcontroller as described above to yield a calculated measurement of the overall length of the vehicle. Calculated values are passed from time to time by a line 13 to a central computer for analysis.
Experimental operation of the illustrated apparatus has given results which are within a few centimetres of the actual lengths of vehicles as rreasured by mechanical means.
Even when a vehicle has stalled as it passes along the pathway, the resulting false readings have been eliminated by the averaging procedure adopted.
Claims (14)
1. A method for determing the length of a moving vehicle, Avrising measuring the time required for a fixed point on the vehicle to pass from a first location to a second location spaced at a predetermined distance from said first location so as to determine the speed of movement of the vehicle, causing the vehicle to pass at said speed between a light source and a light detector and measuring the time for which the vehicle impedes the detection by said light detector of light emitted by the light source, and calculating from said two time measurements the overall length of the vehicle.
2. A method as claimed in claim 1, wherein a further measurement is made of the time required for said fixed point on the vehicle to pass from said first or second location to a third location spaced at a predetermined distance from said first or second location so as to make a second determination of the speed of movement of the vehicle.
3. A method as claimed in claim 2, wherein the two speed deteninations are used to calculate the acoeleration of the vehicle.
4. A method as claimed in any of the preceding claims, wherein further similar speed determinations are made in respect of at least one further fixed point on the vehicle.
5. A method as claimed in claim 4, wherein the overall length of the vehicle is determined by calculating the length from the front of the vehicle body to its front wheels, the length fram front wheels to rear wheels, and the length from the rear wheels to the rear of the vehicle body and then adding together those three calculated lengths.
6. Apparatus for determining the length of a vehicle by the method of claim 1, camprising at least two pressureresponsive indicators disposed at a predetermined distance apart along a defined vehicle pathway, a first time measurement means for measuring the time interval between a vehicle passing over each of said pressure-responsive indicators in turn, a light source located at one side of said pathway, a light detector at the other side of said pathway, a second time measurement means for measuring a length of time for which the lightpath between the light source and the light detector is interrupted, and calculator means for calculating from said time interval and said length of time the overall length of a said vehicle passing along said pathway.
7. Apparatus as claimed in claim 6, comprising at least three said pressure-responsive indicators, spaced apart at pre-determined intervals.
8. Apparatus as claimed in claim 6 or 7, wherein said pressure-responsive indicators are strips of cable laid parallel to each other at spaced intervals transverse to the vehicle pathway.
9. Apparatus as claimed in claim 8, wherein said cable comprises a piezoelectric material sandwiched between a pair of electrodes.
10. Apparatus as claimed in any of claims 6 to 9, wherein the light path coincides with the position of one of said pressure-responsive indicators.
11. Apparatus as claimed in any of claims 6 to 10, wherein the light source comprises an elongated source extending generally vertically.
12. Apparatus as claimed in claim 11, comprising two said light detectors, spaced apart in a generally vertical direction.
13. Apparatus as claimed in any of claims 6 to 12, wherein the or each light detector is a video camera.
14. Apparatus for determining the length of a vehicle, said apparatus being substantially as hereinbefore described with reference to the acoompanying drawing.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8910079A GB2231952A (en) | 1989-05-03 | 1989-05-03 | Vehicle length measurement system |
| FR9005852A FR2646709A1 (en) | 1989-05-03 | 1990-05-03 | METHOD FOR DETERMINING THE LENGTH OF A VEHICLE WHILE MOVING AND APPARATUS FOR IMPLEMENTING SAME |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8910079A GB2231952A (en) | 1989-05-03 | 1989-05-03 | Vehicle length measurement system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8910079D0 GB8910079D0 (en) | 1989-06-21 |
| GB2231952A true GB2231952A (en) | 1990-11-28 |
