JPH0749942B2 - Road surface unevenness measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a road surface unevenness measuring device, and more particularly to improvement of the maximum measurable width thereof.

[Prior Art] Various types of devices are known that perform measurement based on video information captured by a camera or the like, such as non-contact distance measurement.

An example of such a device is a road surface unevenness measuring device. This device is a device for measuring unevenness of a road surface cross section in a non-contact manner.

As a typical measuring method adopted by the road surface unevenness measuring device, there is a light cutting method.

This method is a method of irradiating a light ray from above the road surface, capturing the trajectory drawn by the light ray on the road surface with a camera, and obtaining the road surface unevenness from the information obtained thereby. The irradiation of the light beam is performed in a fan shape from diagonally above the road surface because it is necessary to scan the road surface. This fan-shaped light beam is generally called a fan beam.

The road surface unevenness measuring device is usually loaded on a vehicle. That is, while moving the vehicle, the unevenness of the vehicle cross section is measured at any time, information regarding the road surface is collected, and the result of the collection is used for vehicle operation control and the like.

As described above, conventionally, it was possible to measure the unevenness of the road surface without contact.

[Problems to be Solved by the Invention] However, the maximum measurable width is limited in the conventional device.

For example, as the simplest structure, consider a structure in which only one fan beam light source and one camera are mounted on a vehicle. In this case, the maximum measurable width is improved by increasing the mounting height of the camera, but the resolution of the camera is deteriorated. Therefore, in order to ensure the resolution, the measurement width is limited to about 3 m.

Further, if a plurality of fan beam light sources and cameras are installed side by side, it is possible to expect to secure the maximum measurable width exceeding the maximum measurable width per camera as a whole. However, simply arranging them in parallel cannot compensate for fluctuations in the fan beam trajectory due to vehicle tilt, errors in the mounting positions of the fan beam light source and the camera, and the like. As a result, it has been difficult to accurately measure the road surface unevenness.

The present invention has been made to solve such a problem, and secures the maximum measurable width without deteriorating the resolution, and obtains an accurate measurement result. The purpose is to provide a device.

[Means for Solving the Problem] In order to achieve such an object, according to the present invention, adjacent fan beam light sources illuminate a part of a common area, and adjacent cameras capture a part of a common area. A plurality of fan beam light sources and cameras are mounted on a vehicle body, and a spot beam light source that irradiates adjacent fan beam light sources in common and irradiates at least a part of an area commonly photographed by adjacent cameras is provided. The analyzing means for processing the photographed information synthesizes the loci obtained by the adjacent cameras with the irradiation spot of the light beam from the spot beam light source as a reference point.

According to the present invention, the analyzing means further translates a locus obtained by one of the adjacent cameras with respect to a locus obtained by the other of the adjacent cameras so that the irradiation spots obtained by the adjacent cameras coincide with each other. Further, by rotating the trajectory obtained by one of the adjacent cameras with respect to the trajectory obtained by the other camera according to the amount of rotation given in advance by photographing the reference trajectory, the photographing range of the adjacent camera Also, the trajectory obtained by the adjacent cameras is synthesized while compensating the error of the posture.

According to the present invention, the analyzing means synthesizes the loci obtained by the adjacent cameras, approximates the obtained synthetic locus to a straight line, and obtains the angle between the obtained approximate straight line and a predetermined reference straight line indicating the road surface. It is characterized in that the inclination of the vehicle body is corrected by obtaining the difference and rotating the locus obtained by the adjacent camera according to the obtained difference.

[Operation] In the present invention, the images captured by the camera are combined with the irradiation spot of the spot beam light source as a reference. As a result, even if the trajectory fluctuates due to the asymmetry of the installation site or the inclination of the vehicle body, it is compensated for accurate measurement, the deterioration of the resolution is prevented, and the maximum measurable width can be widened. .

In the present invention, further, the analyzing means parallelizes the locus obtained by one of the adjacent cameras with the locus obtained by the other so that the irradiation spots obtained by the adjacent cameras coincide with each other. To move.
As a result, the parallel movement component of the difference in the shooting range and the error between the adjacent cameras is compensated. Next, the analysis means rotates the locus obtained by one of the adjacent cameras with respect to the locus obtained by the other, in accordance with the rotation amount given in advance by photographing the reference locus. As a result, the rotation component of the error in the shooting range and the posture of the adjacent cameras is compensated. As described above, the compensation of the above-mentioned installation site asymmetry and the like is realized.

