JP2002148184A - Road surface condition detecting device and traffic flow detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a road surface condition detecting device capable of properly detecting the road surface condition at a low cost and a traffic flow detecting device. SOLUTION: Reflected light of a laser beam radiated from a radiating device 14 from an area of a road surface is photographed by a camera 12, and the luminance of reflected light and a reflection pattern are extracted from an image of the area photographed by the camera 12 by a data extraction circuit 17. The comparison determining circuit 18 determines the existence/absence of drying or freezing of the road surface according to the luminance of reflected light and the reflection pattern extracted by the data extraction circuit 17 and the reference reflected light luminance and the reference reflection pattern previously stored in a data base 19, displays the information on the frozen road surface on a warning display plate 21, and provides the same to a driver of a passing vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road surface condition detecting device and a traffic flow detecting device which detect a freezing point on the road surface of a general road or an expressway on which a vehicle travels and notify a vehicle driver or a road manager.

[0002]

2. Description of the Related Art Generally, freezing of a road surface caused by rainfall or snowfall causes an increase in a braking distance or a slip when a traveling vehicle stops, which leads to a traffic accident. In order to prevent traffic accidents, road managers regularly patrol the roads, find frozen spots, take measures to melt snow, and post warnings about freezing on the road to alert drivers of passing vehicles. Are doing.

In addition, a camera is installed along a road, and a road image taken by the camera is sent to a central control room where a road manager is located via a transmission line, and the road manager transmits the road surface image displayed on a monitor. We look at it to determine if it is frozen.

FIG. 9 is an explanatory diagram of a monitoring device for detecting a frozen area W on a road 10. First, the camera 12 installed on the support 11 along the road 10
Is photographed and displayed on a monitor (not shown). The road manager checks the presence or absence of the frozen area W from the road surface image displayed on the monitor. The camera 12
Although the road surface can be photographed during the daytime when there is a day, but cannot be taken at nighttime when there is no daylight, the streetlight 13 is installed near the area PR and the light emitted from the streetlight 13 is taken by the camera 12 as an illumination source.

[0005]

However, regular patrol of the road can surely grasp the road surface condition, but lacks real-time properties and requires a large amount of cost for patrol. Further, in monitoring using a camera, when nighttime monitoring is performed by the camera 12, a large cost is required for the main body of the streetlight 13 installed near the shooting area PR and the installation work.

An object of the present invention is to provide a road condition detecting device and a traffic flow detecting device which can detect a road condition properly at low cost.

[0007]

According to a first aspect of the present invention, there is provided a road surface state detecting device for irradiating a road surface on which a vehicle travels with a laser beam, and an area of the road surface irradiated with the laser beam by the irradiating device. A camera that captures the reflected light from
A data extraction circuit for extracting a reflected light luminance and a reflection pattern from the image of the area taken by the camera; a database storing a reference reflected light luminance and a reference reflection pattern in a dry or frozen state of the road surface; A comparison and determination circuit that determines whether the road surface is dry or frozen based on the reflected light luminance and the reflection pattern extracted by the circuit and the reference reflected light luminance and the reference reflection pattern stored in the database; A warning display plate for providing the obtained information on the frozen road surface to the driver of the passing vehicle.

In the road surface state detecting apparatus according to the first aspect of the present invention, the reflected light from the area of the road surface of the laser light emitted from the irradiation device is photographed by a camera, and the reflected light luminance and the reflected light intensity are obtained from the image of the area photographed by the camera. The reflection pattern is extracted by a data extraction circuit. The comparison determination circuit determines whether the road surface is dry or frozen based on the reflected light luminance and the reflection pattern extracted by the data extraction circuit and the reference reflected light luminance and the reference reflection pattern stored in the database in advance. Road surface information is displayed on a warning display board and provided to a driver of a passing vehicle.

A road surface state detecting device according to a second aspect of the present invention is the invention according to the first aspect, wherein the irradiation device forms a surface irradiation area on the road surface by using the laser beam with a scanning device. I do.

