JP3122258B2 - Road surface condition inspection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used for monitoring road conditions. In particular, it relates to a road surveillance technology using a television camera using a line sensor.

[0002]

2. Description of the Related Art It is important to constantly monitor the condition of a pavement surface of a road in order to perform maintenance management. Until now, it has been mainly performed visually, and the work is enormous. ing.

[0003] For monitoring, a slit camera using a silver halide film is used in part, but it requires development work and is not instantaneous. And it has not yet been fully introduced.

[0004] For this reason, a method of monitoring with a television camera is desired, but the conventional television camera is expensive and impractical for use in a wide range such as road monitoring.

Therefore, there is a television camera using a line sensor as a television camera which can be constructed at a low cost. Since the line sensor is small and inexpensive, it is widely used as a character or pattern reading unit in OA equipment such as a facsimile and a copy machine. CC for line sensor
D (Charge Coupled Device) and MOS (Metal OxideSe)
The structure is such that many bits composed of these elements are arranged in a line. It is also known that this line sensor is used as an image pickup unit of a television camera device and is used to determine the arrival order in boat tracing or the like (see Japanese Patent Publication No. 55-24831). The one-dimensional image captured by the line sensor is synthesized at the moving distance and used as a two-dimensional image. That is, an image is formed when there is a relative movement between the line sensor and the subject.

[0006]

It is conceivable to use this line sensor for monitoring road conditions. This is shown in FIG.
This will be described with reference to FIG. FIG. 6 is a diagram showing the principle of photographing a subject by a line sensor. As shown in FIG.
An image of the subject 54 is formed on the line sensor 51 by the lens 50, which is shaped like a slice of the subject 54.

When the subject 54 moves, this section of the wheel moves, and this continuous signal is sent to the monitor 5.
3 is displayed. When the moving speed of the subject changes, the shape displayed on the monitor 53 becomes different from the actual subject.

FIG. 6B and FIG. 6C show this state. If the moving speed changes during photographing as shown in FIG. 6B, the image of the subject on the monitor 53 becomes different from the actual image as shown in FIG. 6C. That is, a portion where the subject has moved slowly is displayed to be stretched as compared with a portion which has moved fast. In order to prevent this, it is necessary to always keep the moving speed of the subject constant.

In order to mount a television camera constituted by such a line sensor on an automobile or the like to photograph a road, it is necessary to keep the moving speed of the automobile or the like constant at all times. However, it is impossible to keep the speed constant at all times in view of the circumstances of automobiles and roads.

[0010] When the speed is not constant as described above, unevenness appears in the obtained image, and the quality of the image is low, which is not practical. Even more than one hour on the road,
It is impossible to detect cracks less than mm.

The present invention has been made in such a background, and is capable of monitoring a road condition by a television camera using a line sensor capable of changing a scanning speed of the line sensor according to a moving speed of a subject. The purpose is to provide.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a road surface condition inspection apparatus, which is characterized in that a television camera is mounted on an automobile so as to photograph the traveling road surface. A pulse generating means including a line sensor having sensitivity in a direction perpendicular to the traveling direction, and generating an electric pulse synchronized with rotation of the wheel of the vehicle,
There is provided control means for taking in the output of the line sensor in synchronization with the electric pulse, recording means for holding the output, and display means for displaying the recorded contents of the recording means.

Further, not only a planar state such as a crack in a road, but also irregularities due to rutting can be monitored. To this end, a plurality of the television cameras are provided, and the plurality of the television cameras are arranged so as to photograph the same portion of the road surface at different angles of view, and the recording means individually records the outputs of the plurality of the television cameras. The display means may include a means for detecting a phase difference between the outputs of the plurality of television cameras.

[0014]

The scanning pulse for the line sensor is generated by utilizing the rotation of the axle of the automobile. As a result, a scanning pulse proportional to the speed of the vehicle can be generated.

Therefore, the measuring vehicle does not need to be at a constant speed, and even if the speed changes according to the flow of another vehicle, the image of the subject can be accurately photographed and the road surface can be monitored reliably.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of the first embodiment of the present invention. FIG. 2 is a block diagram of the control unit.

The present invention is a road surface condition inspection apparatus, which is characterized in that a television camera 1 is mounted on an automobile 4 so as to photograph the traveling road surface.
Includes a line sensor having sensitivity in a direction perpendicular to the traveling direction of the vehicle 4, and a pulse generating means for generating an electric pulse synchronized with the rotation of the wheel of the vehicle 4 by using a distance meter input of the vehicle 4. A generating unit 3, a camera control unit 14 which is a control unit for taking in the output of the line sensor in synchronization with the electric pulse, a data recorder 8 which is a recording unit for holding the output, and a recording of the data recorder 8. The control unit 2 includes a high-definition monitor 10 which is a display means for displaying contents.

Next, the operation of the first embodiment of the present invention will be described with reference to FIG. The video signal from the line sensor generated as shown in FIG. 1 is digitized and recorded in the data recorder 8, but in this case, the amount of data varies depending on the speed of the vehicle, so that it cannot be recorded directly. Therefore, the buffer memory 16 is prepared and the data from the temporary television camera 1 is temporarily stored in the buffer memory 16 and is recorded on the data recorder 8 while controlling so that the data does not exceed and is not interrupted.

The apparatus of the first embodiment of the present invention is roughly divided into recording and reproducing operations. At the time of recording, the line sensor of the television camera 1 is driven by a pulse generated from the pulse generator 3 according to the moving speed. Obtain accurate video signals without coarse and dense. This is temporarily recorded in the buffer memory 16 and further recorded in the data recorder 8.

