JPH06242259A - Vehicle detector - Google Patents

Abstract

PURPOSE:To accurately detect a vehicle even under a special passing condition such as the side-by-side advance of vehicles within a lane or the outrunning of a motorcycle at the time of stagnation or a special condition such as the weather generating the shade. CONSTITUTION:A unidimensional CCD camera 2 is arranged above a road surface so as to obtain the unidimensional quantity-of-light signal in a lane width direction from the road surface and intermittent marking 6 is preliminarily arranged on the road surface within the visual field of the unidimensional CCD camera 2 so as to apply modulation to the unidimensional quantity-of-light signal. When a vehicle 3 enters the visual field of the unidlmensional CCD camera 2, since the modulation of the unidimensional quantity-of-light signal is disturbed, the vehicle is detected on the basis of the output signal of the unidimensional CCD camera 2 by a signal processing device 5 using the presence of the disturbance of modulation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle detector for use in toll collection machines on toll roads and in traffic equipment such as traffic volume measurement.

[0002]

2. Description of the Related Art As a conventional method for detecting and counting passing vehicles on the road from above the road surface, the following (1) to
It is like (3). (1) Ultrasonic system shown in FIG. 15: In this system, a transducer 101 that oscillates and receives an ultrasonic wave 101A is provided above the road surface to detect the distance to the road surface. That is, as shown in FIG. 15, when the vehicle 103 passes through, the time required for the reflected echo 104 to return is shortened, and the presence of the vehicle 103 is detected. (2) Microwave method (not shown): In this method, the frequency of the reflected wave with respect to the oscillated microwave is measured. That is, the wave reflected back to the passing vehicle undergoes a Doppler shift (frequency shift), and the wave reflected back to the road surface does not undergo frequency shift. Therefore, the passage of the vehicle can be detected by detecting this frequency shift. (3) Optical system shown in FIG. 16: In this system, as shown in FIG. 16, the illuminance on the road surface 102 is monitored by the optical sensor 105, and when the vehicle 103 passes, the coating color of the roof is different from the road surface. Therefore, the vehicle 103 is detected. In the optical system, an optical lens can be used to reduce the field of view or to form an array for multiple detection.

[0003]

The conventional vehicle detection technique described above has the following problems.

Since the ultrasonic system and the microwave system have a long wavelength, they have a wide beam width, and thus widely cover the lane below from the installation position on the road surface. That is, it is possible to detect wherever a small vehicle 103 such as a motorcycle passes in the lane immediately below. This makes 1
One sensor has the advantage of covering the entire width of one lane, but conversely, when a plurality of motorcycles translate in the same lane, they cannot be counted separately. In addition, it is not possible to detect a motorcycle that slips beside a truck on a stagnant road. As described above, the method using ultrasonic waves or microwaves has a limit in accurately detecting a passing vehicle. In the case of traffic volume measurement for controlling traffic lights at intersections, it is not a big problem even if miscounting in the special case as described above, but when applying to toll road toll collection, Exceptions are not allowed.

Unlike the microwave and ultrasonic methods, the optical method is based on the light beam 106, so that the optical sensor 1
If 05 is provided so that the visual field has a fine pitch in the width direction in the lane, as shown in FIG. 16, a case such as a translation of the motorcycle 103 can be counted separately. However, in this case, when the altitude of the sun 107 is low in the morning or in the evening, a shadow 108 of one vehicle is generated on the road surface 102. Therefore, depending on the time, translation of two motorcycles is also detected as one vehicle. It is possible.

[0006] Therefore, an object of the present invention is to provide a vehicle detection device that is not easily affected by traffic patterns such as translation and stagnation, and is also less affected by weather conditions.

[0007]

A vehicle detection device of the present invention which achieves the above object is an optical array sensor which is installed above a road surface and obtains a one-dimensional light amount signal in the lane width direction from the road surface, and this optical array. An optical system installed on the sensor, an intermittent marking installed on a road surface within a one-dimensional field of view of the optical array sensor, and a signal processing device for performing vehicle detection processing from an output signal of the optical array sensor. It is characterized by having done.