In the present invention, after combining the loci obtained by the adjacent cameras, the analyzing means approximates the obtained combined locus to a straight line. The obtained approximate straight line is compared with a predetermined reference straight line indicating the road surface. The analyzing means rotates the locus obtained by the adjacent cameras according to the obtained angle difference between the two. As a result, the error due to the inclination of the vehicle body is corrected.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show the arrangement of a light source and a CCD camera in a road surface unevenness measuring apparatus according to an embodiment of the present invention.

Of these drawings, FIG. 1 is a view from the side of the vehicle body,
FIG. 2 is a view from the rear of the vehicle body.

In this embodiment, a fan beam 100-1 which is a fan-shaped light beam emitted obliquely from above toward the road surface is used.
And 100-2 are emitted by the fan beam sources 10-1 and 10-2. This fan beam light source 10-1 and 10-
2 are installed on the left and right sides of the rear part of the vehicle body 12.

The fan beam light sources 10-1 and 10-2 are light sources such as a laser oscillator. The installation height is about 0.65 m from the road surface, and the irradiation positions of the fan beams 100-1 and 100-2 are set about 1.3 m from the emission position behind the vehicle body 12. These positional relationships are determined by the divergence angle of the fan beam 100, the incident angle θ, the irradiation width on the road surface reference surface 110, and the like.

For example, as shown in FIG. 3, the incident angle θ of the fan beam 100 is set to θ = tan ⁻¹ (1/2).

Further, the actual road surface irradiated by the fan beam 100 is not an accurate flat surface but a surface having a depression.

Here, the actual road surface is approximated to the road surface reference surface 110 that is an ideal plane. If the actual road surface and the road reference surface 110 are exactly the same, the fan beam 100 will draw a linear locus on the road surface at a position determined by parameters such as the incident angle θ.

However, the actual road surface has crossing irregularities. That is, a part of the actual road surface is in a recessed position when viewed from the road surface reference surface 110.

If this dent is L and the plane at a position lower by L from the road reference surface 110 is represented by the dent surface 120, the trajectory drawn in the portion where the actual road surface and the road reference surface 110 coincide In comparison, at the recessed position, a locus is drawn behind the vehicle body 12 by a distance determined by the incident angle θ as compared with the road reference surface 110. In this case, from the above equation of the incident angle θ, the positional deviation of the locus due to the depression is 2L.

The irradiation widths of the fan beams 100-1 and 100-2 are set so that the irradiation areas overlap, for example, with a width of about 0.8 m.

The loci of the fan beams 100-1 and 100-2 emitted by the fan beam light sources 10-1 and 10-2 are shown by the CCD camera 14
-1 and 14-2 respectively. The CCD cameras 14-1 and 14-2 include a fan beam light source 10-1 and
It is located above 10-2, specifically, at a height of about 1.9 m on the rear surface of the vehicle body 12. CCD cameras 14-1 and 14-2
Has a scanning direction set at right angles to the loci (that is, perpendicular to the rear surface of the vehicle body 12) so that the loci of the fan beams 100-1 and 100-2 can be easily discriminated.

The mounting height of the CCD cameras 14-1 and 14-2 is determined by the focal length of the lens used, the size of the light receiving element surface, and the measurable width per unit, and the mounting interval is determined by the width of the vehicle body 12. It

Also, in correspondence with the fan beam light sources 10-1 and 10-2,
The fields of view of both CCD cameras 14-1 and 14-2 are set to overlap. The overlapping width is about 0.4m, and CCD camera 14-1
The angle of contact of the road surface 110 from 14 and 14-2 is about 18 °.

When the trajectory of the fan beam 100 by the corresponding fan beam light source 10 is photographed from the CCD camera 14, it becomes as shown in FIG. This figure is a view when the locus 130 is viewed from the vertical direction of the road surface (that is, the direction of the CCD camera 14 with respect to the road surface).

For example, when a part of the road surface is depressed by L, the locus is moved backward by 2L according to the above-mentioned equation of the incident angle θ in this depressed portion.
0 bends in. The CCD camera 14 photographs such a locus 130 and provides it for the processing described later.

