EP0612049B1 - Method for classifying vehicles passing a predetermined point on the road - Google Patents

Description

The invention relates to a method for classifying vehicles passing a given waypoint.

For military reconnaissance it is necessary to make movements of troops in a deployment area in time recognize and reliably analyze. For this is the Observation of vehicle shifts in certain Path sections indispensable, and not only the number of vehicles passing a waypoint but also theirs Nature must be established.

In a known method of the type mentioned (FR 2 670 404 Al) the optical measurement of a Waypoint passing at any speed Vehicle through a variety of between each light emitting photodiode on one side and one photosensitive sensor on top of the other Pathside clamped light barriers with constant Distance from each other arranged in a vertical measuring plane are, and by a variety of similar Photoelectric sensors that are in constant distance from each other a horizontal one parallel to the path Measurement plane are arranged. The one with constant assumed Vehicle passing through this measuring device interrupts the light barriers in the two Measurement levels, so that the photo sensors in both measurement levels emit time-dependent signals. While the signals of the vertical measuring plane a line of intersection of the vehicle record its current vertical extent, represent the signals of the horizontal measuring plane Feed the vehicle along the path. The one of the two Signals delivered to measurement levels become continuous in time composed and deliver a silhouette or one Silhouette of the passing vehicle, based on which or whose the vehicle by comparison with known ones Vehicles is classified. The for this procedure required measuring device requires a considerable Installation effort at the measuring location. It also results from the length of the required carrier for the photodiodes and A photo sensor for spanning both measurement levels voluminous structure that the application of the known Procedure for military reconnaissance purposes forbids, has such a considerable Soaring structure a large Probability of treason.

In a likewise known method for Vehicle classification (US-PS 4 158 832) is used to distinguish between tracked vehicles, such as tanks or the like, and wheeled vehicles such as articulated lorries, Trucks and the like, a seismic detector which near the monitored path in the ground is buried. The driving generated by the vehicles and engine noise couple into the floor and spread in the form of seismic or ground sound waves in the ground. These ground sound waves are preferred by the Received geophone trained seismic detector. From the Output signals of the geophone are made using more suitable Signal processing method won criteria that show whether the received sound waves from a tracked or wheeled vehicle has been triggered.

With such a seismic detection and Classification procedures can be determined Genera of vehicles, such as cycling and Track vehicles, separate from each other, but can not certain vehicle types within a category, like heavy, multi-axle semitrailers or lighter ones Trucks with one or more drive axles, or Tanks and lighter ones also equipped with chains Reconnaissance vehicles, can be distinguished from each other.

The invention is based on the object Classification procedure for vehicles to indicate that recognizes vehicles passing a waypoint and uses them for military intelligence purposes of sufficient delicacy can make a difference, even vehicles with the same Design features, such as chains or wheels, still within their genus in different vehicle types broken down, i.e. classified.

The task is in a procedure in the preamble of Claim 1 specified genus according to the invention by the Features solved in the characterizing part of claim 1.

With the inventive method by measuring the Distance to a vehicle passing the waypoint from a single measuring point lying transversely of the path along a measuring line just a little above the floor Profile of the chassis in the direction of the longitudinal axis of the vehicle won, at least with its characteristic Parameters used to identify the vehicle becomes. Such characteristic chassis parameters that specifically occur only with certain vehicle types and are therefore best suited for their identification e.g. B. the number of vehicle wheels, the number of Wheel axles, the distances between the wheel axles and the diameter of vehicle wheels and wheel covers Tracked vehicles and vehicle aprons and the like. These in Chassis parameters measured in the vehicle longitudinal direction with a variety of similar chassis parameters known reference vehicles compared, and at the measured vehicle will be of sufficient agreement identified as that reference vehicle.

Here it is possible, on the one hand, the typical ones Extract chassis parameters from the measurement profile and with the corresponding chassis parameters of the known To compare reference vehicles, and on the other hand, based on the typical chassis parameters of the reference vehicles synthetic measurement profile of the chassis of the known Create reference vehicles and use them immediately to correlate the measurement profile.

