JP3473299B2 - Road condition monitoring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a vehicle speed on a highway or a general road, a vehicle traffic condition, an obstacle detection, and a road surface condition, and an alarm is displayed to an observer or a passing vehicle and the road condition is displayed. It relates to the device.

[0002]

2. Description of the Related Art Conventionally, for monitoring road conditions, there are a method of installing a camera at a certain measuring point and using image data to be taken, and a photoelectric method of installing an infrared device or a laser device.

The monitoring by the camera is performed by a person who directly monitors the image data taken by the observer, or by Japanese Patent Laid-Open No. 7-3705.
As disclosed in Japanese Patent Publication No. 7, a means for detecting a contour component of image data of a moving object that has passed through the surveillance visual field by image processing has been devised. However, there is a weak point that it becomes difficult to monitor when the captured image data does not include sufficient image components due to the visibility condition at night or in bad weather such as fog.

In the case of the photoelectric type, as shown in FIG. 1, a pair of light transmitters 2A and 3A and a pair of light receivers 2B and 3B are provided on one side of the track 1, and a pair of light transmitters 4A and a pair of light receivers are provided on both sides of the track 1. The device 4B is installed, and the light emitted from the light transmitter is received by the light receiver. If there is no obstruction, it is determined that both sides of orbit 1 and on the orbit are safe. However, the photoelectric type is vulnerable to dirt on the lens and deviation of the optical axis, and requires regular maintenance. It is also weak against snowfall and fog.

As shown in FIG. 2 of Japanese Unexamined Patent Publication No. 7-73394, an ultrasonic wave transmitter / receiver 5 transmits a transmitted wave 7 to a monitoring target area,
Due to the difference in the amplitude of the vehicle reflected wave 8 reflected by the vehicle 6 and the road surface reflected wave 9 reflected on the road surface and the difference in the time delay as shown in FIG. The time t2- when the receiving gate is opened and closed by opening and closing the receiving gate by the value t1 and the time threshold value t2.
A means for detecting the presence or absence of a vehicle by detecting the presence or absence of a received signal at t1 has been devised.

[0006]

However, in the above-mentioned method, the installation height and time threshold are set in advance for each installed ultrasonic wave transmitter / receiver, the waveform is observed, and the sensor There was a problem that had to be adjusted.

In this patent, it is not necessary to set the installation height and time threshold value in advance, observe the waveform, and adjust the sensor, are not affected by the weather such as snowfall or fog, and are well-known phasing processing. By applying (beamforming), it is possible to monitor multiple lanes, roadside belts, and road surfaces at the same time, and detect multiple information such as the traffic volume and speed of the vehicle, the presence or absence of obstacles, and road surface conditions at the same time. The purpose is to constantly monitor this information and to display warnings and road conditions to the observers and passing vehicles.

[0008]

In order to achieve the above object, the road condition monitoring device of the present invention comprises a transmitting means for transmitting an ultrasonic wave from a wave transmitter and one or more ultrasonic wave receivers. Receiving means for receiving ultrasonic waves in the configured receiver, means for detecting signal components that are not Doppler signal components and Doppler signals, means for discriminating Doppler signal components and signal components that are not Doppler signals, and Doppler signal components A means for determining the vehicle speed and the traffic volume, a means for determining what kind of object the signal component other than the Doppler signal corresponds to, a means for detecting the probability distribution of the sound pressure value of the background reverberation sound, and a background reverberation sound. Means for determining what kind of road surface situation the probability distribution of the sound pressure value of the vehicle corresponds to, and Doppler signal component or non-Doppler signal component or background reverberation sound Means for statistically measuring the probability distribution of values, means for determining the position, size, shape of the reverberant object or road surface conditions from the statistical measurement results, vehicle traffic, speed and the presence or absence of obstacles and A means for communicating the road surface condition, a means for displaying the traffic volume, speed and the presence / absence of an obstacle and the road surface condition to an observer or a passing vehicle, and monitoring from the traffic amount, the speed and the presence / absence of an obstacle and the road surface condition It is composed of means for alerting a person or a passing vehicle.