Further, in FIG. 2, a spot beam light source 16 according to the features of the present invention is shown.

The spot beam light source 16 is a fan beam light source 10-1.
And 10-2 are light sources such as laser oscillators. The mounting position for the vehicle body 12 is an arbitrary position on the center line of the vehicle body 12. The spot beam light source 16 has a road reference surface 110.
The spot beam 140 is irradiated onto the predetermined position above. The irradiation position of the spot beam 140 is set so that the fan beam 100 can be easily distinguished from the fan beams 100-1 and 100-2.
It is set about 50 mm ahead of the irradiation positions of -1 and 100-2. The CCD cameras 14-1 and 14-2 use this spot beam along with the trajectory of the fan beams 100-1 and 100-2.
It also shoots 140 irradiation spots.

With this arrangement, if the width of each fan beam light source 10 is about 2.9 m, the fan beams 100-1 and 100-
The total width of irradiation of 2 is about 4.8m, CCD camera 14-1
The total width of shooting for 14 and 14-2 is about 5m.

FIG. 5 shows the circuit configuration of this embodiment.

The circuit shown in this figure is particularly suitable for CCD cameras 14-1 and 14
2 is a circuit of a system that performs information processing of a video image captured. The fan beam light sources 10-1 and 10-2 and the spot beam light source 16 are driven only by a power supply for supplying electric power to them and a switch system thereof, and therefore description thereof is omitted here.

In FIG. 5, 8-bit A / D converters 18-1 and 18-2 are connected to the CCD cameras 14-1 and 14-2, respectively. That is, the images captured by the CCD cameras 14-1 and 14-2 are quantized into 8 bits, and A / D converters 18-1 and 18-1 are provided as 8-bit luminance resolution data.
-2 is output.

Line memories 20-1 and 20-2 are connected to the subsequent stages of the A / D converters 18-1 and 18-2, respectively. The line memories 20-1 and 20-2 are the A / D converter 18-
The outputs of 1 and 18-2 are stored for one scanning line period and output to the subsequent stage.

The line memories 20-1 and 20-2 have an interface 22.
Is connected to the data processing device 24 via. The data processing device 24 is a device that calculates road surface unevenness.

Next, the operation of this embodiment having such a configuration will be described.

First, each fan beam light source 10 emits a fan beam 100 with a predetermined irradiation width. The fan beam 100 draws a locus 130 on the road surface, and the corresponding locus 130 is photographed by the corresponding CCD camera 14.

FIG. 6 shows the power distribution of the CCD camera 14 in the scanning line direction.

The CCD camera 14 is a camera whose output has 8-bit luminance resolution (power) by an A / D converter. When photographing the locus 130, as shown in FIG. 6, a signal having a luminance peak is output.

In the present embodiment, the locus 130 is obtained by the data processing device 24 based on such a brightness distribution.

For example, the brightness of the pixel having the maximum brightness and the brightness of a total of n pixels adjacent thereto may be averaged to obtain the barycentric position of the brightness distribution.

If such a calculation result is executed over all scanning lines, a locus 130 as shown in FIG. 4, for example, can be obtained as a line connecting the barycentric positions.

The above operation is performed by a pair of fan beam light source 12 and CCD.
This is an operation performed for the camera 14. A feature of the present invention is an operation of combining loci obtained by a plurality of (two in the embodiment) fan beam light sources 12 and CCD cameras 14 arranged in parallel. Hereinafter, this operation will be described.

FIG. 7 shows the principle of extraction of the combined pointer performed by the data processing device 24 in this embodiment.

In this figure, reference numeral 150 denotes an image taken by the CCD camera 14. In this figure, for the sake of explanation, one CCD camera 14, specifically, the left CCD camera 14-
Two images 150-2 are shown.

In this embodiment, the spot beam light source 16 provided on the center axis of the vehicle body 12 emits a spot beam 140 in a predetermined direction with respect to the road surface. The spot beam 140 is applied to a predetermined position inside the overlapping irradiation area of the fan beams 100-1 and 100-2 as described above.

The data processing device 24 extracts the combined pointer based on the image 150-2 captured by the CCD camera 14-2.

Here, the combined pointer refers to the irradiation position of the spot beam 140.