With the chassis parameters mentioned above and their Combination on a measured vehicle can not only Wheeled vehicles are divided into different categories but also tracked vehicles in their various Training courses are identified because of the number of Chain wheels, their diameter and wheelbase as well Wheel cover for different types of Tracked vehicles are also designed differently.

Advantageous embodiments of the invention Procedure with appropriate configurations and Improvements of the invention result from the others Claims.

According to a preferred embodiment of the invention Processes are used to obtain suspension parameters the measured profile of the undercarriage Addition of the measured value intervals of successive measured values with approximately the same measured value and the Position of the individual cutting lengths determined. Distance measurements with the same measured variable are created based on the same distance measurement Undercarriage part so that the cutting lengths are the length of this Play chassis parts in the vehicle's longitudinal axis. There According to the invention, the measuring height, i.e. the distance of the measuring line is kept quite low from the earth's surface, characterize repeatedly, i.e. at least twice, Same cutting lengths occurring in the measuring profile parallel to secant sections of the earth 's surface Vehicle wheels. From the cutting length can be due to the known measuring height and known geometric relationships determine the wheel diameter. Every wheel axle lies on the Middle of the respective cut lines, and the distance of the Wheel axles can thus be taken directly from the measurement profile remove. The classification of the waypoint passing vehicle is then due to the large number in accordance with the chassis parameters with the same Chassis parameters of one of the known reference vehicles.

The one based on the distance measurement to the vehicle compared to the inventive method Video surveillance of a path section or surveillance the route section with a thermal imager the advantage that to create a meaningful measurement profile only few data are processed and thus to the corresponding evaluation points must be transferred. The measured values are relatively robust Transmission error. A measuring device for implementation The distance measurement can therefore be very inexpensive manufactures and thus a variety of different waypoints can be installed. The evaluation of the measured values at the individual measuring points, i.e. the creation of the Measurement profile, the extraction of chassis parameters and the comparison with reference vehicles can be made in one of the Remote control center for all Measuring devices are carried out. For a variety of Waypoint monitoring is therefore only one Evaluation center necessary.

Fig. 1

eine Seitenansicht eines auf einer Straße fahrenden Lastkraftwagens mit einer querab der Straße angeordneten Meßvorrichtung,

Fig. 2

eine Draufsicht von Fahrzeug und Meßvorrichtung gemäß Pfeil II in Fig. 1,

Fig. 3

eine Darstellung eines Meßprofils vom Fahrwerk des Fahrzeugs in Fig. 1 und 2,

Fig. 4

eine Darstellung der geometrischen Beziehungen zur Ermittlung eines Raddurchmessers R,

Fig. 5

ein Blockschaltbild einer Vorrichtung zur Durchführung des Klassifizierungsverfahrens.

The invention is described below with reference to an embodiment shown in the drawing. They show, each in a schematic representation,

Fig. 1

2 shows a side view of a truck traveling on a street with a measuring device arranged transversely of the street,

Fig. 2

2 shows a top view of the vehicle and measuring device according to arrow II in FIG. 1,

Fig. 3

1 shows a measurement profile of the chassis of the vehicle in FIGS. 1 and 2,

Fig. 4

a representation of the geometric relationships for determining a wheel diameter R,

Fig. 5

a block diagram of an apparatus for performing the classification method.

With the classification procedure described below vehicles are detected and identified, the one pass the given waypoint on a route 10.

It is assumed that the vehicles reach the waypoint one after the other and not at the same time what happens at appropriate waypoint selection is usually the case is. The procedure is based on the following Identification of a truck 11 with double Rear axle described, which is on the route 10 in Direction of travel moves according to arrow 12 and the given waypoint happens.