In this case, it is preferable that the intermittent period of the intermittent marking be longer than the period of the pixels of the optical array sensor on the road surface and shorter than the minimum width of the vehicle to be detected. Alternatively, preferably, at least one of a tread having a contact buried in the road surface, a loop coil buried in the road surface, an ultrasonic transmitter / receiver installed above the road surface, and a microwave transceiver installed above the road surface. Further, it is provided with one sensor, and the signal processing device performs vehicle detection processing from the output signal of this sensor and the output signal of the optical array sensor.

[0009]

The optical array sensor and the optical system obtain a one-dimensional light amount signal in the width direction of the lane from the road surface. Intermittent marking on the road surface is to add modulation to the one-dimensional light amount signal, and there is actually a vehicle on the road surface depending on the presence or absence of modulation disturbance, or there is no vehicle and the vehicle simply passes through the adjacent lane. It is used to discriminate whether or not the vehicle has a shadow. That is, the signal processing device processes the one-dimensional light amount signal by using the presence or absence of modulation by intermittent marking, separates and discriminates the background road surface and passing vehicles, and performs passage detection for each individual vehicle. .

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a vehicle detection device according to an embodiment of the present invention. In FIG. 1, a gantry 1 is used to install a device 2 above a road surface 102 of the road. The device 2 is an optical array sensor and an optical system. In this embodiment, a one-dimensional CCD optical device is incorporated. It is a one-dimensional CCD camera. The one-dimensional CCD cameras 2 are installed directly below each lane, and each one-dimensional CCD camera 2 has a road surface 102.
On the other hand, a one-dimensional visual field 2A in the lane width direction is obtained. Note that one lane width may be included in the field of view with a plurality of one-dimensional CCD cameras. 3 is a passing vehicle.
The output signal of the one-dimensional CCD camera 2 is transmitted to the signal processing device 5 through the cable 4, and the signal processing device 5 detects the passing vehicle 3. The signal processing device 5 outputs a pulse signal 5A each time one vehicle passes. The intermittent marking 6 is a periodic marking provided on the road surface 102 in the field of view of the one-dimensional CCD camera 2. In this embodiment, the reflective paint is periodically applied to the road surface 102 to form the marking 6.

Next, the role of the intermittent marking 6 will be described with reference to FIGS. FIG. 2 shows an example of the output signal 2B when the road surface is captured by the one-dimensional CCD camera 2,
The offset changes depending on the sunshine conditions, but marking 6
It is possible to obtain a periodic signal modulated by. Therefore, if the vehicle passes through, the periodic signal is disturbed at the passing portion as shown by reference numeral 2C in FIG. 3, and the position at which the vehicle passed can be known from the disturbance. For example, even if the motorcycle is translated, there are two places 2C where the periodic signal is disturbed, so that the two can be separated. Further, if there is no passing vehicle in the lane directly below the one-dimensional CCD camera 2 and a large truck passes through the adjacent lane, a shadow of the truck is formed in the visual field of the one-dimensional CCD camera 2 depending on the direction of the sun. At this time, the waveform 2D as shown in FIG. 4 is obtained. That is, since the offset decreases in the shaded portion 2D, but the periodic signal does not disappear, it can be seen that there is no vehicle in this lane. As described above, the vehicle can be accurately detected by detecting where the periodic signal is disturbed based on the periodic signal.

Next, a specific example of the signal processing device 5 will be described with reference to FIG. The signal processing device 5 includes an amplifier 10, a bandpass filter 11, an A / D converter 12, a reference signal pattern memory 13, a matching circuit 14, and a binarization circuit 1.
5, a reference register 16, a one-dimensional memory 17, a timing generation circuit 18, and a computer 19.