[0009]

An embodiment of claim 1 is shown in FIG.
The wave transmitter 12, the wave receiver 13, and the signal processing device 14 are installed for each certain section in a position that does not obstruct the passage of the vehicle.

In this embodiment, the signal processing device 14 detects the speed and the traffic of the vehicle by detecting the Doppler signal component shown in FIG. 5 of claim 2 and the Doppler shown in FIG. 8 of claim 3. The apparatus is a combination of an apparatus that detects the presence or absence of an obstacle by detecting a signal component that is not a signal, and a road surface condition by detecting the probability distribution of the sound pressure value of the background reverberation sound shown in FIG. Or a device for detecting a statistical value of a Doppler signal component or a non-Doppler signal component shown in FIG. 11 or FIG. 12 of claim 5, to determine the position, size, shape, or the sound pressure value of the background reverberation sound. A device for determining the road surface condition from the sound field condition of the statistical value of the probability distribution, or a combination of two or more of these may be used.

The installed ultrasonic wave transmitter 12 transmits the sound wave of a certain specific frequency generated by the signal processing device 14 to the monitored area of the road. The sound wave transmitted from the wave transmitter echoes on the vehicle on the road, and is received by the wave receiver 13 composed of one or more ultrasonic wave receivers. The received signal can be directed to each lane by the phasing process (beamforming) of the signal processor 14 so that a plurality of lanes can be simultaneously monitored. The signal processing device 14 communicates the detected vehicle speed and traffic to the central monitoring device 11. The central monitoring device 11 monitors the speed and traffic of the vehicle communicated from the signal processing device 14 in each section for each section, and the accident vehicle 16 detects a signal component that is not a Doppler signal in the accident vehicle section L1. Further, the vehicle speed and the traffic volume of the congestion section L2 and the section L3 in which the vehicle is normally traveling are detected, and it is determined that there is an obstacle at L1 and that congestion is occurring at the congestion section L2. The alarm device 15 in the section L2 and the section L3 in which the vehicle is normally traveling gives an alarm, and the display device 34 displays the alarm on the passing vehicle. At the same time, an alarm device 15 also gives an alarm to an observer who monitors the central monitoring device 11 that there is an obstacle at L1 and that a traffic jam is occurring at a traffic jam section L2, and a display device. Display at 34.

An embodiment of claim 2 is shown in FIG. The wave transmitter 12 installed at a position that does not obstruct the passage of the vehicle transmits a sound wave of a certain specific frequency, which is generated by the signal generator 171 of the sound wave generator 17 for wave transmission and amplified by the wave signal amplifier 172. Transmit to the monitored area. The transmitted sound wave reverberates in the vehicle 6 running on the road, and is received by the wave receiver 13 composed of one or more ultrasonic wave receivers.
At this time, the frequency of the sound wave transmitted is f0, the frequency of the received sound wave is f1, the speed of the running vehicle is v, and the speed of sound is c.
Then, there is a relation of the following equation.

[0013]

[Equation 1]

