JPH10105869A - Vehicle type discrimination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle type discrimination device which can easily detect a high speed vehicle, whose measurement precision is not affected by peripheral environment and whose installation is easy. SOLUTION: The device is provided with LD1, a light projection lens 2, a polygon mirror 3 and a motor 4. A light projection means 5 projecting light beams in the crossing direction of the road R so as to execute scanning, a light reception lens 6 and a one-dimensional photodiode array 7 are provided. A light reception means 8 receiving reflected light, and a position information detection means detecting information of the vehicle 70 passing on the road R from a signal from the light reception means 8 and discriminating a vehicle type based on obtained vehicle information are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle type discriminating apparatus which is installed in a toll road, a toll parking lot, a multi-story parking facility, and discriminates the type of passing vehicle.

[0002]

2. Description of the Related Art Conventionally, as a device for measuring a vehicle width, a vehicle length, a vehicle shape, and the like, there are a device using a television camera and a device using an array in which photoelectric switches are juxtaposed. A device using a television camera detects a vehicle based on image information of a road surface captured by a television camera, and an array device using a photoelectric switch includes a light projecting unit and a light receiving unit. The vehicle is detected on the basis of a light receiving pattern obtained when light emitted from the unit is blocked by the vehicle and received by the light receiving unit.

[0003]

However, with a system using a television camera, it is difficult to detect a vehicle running at high speed. (2) Measurement accuracy is greatly affected by ambient illuminance. There is a problem.

In an array type device using a photoelectric switch, (3) in order to measure the vehicle width, it is necessary to embed a light emitting portion or a light receiving portion in a road, so that installation work is troublesome and
It is easily affected by dirt such as mud. There is a problem. Therefore, the present invention has been made in view of such problems (1) to (3), and it is easy to detect a high-speed vehicle, the measurement accuracy is not affected by the surrounding environment, and the installation work is simple. It is an object to provide a simple vehicle type discriminating apparatus.

[0005]

According to a first aspect of the present invention, there is provided a vehicle type discriminating apparatus for projecting and scanning a light beam in a direction transverse to a road surface. A light receiving means having a one-dimensional light receiving element array for receiving reflected light, and a position for detecting information of a vehicle passing on a road surface from a signal from the light receiving means and determining a type of the vehicle based on the obtained vehicle information Information detecting means.

[0006] This vehicle type discriminating device is configured to project and scan a light beam in a direction transverse to the road surface, receive the reflected light, and discriminate the vehicle type based on vehicle information obtained from a received light signal. A high-speed vehicle can be detected, and it is hard to be affected by the surrounding environment (illuminance). Moreover, it can be installed above the road surface, installation work is easy, and it is hard to be affected by dirt such as mud.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. FIG. 1 shows a schematic configuration diagram of a vehicle type discriminating apparatus according to one embodiment (claim 2). This vehicle type discriminator
A light projecting means 5 for emitting a light beam, a light receiving means 8 for receiving light reflected by the light beam, and information on a vehicle 70 passing on a road surface R is detected from a signal from the light receiving means 8, and the obtained vehicle information Position information detecting means (not shown) for determining the type of the vehicle 70 based on the information. FIG.
Although the light projecting means 5 and the light receiving means 8 are shown at a distance for convenience of explanation, they are actually unitized in the same casing.

The light projecting means 5 emits a laser diode (LD) 1 as a light beam light source, a light projecting lens 2 for converting laser light into parallel light, and projects and scans the parallel light in a direction transverse to the road surface R. An optical scanning mechanism having a polygon mirror 3 and a motor 4 for driving the polygon mirror 3 to rotate; The light receiving means 8 includes a light receiving lens 6 for condensing the reflected light, and a one-dimensional photodiode array (one-dimensional light receiving element array) 7 for receiving the condensed light. Photodiode array 7
Is positioned so that its longitudinal direction (length a direction) coincides with the transverse direction of the road surface R. The light beam from the light projecting means 5 is projected and scanned along an optical scanning line C extending in the transverse direction of the road surface R, and the reflected light is received by the light receiving means 8.

The principle of discriminating the vehicle type of this device is as follows. As the irradiation position of the light beam from the light projecting means 5 moves, the position of the incident light on the photodiode array 7 of the light receiving means 8 also moves. Accordingly, the distance from the light receiving means 8 (and the light projecting means 5) to the vehicle (detected object) 70 can be measured by determining the position of the center of gravity of the light on the photodiode array 7, so that the light beam is projected and scanned. Thereby, the cross-sectional shape of the vehicle 70 on the optical scanning line C is obtained.
That is, in (a) of FIG.
Assuming that the height of the vehicle 70 from the road surface R is H, as shown in FIG. 3B, the vehicle 70 of the vehicle 70 is calculated from the light scanning position and a value obtained by subtracting the height H from the distance output obtained by the position information detecting means. A height h, a vehicle width d, and a cross-sectional shape f viewed from above are obtained. Then, the position information detecting means collates, for example, the obtained cross-sectional shape f with the cross-sectional shape data of various types of vehicles stored in advance,
The vehicle type of the vehicle 70 is determined (see FIG. 14).