The data recorder 8 must have a sufficient recording speed and capacity. In this case, a commercially available product capable of recording at a speed of 32 megabytes / second with a capacity of about 100 gigabytes is used. According to this, road width 2m, wound 1mm
With the following detection capability, it has a capability of continuous 100 minutes at a speed of 100 km / h, and is sufficiently practical.

As an auxiliary function, a real-time monitor 6 is provided for monitoring a photographing state during photographing. Further, the signal from the TV camera 1 includes a line number, a time,
Add data such as location. At the time of reproduction, the data from the data recorder 8 is temporarily recorded in the buffer memory 16 by specifying a necessary portion. Then, only the necessary portion is transferred to the frame memory 18 and displayed on the high definition monitor 10. This high-definition monitor 10 has 2000 pixels × 2
About 000 lines. Therefore, the buffer memory 16 was 100 megabytes, and the frame memory 18 was 4 megabytes.

The high-definition monitor 10 is for checking an image, and image processing by a computer is separately performed. For this reason,
The image input / output interface 22 is connected to an external computer to perform image processing. When an external computer receives the video signal, it performs binary control at an appropriate level based on the difference in brightness between the cracks on the road and the road, and displays the road surface in black and the cracks in white to clearly show the cracks. Can be identified. Further, the real-time monitor 6 records the location where the crack exists and the state of the crack using the information on the time and location.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing the configuration of the second embodiment of the present invention. In the apparatus according to the second embodiment of the present invention, television cameras 1 and 1 'are prepared, and the rutting of a road is measured.

The television cameras 1 and 1 'are installed at a distance L from the road at a height M, and the directions of the television cameras 1 and 1' are accurately adjusted so that the same portion can be photographed. At this time, a video signal that crosses a part of the road is generated on the line sensor. If the surface of the road is flat, the video signals of the two television cameras 1 and 1 'are the same. However, if there is an uneven portion on the road surface, it appears as a phase difference in the video signals of the two television cameras 1 and 1 ', so that the amount of unevenness can be measured.

Referring to FIG. 4, the principle of measurement of rutting will be described in more detail. FIG. 4 is a diagram showing the rutting measurement principle. If point A is a point on the road, it is imaged through lenses 31 and 31 'at specific locations on line sensors 30 and 30'. If the point A moves downward by the distance m and does not move the imaging point of the line sensor 30 ′, the subject becomes the point B. At this time, the image of the point B on the line sensor 30 moves by Δd from the point A. At this time, Δd is as follows: Δd = (f · L / M ² ) × m (where f = focal length of the lens). Therefore, the state of the rutting can be easily calculated by calculating the phase of the video signal obtained from the line sensors 30 and 30 '.

The block configuration of the second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram of the device according to the second embodiment of the present invention. The television cameras 1 and 1 'are controlled in the same state by the two control units 2 and 2', and the calculation unit 40 calculates the amount of unevenness from the phase difference of each signal and outputs data. In the actual measurement, the width of the road is divided into several sections, and the average value is calculated. The image input / output interface 22 is connected to an external computer to perform image processing. When the external computer receives the video signal, it detects irregularities on the road from the phase difference and records the depth. Further, the real-time monitor 6 uses the time and place information to record the place where the irregularities exist and the state thereof.

[0027]

As described above, according to the present invention, the scanning speed of the line sensor can be changed according to the moving speed of the subject.

Thus, a television camera using a simple and small line sensor can be mounted on an automobile or the like, and the surroundings can be accurately photographed while moving. You can photograph the road and monitor the situation. Therefore, the analysis and the recording can be easily performed as compared with the visual observation. Also, the monitoring amount is greatly increased. In addition, the traveling of the car can be performed in the flow of another car.

Further, in the apparatus using two television cameras, it is possible to photograph and monitor the unevenness of the road.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a block diagram of a control unit.

FIG. 3 is a configuration diagram of a second embodiment of the present invention.

FIG. 4 is a diagram showing the principle of rutting measurement.

FIG. 5 is a block diagram of a second embodiment of the present invention.

FIG. 6 is a view showing the principle of photographing a subject by a line sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1 'TV camera 2, 2' control part 3 pulse generation part 4 Automobile 6 Real time monitor 8 Data recorder 10 High definition monitor 12 Remote control 14 Camera control part 16 Buffer memory 18 Frame memory 20 CPU 30, 30 'line sensor 31, 31 'lens 40 calculation unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01B 11/00-11/30 102 G01C ^7/ 00-7/06

Claims (1)

(57) [Claims] Claims: 1. An automobile is used to photograph its running road surface.
A TV camera is mounted, and the TV camera is mounted in a direction perpendicular to the traveling direction of the automobile.
Direction sensitive line sensor, and generates an electric pulse synchronized with the rotation of the vehicle wheel.
Pulse generating means for obtaining an output of the line sensor in synchronization with the electric pulse.
Control means, a recording means for holding the output, and a display means for displaying the recorded contents of the recording means., The television camera is provided in plurality, These multiple TV cameras capture different parts of the same part of the road surface.
It is arranged to shoot at the corner, The recording means individually outputs the outputs of the plurality of television cameras.
Including means for recording, The display means is provided for the plurality of
Including means for detecting the phase difference of the bicamera output Features
Road surface condition inspection device.