The signal received by the wave receiver 13 is amplified by the received signal amplifier 181 of the received signal preprocessor 18, and a bandpass filter 182 removes an acoustic signal having a frequency unrelated to the echo acoustic signal. , And is sampled by the analog / digital converter 183 at a preset sampling frequency. The sampled received signal is the receiver 1
Phase-adjusting processing (beam forming), which is a known technique for creating directivity in a specific direction by manipulating the phase information of the signals received by the respective ultrasonic wave receivers constituting 3, is performed by the phase-adjusting device 19. The signal for each lane can be detected. With the frequency analyzer 20, the received signal for each lane is
As an example, FFT frequency analysis is performed. The frequency of the received sound wave subjected to frequency analysis is f1, and the frequency f of the transmitted sound wave is f.
Since 0 is known in advance, V is calculated by the control device 21 by using the equation of Formula 1 as an example. At this time, a value stored in advance in the control memory 22 may be used as the sound velocity c, or a value obtained by the temperature sensor or the humidity sensor may be stored in the control memory 22 and a table for sound velocity correction may be used. The sound velocity corrected by may be used. Measurement recorder 2
The V obtained in 3 is recorded on the time axis as shown in FIG. 6, and the V when V exceeds a certain threshold VSH is recorded as the vehicle speed V. There is also a certain threshold VS with V
The time interval that does not exceed H is measured, and when the time interval exceeds a certain time threshold value t3, the number of effective vehicles is set, and the number of vehicles that pass per hour is measured. As an example, when the Doppler signal 25 as shown in FIG. 6 is recorded in the measurement recorder 23, the number of passing vehicles per unit time is 3, and the speed of each vehicle at this time is the speed VD of the vehicle D and the speed of the vehicle E.
Is obtained as the speed VE of the vehicle and the speed VG of the vehicle G. The obtained information is sent to the central monitoring device 1 shown in FIG.
1 is displayed on the display device 34 by the display controller 26 of the central monitoring device 11 and communicated to the communication controller 24 of 1.
For the traveling vehicle, the communication control device 2 of the central monitoring device 11
4 is displayed on the display device 34 of FIG. At the same time, if the alarm controller 27 of the central monitoring device 11 determines that an alarm is required for the monitoring person and the passing vehicle, an alarm is issued to the monitoring person by the alarm device 15 of the central monitoring device 11 and the passing vehicle is notified. Is the communication control unit 24 of the central monitoring unit 11.
An alarm is given to the alarm device 15 of FIG.

An embodiment of claim 3 is shown in FIG. The wave transmitter 12 installed at a position that does not obstruct the passage of the vehicle transmits a sound wave of a certain specific frequency, which is generated by the signal generator 171 of the sound wave generator 17 for wave transmission and amplified by the wave signal amplifier 172. Transmit to the monitored area. The transmitted sound wave reverberates on the obstacle 28 on the road, and is received by the wave receiver 13 including one or more ultrasonic wave receivers. The signal received by the wave receiver 13 is the received signal preprocessor 18
The received signal amplifier 181 removes the acoustic signal having a frequency unrelated to the echo acoustic signal by the band pass filter 182, and the analog / digital converter 183 samples the acoustic signal at a preset sampling frequency. The sampled received signal is a well-known technique for phasing that creates directivity in a specific direction by manipulating the phase information of the signal received by each ultrasonic receiver constituting the receiver 13 ( Beam forming) is performed by the phase rectifier 19, and the sampled received signal is subjected to FFT frequency analysis by the frequency analyzer 5 as an example. A signal component in which the frequency component of the received sound wave subjected to the frequency analysis is the same as the transmission frequency f0 becomes a signal component which is not a Doppler signal. The control device 21 extracts the amplitude information and the phase information of only the signal component which is not the Doppler signal, and compares the amplitude information and the phase information stored in the control memory 22 with a certain threshold value in advance by the control device 21. When the value exceeds the value, it is determined that there is an obstacle and is recorded in the measurement recorder 23. When it is determined that there is an obstacle, the control storage unit 22 is previously stored.
The amplitude information and the phase information of some obstacles stored in the above are compared with the amplitude information and the phase information of the received sound wave obtained, the corresponding obstacle is determined by the control device 6, and the determination result is measured and recorded. It is recorded in the device 23 and this information is stored in the communication controller 24.
To communicate with the central monitoring device 11. Based on the obtained information, the central monitoring unit 11 performs the same processing as the processing of claim 2 described above.