The operation of the signal processing device 5 will be described. First,
The signal 2B from the one-dimensional CCD camera 2 is amplified by the amplifier 10, and the amplified signal a passes a frequency component centered on the periodic component of the marking 6 to remove a low frequency component due to sunshine or shadow. This signal b is further digitized by the A / D converter 12 through the band pass filter 11. The reference signal pattern memory 13 stores a standard periodic pattern when there is no vehicle on the road surface and all the intermittent markings 6 are in the visual field. The capacity is for one-dimensional field of view. The matching circuit 14 inputs the road surface signal from the A / D converter 12 and the reference pattern c from the reference signal pattern memory 13, and removes the periodic component from the road surface signal of the A / D converter 12. The signal d from which the periodic component has been removed is added to the binarization circuit 15. A reference value which is one input of the binarization circuit 15 is set in the reference register 16.
Therefore, the binarization circuit 15 divides the vehicle-existing portion into a level "1" and the road surface into a level "0", for example, and the binarized signal e is thus divided into the one-dimensional memory 17. Stored in. As a result, when the contents of the one-dimensional memory 17 are all "0", the vehicle does not exist. The timing generation circuit 18 controls the entire timing inside the signal processing device 5. As the timing, for example, a synchronization signal of the one-dimensional CCD camera 2 or
A conversion command signal of the A / D converter 12 and the one-dimensional memory 17
Data storage, notification to the computer 19, and the like. The signal processing device 5 generates an output for entering the vehicle when the content of the one-dimensional memory 17 changes from "0" to non- "0". The contents of the one-dimensional memory 17 are updated one after another based on the signal from the timing generation circuit 18. The computer 19 controls and determines the entire device. Also, the computer 19 checks the contents of the one-dimensional memory 17 every time the contents are updated, as described above, whether or not it is non- “0”,
When it is not "0", the presence of the vehicle is detected. FIG. 6 shows the waveforms of the signals a, b, c, d, and e of the respective parts of FIG.

Next, a vehicle detection procedure in the computer 19 will be described with reference to FIGS. 7 and 8. FIG. 7 shows the contents of the one-dimensional memory 17 over time, and FIG. 8 shows a flowchart.

As shown in FIG. 7, the contents of the one-dimensional memory 17 are non- “0” as t = 1 and t = 2 for one vehicle 3.
However, when a region of "1" occurs with "0" in another place of the one-dimensional memory 17 as at t = 3, the entry of another vehicle 3A is detected. However, the computer 19 checks the contents of the one-dimensional memory 17 each time it updates,
There is a block of "1" divided into two areas, and this is t
If it is found that they will be merged into one later, as in = 4, it is determined again that this is one vehicle 3A. That is, the determination is completed not when the one-dimensional memory 17 changes from all “0” to non- “0” but when the vehicle exits. In addition, the non- “0” part is “0” due to sequential update and determination.
If so, it is determined that the vehicle has passed the detection area, and the output signal is dropped. That is, when detecting the entry of a vehicle,
The detection of the first vehicle and the detection of the second vehicle are also included, and exit detection is also performed for each vehicle detected. As described above, the computer 19 judges the content of the one-dimensional memory 17 while comparing it with the content of the one-dimensional memory 17 at the time of the previous scanning. This is performed by performing labeling processing such as labeling each vehicle.

The output from the computer 19 is obtained through a passing number counter 20 and an existing counter 21. The passing vehicle number counter 20 is incremented next when a vehicle is detected. Therefore, this counter 20 clearly indicates the cumulative number of passing vehicles. In addition, the existing counter 21 is CC
The number of vehicles existing in the field of view of the D camera 2 is specified. Therefore, if there are translational motorcycles, the counter 21 will display, for example, two motorcycles.

Here, the size of the one-dimensional memory 17 is determined in relation to the number of pixels of the optical sensor which constitutes the one-dimensional CCD camera 2. As a general rule, when a 1000-pixel CCD camera is used, the one-dimensional memory 17 also has a capacity of 1000 bits. If the number of pixels of the one-dimensional CCD camera 2 is 1000 and the road width is 5000 mm,
One pixel corresponds to 5 mm on the road surface.