According to a second aspect of the present invention, in addition to the function of the first aspect, the irradiating device irradiates a laser beam so as to form a surface irradiation area on the road surface by using a scanning device. .

According to a third aspect of the present invention, there is provided a road surface state detecting device, comprising: a temperature sensor installed behind a manhole cover buried in a road on which a vehicle travels; and a temperature sensor installed behind the manhole. A rainfall sensor that measures the amount of rainfall from the formed rainfall intake window, and a road surface state determination circuit that determines a dry, wet, or frozen state of the road surface based on measurement data from the temperature sensor and the rainfall sensor. It is characterized by having.

In the road surface state detecting device according to the third aspect of the present invention, the road surface state determination circuit determines the dry, wet, or frozen state of the road surface based on the measurement data from the temperature sensor and the rainfall sensor.

According to a fourth aspect of the present invention, there is provided a traffic flow detecting device provided behind a manhole cover buried in a road surface on which a vehicle travels, and radiates radio waves into the air through the manhole cover and transmits the radio wave to the manhole cover. It is characterized by comprising a radio wave transmitter / receiver for receiving a reflected radio wave reflected by a vehicle traveling above, and a traffic flow detection circuit for detecting a traffic flow of the traveling vehicle based on the presence or absence of the reflected radio wave.

According to a fourth aspect of the present invention, in the traffic flow detecting device, the radio wave transmitter / receiver is provided behind a manhole cover buried in the road surface on which the vehicle runs, and radiates radio waves into the air via the manhole cover. At the same time, it receives a reflected radio wave reflected by a vehicle traveling above the manhole cover. The traffic flow detection circuit determines that a traveling vehicle is present when there is a reflected radio wave received by the radio wave transceiver, and detects a traffic flow.

According to a fifth aspect of the present invention, there is provided a traffic flow detecting device, comprising: a first coil installed behind a manhole cover buried in a road surface on which a vehicle travels; and an exciting circuit for exciting the first coil. A second coil installed behind the cover of the manhole and electromagnetically coupled to the first coil;
An electromagnetic induction monitoring circuit that detects a traffic flow of the traveling vehicle based on the presence or absence of coupling of the electromagnetic induction between the second coil and the vehicle traveling above the manhole cover.

In the traffic flow detecting device according to the fifth aspect of the present invention, the electromagnetic induction monitoring circuit determines that there is no traveling vehicle when the electromagnetic induction coupling between the first coil and the second coil is present, Otherwise, it is determined that there is a traveling vehicle and the traffic flow is detected.

[0017]

Embodiments of the present invention will be described below. FIG. 1 is a configuration diagram of a road surface state detecting device according to a first embodiment of the present invention.

The irradiation device 14 provided on the column 11 irradiates a laser beam to the road surface of the road 10 on which the vehicle travels, generates a laser beam of a single wavelength, and uses the laser light by using a scanning device. To form a surface irradiation area IR. FIG.
Shows a case where the freezing area W is included in the surface irradiation area IR.

A camera 12 is provided on the support 11, and the camera 12 captures the reflected light from the surface irradiation area IR of the road surface irradiated with the laser light by the irradiation device 14. The camera 12 is provided with a band-pass filter having a center wavelength at the wavelength of the laser light of the irradiation device 14, and transmits only the wavelength light of the laser light reflected by the surface irradiation area IR irradiated by the irradiation device 14.

An image of the irradiation area taken by the camera 12 is input to an image processing device 15 and is converted into an A / D conversion circuit 16.
Is converted into a digital signal. Then, in the data extraction circuit 17, the reflected light luminance and the reflected pattern are extracted from the image data of the irradiation area converted into the digital signal.

The comparing and judging circuit 18 includes a data extracting circuit 17
Is compared with the reference reflected light luminance and the reference reflection pattern stored in the database 19 in advance to determine whether the road surface of the road 10 is dry or frozen. When it is determined that there is freezing, the information is output to a warning display board 21 provided near the road 10 via the interface circuit 20, and information on the frozen road surface is provided to the driver of the passing vehicle.

