EP0303848B1 - Traffic-monitoring device - Google Patents

Description

Technical field

(a)

einen auf durchfahrende Fahrzeuge ansprechenden Sensor,

(b)

Mittel zur Feststellung einer Übertretung von Verkehrsregeln durch das durchfahrende Fahrzeug,

(c)

Mittel zur Erzeugung von Zeitinformationen in Verbindung mit den durchfahrenden Fahrzeugen und

(d)

eine photographische Aufnahmeeinrichtung mit einem Auslöser, der von den Mitteln zur Feststellung einer Übertretung von Verkehrsregeln gesteuert ist, zur Aufnahme eines die Verkehrsregeln übertretenden, durchfahrenden Fahrzeugs und der zugehörigen Zeitinformationen.

The invention relates to a device for traffic monitoring, comprising

(a)

a sensor responsive to passing vehicles,

(b)

Means for determining a violation of traffic rules by the passing vehicle,

(c)

Means for generating time information in connection with the passing vehicles and

(d)

a photographic recording device with a trigger, which is controlled by the means for determining a violation of traffic rules, for recording a vehicle violating the traffic rules and the associated time information.

It can be a device for photographic traffic monitoring, in which a photograph of the vehicle is taken when a violation of a traffic rule is determined. Examples of such devices are traffic light monitoring systems or photographic speed monitoring systems operating with Doppler radar.

Underlying state of the art

Devices for the automatic photographic monitoring of traffic light-controlled intersections are known. A sensor, such as an induction loop installed in the roadway, gives a signal when a vehicle enters an intersection monitored by traffic lights. Another signal is provided by the traffic light when the traffic light goes into its blocking phase. If the vehicle enters the intersection during the blocking phase, a photograph is taken, which records the vehicle and its license plate. This enables the vehicle to be identified and the violation to be documented. In order to improve the evidential value of the photographic registration, several shots are usually triggered one after the other.

Such devices are described, for example, in DE-C-683658, US-A-2871088, AT-C-225077, DE-B-1078797, an article in "Polizei, Technik, Verkehr" Issue 8 (1965), 269-272, and DE-C-2365331.

A device of this type is also described in FR-A1-2547263. It signals signals indicating the position of traffic lights, the passage of a vehicle and the time, as well as a start signal for a paper or magnetic printer to a microprocessor. A first output of the microprocessor leads to a strip registration device, a second to one photographic camera and a third to a calculator.

It is also known to measure the speed of a vehicle and, if a permissible maximum speed is exceeded, to trigger a photograph, by means of which the vehicle is held with its number plate.

The already mentioned AT-C-225077, as well as the US-A-3165373 describes in one exemplary embodiment a traffic monitoring system with two sensors arranged at a fixed distance from one another in the roadway. A camera is triggered and the vehicle is photographed when the time interval between the two sensors being passed is less than a predetermined value. A similar arrangement is known from AT-C-246617.

It is also known to trigger two recordings at fixed time intervals if the two sensors located in the carriageway and the evaluation circuit acted upon by their signals indicate that the permissible maximum speed has been exceeded. A further measured value for the speed can be obtained from the positions of the vehicle on the two recordings.

Instead of the photographic camera, video cameras, generally electronic cameras (JP-A-5251884; DE-A1-3422764) can also be used, the recording being stored electronically together with the associated data, such as measured speed, date and time, and the data stored in this way Playback on a screen, by printing or the like can be retrieved from the memory.

US-A-4173010 describes the use of a film camera for traffic monitoring in its field of view, the film camera being triggered only when the vehicle is traveling at excessive speed and the number of film pictures is a measure of the speed. The speed is first recorded by two sensors, which are arranged at a predetermined distance from each other. A module connected to the sensors contains, among other things, a counter for counting speed violations and a traffic counter.

It is also known to determine the speed of a vehicle to be monitored by means of a Doppler radar. Such a speed monitoring system is described for example in US-A-2683071, CH-A-414210 or CH-A-470674. In conventional photographic speed monitoring systems with Doppler radar, the measured speed is displayed. If the permitted speed is exceeded by the vehicle to be monitored, the vehicle is photographed and the display of the measured speed is reflected in the recording (e.g. DD-A-66974).

EP-A1-0067905 describes a device of this type which also responds to the length of the vehicles passing through and which differentiates, for example, between passenger cars and trucks and the respectively permissible maximum speeds.

Practically all of the aforementioned devices for traffic monitoring contain devices for generating time information, that is to say a clock for displaying the time and a date generator which displays the date.