Family
ID=10656099
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8910079A Withdrawn GB2231952A (en) | 1989-05-03 | 1989-05-03 | Vehicle length measurement system |
Country Status (2)
| Country | Link |
|---|---|
| FR (1) | FR2646709A1 (en) |
| GB (1) | GB2231952A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993019429A1 (en) * | 1992-03-18 | 1993-09-30 | In-Mar-Tech Australia Pty. Ltd. | Vision apparatus |
| US6404506B1 (en) * | 1998-03-09 | 2002-06-11 | The Regents Of The University Of California | Non-intrusive laser-based system for detecting objects moving across a planar surface |
| CN105136045A (en) * | 2015-09-22 | 2015-12-09 | 北京佰能电气技术有限公司 | Coil down length measurement method for coil collecting station |
| CN106679575A (en) * | 2016-12-29 | 2017-05-17 | 重庆交通大学 | System and method for detecting overheight and overwidth of vehicle based on laser calibration |
| CN106767450A (en) * | 2016-12-28 | 2017-05-31 | 重庆交通大学 | A kind of vehicle super-high ultra-wide detecting system and method demarcated based on function |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB825243A (en) * | 1957-05-30 | 1959-12-09 | Elliott Brothers London Ltd | Improvements in or relating to apparatus for measuring the length in their directionof motion of objects which are travelling along a predetermined path |
| GB960922A (en) * | 1961-11-14 | 1964-06-17 | British Iron Steel Research | Improvements in and relating to measuring apparatus |
| US3816001A (en) * | 1972-06-20 | 1974-06-11 | W Duncan | Measuring length and velocity of single staple fibers within an airflow |
| GB1408521A (en) * | 1972-04-27 | 1975-10-01 | Dso Resprom | Apparatus for determining the length of a moving object |
| GB1573188A (en) * | 1977-09-23 | 1980-08-20 | British Railways Board | Measuring systems |
| GB2129126A (en) * | 1982-11-01 | 1984-05-10 | De La Rue Syst | Dimension of rectangular sheets |
| GB2203540A (en) * | 1987-04-01 | 1988-10-19 | Birtingur H F | Measuring, counting & classifying fish |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL184645C (en) * | 1979-08-09 | 1989-09-18 | Philips Nv | METHOD FOR DETERMINING THE SPEED OF A VEHICLE. |
-
1989
- 1989-05-03 GB GB8910079A patent/GB2231952A/en not_active Withdrawn
-
1990
- 1990-05-03 FR FR9005852A patent/FR2646709A1/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB825243A (en) * | 1957-05-30 | 1959-12-09 | Elliott Brothers London Ltd | Improvements in or relating to apparatus for measuring the length in their directionof motion of objects which are travelling along a predetermined path |
| GB960922A (en) * | 1961-11-14 | 1964-06-17 | British Iron Steel Research | Improvements in and relating to measuring apparatus |
| GB1408521A (en) * | 1972-04-27 | 1975-10-01 | Dso Resprom | Apparatus for determining the length of a moving object |
| US3816001A (en) * | 1972-06-20 | 1974-06-11 | W Duncan | Measuring length and velocity of single staple fibers within an airflow |
| GB1573188A (en) * | 1977-09-23 | 1980-08-20 | British Railways Board | Measuring systems |
| GB2129126A (en) * | 1982-11-01 | 1984-05-10 | De La Rue Syst | Dimension of rectangular sheets |
| GB2203540A (en) * | 1987-04-01 | 1988-10-19 | Birtingur H F | Measuring, counting & classifying fish |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993019429A1 (en) * | 1992-03-18 | 1993-09-30 | In-Mar-Tech Australia Pty. Ltd. | Vision apparatus |
| US6404506B1 (en) * | 1998-03-09 | 2002-06-11 | The Regents Of The University Of California | Non-intrusive laser-based system for detecting objects moving across a planar surface |
| CN105136045A (en) * | 2015-09-22 | 2015-12-09 | 北京佰能电气技术有限公司 | Coil down length measurement method for coil collecting station |
| CN105136045B (en) * | 2015-09-22 | 2018-01-05 | 北京佰能盈天科技有限公司 | One kind collection volume station, which is coiled, surveys long method |
| CN106767450A (en) * | 2016-12-28 | 2017-05-31 | 重庆交通大学 | A kind of vehicle super-high ultra-wide detecting system and method demarcated based on function |
| CN106679575A (en) * | 2016-12-29 | 2017-05-17 | 重庆交通大学 | System and method for detecting overheight and overwidth of vehicle based on laser calibration |
| CN106679575B (en) * | 2016-12-29 | 2018-07-03 | 重庆交通大学 | A kind of vehicle super-high ultra-wide detecting system and method based on laser calibration |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8910079D0 (en) | 1989-06-21 |
| FR2646709A1 (en) | 1990-11-09 |
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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) |