An embodiment of claim 4 is shown in FIG. The wave transmitter 12 installed at a position that does not obstruct the passage of the vehicle generates a sound wave pulse wave having a specific frequency, which is generated by the signal generator 171 of the sound wave generator 17 for wave transmission and amplified by the wave signal amplifier 172. The waves are transmitted toward the road surface 29 that is the monitoring target of the road. The transmitted sound waves reverberate on the road surface 29 on the road, and after the propagation delay time proportional to the distance between the ultrasonic wave transmitter 13 and the target road surface, the echo sound 30 from the road surface is transmitted by the ultrasonic wave receiver 13 at t4. Received. Here, the acoustic signal 3 of FIG.
As shown in FIG. 2, after the propagation delay time t4, the received signal preprocessor 18 invalidates the signal of the echo sound 30 from the road surface that is echoed and received from the target road surface, and then the background reverberation reception section. Only the background reverberation sound 31 received at t5 is extracted.
If the interval between the pulse waves transmitted from the wave transmitter 12 is made longer, the background reverberation sound 31 can be made longer, so that it is not necessary to strictly set the propagation delay time invalidated by the received signal preprocessor 18. You can see from 10. The extracted background reverberant sound 31 is a signal received by the wave receiver 13 and is amplified by the wave reception signal amplifier 181 of the wave reception signal pre-processor 18, and is amplified by the band pass filter 182 to have a frequency unrelated to the echo sound signal. The acoustic signal is removed, and sampling is performed by the analog / digital converter 183 at a sampling frequency set in advance. The sampled received signal is a well-known technique for phasing that creates directivity in a specific direction by manipulating the phase information of the signal received by each ultrasonic receiver constituting the receiver 13 ( Beamforming) Phaser 19
The control device 21 calculates the sound pressure value component of the sampled received signal for each sample value, and obtains the probability distribution of the sound pressure values at the transmission intervals. Like the reverberant sound, the probability distribution of the sound pressure value of the background reverberation depends on the surface scattering intensity of the reverberant object. Therefore, the probability distribution of the obtained sound pressure value and the control memory 22 are stored in advance.
In comparison with the probability distribution of the sound pressure value of the background reverberation signal of some road surface states stored in, the road surface state of the corresponding road is determined by the control device 21, and the determination result is recorded in the measurement recorder 23, This information is sent to the central monitoring device 11 by the communication controller 24.
Communicate to. Based on the obtained information, the central monitoring unit 11 performs the same processing as the processing of claim 2 described above.

An embodiment of claim 5 is shown in FIG. Figure 5,
The sound pressure value of the Doppler signal component or the non-Doppler signal component or the background reverberation sound recorded in the measurement recorder 23 of the ultrasonic signal processing device 14 of claims 2, 3, and 4 shown in FIGS. 8 and 9. The probability distribution is statistically processed and recorded by the statistical processor 33 at predetermined time intervals. The obtained statistical values and some statistical values regarding the position, size, and shape of the reflecting object stored in advance in the statistical processor 33 and the statistical values of the Doppler signal component or the non-Doppler signal component are statistically processed by the statistical processor 33. And the corresponding statistical value is determined, and the information is recorded in the statistical processor 13.

Further, the obtained statistical value is compared with the statistical value of the probability distribution of the sound pressure value of the background reverberant sound of the road road surface which is stored in advance in the statistical processor 33 in the statistical processor 33, and the corresponding statistical value is obtained. And the statistical processor 3
3 and the information is communicated to the central monitoring device 11 by the communication controller 24. Central monitoring device 1 from the obtained information
1 performs the same processing as the processing of claim 2 described above. Figure 1
1, the statistical processor 33 is in the signal processing device 14, but FIG.
As in 2, the central monitoring device 11 may perform the same processing as described above.

[0019]

INDUSTRIAL APPLICABILITY The present invention uses the Doppler signal component of the acoustic signal and the background reverberant sound, so that it is not necessary to adjust the device in advance. Simultaneously monitor multiple monitoring target areas such as the road surface, constantly monitor the traffic volume and speed of passing vehicles, the presence or absence of obstacles and road surface conditions, and display warnings and road conditions to the observer and passing vehicles. It becomes possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a conventional technique.

FIG. 2 is a block diagram showing an example of a conventional technique.

FIG. 3 is a conceptual diagram of vehicle detection in the related art.

