JPH1096694A - Road surface condition determining device, vehicle equipped with the device, and road surface information management system using the device - Google Patents

Abstract

(57) [Summary] To determine a road surface state with a simple configuration and at low cost. SOLUTION: A reflected light measuring sensor 2 for measuring the reflected light from a road surface, a wheel speed sensor 3, and a control device 4 constitute a road surface state determination device, which is mounted on a vehicle 5. The reflected light measurement sensor 2 includes a light projecting unit that irradiates infrared light toward a road surface, and a light receiving unit that receives reflected light of the irradiated light from the road surface, and is received while the vehicle is moving. The reflected light amount is provided to the control device 4, and its spatial frequency characteristics are extracted. The control device executes a process of determining the state of the road surface LD based on the analysis result of the spatial frequency and the measurement result of the wheel speed sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for judging the condition of a road surface of a vehicle such as an automobile, a vehicle equipped with the device, and a road surface information management system using the device. About.

[0002]

2. Description of the Related Art As a conventional device of this type, there is a vehicle-mounted road surface condition determination device proposed by the applicant (WO 95/01549).
This device irradiates light from a traveling vehicle toward a road surface, passes the diffuse reflected light through a spatial filter, extracts a predetermined spatial frequency component indicating the state of the road surface, and uses the extraction result to extract the road surface. The state is determined.

[0003]

However, the above-mentioned apparatus uses a spatial filter, so that it is necessary to use a large number of light sources, and the structure of the optical system becomes complicated, resulting in high costs.

The present invention has been made in view of the above-mentioned problems, and performs a spatial frequency analysis of diffused light indicating a road surface state without using a spatial filter so as to obtain a road surface state with a simple configuration and at low cost. The determination is a technical task.

A second technical object of the present invention is to provide a vehicle having a road surface state discriminating function at low cost by mounting the above-mentioned road surface state discriminating device on the vehicle.

A third technical object of the present invention is to provide a system for managing information relating to road surface safety by using a result of the road surface state determination by the above-mentioned device.

[0007]

According to a first aspect of the present invention, there is provided a road surface state determining apparatus for irradiating a road vehicle with light toward a road surface, detecting a reflected light amount, and determining a moving distance of the detecting unit. There is provided a measuring means for measuring, and a judging means for judging a road surface state based on a detected value of the reflected light amount and a measured value of the moving distance obtained within a predetermined period.

[0008] According to a second aspect of the present invention, there is provided a road surface condition determining apparatus.
The determining means analyzes the spatial frequency of the road surface from the reflected light using the detected value of the reflected light amount and the measured value of the moving distance,
The road condition is determined based on the analysis result.

According to a third aspect of the present invention, there is provided a road condition determining apparatus.
The detection means is configured to individually detect a regular reflection light amount and a diffuse reflection light amount of the irradiation light from a road surface.

[0010] In the road condition determining apparatus according to the fourth aspect,
The detection means is configured to irradiate light to a plurality of positions in a width direction of a road surface, respectively, and to individually detect a reflected light amount of each irradiation light.

According to a fifth aspect of the present invention, there is provided a vehicle on which the above-mentioned road surface condition determining device is mounted. Further, in the sixth aspect of the present invention, the vehicle is provided with a road surface hazard by using the result of the determination by the road surface condition determining device. A recognition means for recognizing the degree and a warning means for outputting warning information when the road surface is recognized as dangerous by the recognition means are provided.

According to a seventh aspect of the present invention, there is provided a system comprising a vehicle equipped with the above-mentioned road surface condition determination device and a control device, wherein the vehicle transmits a result of the determination of the road surface condition to the control device. Means, and the control device comprises: information editing means for editing information relating to traveling safety using transmission information from the vehicle; and information output means for outputting the edited information to the outside. I have.

[0013]

According to the first aspect of the present invention, the road surface condition is determined based on the reflected light amount of light emitted from the traveling vehicle within a predetermined period and the measured value of the moving distance during this period.
The configuration is simplified.

According to the second aspect of the present invention, the spatial frequency of the road surface is analyzed from the reflected light reflecting the road surface condition using the detected reflected light amount and the measured value of the moving distance.
A road surface state determination process is performed.

According to the third aspect of the present invention, the road surface condition can be determined in detail by separately detecting the regular reflection light amount and the diffuse reflection light amount from the road surface.