Next, the internal configuration of the irradiation device 14 will be described with reference to FIG. FIG. 2 is an explanatory diagram of the irradiation device 14. The laser light source LA is, for example, a laser light source composed of a semiconductor laser, and is ON / OFF controlled by a control signal CON-LA from a control circuit EC. Also, the scanning device SCAN
-H and the scanning device SCAN-V are controlled to reciprocate by a control signal RD-H and a control signal RD-V from the control circuit EC. By the control of the reciprocating rotation, the axes of the scanning devices SCAN-H and SCAN-V reciprocate in a predetermined angle range, and the mirror MIR attached to the scanning devices SCAN-H and SCAN-V.
The movement of the RH and the mirror MIRR-V is controlled.

The control circuit EC turns on / off the laser light source LA in synchronization with the control signals RD-H and RD-V of the scanning devices SCAN-H and SCAN-V.
A control signal CON-LA to be performed is generated.

Here, the positional relationship between the scanning device SCAN-H and the scanning device SCAN-V is arranged at an interval of π / 2 in FIG. 2, but it is not necessarily required to be π / 2. May be arranged at an angle.

The laser light emitted from the laser light source LA is
The light is projected by the scanning device SCAN-H onto the mirror MIRR-H that reciprocates in a predetermined angle range θH, and the reciprocating rotation causes the outgoing light to become scanning light having a twice angle of the angle θH. Next, the scanning light is projected by a scanning device SCAN-V onto a mirror MIRR-V that reciprocates in a predetermined angle range θV,
Similarly, the scanning light becomes twice the angle θV, and the emitted light is scanned in a direction different from the scanning light of the mirror MIRR-H in the π / 2 direction.

Further, the scanning of the laser light including ON / OFF of the laser light source LA will be described below. Mirror M
With the IRR-V at one end of the angle θV, the mirror MI
When RR-H is rotated from the end θH to the other end, the laser light becomes the scanning light indicated by L1.

Next, the mirror MIRR-V is set at a predetermined angle θV.
And the mirror MIRR-H
Is rotated in the opposite direction, the laser beam L2 is scanned by reflection of the mirrors MIRR-H and MIRR-V. During this period, the control signal CON-LA of the laser light source LA becomes an OFF signal, and the laser light Does not exit.

Hereinafter, by repeating the same operation, L
3, L4 and L5 are performed, and the scanning device SCAN-
When the scanning N at the end of the predetermined angular range θV is completed, the scanning device SCAN-V rotates the mirror MIRR-V to the opposite end of the angle θV to perform the scanning of R. During this scan R, the control signal CON-LA becomes an OFF signal, and no laser light is emitted.

FIG. 3 is a flowchart showing the irradiation operation of the irradiation device 14. First, the control circuit EC outputs the control signal R
DH and control signal RD-V to output scanning device SC
The angles θH and θV of the AN-H and the scanning device SCAN-V are set to initial values (S1), and the index i is also initialized (S2). Then, the control signal CON-LA to the laser light source LA is turned on (S3), and the control signal RD-
H rotates the scanning device SCAN-H at an angle θH (S
4) After that, the control signal CON- to the laser light source LA
LA is turned off (S5). And index i
(S6), the angle θ of the scanning device SCAN-V
It is determined whether or not V is equal to or smaller than i × ΔθV (S7). If the condition is not satisfied, the angle θ of the scanning device SCAN-H is determined.
H is rotated in the opposite direction, and the angle θV of the scanning device SCAN-V is rotated by the unit angle ΔθV (S8).
Return to 3. On the other hand, if the condition is satisfied in the determination in step S7, the angle θH of the scanning device SCAN-H and the scanning device S
The CAN-V angle θV is reversely rotated (S9), and step S9 is performed.
Return to 2.

As described above, the ON / OFF of the laser light source LA and the rotations of the scanning devices SCAN-H and SCAN-V are synchronized by each control signal of the control circuit EC, and the laser light from the laser light source LA It is converted into two-dimensional surface irradiation light to form a surface irradiation area IR shown in FIG.