For example, a region expected to be irradiated with the spot beam 140 is preset as the combined pointer search area 160-2. This combined pointer search area 160-
When the center of the luminance is extracted for No. 2 according to the same principle as the extraction of the locus 130 in FIG. 6, the combined pointer 170-2 is obtained.

Next, the data processing device 24 determines that both CCD cameras 14-1 and 14
-2, collate the combined pointers 170-1 and 170-2,
The loci 130-1 and 130-2 are synthesized using this result.

FIG. 8 shows the trajectory synthesis principle in this embodiment.

It is assumed that the CCD cameras 14-1 and 14-2 are arranged symmetrically with respect to the center plane of the vehicle body 12 and the vehicle body 12 is not inclined at all. At this time, the images 150-1 and 150-2 captured by the CCD cameras 14-1 and 14-2 are CC
If combined according to the positions of D cameras 14-1 and 14-2,
The loci 130-1 and 130-2 are one combined locus.

However, in general, due to the displacement of the mounting positions of the CCD cameras 14-1 and 14-2 and the inclination of the vehicle body 12, the loci 130-1 and 130-
2 does not match.

In this embodiment, the combined pointers 170-1 and 170 are used to eliminate this inconsistency and obtain one combined trajectory.
-180 perpendicular to the trajectories 130-1 and 130-2
Image parallel translation and rotation processing is performed so that 1 and 180-2 match.

First, the image 150-2 is moved by the coordinate difference of the combined pointer 170-2 with respect to the combined pointer 170-1 in the arrow directions indicated by 190 and 200 in FIG. As a result, the trajectory 130
The parallel movement component of the deviation between −1 and 130-2 is corrected.

Next, the rotation component is corrected. For this correction, for example, the reference trajectory on the horizontal road surface is set in advance for each CCD camera 1
This is done by taking pictures of each of 4-1 and 14-2 and matching them. That is, the image 150-2 is rotated relative to the image 150-1 so that the reference locus of the CCD camera 14-1 and the reference locus of the CCD camera 14-2 are aligned with each other. Thereby, the correction of the rotation component is achieved.

In this way, it is possible to obtain a single trajectory that is combined using the combining pointers 170-1 and 170-2. This trajectory is
By using the two pairs of fan beam light sources 12 and the CCD camera 14, the locus is related to the width which is enlarged as compared with the conventional pair. Further, the shape represents unevenness in the transverse direction of the road surface, and it is possible to obtain the unevenness across the road surface by converting the data into the data in the transverse direction of the road surface by XY conversion. Therefore, it becomes possible to measure the unevenness across the road surface without any obstacle such as deterioration of the measurement system, and the maximum measurable width is expanded.

FIG. 9 shows the principle of correcting the inclination of the road surface unevenness due to the combined trajectory when the inclination of the vehicle body 12 occurs.

That is, when the vehicle body 12 is tilted, an angular deviation occurs in the road surface cross section between the actual road surface unevenness and the road surface unevenness obtained by the photographed / synthesized trajectory.
This is because the CCD cameras 14-1 and 14-2 have a difference in distance from the road surface.

In this embodiment, this is corrected using the least squares approximation.

First, when the road surface cross-section unevenness obtained by the trajectory photographed and combined as described above is directly represented on the road surface cross section, it is assumed to be represented by a curve 210 as shown in FIG.

However, when the vehicle body 12 is inclined, the inclination is actually included in the curve 210 as an angular error on the road surface cross section.

Therefore, using this curve 210, the approximate straight line 220 is obtained by the method of least squares. The approximate straight line 220 indicates the road reference surface expected from the curve 210, and the actual road reference surface 110
They intersect at an angle. This angle can be regarded as equal to the inclination angle of the vehicle body 12.

For this reason, in this embodiment, the angle formed by the approximate straight line 220 and the road surface reference surface 110 is obtained, and the curve 210 is rotated by this angle to obtain the actual road surface unevenness 230.

As described above, in this embodiment, even if the vehicle body 12 is inclined, the inclination angle of the vehicle body can be approximately obtained and corrected based on the combined trajectory.

Note that the settings such as the arrangement used in the above description are not limited. For example, it may be appropriately set according to the vehicle type or the environment of the road surface to be measured.

Also, the number of pairs of CCD camera and fan beam light source is
It is not limited to each pair. If you use more logarithms,
A spot beam light source may be arranged at an intermediate position between adjacent fan beam light sources and used for matching both fan beams.