Therefore, the period of the intermittent marking 6 is set to a period larger than 5 mm corresponding to one pixel and smaller than the width of a small vehicle such as a motorcycle. In the present invention, since the vehicle is detected by the disturbance of the cycle in the output signal of the optical array sensor, if a vehicle having a minimum width of 500 mm is to be detected, the mark needs to have about 2 to 5 cycles per 500 mm. If the cycle is 5 cycles, the cycle of the marking 6 on the road surface is 100 mm. That is, the period of the marking 6 is set to be larger than one pixel of the CCD camera 2 on the road surface and smaller than the minimum width of the passing vehicle.

As described above, by using the one-dimensional CCD camera 2 and the intermittent marking 6, when the toll collection is carried out by using the wireless IC card in the main lane of the toll road, the vehicle detection device in the traffic volume measurement etc. As a result, the vehicle can be accurately detected even under special conditions such as translation in the lane of the vehicle, overtaking of the motorcycle at the time of stagnation, or shadowing.

Next, a vehicle detection device according to another embodiment of the present invention will be described with reference to FIGS.

In the vehicle detection device shown in FIG. 9, in addition to the one-dimensional CCD camera 2, the signal processing device 5 and the intermittent marking 6 shown in FIG. 1, the one-dimensional CCD camera 2 is embedded in the road surface in the visual field. One or more vehicle type discriminating treads 30 are provided as auxiliary sensors for vehicle detection, and the signal processing device 5 uses not only the signal from the one-dimensional CCD camera 2 but also the signal from the vehicle type discriminating tread 30 to detect the vehicle. Perform processing.

FIG. 10 shows the structure of the vehicle type discrimination tread plate 30.
The vehicle type discrimination tread 30 is used by being embedded on the road 109 as described above. Conductive contact 3 inside the vehicle type disc
A plurality of 1, 32 are arranged in the vehicle width direction. Then, when the tire 33 of the vehicle passes over this contact point, a pressure 34 is generated, the conductor contact points 31 and 32 come into contact with each other, and a current flows. If this contact information is mapped on the memory, the contact information 35 to 38 and 4 as shown in FIG.
Map information consisting of 0 and 41 is obtained. That is, 35
When four contact information items of 38 to 38 are obtained, the contact information group indicated by 39 is recognized from the arrangement, it is determined as a passenger car, and when two contact information items of 40 to 41 are obtained, the contact information group indicated by 42. It can be recognized as a motorcycle.

FIG. 12 shows an example of a schematic configuration of the signal processing device 5. The memory 43 for the vehicle type discriminating tread 30, the line sensor memory 44 for the one-dimensional CCD camera 2, and the composition memory 4 are shown.
5 and a matching device 46. A more detailed structure of this is as shown in FIG. 13, and when compared with FIG. 5, the one-dimensional memory 17 of FIG. 5 corresponds to the line sensor memory 44 of FIG. 13, and instead, the synthesizing memory 4 of FIG.
5 corresponds to the one-dimensional memory 17 of FIG. Further, the computer 19 is responsible for the function of the matching device 46.

The vehicle detection system of this embodiment will be described with reference to FIG. In FIG. 12, first, the tires of the passing vehicle apply a pressing force to the vehicle type identification tread 30 to cause the vehicle type identification tread 3 to pass.
The 0 contact is made conductive. Then, in synchronization with the synchronization signal 47 sent from the one-dimensional CCD camera 2, the conduction / non-conduction state of each contact in the vehicle width direction, that is, the contact information is transmitted to the vehicle type discrimination tread memory 43. Then, the map information 49 as shown in FIG. 14 can be obtained in the vehicle type determination tread memory 43 with the passage of time. 49A is information of contact ON.