Each width of the laser beam in the irradiation area shown in FIG. 2 in the H and V directions is determined by each reciprocating rotation angle and the distance between the laser light source LA and the irradiation surface.
The distance between the scanning lights in the direction (for example, the distance between the scanning lights L1 and L3) is also determined by the unit angle △ θV and the distance between the laser light source LA and the irradiation surface. The wavelength of the laser beam is a wavelength that is insensitive to human eyes, and its intensity is such that it does not damage humans.

As described above, by using the semiconductor laser LA as the light source of the irradiation device 14, the life of the light source can be improved and the maintenance work and cost can be reduced as compared with a lamp generally used as the light source of the streetlight 13. There is.

Next, detection of a road surface condition by the irradiation device 14 and the camera 12 will be described. FIG. 4 shows the irradiation device 1
4 is an image diagram of a road surface condition of a surface irradiation area IR in which the road 10 is irradiated with the laser light in FIG. 4, FIG. 4A is an image diagram of reflected light when the road surface is dry, and FIG. 4B is an image diagram when the road surface is frozen It is.

As shown in FIG. 4A, in a dry state, a reflection pattern that is finely meandered according to the unevenness of the road surface of the road 10 is photographed. When the vehicle is in a frozen state, as shown in FIG. 4B, a reflection pattern that is depressed at a rut 22 generated by the running of the vehicle is photographed.

The luminance in each road surface condition is not significantly changed in the dry state, although the luminance of the reflected light in the form of a scanning line does not greatly change.
In the frozen state, the brightness is dark because the other parts are mirrored, except for the rut portion 22. However, the rut portion 22 is photographed as bright because the ice chips and sherbet-like ice scraped up by the tires of the traveling vehicle are scattered.

The reflected light of the laser light on the road surface is photographed by the camera 12 and the video signal is converted to an A / D conversion circuit 16.
After that, the data is extracted by the data extraction circuit 17. The extracted reflected light luminance and reflection pattern are
The comparison determination circuit 18 compares the reflection pattern from the road surface in a dry state or a frozen state with the reference reflection light luminance and the reference reflection pattern in the database 19 in which the luminance data of the reflection light are stored in advance. As a result of the comparison, when a frozen state is detected, the alarm display board 21
For example, a message such as "Frozen in the future" is displayed to alert the vehicle driver and alert the road manager.

According to the first embodiment, since the surface irradiation area IR is photographed by the camera 12 having sensitivity to the wavelength of the laser beam, it is not affected by the reflected light from the road surface due to external light such as sunlight. There is no. Therefore, it is not necessary to perform the aperture operation of the camera 12 according to the intensity of the reflected light. Further, even at night, it is possible to capture scanning light of uniform brightness.

Next, a second embodiment of the present invention will be described. FIG. 5 is a configuration diagram of a road surface state detection device according to the second embodiment of the present invention.

A temperature sensor 25 and a rainfall sensor 26 are provided behind the lid 24 of the manhole 23 buried on the road surface on which the vehicle runs. The temperature sensor 25 measures the temperature near the manhole cover 24, and the rainfall sensor 26 measures the amount of rainfall from the rainfall intake window 27 formed on the manhole cover 24. That is, the rainfall sensor 26 is
And the water content such as rainfall on the road surface side flowing in through the rainfall intake window 27 formed at the bottom. Rainfall sensor 2 from rainfall intake window 27
The moisture from the road surface side guided to 6 is the moisture that has been melted by rainfall or snow or freezing on the road surface of the road 10.

The road surface state determination circuit 28 includes a temperature sensor 25
Then, the condition of dry, wet or frozen road surface is determined based on the measurement data from the rainfall sensor 26.

For example, if the measured data of the rainfall sensor 26 is free of moisture and the measured data of the temperature sensor 25 is below the freezing point, it is determined to be "dry". If the measurement data of the rainfall sensor 26 has moisture and the measurement data of the temperature sensor 25 is below the freezing point, it is determined to be “wet”, and the measurement data of the rainfall sensor 26 has moisture and the measurement of the temperature sensor 25 If the data is below the freezing point, it is determined as "freezing".