According to the fourth aspect of the present invention, the road surface condition is determined using the amount of reflected light from a plurality of positions in the width direction of the road surface. Therefore, when the road surface condition such as a snowy road or a frozen road needs to be determined in detail. Can respond to.

According to the fifth aspect of the present invention, by mounting the above-described road surface state determining device on a vehicle, a road surface state determining function can be created simply and at low cost.

According to the invention of claim 6, in the vehicle,
When it is determined that the road surface is dangerous based on the determination result of the road surface condition, warning information is output.

According to the seventh aspect of the present invention, the control device edits the road surface condition determination result transmitted from the vehicle and outputs the result to the outside. It is possible to promptly provide information related to safety.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following FIGS. 1 to 19 show an example of the construction of a road surface condition judging device according to the present invention and the principle of judging the road surface condition.
Preferred embodiments according to the present invention will be described. Further, FIG.
A preferred embodiment of a vehicle equipped with the road surface condition determination device will be described with reference to FIG. 21, and a preferred embodiment of a road surface information management system using the road surface condition determination device will be described with reference to FIG.

[0021]

1 shows a state in which a road surface condition discriminating apparatus 1 according to one embodiment of the present invention is installed in a vehicle 5. FIG. The road surface state determination device 1 receives a reflected light measurement sensor 2 for measuring the amount of reflected light from a road surface LD, a wheel speed sensor 3 for measuring a rotation speed of a wheel, and inputs detection signals from these sensors. And a control device 4 for performing a road surface state determination process.

The wheel speed sensor 3 is attached to an ABS (anti-lock brake system), and as shown in FIG. 2, a rotating body 7 around which a number of magnetic pole teeth 6 are arranged at equal intervals, and each magnetic pole A detection unit 8 for detecting the approach of the teeth 6 and outputting a pulse signal; the rotation speed of the wheel is recognized based on the frequency of the pulse signal from the detection unit 8;

As shown in FIG. 3, the reflected light measuring sensor 2 includes a light projecting unit 9 for irradiating light toward a road surface and a light receiving unit 10 for receiving reflected light of the irradiated light from the road surface. The light source of the light projecting unit 9 is an infrared LED 12
(Hereinafter simply referred to as “LED 12”), and a photodiode 14 is used as a light receiving element of the light receiving unit.
3, reference numeral 13 denotes a light projecting lens for diffusing light from the LED 12, and reference numeral 15 denotes a light receiving lens for condensing reflected light to the photodiode 14.

The light projecting unit 9 has its optical axis adjusted so as to irradiate the road surface LD with light from an obliquely upward position, and receives a driving pulse from the control device 4 as described later. A pulsed light is emitted at predetermined time intervals. On the other hand, the optical axis of the light receiving unit 10 is aligned in an axial direction perpendicular to the road surface LD, and receives, among diffusely reflected light from the road surface LD, light reflected on and near the vertical axis.

When light is irradiated to a certain position on the road surface, light containing various frequency components reflecting the state of the road surface is reflected from the irradiated position. FIG. 4A shows the ratio of the amount of reflected light received by the light receiving unit 10 to the amount of irradiated light (hereinafter, simply referred to as “reflectance”) in a predetermined sampling period, corresponding to a change in the position of the vehicle 5. It is. FIG. 4B shows the result of applying the fast Fourier transform to the waveform signal of the reflectance of FIG. 4A to extract the spatial frequency contained in the waveform of the reflectance. Represents the frequency characteristics of the reflected light for the distance moved by.

FIG. 5 shows the results of Fourier transform of the actually measured diffuse reflection light amount for each of the dry asphalt or concrete road surface (hereinafter collectively referred to as "dry road surface") and the snow-covered road surface condition. In the illustrated example, the reflected light rate at that time is sampled at predetermined time intervals, and the conversion result of each sampling point obtained while the vehicle moves by 4 mm is dot-distributed.

As is apparent from the illustrated example, each of the road surface conditions has a spatial center frequency μ corresponding to the sampling period.
Many frequency components are concentrated in a frequency band centered at (approximately 0.25 mm ^-1 ), and the intensity of each component is
It is included in the range where no significant difference is recognized in each road surface condition and between road surface conditions.