FIG. 4 is a block diagram showing an embodiment of claim 1.

FIG. 5 is a block diagram showing an embodiment of claim 1.

FIG. 6 is a conceptual diagram of vehicle speed and traffic detection in claim 2.

FIG. 7 is a block diagram showing a central monitoring device according to claims 1, 2, 3, and 4.

FIG. 8 is a block diagram showing an embodiment of claim 3;

FIG. 9 is a block diagram showing an embodiment of claim 4;

FIG. 10 is a conceptual diagram of an acoustic signal according to claim 4.

FIG. 11 is a block diagram showing an embodiment of claim 5;

FIG. 12 is a block diagram showing a central monitoring device according to claim 5;

[Explanation of symbols]

1: Orbit 2A, 3A, 4A: Transmitter 2B, 3B, 4B: Light receiver 5: Ultrasonic handset 6: Vehicle 7: Transmission wave 8: Vehicle reflected wave 9: Road surface reflected wave 10: Control unit 11: Central monitoring device 12: Transmitter 13: Receiver 14: Signal processing device 15: Alarm device 16: Accident vehicle 17: Sound wave generator for wave transmission 171: Signal generator 172: Transmission signal amplifier 18: Received signal preprocessor 181: Received signal amplifier 182: bandpass filter 183: Analog / digital converter 19: Phaser 20: Frequency analyzer 21: Control device 22: Control memory 23: Measurement recorder 24: Communication controller 25: Doppler signal 26: Display controller 27: Alarm controller 28: Obstacle 29: Road surface 30: Reverberation from the road surface 31: Background reverberation 32: Acoustic signal 33: Statistical processor 34: Display

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akashi Nagayama 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Stock company Hitachi Information & Communications Division (72) Inventor Kenhiro Sueyoshi 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Address Stock Company Hitachi Information Technology Division (72) Inventor Toshiya Masuda 216 Totsuka-cho, Totsuka-ku, Yokohama, Kanagawa Prefecture Address Company Hitachi Information Technology Division (72) Inventor Yosuke Funazaki Totsuka-ku, Yokohama City, Kanagawa Prefecture 216 Totsukacho, Ltd. Information and Communication Division, Hitachi, Ltd. (56) References JP-A-8-249596 (JP, A) JP-A-8-75711 (JP, A) (58) Fields investigated (Int.Cl . ⁷ , DB name) G08B 23/00-31/00 G01N 29/16 G08G 1/127

Claims (2)

(57) [Claims] 1. A device for monitoring road conditions, wherein a wave receiver comprising a wave transmitter and one or more ultrasonic wave receivers is installed at a position on a road where a vehicle is not obstructed. A means for transmitting an ultrasonic wave, a means for receiving a sound wave reflected by a vehicle or an object on the road by a wave receiver, and a plurality of lanes and roads by phasing the received signal (beamforming). Means for arbitrarily detecting sideband reverberant sound, means for detecting Doppler signal and non-Doppler signal component of reflected sound received by ultrasonic receiver, and discrimination between Doppler signal component and non-Doppler signal component And a means for determining what kind of object the signal component other than the Doppler signal corresponds to, and monitoring the presence or absence of an obstacle on the road. 2. A device for monitoring road conditions, wherein a wave receiver comprising a wave transmitter and one or more ultrasonic wave receivers is installed at a position on the road that does not obstruct the passage of vehicles. A means for transmitting an ultrasonic wave, a means for receiving a sound wave reflected by a vehicle or an object on the road by a wave receiver, and a plurality of lanes and roads by phasing the received signal (beamforming). Means for arbitrarily detecting the background reverberation sound of the sound field formed by the sideband road surface echo sound and ultrasonic wave transmitter,
It has means for detecting the probability distribution of the sound pressure value of the background reverberation sound and means for determining what kind of road surface condition the probability distribution of the sound pressure value of the background reverberation sound corresponds to, and monitoring the road surface condition of the road. A road condition monitoring device characterized by the above.