From a measuring location 13 lying transversely of the route 10 becomes one along the given waypoint running fixed measuring line 14 continuously the distance measured to the chassis of the vehicle 11. The Distance measurement is optically active with an am Measuring site 13 installed known per se Laser rangefinder with an infrared laser transmitter a sharply focused beam of light along measuring line 14 transmits and with a receiver that on chassis parts of the vehicle 11 receives reflected light. By means of a The evaluation unit becomes the received signals Distance to vehicle 11 determined. The laser beam can consist of pulsed or modulated light. At Emission of light pulses will reduce the running time of the the respective laser pulse and the distance from it certainly. The measuring line 14 is perpendicular to Direction of travel 12 of the vehicle 11, that is perpendicular to Route 10, aligned to depend on the aspect angle Avoid problems with distance measurement. The Measuring line 14 keeps the smallest possible distance D from the Surface of the driveway 10, which is typically about Is 20 cm. For the selection of an optimal measuring height D The following boundary conditions apply: The measurement should above road bumps, e.g. B. at Gravel roads. The measurement should also be narrow Adjacent wheels or rollers in motor vehicles separate from each other, d. H. the gaps between the wheels or rollers should be as large as possible, the measuring line should be below the wheel axles since the chassis above the axes often through aprons and the like is covered.

In addition to the continuous distance measurement, the Driving speed v of the vehicle 11 when passing Waypoint measured. The measurement of driving speed can be done by various methods, e.g. B. by Arrangement of two at a distance from each other in the direction of travel 12 of the vehicle 11 arranged sensors for detecting the passing vehicle and determining the time difference. The detection of the vehicle can, for example, with Magnetic sensors take place, the changes of the magnetic earth field when passing the vehicle capture.

The spatial distance .DELTA.L of the measured values in the vehicle longitudinal axis is determined from the known measuring frequency F of the distance measurement and the measured vehicle speed v, and a measuring profile of the chassis of the vehicle 11 is created with this spatial distance of the measured values. For this purpose, the successively determined distance measured values are strung together with an interval predetermined by the calculated distance in a direction corresponding to the longitudinal axis of the vehicle. The resulting measurement profile of the chassis of the vehicle 11 is shown schematically in FIG. 3. The measured value, ie the measured distance E, is plotted on the ordinate and the number of measurements with successive distances ΔL is plotted on the abscissa. The measurement profile clearly shows that some successive measurement values have the same measurement value size, which means that these measurement values originate from the same chassis part of the vehicle 11. To evaluate the measurement profile for the purpose of identification and classification of the vehicle 11, so-called cut lengths I are defined by adding the measured value distances L of successive measured values with approximately the same measured value size, and the position of these cut lengths I within the measurement profile is determined. Due to the measuring height D, i.e. the distance of the measuring line 14 from the surface of the route 11, and the repeated occurrence of identical cutting lengths I in the measuring profile shown, it can be assumed that the measured values within the cutting lengths I of the vehicle wheels of the vehicle 11 in Fig 1, the cutting lengths I thus represent secants of the vehicle wheels extending parallel to the route 10. 4 shows the geometrical relationships on the vehicle wheel taking into account the measuring height D and the cutting lengths I. As can easily be derived from this sketch, the diameter R of the vehicle wheel can be determined from the cutting length I R = D + I. 2nd 4D calculate. A first characteristic chassis parameter for the vehicle 11 is thus derived from the measurement profile. In order to eliminate errors, this wheel diameter R is only permitted for reasons of plausibility if the condition D / 2 <R <3 m is satisfied. If R is greater than 3 m, the cutting line cannot originate from a vehicle wheel, but rather must come from a side apron.

The center of the wheel and thus the point of penetration of the The wheel axis lies on the middle solder of the cutting length I. The Distance of the wheel axles can thus be easily from the Take the measurement profile. So that's another Vehicle parameters that typify the vehicle 11 are known. Likewise, the number of wheel axles, here three, without further from the presence of three for vehicle wheels take characteristic cutting lengths I. So that's a further chassis parameters for the vehicle 11 are known.

The suspension parameters derived as above: number of the wheel axles, distance of the wheel axles and diameter of the Wheels are made with a variety of the same Compared chassis parameters of known reference vehicles, and the measured vehicle 11 is called that Reference vehicle identified or classified, the Chassis parameters in total the smallest deviation of the three derived from the measurement profile Have chassis parameters. Here, so as Truck with two type XY rear axles. Based the vehicle data of the reference vehicle maximum permissible loading weight, unladen weight Etc..