This time information is registered together with the recording of the vehicle to be monitored, usually reflected in the recording (DD-A-66974).

It is also known to use Doppler radar to generate a sequence of measured speed values while a vehicle to be monitored is driving through the radar beam. These speed measurement values are stored in a classified manner in such a way that a histogram is obtained, that is to say a frequency distribution of these speed measurement values. Conclusions about overtaking maneuvers or the like can be drawn from such a histogram. It is also possible to use the histogram to infer the type of vehicle passing through, i.e. whether it is a car or a truck.

It is also known from SU-A-767810 to measure the speed of vehicles with an induction loop by changing the frequency of the oscillator acting on the induction loop and to determine average values of the speed of groups of vehicles.

From FR-A1-2549625 a device with an induction loop is also known, which makes it possible to carry out a traffic count and at the same time to determine the number of axles, the axle spacing and the axle load of vehicles.

GB-A-1494945 finally describes a registering counting device for traffic counting with up to four vehicle detectors. In it, the detectors are connected to counters, and the counting results are stored in an associated memory at the end of the counting period transfer; Different counting periods are specified for the different counters. The memory contents can be evaluated on a central computer for statistical purposes.

Disclosure of the invention

The invention is based on the knowledge that, in traffic monitoring systems of the type mentioned above, a large amount of information about the traffic situation is obtained to a certain extent as "waste products", which are interesting for traffic planning and traffic statistics and possibly also for the assessment of an individual registered violation, but which are not recorded in the known systems. This information is particularly interesting because such traffic monitoring systems are usually used at traffic foci where statistical documents on traffic density, temporal distribution of traffic and frequency of violations of traffic rules are of particular importance for traffic planning and control.

The invention is accordingly based on the object of making it possible to use such additional information which is obtained in traffic monitoring devices.

The invention is further based on the object of facilitating the evaluation of the violations detected by means of electronic data processing.

According to the invention, this object is achieved by an electronic memory which is connected to the sensor and the means for generating the time information, for storing sensor signals and the associated time information for all vehicles passing through.

It is not only possible to record the vehicles which violate a traffic rule and are photographed, but also all vehicles passing the device. The vehicle density can therefore be determined and, with the help of the clock and date provided anyway, the temporal distribution of the vehicle density can also be determined. The number of violations can be related to the vehicle density, or the time distribution of the violations can be determined. If the device can differentiate between cars and trucks based on a histogram, then this can also be statistically evaluated.

The statistical analysis can also be used to draw conclusions about the traffic situation at the time of a certain violation. For example, one can determine whether there was heavy traffic or the road was empty during the period in which, for example, a monitored vehicle was driving at excessive speed.

The electronically stored data of the detected violations can also be used, for example, to carry out the form-based processing (writing an advertisement) of the registration using electronic data processing. Then only the stored data (eg date, time, location and speed) need to be identified by a number that also appears on the recording. The evaluating official only needs to enter the vehicle registration number recognizable in the recording in a form which has been filled or written by a computer after the memory. This can significantly reduce the burden on the Police can be reached by routine paperwork.

Embodiments of the invention are the subject of the dependent claims.

Brief description of the drawings

Fig. 1

ist eine schematisch-perspektivische Darstellung einer ampelgeregelten Kreuzung mit einer Vorrichtung zur photographischen Überwachung dieser Kreuzung.

Fig. 2

ist ein Blockdiagramm einer Vorrichtung zur Überwachung einer ampelgeregelten Kreuzung mit einem Speicher zur Registrierung der erfassten Vorgänge.

Fig. 3

ist eine schematische Darstellung einer mit Doppler-Radar arbeitenden Geschwindigkeits-Überwachungsvorrichtung.

Fig. 4

ist ein Blockdiagramm der Geschwindigkeits-Überwachungsvorrichtung von Fig. 3.

Embodiments of the invention are explained below with reference to the accompanying drawings.

Fig. 1

is a schematic perspective view of a traffic light controlled intersection with a device for photographic monitoring of this intersection.

Fig. 2

is a block diagram of a device for monitoring a traffic light controlled intersection with a memory for registering the detected operations.

Fig. 3

Figure 3 is a schematic illustration of a speed monitoring device using Doppler radar.

Fig. 4

FIG. 3 is a block diagram of the speed monitor of FIG. 3.

Preferred embodiment of the invention

1 is a schematic perspective illustration of an intersection 10, which is regulated by a traffic light 12.