On the other hand, focusing on the intensity of the frequency component extracted in a band lower than the spatial center frequency, the component intensity on the snowy road surface is much higher than the component intensity on the dry road surface. This difference is based on the fact that light projected on a snowy road surface is easily diffused and reflected.Checking the component intensity in the frequency region where this large difference is recognized, the road surface is either snowy or dry. It is possible to determine whether the vehicle is on a road surface. Although not shown here, in the case of a road surface with severe irregularities such as a gravel surface or a sand surface (hereinafter collectively referred to as a “gravel road surface”), the strength extracted in the low frequency band is an intermediate value between the intensities of the dry road surface and the snowy road surface. Take a value near.

In the embodiment described below, based on the principle shown in FIG. 5, the intensity (Da) of the spatial center frequency component is used as an index for determining the road surface condition from the reflectance conversion result. A ratio of the intensity (Db) of the frequency component in a predetermined low frequency band (hereinafter referred to as “frequency component intensity ratio Db / Da”) is employed, and the snowy road and the gravel road are identified based on the frequency component intensity ratio. And a threshold T2 for discriminating between a gravel road and a dry pavement.
Based on this, in the embodiment described below, the light receiving unit 10
The frequency component intensity ratio Db / Da calculated based on the received light amount data obtained by the above is compared with the threshold values T1 and T2, and the road surface condition is any of a dry pavement road, a gravel road, and a snowy road. Is determined.

In order to determine the state of the road surface in more detail, it is necessary to measure not only diffusely reflected light but also regular reflected light from the road surface. Especially, on a pavement road, when the road surface is wet due to rain or the like (hereinafter, this road surface is referred to as a “wet road surface”) or in a frozen state, the road surface is close to a mirror surface. , Greatly increased than in the dry state.

FIG. 6 shows the relationship between the diffuse reflectance and the regular reflectance on a pavement road in association with each of the dry, wet, frozen and snowy road surface conditions. Significantly higher than the state. Although there is no difference in diffuse reflectance between the dry, wet and frozen states, a clear difference is seen between the dry road surface and the wet / freeze road surface when the regular reflectance is compared. In order to determine the wet state and the frozen state, the road surface temperature may be measured using an infrared radiation type temperature sensor or the like.

FIG. 7 shows an example of the construction of a road surface condition determining device 1 which measures diffuse reflected light and specular reflected light simultaneously. The first reflected light measuring sensor 2a for measuring diffuse reflected light is shown in FIG. And a second reflected light measurement sensor 2b for measuring specularly reflected light, and a wheel speed sensor 3 similar to the above, connected to the control device 4. As shown in FIG. 8, each of the reflected light measuring sensors 2a and 2b includes a separate light projecting unit 9a, 9b and a light receiving unit 10a, 10b.

FIG. 9 shows another example of the configuration of the reflected light measuring sensor 2, in which a single light projecting portion 9, a first light receiving portion 10a for measuring diffuse reflected light, and a light receiving portion 10a for measuring regular reflected light are shown. And the second light receiving portion 10b are housed and arranged in the housing 2 '.
In the figure, 14a and 14b are photodiodes of each light receiving unit. According to this configuration, the diffuse reflection light and the specular reflection light at the same place can be measured simultaneously, so that there is no possibility that the measurement result of each reflection light is affected by the difference in the measurement position, and the road surface state can be accurately determined. Can be.

FIG. 10 shows an example in which the reflected light measuring sensor 2 is constituted by two light projecting units 9a and 9b and a single light receiving unit 10. The first and second light projecting units 9a and 9b are arranged so as to emit light toward the same position on the road surface LD, and the light receiving unit 10 receives the light from the first light projecting unit 9a. The optical axis is adjusted so as to receive the diffuse reflection light of the irradiation light and the regular reflection light of the irradiation light from the second light projecting unit 9b. Note that the LEDs 12a, 12b of the light emitting portions 9a, 9b
Are controlled so as to emit light alternately at predetermined time intervals, as shown in FIG.
In synchronization with the drive pulses to the EDs 12a and 12b, signals indicating specular reflection light and diffuse reflection light are output alternately.

FIG. 12 shows an electrical configuration of the road surface condition determining apparatus 1. Note that this illustrated example and the other configuration examples shown in FIGS. 16 and 17 below use the reflected light measurement sensor 2 of the type shown in FIG. 10, and in an apparatus using another type of sensor, The configuration relating to the light emitting and receiving unit is added or deleted.