To evaluate the measurement profile for the purpose of identifying the Waypoint passing vehicle 11 can also do so be proceeded that from the chassis parameters one Numerous well-known reference vehicles Including the measuring height D of the measuring line 14 a variety of synthetic chassis profiles, in the following Called reference profiles are generated, designed in this way are, like the measurement profile shown in Fig. 3. The so obtained synthetic reference profiles of the multitude of Reference vehicles are successively with the measurement profile 3 of the vehicle 11 to be identified correlated, d. H. checked for agreement. That too identifying vehicle 11 is then called that Reference vehicle classified, with the measurement profile 3 correlated reference profile the largest Correlation factor results, i.e. as close as possible to 1. A limit value of the Correlation factor can be set at which such Assignment of vehicle 11 to a reference vehicle is allowed so that misclassifications largely be excluded.

FIG. 5 shows a block diagram of a device for carrying out the described classification method for vehicles. 15 is a laser rangefinder and 16 a speed measuring device. Laser range finder 15 and speed measuring device 16 are activated by a wake-up device 17 when a vehicle 11 approaches the predetermined measuring point through which the measuring line 14 passes. The wake-up device 17 can be, for example, a passive sensor system, such as, for. B. magnetic sensors that register a change in the magnetic field caused by the vehicle when approaching. When activated, the laser rangefinder 15 and the speed measuring device 16 enter their measuring mode, ie the laser rangefinder 15 continuously measures with the measuring frequency F the distance E along the measuring line 14 to the vehicle 11 passing through the measuring line 14. At the same time, the speed measuring device 16 measures the current driving speed of the vehicle Vehicle 11 when passing the measuring line 14. The measured values output by the laser range finder 15 are passed through a filter 18, in which incorrect distance measured values, e.g. B. due to disturbed laser reflection, detected and removed. The distance measured values filtered in this way are fed to a measured value evaluation unit 19 which additionally receives a measuring signal representing the vehicle speed v from the speed measuring device 16 and a signal indicating the measuring frequency F from the laser range finder 15. The measured value evaluation unit 19 calculates the spatial distances between the individual measured values in the direction of the vehicle longitudinal axis from the quotient of the vehicle speed v and the measurement frequency F in accordance with L = v F

With this measured value distance from the Measured value evaluation unit 19, the measurement profile according to FIG. 3 created and a parameter extraction unit 20 fed. The extraction unit 20 determines how described above, typical from the measurement profile Chassis parameters such as wheel diameter, number of Wheel axles and wheel spacings and gives the determined Suspension parameters to a comparator 21. In one Reference memories 22 are a multitude of the same Chassis parameters from known reference vehicles in Assignment to these reference vehicles saved. This Chassis parameters are successively in the comparator 21 read out. The comparator 21 determines the degree of Agreement of all chassis parameters of the same Reference vehicle with the vehicle parameters of the identifying vehicle 11 and gives that Reference vehicle from which the degree of agreement is maximum. This means that what is to be identified Vehicle 11 as the output reference vehicle is classified.

Instead of blocks 20 and 21, blocks 23 and 24 can be used be provided, the block 23 a Computing device and block 24 a correlation unit represents. With the computing device 23 from the A large number of stored in the reference memory 22 each belonging to a large number of reference vehicles Vehicle parameters taking into account the measuring height D. synthetic reference profile for each of the stored Created reference vehicles that are configured the same, as the measurement profile for the chassis of the vehicle 11 in Fig. 3. The one created in the measured value evaluation unit 19 Measurement profile of the chassis of the vehicle 11 is the Correlation unit 24 supplied. The correlation unit 24 successively correlates this measurement profile with everyone that calculated by the computing device 23 Reference profile from the chassis of a known Reference vehicle and determines the correlation factor. Out the large number of correlation factors becomes the maximum Correlation factor determined, preferably still must also exceed a minimum size. The Reference vehicle that has this maximum correlation factor results, is output as a classification vehicle, i.e. H. the vehicle 11 to be detected is considered to be that at the exit the correlation unit 24 output reference vehicle classified.