The remaining traffic lights of the intersection are not shown to simplify the illustration. A sensor 16 in the form of an induction loop is embedded in the road surface of a road 14 that opens into the intersection just before the intersection with the intersection 10. The sensor 16 responds when a vehicle 40 drives over it.

A device 18 for photographically monitoring the intersection 10 is arranged in a housing 20 which is arranged on a column 22 at a short distance from the intersection 10. The device 18 includes a signal processing unit 24, a photographic camera 26 controlled by the signal processing unit and a flash unit 28. The signal processing unit 24 receives a sensor signal from the sensor 16 via a line 30 and a blocking phase signal from the traffic light 12 via a line 32 when the traffic light switches to blocking phase.

As can be seen from the block diagram of FIG. 2, the traffic light 12 contains a transmitter 34 which supplies the blocking phase signal. The signal processing unit 24 supplies a trigger signal to a camera trigger 36 if a sensor signal appears during the blocking phase. The camera trigger 36 then triggers the camera 26. The camera then takes a picture of the intersection 10 with the traffic light 12 on the blocking phase and the vehicle 40 (FIG. 1), which has triggered the sensor signal. Furthermore, a clock 42 and a date generator 44 provided. These form means 46 for generating time information. The displays of clock 42 and date generator 44 are reflected in the recording or otherwise recorded on the film.

When the sensor 16 responds, at least two recordings are usually triggered during the blocking phase. Precautions have been taken to prevent additional triggering between these shots and during the film transport by another vehicle. Provisions have also been made to detect such a vehicle that also enters the intersection between these two images. These measures are known and are therefore not shown in detail.

In such a device for monitoring a traffic light-controlled intersection, a memory 48 is now provided. The processes recorded by the device can be stored in this memory for later evaluation for statistical purposes.

The sensor signals from the sensor 16 can be applied via a line 50. These provide the total number of all vehicles that entered the intersection, regardless of whether they entered the intersection during the blocking phase and were photographed or not. This information is lost in conventional devices of this type. The memory 48 also receives the signals from the signal processing unit 24 via a line 52, through which the camera trigger 36 is controlled. These signals provide the number of violations detected. Finally, the memory 48 also receives time information from the clock 42 via a data line 54 and from the date generator 44 via a data line 56.

The memory can be part of a microprocessor, in which the information is classified, so that the number of events received in predetermined time intervals (pulses on lines 50 and 52) together with the associated time information (time and date) are stored.

The information thus obtained during the operation of the device can be statistically evaluated later. For example, the traffic density in the street 14 can be determined as a function of time. It can be determined what the ratio of the number of violations to the total number of vehicles driven is and whether this ratio changes with time or with the vehicle density. It can also be determined what influence traffic light settings, for example an extension of the "yellow phase", has on the absolute or relative number of registered violations. The stored data of various devices of the present type arranged at traffic hotspots of a city provide a continuous overview of the traffic events in the city and thus documents for traffic planning. All of this is achieved using existing components with a relatively small additional effort.

3 shows schematically a speed monitoring device working with Doppler radar. The device 58 is arranged laterally from a street 60. 62 denotes a vehicle to be monitored. The device 58 contains a radar antenna 64 which emits a "radar lobe" 66, which is shown in broken lines. The "radar lobe" represents the emitted radiation energy per solid angle as a function of the angle. The device 58 also contains one photographic camera 68 that captures a field of view 70. The signals of the radar antenna 64 are connected to a measuring and evaluation circuit 72. The measurement and evaluation circuit provides speed measurements when the vehicle 62 passes through the radar lobe. The camera 68 is triggered when a permissible maximum speed is exceeded. It is triggered at a point in time at which the vehicle 62 is essentially in the middle of the field of view 70 of the camera 68.

Information provided by the measurement and evaluation circuit, including the number of vehicles passing through (regardless of whether it is too fast or not), is stored in a memory 74 for later statistical processing.