Here, when the rainfall sensor 26 measures the absence of moisture and the temperature sensor 25 measures the temperature below the freezing point, both "drying" and "freezing" due to moisture freezing are considered. In this case, the determination is made from the history of the measurement data before that. For example, if the history data of the rainfall sensor 26 has moisture, it is determined to be "freeze", and if there is no moisture, it is determined to be "dry". The information of wetness or freezing thus obtained is output as a warning signal to the warning display board 21.

According to the second embodiment, the temperature sensor 25 and the rainfall sensor 26 are provided on the back surface of the manhole cover 24, and the frozen state of the road surface of the road 10 is determined based on these measurement data. There is no need to provide a column for attaching a camera or an irradiation device to the camera.

Next, a third embodiment of the present invention will be described. FIG. 6 is a configuration diagram of a traffic flow detection device according to the third embodiment of the present invention.

A radio transmitter / receiver 29 and a traffic flow detection circuit 30 are provided behind the cover 24 of the manhole 23 buried on the road surface on which the vehicle runs. The radio transmitter / receiver 29 radiates radio waves into the air using the manhole cover 24 as an antenna and receives reflected radio waves reflected by a vehicle traveling above the manhole cover 24. When the manhole cover 24 is conductively connected to the manhole 23, the manhole cover 24 does not operate as an antenna.
Is installed.

The traffic flow detection circuit 30 includes a radio transceiver 29.
When there is a reflected radio wave received in step (1), it is determined that a traveling vehicle is present, and a traffic flow is detected.

That is, a radio wave such as a microwave is generated by the radio wave transceiver 29 and the radio wave is transmitted to the upper manhole cover 24.
And emits a radio wave in the upper direction of the road surface using the manhole cover 24 as an antenna. The radio wave emitted toward the upper part of the manhole cover 24 does not return as long as the vehicle does not travel or stop above the manhole cover 24.

On the other hand, if the vehicle is running or stopped,
The electric wave is reflected by the metal part of the vehicle and returns to the manhole cover 24. The returned reflected radio wave is received by the manhole cover 24 instead of the antenna and is input to the radio wave transceiver 29. FIG. 7 shows an example of the emission radio wave and the reception signal of the radio wave transceiver 29. FIG. 7 shows a signal waveform of the pulse radar system.

According to the third embodiment, the radio transmitter / receiver 29 and the traffic flow detection circuit 30 are arranged behind the manhole cover 24, and the presence or absence of a vehicle is determined based on the presence or absence of reflected radio waves. The traffic flow can be detected properly without installing equipment on the ground.

Next, a fourth embodiment of the present invention will be described. FIG. 8 is a configuration diagram of a traffic flow detection device according to a fourth embodiment of the present invention.

Behind the lid 24 of the manhole 23 buried on the road surface on which the vehicle runs, the first coil 32 and the second coil
The first coil 32 is excited by an exciting circuit 34. When the first coil 32 is excited, the first
And the second coil 33 are electromagnetically inductively coupled. The electromagnetic induction monitoring circuit 35 monitors the electromagnetic induction coupling between the first coil 32 and the second coil 33, and
When there is a vehicle traveling on the upper part of 4, the electromagnetic flow of the traveling vehicle is detected because its electromagnetic induction coupling is impeded.

That is, if the vehicle is not running or stopped above the manhole cover 24, the signal excited by the first coil 32 is guided to the second coil 33. However, if the vehicle is running or stopped above the manhole cover 24, the signal that is electromagnetically coupled to the metal of the vehicle body is received by the second coil 33, so that the presence or absence of the vehicle can be detected. The electromagnetic induction monitoring circuit 35 determines whether or not there is electromagnetic induction coupling with the vehicle, and outputs a traffic flow signal.

[0053]

As described above, according to the present invention, detection of a road surface condition and a traffic flow can be automated.
In addition, since it is configured to be mounted on the back side of the manhole cover, compared to sensors buried directly under the road surface, installation of the sensor is simpler and re-installation of the sensor that occurs every time the road is repaired is omitted. Cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a road surface state detection device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an irradiation device according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing an irradiation operation of the irradiation device according to the first embodiment of the present invention.