The control device 4 includes a pulse oscillating circuit 15 for giving a driving pulse to the light source of each light projecting unit, two conversion circuits 16a and 16b for processing each reflected light, a speed detecting unit 31, It is composed of a circuit 17 and the like. The light receiving section 10 is provided with an amplifier circuit 18 for amplifying an output signal from the photodiode 14.

The conversion circuits 16a and 16b are for converting the electric signal of the amount of reflected light input from the light receiving section 10 into a spatial frequency, and respectively include a comb filter 20, an A / D conversion circuit 21, a memory 22, and a fast Fourier filter. Conversion circuit 23
(Hereinafter abbreviated as "FFT circuit 23").

As described above, the pulse oscillation circuit 15
Driving pulses to each light projecting section are output alternately, a driving pulse to the LED 12a for diffuse reflection is supplied to the first conversion circuit 16a, and an LED for regular reflection is supplied to the second conversion circuit 16b.
The drive pulse to 12b is input. Thereby, the spatial frequency of the diffuse reflection light is output from the first conversion circuit 16a, and the spatial frequency of the specular reflection light is output from the second conversion circuit 16b.

The LEDs 12a and 12b of each light emitting section receive the drive pulse shown in FIG. 11 from the pulse oscillation circuit 15 and emit pulsed light. Thereby, the light receiving unit 10
Outputs a rectangular signal synchronized with each drive pulse, but since disturbance light other than reflected light also enters at the same time,
The level of the output signal waveform fluctuates as shown in FIG.

The comb filter 20 removes the influence of the disturbance light and smoothes the rectangular signal of the reflected light. As shown in FIG.
It comprises four or three sample-and-hold circuits (hereinafter abbreviated as “S / H circuits”) 25 a, 25 b, 25 c and an arithmetic circuit 30.

The timing generating circuit 24 receives the driving pulse from the pulse oscillating circuit 15 and generates a timing signal at a rising time point t1, a falling time point t3, and an intermediate time point t2 thereof. This timing signal is supplied to each of the S / H circuits 25a, 25b, 25c.
, And the signal levels V1, V2, and V3 from the light receiving unit at each time are sampled and held as shown in FIG.

The arithmetic circuit 30 includes S / H circuits 25a, 25
c and an S / H circuit 2
Doubling circuit 29 for inputting the output from 5b, and adding circuit 2
The output level V is determined by executing the arithmetic processing of the following equation (1) by the subtraction circuit 28 which receives the output from the doubling circuit 29. As a result, a change in level due to disturbance light is removed, and the amount of received light can be accurately grasped.

[0043]

(Equation 1)

Returning to FIG. 12, the data on the amount of received light passing through the comb filter 20 is digitally converted by the A / D conversion circuit 21 and then stored in the memory 22. The speed detector 31 detects the moving speed of the vehicle 5 based on the output pulse from the wheel speed sensor 3 and outputs the detection result to the discriminating circuit 17 and the FFT circuits 23. Each of the FFT circuits 23, 23 takes out the received light amount data from the memory 22 at the preceding stage at a predetermined timing based on the speed data, executes the fast Fourier transform, and outputs the result to the discriminating circuit 17.

Based on the moving speed of the vehicle 5, the determination circuit 17 determines the intensity Da of the high frequency band including the spatial center frequency μ and the intensity Db of the low frequency band based on the conversion results input from the conversion circuits 16a and 16b. Then, a road surface state determination process (to be described in detail later) is executed using the extraction result and the measurement value obtained by the above-described road surface temperature measurement temperature sensor.

FIG. 16 shows another example of the structure of the road surface condition determining apparatus 1. This embodiment also basically has the same configuration as that of FIG. 12, but the result of detection by the speed detector 31 is input to the pulse oscillation circuit 15. The pulse oscillation circuit 15
Based on the input speed data, each conversion circuit 16
In a and 16b, the generation timing of the drive pulse is adjusted so that the number of received light amount data input during the sampling period is always constant. As a result, the number of data input to each of the FFT circuits 23 can be made constant, so that the capacities of the memories 22 can be set according to the number of data.