Further, various calculations in the data processing device 24 may be based on other algorithms. That is,
It does not matter as long as they are common in that images from a plurality of CCD cameras 14 adjacent to each other are combined by the combined spot.

The camera, light source, etc. may be something other than a CCD camera, a laser oscillator, etc.

[Effects of the Invention] As described above, according to the present invention, the loci obtained by a plurality of pairs of cameras and light sources are matched by the spot beam and combined, so that the maximum measurable width can be expanded. Therefore, the measurement system can be maintained.

According to the present invention, further, the locus is translated so that the irradiation spots obtained by the respective adjacent cameras coincide with each other, and further the locus is rotated according to the rotation amount given in advance by photographing the reference locus. Because
It is possible to compensate the error of the shooting range and the attitude of the camera for both the parallel movement component and the rotation component.

According to the present invention, the locus is rotated according to the result of comparison between the approximate straight line of the locus and a predetermined reference straight line indicating the road surface. Therefore, the error due to the inclination of the vehicle body can be corrected.

[Brief description of drawings]

1 is a side view showing a light source and a camera arrangement in a road surface unevenness measuring apparatus according to an embodiment of the present invention, FIG. 2 is a rear view showing a light source and a camera arrangement in this embodiment, and FIG. FIG. 4 is a longitudinal sectional view of a road surface showing a mode of fan beam irradiation in this embodiment. FIG. 4 is a locus diagram of a fan beam in this embodiment. FIG. 5 is a circuit diagram of a data processing system in this embodiment. FIG. 7 is a histogram diagram showing the power distribution in the scanning line direction of the CCD camera used in this embodiment, FIG. 7 is a video diagram showing the combined pointer in this embodiment, and FIG. Principle Diagram, FIG. 9 is a principle diagram of a vehicle body inclination correction process in this embodiment. 10 …… Fan beam light source 12 …… Car body 14 …… CCD camera 16 …… Spot beam light source 24 …… Data processing device 100 …… Fan beam 130 …… Track 140 …… Spot beam 150 …… Image 170 …… Join pointer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuhide Nakane 2nd No. 6 Bancho, Chiyoda-ku, Tokyo Within the international shipping company (56) References JP-A-63-108207 (JP, A) JP-A-SHO 60-84680 (JP, A) Actual Kohei 3-18882 (JP, Y2)

Claims (3)

[Claims] 1. A fan beam light source mounted on a vehicle so as to radiate a fan-shaped light beam obliquely downward from a rear part of a vehicle body, and a light beam emitted from the fan beam light source, which is installed above the light source so as to photograph a trajectory of the light beam. In a road crossing unevenness measuring device having a camera and an analyzing means for analyzing a trajectory of a photographed light ray to obtain crossing unevenness of a road surface, adjacent fan beam light sources irradiate a common area to a part of an adjacent camera. A plurality of fan beam light sources and cameras are mounted on the vehicle body so as to capture a part of the common area, and adjacent fan beam light sources illuminate in common and at least part of the area in which adjacent cameras capture in common Equipped with a spot beam light source that enables the analysis means to trace the locus obtained by an adjacent camera with the irradiation spot of the light beam from the spot beam light source as the reference point. Road crossing irregularities measuring apparatus, characterized by forming. 2. The road surface unevenness measuring device according to claim 1, wherein the analyzing means obtains by one of the adjacent cameras so that the irradiation spots obtained by the adjacent cameras coincide with each other. The locus is moved in parallel with the locus obtained by the other, and the locus obtained by one of the adjacent cameras is changed to the locus obtained by the other in accordance with the rotation amount given in advance by photographing the reference locus. A road surface unevenness measuring device characterized by synthesizing loci obtained by adjacent cameras while compensating for errors in the photographing range and posture of the adjacent cameras by rotating the cameras relative to each other. 3. The road surface unevenness measuring apparatus according to claim 1, wherein the analyzing means synthesizes the loci obtained by the adjacent cameras,
By approximating the obtained synthetic trajectory to a straight line, obtaining the angular difference between the obtained approximate straight line and a predetermined reference straight line indicating the road surface, and rotating the locus obtained by the adjacent camera according to the obtained difference. A road crossing unevenness measuring device characterized by correcting the inclination of a vehicle body.