The invention is not based on the described Embodiment limited. So z. B. at Embankments next to 10, which has little space for the Establishment of the measurement site 13 near the route 10 leave a look right on the edge of route 10 with an entrance and exit pupil at measuring height D installed, the optical axis with the measuring line 14 coincides. The optics is via a light guide cable with the measuring point set up behind the embankment installed laser rangefinder connected, namely there coupled to the laser transmitter and receiver. The Fiber optic cables can be laid as desired, including through the Embankment led through or buried in the earth will. When measuring distance, the length of the Fiber optic cable to be considered. It is possible in the Optics to provide a separate entrance and exit pupil, each with separate fiber optic cables with the Laser transmitter and the receiver can be connected. It is however, the entry and exit pupil are also possible fold so that only one light guide cable to the Laser rangefinder performs.

Claims (11)

1. Method of classifying vehicles passing a predetermined point on the road, in which the vehicle (11) respectively passing the point on the road is actively optically surveyed at the point on the road from abreast of the road, and a measurement profile of the vehicle (11) is generated, which is compared indirectly by derivation of parameters or directly with a plurality of known reference vehicles, characterised in that the optical surveying of the vehicle (11) is performed by means of a continuous optical distance measurement along a fixed measurement line (14), which runs through the point on the road on a level with the chassis of the vehicle (11), of a single measurement location (13) located abreast of the road (10), that the speed (v) of the respective vehicle (11) passing the point on the road is measured, and from the vehicle speed (v) and the measurement frequency (F) the spatial distance (L) between the measured values is determined in the longitudinal axis of the vehicle, and that by aligning the measured values predetermined by the distances (L) in the direction of the longitudinal axis of the vehicle, a measurement profile of the chassis of the vehicle (11) is drawn up.
2. Method according to Claim 1, characterised in that for derivation of chassis parameters such as number of vehicle wheels, distance between axles, diameter of the vehicle wheels and suchlike, cut lengths (I) are defined in the measurement profile by addition of the measured value distances (ΔL) of consecutive measured values with approximately equal measured value magnitude and the position of the individual cut lengths (I) is determined.
3. Method according to Claim 2, characterised in that the vehicle parameter "wheel diameter (R)" is calculated from the cut length (I) according to the equation R = D + I2 4D wherein D is the distance of the measurement line (14) from the road surface, and that the vehicle parameter "wheel diameter (R)" is only permitted when D/2 < R < 3 m.
4. Method according to Claim 3, characterised in that the vehicle parameter "wheel distances" is determined from the cut lengths (I) permitted as vehicle parameter "wheel diameter (R)" and their relative position in the measurement profile.
5. Method according to one of Claims 2 to 4, characterised in that the derived chassis parameters are compared with a plurality of like chassis parameters of known reference vehicles, and that the vehicle (11) respectively passing the point on the road is identified as the reference vehicle whose chassis parameters exhibit the smallest deviations in total from the chassis parameters derived from the measurement profile.
6. Method according to Claim 1, characterised in that a plurality of artificial chassis profiles (reference profiles) belonging to one respective vehicle is generated from the chassis parameters of the plurality of known reference vehicles, including the measurement height (D) of the measurement line (14), that the measurement profile is correlated with the plurality of reference profiles, and that the vehicle (11) respectively passing the point on the road is identified as the reference vehicle, whose reference profile correlated with the measurement profile provides the highest correlation factor.
7. Method according to one of Claims 1 to 6, characterised in that the measurement line (14) is oriented essentially horizontally and at right angles to the direction of travel (12) of the vehicle (11).
8. Method according to Claim 7, characterised in that the distance (D) of the measurement line (14) from the road surface is kept as small as possible, typically amounting to about 20 cm.
9. Method according to one of Claims 1 to 8, characterised in that a laser range finder known per se, preferably an infrared laser range finder, with a laser transmitter, which transmits a finely focussed light beam, a receiver, which receives reflected light, and an evaluation unit, which calculates the distance, is used for the optically active distance measurement.
10. Method according to Claim 9, characterised in that the light transmitted by the laser transmitter and the reflected light absorbed by the receiver is emitted and absorbed respectively via an optical unit installed on the road edge at measurement height (D) with an exit and entrance pupil, which is connected to the laser transmitter and receiver via at least one light guide.
11. Method according to one of Claims 1 to 10, characterised in that the vehicles (11) are detected at a distance in front of the point on the road and the distance measurement is activated with the detection signal.

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