FIG. 17 shows a third example of the configuration of the road surface condition determining apparatus 1. As shown in FIG. The control circuit 4 of this embodiment also includes a speed detector 31 for detecting the moving speed of the vehicle, as in FIG. 15, and each of the drive circuits 16a and 16b includes a comb filter 20 and two tracking bands. Pass filter 32,
33 (hereinafter abbreviated as “tracking BPF (C) 32” and “tracking BPF (L) 33”), and amplitude detecting circuits 34 and 35 for detecting output amplitudes from the tracking BPFs 32 and 33.

The structure of the comb filter 20 is the same as that shown in FIG. 14; the first drive circuit 16a receives the diffused light reception amount data, and the second drive circuit 16b receives the regular reflection light. Light reception amount data is input.

In each of the driving circuits 16 a and 16 b, data indicating the amount of reflected light, either positive or diffuse, extracted by the comb filter 20 is input to each of the tracking BPFs 32 and 33, and the first tracking BPF (C) 32. the spatial frequency components centered at 1/4 mm ^-1, the second tracking BPF (L) 33 is the spatial frequency components centered at 1/40 mm ^-1, pass respectively. In addition, each of the tracking BPFs 32 and 33 receives the speed data detected by the speed detection unit and changes the width of the frequency band to be cut off by following the moving speed of the vehicle.
It is configured to keep the extracted spatial frequency component constant.

FIG. 18 shows a procedure of the road surface state determination processing by the determination circuit 17. In FIG.
_{1, TH2, TH3, TH c} , TH d1, TH d2, TH e
Indicates a threshold value for determining the road surface condition (TH1 and TH2 are the same as those described with reference to FIG. 5).

First, in step 1, the temperature sensor 1
Track temperature D _e measured by 9 is compared with a threshold value TH _e. The threshold TH _e is intended to be set to 0 near ° C is a freezing temperature of water, when the temperature D _e exceeds the threshold value TH _e, the possibility that the road surface is frozen It is determined that it does not exist, and the process proceeds to step 2 and subsequent steps.

In steps 2 and 3, for the diffuse reflected light, the frequency component intensity ratio Db / Da and the threshold value TH
1 and TH2. In this case, according to the principle described with reference to FIG. 5, the frequency component intensity ratio Db / Da
Is greater than the threshold value TH1, the traveling road surface is determined to be a snow-covered road surface (step 5), and if the frequency component intensity ratio Db / Da is between the threshold values TH2 and TH1, the traveling road surface is determined. The road is determined to be a gravel road surface (step 6).

On the other hand, when the frequency component intensity ratio Db / Da is equal to or smaller than the threshold value TH2, it is determined that the road surface is a pavement road surface. In this case, in the next step 4,
Intensities Da and D of the components included in the frequency band centered on the spatial center frequency for both the positive and diffuse reflected light
f is taken out, and the intensity ratio Df / Da (hereinafter referred to as “reflected light ratio Df / Da”) and the threshold value TH _d1
Is compared.

As described above, when the pavement is wet, the road surface is close to a mirror surface, so that the amount of specular reflection increases, and the value of the reflection light ratio Df / Da increases accordingly. The threshold value TH _d1 is set at an intermediate level between the reflected light ratio Df / Da when the road surface is in a wet state and the reflected light ratio Df / Da when the road surface is in a dry state. If the ratio Df / Da exceeds the threshold TH _d1 is determined to road is wet road (step 8). On the other hand, when the reflection light ratio Df / Da is equal to or less than the threshold value TH _d1, it is determined that the traveling road is a dry road surface (step 7).

[0055] If the road surface temperature D _e is equal to or less than the threshold value TH _e, the process proceeds to step 9, the frequency component intensity ratio Db / Da is compared with a predetermined threshold value TH3. As a result, when the frequency component intensity ratio Db / Da exceeds the threshold value TH3, the road surface is recognized as a snow-covered road surface or a gravel road surface, and further in step 10 it is determined which road surface state the vehicle is in. Is performed.

In step 10, the reflection light ratio Rv of the diffuse reflection light (the ratio of the amount of reflected light to the amount of light projected on the road surface LD) is determined.
The intended to be compared with a predetermined threshold value TH _c, when the diffusion reflection light factor Rv exceeds the threshold value TH _c is the road surface is determined to be a snow surface (step 5), the diffuse reflection light rate is the case of below the threshold TH _c is the road surface is judged to be a gravel road (step 6).