Further, using the one-dimensional CCD camera 2, the contour of the image of the vehicle passing from the gantry 1 on the vehicle type discrimination tread 30 is cut out and stored in the line sensor memory 44 as in the previous embodiment. In this way, the map information 50 as shown in FIG. 14 can be obtained in the line sensor memory 44 over time. 44A is non- "0"
Area. At this time, the vehicle type identification tread 30 and the CC
In order to match the time axis of the D camera 2, CC as described above
A sync signal 47 is output from the D camera to the vehicle type discrimination tread 30.

Then, the contents of the two memories 43 and 44 are overlapped and stored in the composition memory 45. The matching device 46 uses the contents of the synthesizing memory 45 as shown in FIG.
The areas 51 and 52 are recognized as two motorcycles instead of the passenger car, and the area 54 is recognized as a large vehicle. Further, with the one-dimensional CCD camera 2 alone, the contents of the memory 43 for the vehicle type discrimination tread and the contents of the line sensor memory 44 are displayed for a vehicle that cannot be seen due to the shadow of a large vehicle, such as the area indicated by 53 in FIG. By comparing,
Recognize as a motorcycle.

When the road is congested and the vehicle does not move, the vehicle type discrimination tread memory 43 and the line sensor memory 44 may store the same information. At this time, the memory capacity becomes insufficient and the memory overflows. In order to prevent this, in the present embodiment, the matching circuit device 46 cuts out the vehicle width information from the vehicle type discrimination tread memory 43, and predicts the vehicle length from the ratio of the vehicle width and the length direction of a general vehicle. However, when the memory contents longer than the predicted length continues, the delete signal 48 is output to output unnecessary memory data in the elapsed time direction to the memories 43 and 4.
I am going to delete it from 4. Thus, for example, even if a passenger car is stopped due to a traffic jam, it is not erroneously determined as a trailer truck. If the data input to the vehicle type discrimination tread memory 43 or the line sensor memory 44 does not change for a certain period of time, a deletion signal 48 is similarly output,
We are going to delete monotonous memory data. This eliminates memory overflow.

In the vehicle detection device of the above embodiment, the vehicle type discriminating tread 30 detects the vehicle width and the number of axles by the tire of the vehicle, the contact information is stored in the vehicle type discriminating tread memory 43, and the one-dimensional CCD camera 2 is also used. The image of the vehicle is captured by and the image information is stored in the line sensor memory 44. At this time,
From the one-dimensional CCD camera 2, the scanning signal is converted into the synchronization signal 47.
Is output to the vehicle type discriminating tread 30 and the contact information of the vehicle type discriminating tread 30 is sampled in synchronization with the synchronization signal 47. The contents of these two memories 43 and 44 are combined in the combining memory 45, and the matching device 46 determines the type and number of passing vehicles and detects the vehicles. Therefore, it is possible to avoid misidentifying a motorcycle running in parallel as a passenger car, or to overlook a motorcycle that is hidden in a shadow when approaching a large vehicle. Further, by outputting the deletion signal 48 from the matching device 46, it is possible to prevent the memory from overflowing with unnecessary information during traffic jam. As described above, by using the vehicle type identification tread 30 as an auxiliary sensor for vehicle detection, the vehicle type and number of passing vehicles can be accurately grasped, and unmanned toll collection on a toll road or the like can be greatly accelerated.