4, the device 58 is shown schematically as a block diagram. A Doppler radar 76, which comprises the radar antenna and the associated transmitting and receiving device and an evaluation circuit, provides measured speed values. The speed measurement values are processed into a histogram, that is to say a distribution of the frequencies of speed measurement values over different speed classes. Overtaking processes or the like can be made from this histogram. can be recognized, which could lead to incorrect measured values, so that measured values obtained in this way are suppressed and do not lead to the camera being triggered. It can also be recognized whether the detected vehicle is a car or a truck. And the histogram results in a measured value for the speed of the monitored vehicle 62. In FIG. 4, the evaluation "car / truck" is symbolized by a block 80. The determination of the speed from the histogram is represented by a block 82. The evaluation "car / truck" controls a comparator 84 or 86. On the Comparator is the measured value of the speed of vehicle 62 from block 82 and is compared in each of the comparators with a permissible maximum speed predetermined for the type of vehicle in question, for example of 120 or 80 km / h. Depending on the type of vehicle, a trigger signal is given to a camera trigger 88 at a measured value of more than 120 km / h or a measured value of more than 80 km / h. The camera trigger 88 then triggers the camera 68. The time then taken from a clock 90 and the date from a date generator are simultaneously reflected in the recording that is then made.

This technique is known per se and is therefore not described in detail here.

The various information accumulating in this device are transferred to the memory 74. In particular, the memory 74 receives the time from the clock 90 via a data line 94 and the date from the date generator 92 via a data line 96. Furthermore, the memory 74 receives the measured value of the speed from block 82 via a data line 98. The memory 74 also receives Pulses from the evaluation "car / truck" 80 depending on whether a car or a truck is detected via line 100 or 102. Finally, the memory 74 receives pulses from the comparators 84 and 86 via line 104 or line 106, if a vehicle has exceeded the permissible maximum speed specified for his vehicle type and a triggering pulse is given to the camera trigger.

In the memory 74, the events can also be summed and classified according to speed and / or time. In this device too, the information about non-photographed vehicles is also a "waste product" and can be relative little effort can be recorded and statistically evaluated. Of course, it is not necessary to save all the information given here if not all of this information is to be evaluated.

The statistical evaluation can also be important for the assessment of a single, recorded violation. For example, exceeding the speed limit can be more or less serious depending on whether there was heavy traffic at the time or the road was almost empty.

Finally, the electronic storage of the data associated with a detected violation of the traffic rules can be used to relieve the police when dealing with the violations found. This is because the data stored in the electronic memory can be used to fill out or create forms for a notification or a fine notice by means of a computer. These forms then contain the date, time, place and type of violation from the memory. The police need only enter the vehicle registration number in such a form from the photograph.

This routine work when evaluating the recordings is very time-consuming and often represents the limiting factor when using automatically operating traffic monitoring devices: It makes no sense to detect more violations and recordings than can be subsequently worked up with the available personnel .

Claims (7)

1. Device for traffic monitoring, comprising

(a)   a sensor (16; 64; 76) responding to vehicles passing by,

(b)   means (24; 84, 86) for establishing an violation of traffic regulations by the passing-by vehicle (40; 62),

(c)   means (46; 90, 92) for providing time information in connection with the passing-by vehicles (40; 62), and

(d)   a photographic device (26; 68) having a trigger (36; 88) which is controlled by the means (24; 84, 86) for establishing a violation of traffic regulations, for recording a passing-by vehicle (40; 62) violating the traffic regulations and the associated time information, characterized by

(e)   an electronic memory (48; 74) which is connected to the sensor (16; 46; 76) and to the means (46; 90, 92) for providing the time information, for storing sensor signals and the associated time information of all of the passing-by vehicles (40; 62).

2. Device as set forth in claim 1, characterized in that the electronic memory (48; 74) is additionally connected to the trigger (36; 88) of the photographic camera (26; 68) for storing the violations in connection with the associated sensor signals and time information.

3. Device as set forth in claim 1 or 2, characterized in that

(a)   the means (84, 86) for establishing the violation of a traffic regulation comprises a speed measuring device (82) for measuring the speed of the passing-by vehicles (62), and

(b)   the memory (74) is adapted to store the measured speeds.

4. Device as set forth in any one of the claims 1 to 3, characterized in that

(a)   the means (84, 86) for establishing the violation of a traffic regulation comprise a device (80) for establishing the type of the vehicle (passenger car, motor lorry), and

(b)   the memory (74) is adapted to numerically store the type of the passing-by vehicles (62).

5. Device as set forth in claim 1, characterized in that it is a photographic traffic light monitoring installation.

6. Device as set forth in claim 1, characterized in that it is a photographic speed monitoring installation operating with a Doppler radar (76).

7. Device as set forth in claim 1, characterized in that the means (24; 84, 86) for establishing a violation of traffic regulations, the means (46; 90, 92) for providing time information and the electronic memory (48; 74) are combined in a unit which is adapted to be installed at the location of the traffic monitoring.

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