In step 9, the frequency component intensity ratio Db
/ Da is determined that if there was a threshold value TH1 or less road is paved road, by performing the further comparison of the reflection light ratio Df / Da and the threshold TH _d2 described above in step 11, the Detailed determination of the road surface state is performed. Since the frozen road surface is in a state close to a mirror surface, the amount of specular reflection greatly increases, and as a result, the reflection light ratio Df / Da increases. Therefore, when the reflection light ratio Df / Da exceeds the threshold value TH _d2 , it is determined that the road surface is frozen (step 12), and when the reflection light ratio Df / Da is equal to or less than the threshold value TH _d2 , It is determined that the road surface is dry (step 7).

As described above, while traveling on the road, the spatial frequency of the specular reflection light and the diffuse reflection light at a predetermined position is analyzed, and the road surface temperature is further checked, whereby the wet road surface, the dry road surface, the gravel road surface, the snowy road surface, 5 called frozen road surface
The type of road surface condition can be determined. In this case, if a plurality of reflected light measurement sensors 2 are provided and the measurement results from each sensor are individually processed, the road surface state can be determined in more detail.

FIG. 19 shows three reflected light measurement sensors 2A,
1 shows a configuration example of a road surface condition determination device 1 having 2B and 2C. Each of the reflected light measurement sensors 2A, 2B, 2C
Alternatively, it is of the type shown in FIG. 10 and is arranged along the width direction of the vehicle.

In this embodiment, the left and right reflected light measuring sensors 2A and 2C measure the amount of reflected light at the position where the left and right wheels pass, and the central reflected light measuring sensor 2B measures the amount of reflected light from the position where the wheel does not pass. By measuring, the difference in the road surface state between the position where the wheel passes and the position where the wheel does not pass is grasped. According to this configuration, it is possible to determine the road surface state in detail along the width direction of the road surface, especially when it is necessary to determine in detail the difference in road surface state depending on the road surface position, such as a snowy road or a frozen road. Can respond to.

FIG. 20 shows an example in which a warning device 40 is provided on a vehicle 5 on which the road surface condition determination device 1 is mounted. When the control device 4 determines that the traveling road is a snowy road or a frozen road, it outputs a drive signal to the alarm device 40. Warning device 4
0 receives this signal and outputs warning information such as audio output, image display, blinking of an indicator lamp, etc., to alert the driver to the road surface condition.

Further, a system for managing the road surface state of a predetermined section on the road or the entire road can be configured by using the vehicle 2 on which the road surface state determination device 1 is mounted. FIG. 21 shows an example of the above system.
A communication device (not shown) using a wireless or telephone line is provided in the vehicle 5 on which the road surface condition determination device 1 is mounted. The road L is divided into several sections, and each time the vehicle 5 passes through each section, the vehicle 5 transmits the determination result of the road surface state of the section to the information collection station 41 of the management center.
Further, a display device 42 for displaying information relating to traveling safety is provided downstream of the measurement section.

The information collecting station 41 recognizes the contents of the transmission information for each section, creates management data integrating the road surface conditions in each section, freezes the road surface in any section, When information such as the presence of such information is obtained, predetermined warning information is created and transmitted to the display device 42.
As a result, the driver of a general vehicle (indicated by reference numeral 43 in the figure) can be informed in advance that the road surface condition ahead is dangerous.

[0064]

According to the first aspect of the present invention, the road surface condition is determined based on the reflected light amount of the light emitted from the traveling vehicle within a predetermined period and the measured value of the moving distance during this period. It is possible to accurately determine the road surface condition with a simple configuration.

According to the second aspect of the present invention, the road surface state discrimination processing is performed by analyzing the spatial frequency of the road surface from the reflected light reflecting the road surface state using the detected value of the reflected light amount and the measured value of the moving distance. realizable.

According to the third aspect of the present invention, the road surface condition can be determined in more detail by separately detecting the regular reflection light amount and the diffuse reflection light amount from the road surface.

According to the fourth aspect of the present invention, the road surface condition is determined by using the reflected light amount from a plurality of positions in the width direction of the road surface. Therefore, when the road surface condition such as a snowy road or a frozen road needs to be determined in detail. Can also respond.

According to the fifth aspect of the present invention, by mounting the above-described road surface state determination device on a vehicle, it is possible to provide a vehicle having a road surface state determination function at a simple and inexpensive cost.