FIG. 4 is an image diagram of a road surface condition of a surface irradiation area IR obtained by irradiating a road with laser light by the irradiation device according to the first embodiment of the present invention, and FIG. 4A shows reflected light when the road surface is dry; FIG. 4B is an image diagram of a laser reflected light due to a difference in road surface state in the image diagram when the road surface is frozen.

FIG. 5 is a configuration diagram of a road surface state detection device according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram of a traffic flow detection device according to a third embodiment of the present invention.

FIG. 7 is an explanatory diagram of emission radio waves and reception signals of a radio transceiver according to a third embodiment of the present invention.

FIG. 8 is a configuration diagram of a traffic flow detection device according to a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram showing an example of a conventional road surface state detection device.

[Explanation of symbols]

10 ... road, 11 ... prop, 12 ... camera, 13 ... streetlight,
14 irradiation device, 15 image processing device, 16 A / D conversion circuit, 17 data extraction circuit, 18 comparison comparison circuit,
19: database, 20: interface circuit, 2
1: warning display board, 22: rut portion, 23: manhole, 2
4 ... Manhole cover, 25 ... Temperature sensor, 26 ... Rainfall sensor, 27 ... Rainfall intake window, 28 ... Road surface condition determination circuit, 29
... radio wave transmitter / receiver, 30 ... traffic flow detection circuit, 31 ... insulating material, 32 ... first coil, 33 ... second coil, 34 ...
Excitation circuit, 35 ... electromagnetic induction monitoring circuit

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G08G 1/01 G08G 1/01 A 1/09 1/09 CF term (reference) 2G053 AA21 AB21 BA21 BC02 BC14 CA03 CB21 DA06 DB05 2G059 AA05 BB20 EE02 FF01 GG01 JJ15 KK04 MM05 MM09 MM10 PP04 5H180 AA01 CC03 CC04 CC12 CC14 DD01 EE13 JJ03 JJ05

Claims (5)

[Claims] 1. An irradiation device for irradiating a laser beam on a road surface on which a vehicle travels, a camera for photographing reflected light from an area of the road surface irradiated with the laser light by the irradiation device, and the area photographed by the camera. A data extraction circuit for extracting the reflected light luminance and the reflected pattern from the image of the above, a database storing the reference reflected light luminance and the reference reflected pattern in the dry or frozen state of the road surface, and the reflected light luminance extracted by the data extraction circuit And a comparison and determination circuit for determining the presence or absence of drying or freezing of the road surface based on the reflection pattern and the reference reflected light luminance and the reference reflection pattern stored in the database, and information on the frozen road surface obtained by the comparison and determination circuit A road surface condition detection device comprising: a warning display plate provided to a driver of a passing vehicle. 2. The road surface state detection device according to claim 1, wherein the irradiation device forms a surface irradiation area on the road surface using the laser beam by using a scanning device. 3. A temperature sensor installed behind a manhole cover embedded in a road surface on which a vehicle travels, and a rainfall amount from a rainfall intake window formed behind the manhole and formed on the manhole cover. A road surface state detection device comprising: a rainfall sensor to measure; and a road surface state determination circuit that determines a dry, wet, or frozen state of the road surface based on measurement data from the temperature sensor and the rainfall sensor. . 4. A radio wave provided behind a manhole cover buried in a road surface on which a vehicle travels, radiates radio waves into the air through the manhole cover and reflects reflected radio waves reflected by a vehicle traveling above the manhole cover. A traffic flow detection device comprising: a radio wave transceiver for receiving; and a traffic flow detection circuit that detects a traffic flow of a traveling vehicle based on the presence or absence of the reflected radio wave. 5. A first coil installed behind a manhole cover buried in a road on which a vehicle travels, an exciting circuit for exciting the first coil, and a first coil installed behind the manhole cover. A second coil that is electromagnetically coupled to the first coil; and an electromagnetic induction detecting a traffic flow of the traveling vehicle based on whether or not the second coil is coupled to the vehicle traveling above the manhole cover. A traffic flow detection device comprising a monitoring circuit.