In the above embodiment, the vehicle type discrimination tread 30 is used as an auxiliary sensor for vehicle detection, but other than this, a loop coil, an ultrasonic transceiver, or a microwave transceiver may be used although not shown. it can. (1) An appropriate number of loop coils are embedded in the road surface under the intermittent marking 6 so as to be sensitive to the vehicle. As a result, the cardboard box, person,
Alternatively, even if a vehicle exists for the one-dimensional CCD camera 2 hidden by dust or dirt, the loop coil does not respond to these, so do not detect the vehicle unless there is a detection output of the loop coil. The signal processing device 5 is provided with a determination function. (2) The ultrasonic transmitter / receiver is installed, for example, in the gantry 1 so that the intermittent marking 6 is set as a detection area so that a passing vehicle can be detected. When an ultrasonic handset is used, not only a vehicle but also a person is detected, but even if there is dust or dirt, this will be the same detection signal as on the road surface. Therefore, the intermittent marking 6 is hidden by dust or dirt and the one-dimensional CC is
Even if a vehicle is present to the D camera 2, the ultrasonic transmitter / receiver does not respond to them. Therefore, the determination function for not detecting the vehicle unless the ultrasonic transmitter / receiver outputs the vehicle detection signal is signaled. The processing device 5 has it. (3) The microwave transmitter / receiver is also installed, for example, in the gantry 1 so that the intermittent marking 6 is set as a detection area so that a passing vehicle can be detected. When a microwave transceiver is used, it detects moving objects such as vehicles,
Even if there is a person, a cardboard box, dust or dirt, there is no Doppler shift, so these signals will be the same detection signals as the road surface. Therefore, even if there is a vehicle for the one-dimensional CCD camera 2 because the intermittent marking 6 is hidden by a dust box, a corrugated box, or a person, the microwave handset is not sensitive to them. The signal processing device 5 is provided with a determination function of not detecting the vehicle unless there is a vehicle detection output of the microwave transceiver.

[0030]

As described above, according to the present invention, by using the optical array sensor and the intermittent marking, translation in the lane of the vehicle, passing of the motorcycle at the time of stagnation, or special conditions such as shade may occur. The vehicle can be accurately detected even under the vehicle.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a vehicle detection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a waveform of input light.

FIG. 3 is a diagram showing an example of a waveform of input light.

FIG. 4 is a diagram showing an example of a waveform of input light.

FIG. 5 is a block diagram showing a configuration example of a signal processing device.

FIG. 6 is a diagram showing a waveform example of each part of the signal processing device.

FIG. 7 is a diagram showing the state of one-dimensional memory contents.

FIG. 8 is a flowchart showing an example of a signal processing procedure.

FIG. 9 is a schematic diagram of a vehicle detection device according to another embodiment of the present invention.

FIG. 10 is a diagram showing a configuration example of a vehicle type discrimination tread.

FIG. 11 is a diagram showing an example of a map of contact information.

FIG. 12 is a block diagram showing a configuration example of a signal processing device.

FIG. 13 is a block diagram showing a configuration example of the signal processing device corresponding to FIG. 5;

FIG. 14 is an explanatory diagram of the operation of the signal processing device.

FIG. 15 is a diagram showing a conventional ultrasonic type vehicle detection device.

FIG. 16 is a diagram showing a conventional optical vehicle detection device.

[Explanation of symbols]

 1 Gantry 2 1-dimensional CCD camera 3 Passing vehicle 4 Cable 5 Signal processing device 6 Intermittent marking 30 Vehicle type tread

Front page continued (72) Inventor Riichiro Yamashita 2-1-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Takasago Laboratory, Mitsubishi Heavy Industries (72) Inventor Ichiro Fujita 1-1, Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo No. 1 Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (72) Inventor Hideo Uehara 1-1-1, Wadasaki-cho, Hyogo-ku, Kobe, Hyogo Prefecture Mitsubishi Heavy Industries Ltd., Kobe Shipyard

Claims (3)

[Claims] 1. An optical array sensor installed above a road surface to obtain a one-dimensional light amount signal in the lane width direction from the road surface, an optical system installed on the optical array sensor, and a one-dimensional optical array sensor. A vehicle detection device comprising: an intermittent marking installed on a road surface within a field of view; and a signal processing device that performs a vehicle detection process from an output signal of the optical array sensor. 2. The intermittent cycle of the intermittent marking is longer than the cycle of the pixels of the optical array sensor on the road surface and shorter than the minimum width of the detection target vehicle.
The vehicle detection device described. 3. A tread having contacts embedded in the road surface,
The signal processing device further comprises at least one sensor of a loop coil embedded in the road surface, an ultrasonic transmitter / receiver installed above the road surface, and a microwave transceiver installed above the road surface. The vehicle detection device according to claim 1, wherein vehicle detection processing is performed from a signal and an output signal of the optical array sensor.