According to the invention of claim 6, in the vehicle,
When the road surface is determined to be dangerous based on the determination result of the road surface condition, the warning information is output, so that the vehicle can be driven safely.

According to the seventh aspect of the present invention, the control device edits the road surface condition determination result transmitted from the vehicle and outputs the result to the outside. Information related to safety can be promptly provided to prevent an accident.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a vehicle equipped with a road surface condition determination device according to the present invention.

FIG. 2 is a side view showing a detailed configuration of a wheel speed sensor.

FIG. 3 is an explanatory diagram illustrating a basic configuration of a reflected light measurement sensor.

FIG. 4 is an explanatory diagram showing a change in reflectance of diffuse reflection light due to movement of a vehicle and a result of Fourier transform thereof.

FIG. 5 is an explanatory diagram showing spatial frequency characteristics obtained for each type of road surface condition.

FIG. 6 is an explanatory diagram showing the relationship between diffuse reflectance and regular reflectance in association with each type of road surface condition.

FIG. 7 is an explanatory diagram showing a state in which two types of reflected light measurement sensors are attached to a vehicle.

FIG. 8 is an explanatory diagram showing a detailed configuration of each reflected light measurement sensor of FIG. 7;

FIG. 9 is an explanatory diagram showing another configuration example of the reflected light measurement sensor.

FIG. 10 is an explanatory diagram showing another configuration example of the reflected light measurement sensor.

FIG. 11 is a timing chart showing output timings of drive pulses to each light emitting unit in FIG.

FIG. 12 is a block diagram showing an electrical configuration of a road surface state determination device using the reflected light measurement sensor of FIG.

FIG. 13 is an explanatory diagram illustrating a state of light incident on a light receiving unit.

FIG. 14 is a block diagram showing a detailed configuration of the comb filter of FIG.

FIG. 15 is an explanatory diagram showing a processing method for an output signal of the amount of received light.

FIG. 16 is a block diagram showing another example of the configuration of the road surface condition determination device using the reflected light measurement sensor of FIG. 10;

FIG. 17 is a block diagram showing another configuration example of the road surface state determination device using the reflected light measurement sensor of FIG. 10;

FIG. 18 is a flowchart illustrating a procedure of road surface determination.

FIG. 19 is an explanatory diagram showing a state where three reflected light measurement sensors are attached to a vehicle.

FIG. 20 is an explanatory diagram showing a vehicle equipped with a road surface state determination device and an alarm device.

FIG. 21 is an explanatory diagram illustrating an example of a road surface information management system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Road surface condition discrimination device 2 Reflection light measurement sensor 3 Wheel speed sensor 4 Control device 5 Vehicle

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // G01B 11/30 G01B 11/30 W

Claims (7)

[Claims] 1. A detecting means for irradiating light from a running vehicle toward a road surface to detect a reflected light amount, a measuring means for measuring a moving distance of the detecting means, a reflected light amount obtained within a predetermined period A road surface state determination device comprising: a determination unit configured to determine a road surface state based on the detected value of the distance and the measured value of the moving distance. 2. The method according to claim 1, wherein the determining unit analyzes a spatial frequency of the road surface from the reflected light using the detected value of the reflected light amount and the measured value of the moving distance, and determines a road surface state based on the analysis result. The road surface state determination device described in the above. 3. The road surface state determination device according to claim 1, wherein said detecting means separately detects a regular reflection light amount and a diffuse reflection light amount of the irradiation light from the road surface. 4. The road surface state determination device according to claim 1, wherein the detection unit irradiates light to a plurality of positions in a width direction of the road surface, and individually detects a reflected light amount of each irradiation light. 5. A vehicle on which the road surface condition determination device according to claim 1 is mounted. 6. A vehicle equipped with the road surface condition determination device according to claim 1, wherein the recognition of recognizing a degree of danger of the road surface is performed by using a result of the determination by the road surface condition determination device. And a warning means for outputting warning information when the road surface is recognized as dangerous by the recognition means. 7. A system comprising a vehicle equipped with the road surface condition determination device according to claim 1, and a control device, wherein the vehicle controls the determination result of the road surface condition. Transmission means for transmitting to the control device, the control device is an information editing means for editing information relating to traveling safety using transmission information from the vehicle, and an information output for outputting the edited information to the outside Road information management system comprising: