JPS585900A - Road surface state discriminator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for determining road surface conditions and road visibility conditions.

Ensuring the safety of drivers by taking appropriate measures against traffic disturbances caused by frozen roads, snow accumulation, etc., or poor visibility due to snowfall, rain, dense fog, etc.6 is a very important issue in transportation system management. Therefore, in order to take appropriate measures, it is necessary to quickly and accurately grasp the road surface condition.

This invention further improves visibility by changing or adding a signal processing stage without changing the equipment configuration of the conventional road surface condition IIR separate device (Japanese Patent Application No. 55-80429) filed by the same applicant as this application. The present invention provides a road surface condition identification device with an added condition determination function.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 511, a support post 22 is erected on one side of the road 21, and a support arm 23 extends upward from the top of the support post 22 toward the top of the road 21. And this support arm 23
, a light emitter 24, a diffuse reflection receiver 25, a regular reflection receiver 26
and a light emission level measuring device 27 are installed, respectively.
A road surface temperature gauge 28 is provided on the pillar 22. The projector 24 uses a mercury lamp whose light emitting lamp contains not only visible light but also near-infrared light. The projector 24 is arranged so as to be directed toward the road surface at an appropriate angle of incidence. The specular reflection receiver 26 receives specularly reflected visible light of the road surface reflected light projected from the light projector 24 and converts it into an electrical signal. The diffused reflection receiver 25 separately detects visible light and near-infrared light reflected from the road surface. Near infrared light has a wavelength of 1.5-2
．． A range of 5 #l is preferred. The light emitting level measuring device 27 directly receives the light from the light projector 24.
In this embodiment, the amount of visible light is measured. A radiation thermometer is used as the road surface thermometer 28.

In FIG. 2, the floodlight 24 is a constant power ballast 2914.
Therefore, it is driven with constant power. The diffuse reflection light receiver 25 includes light receiving elements 31*32 for infrared light and visible light, and the outputs of these light receiving elements 31 and 32 are amplified by an amplifier 34, and then noise components are removed by a bandpass filter 35, respectively. Ru. The specular reflection light receiver 26 includes a visible light light receiving element 33, and the output signal of this light receiving element 33 is also outputted via an amplifier 34 and a bandpass filter 35. The signals output from the photoreceivers 25, 26 are again amplified and rectified by the amplifier 36 and sent to the comparators 41, 42, 43. Each of these comparators 41, 42, 43 has one or more reference levels AI, A2°B1 . B2. B3. CI is set respectively, and the output of each light receiving element 31, 32, 33 is compared with these reference levels. The logic circuit 44 converts these comparison results into status signals, and the output of the logic circuit 44 is sent to the arithmetic processing section 45. As the arithmetic processing section 45, a microprocessor is suitably used. In addition, the comparators 41, 42, 43, logic circuit 44, arithmetic processing section 45, and A/l) converter 46 are all constructed using a one-chip microprocessor with a built-in converter or ~
A combination of a converter and a microprocessor may also be used.

The light emitting level measuring device 27 includes a visible light light receiving element 30, and the output of this light receiving element 30 also passes through an amplifier 37, a bandpass filter 38, and is amplified and rectified by an amplifier 39. The signal is input to comparators 41, 42 and 43 and an arithmetic processing section 45. The above reference levels AI of comparators 41, 42, 43, A2°B1. B2. B3. C1 is adjusted by the output of the measuring device 27. Although the projector 24 is driven with constant power, the amount of light emitted changes due to deterioration of the mercury lamp itself, dirt on the front surface of the projector, etc. If the amount of projected light changes, the amount of light reflected from the road surface will also change, so if the reference levels of the comparators 41, 42, and 43 are kept constant, false detection may occur. Here, in order to compensate for changes in the amount of light emitted, the comparator 4
The reference level of 1.42°43 is adjusted. Since the amount of projected light and the amount of reflected light are considered to be approximately proportional, the reference level of each i ratio 41, 42, 43 is changed in proportion to the level of the amount of projected light. The output of the thermometer 28 is processed by the arithmetic processing section 45.
Enter.

FIG. 3 shows the relative ranges of the output levels of each light receiver 25, 26 and thermometer 28 for dry, wet, snowy, and frozen conditions, and the judgment results of the road surface condition obtained from these outputs. There is.

During snowfall, rain, fog, etc., the light projected from the projector 24 toward the road surface 21 is reflected and scattered by snowflakes, water droplets, etc. in the optical path, so the output of each light receiver fluctuates. Furthermore, the light path of direct light from the light projector 24 to the light level measuring device 27 is obstructed by snowflakes, water droplets, etc., and the light amount and therefore the output of the measuring device fluctuate. Here, the output fluctuations of the light emitting level measuring device 27 are detected to determine whether the visibility is good or bad, and when the visibility is poor, a warning for poor visibility is displayed.The visibility condition determination function of this invention is as follows. executed. In FIG. 2, the output of the light emitting level measuring device 27 is input to the arithmetic processing section 45 via the converter 46.

Referring to FIG. 4, the arithmetic processing section 45 takes in the level of the projected light amount at appropriate time intervals, and calculates the difference H (previous value - current value) from the level that fell in the previous range (step 1). When this level difference H is greater than or equal to the predetermined value 1, the addressed memory is set to 1#, and when it is less than -, it is set to @0'' (Step, De 2, 3).Then, the memory address is set to +1 (Step 4) o Repeat this cycle n times and set the memories at addresses O to n-1 to 1" and 0#, respectively, according to the value of H (Steps 1 to 5) )
, 11', that is, the number of times the light emission level difference is 19 or more, is counted, and when K exceeds the predetermined value J and 9, it is determined that visibility is poor (step 6), and the visibility is reduced. The defect warning signal is sent to a center or a road surface display device installed on the road, etc., along with other road surface condition identification signals, etc., and visibility conditions are monitored and displayed. Further, when K is less than J, it is determined that visibility is good (step 6), and when a poor visibility warning signal is issued, it is canceled (step 7).

In this example, n memories were used, each memory was set to 1" or "0#, and then the number of memories set to 1# was counted to find the number of '1#'. Using one or more memories or registers, n of these memories or registers
You can count the number of 1's after setting ``l'' or ``0#'' for each bit, or you can count n ``1'' or ``0#'' using one memory or a specific register. may be added and the total may be determined as the number of 11#.

This procedure for determining the visibility state may be performed in series with the procedure for determining the road surface condition, or one of them may be used as the main, and the other may be processed as an interrupt process at appropriate time intervals. Alternatively, the road surface condition may be determined within the visibility condition determination routine (between steps 5 and 1, or between steps 1 and 2.3, 4.4 and 5, etc.).

The procedure for determining the road surface condition is described in the above-mentioned patent application No. 55-80429.
However, it will be explained below with reference to FIGS. 3 and 5.

As shown in FIG. 3, the light receiver 25
．． The 26 output levels vary and each state has a unique range. Therefore, we set the standard level A1 to a level that can distinguish between dry conditions and other conditions (although the dry conditions and some snowy conditions (new snow) overlap), and set the standard level B1 to a level that can distinguish between white snow (fresh snow) and other conditions. The reference level B2t and the level B1 are set to a level that can distinguish snowy and dry states from other states, and the reference level C1 is set to a level that can distinguish a mirror-like wet state from other states. A2. B3 is set to a level (in this embodiment, A2=B3) that can distinguish between normal and abnormal cells.

Each light receiver 25, 26 is a comparator 41, 42.

43 as above reference level A1. A2. Bl.

B2. B3. Based on this state signal, the O arithmetic processing unit 45, which outputs a state signal that is discriminated by the CI and outputs a state signal representing the discrimination result, determines the road surface state according to the following procedure, and generates a road surface state identification signal of dry, wet, snowy, and frozen. Outputs
Alternatively, perform sensor abnormality processing. Referring to Figure 5,
First, each light receiver 25, 26 and thermometer 28 are checked to see if there is any abnormality (step 10), and if there is no abnormality, proceed to step 11. If there is an abnormality, the process moves on to deal with it (step 15). In step 11, based on the infrared light output of the diffuse reflection receiver 25, the reference level A is
Based on the discrimination result based on 1, it is determined whether the road surface condition is dry or not. That is, if the infrared light output of the light receiver '25 is equal to or higher than level A1, it is considered as drying, and if it is less than level A1, it is considered as other than drying.

The area determined to be dry includes part of the snowfall, that is, fresh snow (white snow).

Next, the process proceeds to steps 12 and 16, in which snowfall is determined using the visible light diffused reflection output. The snow included in the snow determined to be in a dry state in step 11 is white snow, and in the case of this white snow, the visible light diffused reflection output is level B1 or higher. Of those determined to be dry in Step 11, if the level is B1 or higher, it is determined to be snowfall, and if it is less than B1, it is determined to be dry (Step 16).

Further, among the items classified as other than dry in step 11, those whose visible light diffuse reflection output is level B2 or higher are determined to be snowfall, and those whose visible light diffused reflection output is level B2 or higher are determined to be wet or frozen (step 12).

In step 13, the visible light specular reflection output is used to determine the wet state (
(mirror surface).

If the visible light specular reflection output is equal to or higher than level C1, it is in a wet state.

In the discrimination processing in Steps 1 and 11 to 13, the frozen state and a part of the wet state are not discriminated. Therefore, in step 14, frozen and wet conditions are distinguished based on the output of the thermometer 28. If the road surface temperature is 0°C or higher, it is wet, and if it is -2°C or lower, it is frozen. When the road surface temperature is between 0° C. and -2° C., if the previous determination was wet, it is determined to be wet, and if it is frozen, it is determined to be frozen (Step 18).

Even if it is determined in step 14 that the area is frozen, it may still be in a wet state. This happens when snow melting agents are sprayed. Spraying a snow melting agent lowers the freezing point, causing a transition from a snowy or frozen state to a wet state. Therefore, even if x is determined to be frozen in step 14, it will remain wet within a certain period of time after the snow melting agent is sprayed (the effective time of the snow melting agent) (step 17). Detection can be done in various ways. For example, a switch may be provided for the spraying staff to operate, an oscillator may be provided on the snow melting agent spraying vehicle, and a receiver may be provided on the road surface condition identification device.
There are methods such as detecting the passage of the scattering wheel with a receiver and checking fluctuations in the specular reflection light reception output of visible light. When snow or ice melts and turns into water, the road surface temporarily becomes mirror-like. As a result, the visible light specular reflection output increases, so it can be known that the snow melting agent has been sprayed.

When the road surface condition is finally determined in this way, a road surface condition identification signal is output (step 19).

This identification signal is transmitted together with the poor visibility warning signal or separately to, for example, a center or a road surface display device installed on the road, and the road surface condition and visibility condition are monitored and displayed. The above road surface condition determination is performed at appropriate time intervals.

In addition, each of the above reference levels A 1 s A 2 = R
1eB2. B3. C1, the reference level difference (2), the number of reference fluctuations J, and the reference temperature (0° C., -2° C.) vary depending on the installation location, so it is preferable to change them as appropriate.

In the embodiments described above, the road surface condition and the visibility condition are determined by the arithmetic processing section (microderosé), but the road surface condition and the visibility condition can also be determined by a logic circuit. Furthermore, the setting of the reference level that is the basis of the discrimination and the method of combining the comparatively discriminated state signals are not limited to the above example, but can be determined as appropriate depending on the road surface and visibility state to be discriminated.

As mentioned above, "According to the present invention, by changing only the signal processing stage without changing the equipment configuration of the conventional road surface condition identification device, the program and some inputs of the microprocessor part in particular can be changed. It is possible to add a visibility condition determination function by simply
Conventional devices can be modified with relatively simple operations such as exchanging modular values or cards.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing the arrangement of the emitter, receiver, and light intensity level measuring device, Figure 2 is a diagram showing the internal configuration of the road surface condition identification device, and Figure 3 is each light reception for each road condition. FIG. 4 is a flowchart showing the procedure for determining the visibility condition, and FIG. 5 is a flowchart showing the procedure for determining the road surface condition. 24... Emitter, 25... Diffuse reflection receiver, 26...
・Specular reflection receiver, 27... Light emission level measuring device, 28
... Road surface temperature meter, 41, 42, 43 ... Comparator, 4
5... Arithmetic processing unit. Patent applicant Tateishi Electric Co., Ltd. Agent Patent attorney Tatsu Izuka Higashi Yui
Tetsuya

Claims (1)

[Claims] A light projector that projects visible light and infrared light toward the road surface, a light intensity level measuring device that directly receives the light from the projector, a light receiver that receives regular reflection and diffuse reflection of visible light from the road surface, and a light receiver that receives visible light from the road surface. It is equipped with a light receiver that receives the diffusely reflected light of the infrared light of The road surface condition identification device is further characterized in that the device further detects visibility conditions from fluctuations in output due to fluctuations in the amount of light received by a light emitting amount level measuring device.