Also, as shown in FIG. 3C, by simultaneously measuring the amount of received light, an edge portion (boundary portion) P between the vehicle 70 and the road surface R can be detected from the signal waveform of the amount of received light. Based on the edge portion P, the sectional shape f shown in FIG.
Can be corrected, a more accurate cross-sectional shape f can be obtained, and the accuracy of vehicle type determination can be improved. FIG. 2 shows FIG.
Here is an example of the change. In this device, the light projecting means 5 and the light receiving means 8 have the same configuration, but the longitudinal direction (length a direction) of the one-dimensional photodiode array 7 is positioned in the longitudinal direction of the road surface R. The principle of determining the type of a vehicle is the same as described above.

When the one-dimensional photodiode array 7 is positioned as shown in FIG. 1, even if the width b of the photodiode array 7 is small, a wide light receiving field for the optical scanning line C can be secured. However, the distance between the center of gravity of the light on the photodiode array 7 and the distance from the light projecting and light receiving means 5, 8 obtained by the position information detecting means to the vehicle 70 differs depending on the position where the light beam is scanned. In order to obtain the value, it is necessary to perform an appropriate calculation from the scanning position and the barycentric position of the light in the processing circuit.

On the other hand, when the one-dimensional photodiode array 7 is positioned as shown in FIG. 2, the position of the center of gravity of the light on the photodiode array 7 corresponds to the distance from the light emitting and receiving means 5, 8 to the vehicle 70. Therefore, the process for obtaining an accurate distance is simpler than that in FIG. However, it is necessary to increase the width b of the photodiode array 7 in order to secure a wide light receiving field for the optical scanning line C. Therefore, the configurations shown in FIGS. 1 and 2 each have advantages and disadvantages, and it is preferable to appropriately select a convenient one when installing the apparatus.

FIG. 4 is a schematic structural view of an apparatus according to claim 3. This device is provided with the light emitting means 5 configured as described above.
The light receiving means 8 is disposed on one side of the road surface R, and scans the light beam toward the road surface R from the side of the road surface R. Also in this device, the cross-sectional shape f viewed from the side of the vehicle 70 can be obtained from the optical scanning position and the distance output obtained by the position information detecting means in FIG. According to the waveform of FIG. 5, first, the waveform of the road surface R is shown, the waveform of the tire 71 of the vehicle 70 is shown next, the waveform of the body 72 is shown next, and the waveform obtained by combining the waveforms of the tire 71 and the body 72 is shown. The sectional shape becomes f. The vehicle type is determined from the sectional shape f as described above. In this case, since the presence or absence of the tire 71 can be determined, the number of axes of the vehicle 70 can also be measured.

FIG. 6 is a schematic structural view of an apparatus according to a fourth aspect, in which light emitting and receiving means 5, 8 are arranged on both sides of a road surface R, respectively. In this case, the cross-sectional shape viewed from both sides of the vehicle 70 is obtained, and the vehicle width of the vehicle 70 is obtained by the distance output from each position information detecting means and the distance L between both the light projecting and light receiving means 5, 8. Can be The cross-sectional shape and the vehicle width are more accurate than the case of FIG. 4, and the vehicle type is determined in the same manner as described above.

By the way, as shown in FIG. 7 (a), if only one light emitting and receiving means 5, 8 is arranged above the road surface R (near the center), especially when the vehicle 70 is high, the light The area where the beam is not projected, that is, the blind spot G of the light receiving field increases. In this case, a problem may occur that the information on the cross-sectional shape as viewed from above the vehicle 70 does not indicate the exact shape of the vehicle 70, and that the motorcycle 75 running in parallel with the vehicle 70 cannot be detected. To solve this problem, FIG.
As shown in (b), a plurality (three in this case) of the light projecting and light receiving means 5, 8 may be arranged at intervals in the transverse direction of the road surface R (claim 5). By doing so, the blind spot G of the light receiving field of view by the vehicle 70 is eliminated, and even when the vehicle 70 and the motorcycle run side by side, the motorcycle can be reliably detected. When a plurality of light projecting and light receiving means 5 and 8 are used, it is desirable that the light projecting pulse periods of the light beams of the light projecting means 5 be shifted and synchronized in order to prevent mutual interference.

FIG. 8 schematically shows the structure of an apparatus according to claim 6. The light receiving means 5 in this device has a plurality of (here, two) one-dimensional photodiode arrays 7 arranged at intervals in the longitudinal direction of the road surface R, and the position information detecting means operates the two photodiodes. The vehicle speed of the vehicle 70 is measured from a signal from the diode array 7. The two photodiode arrays 7 are located at the same height, and the light receiving fields of each photodiode array 7 are arranged in the longitudinal direction of the road surface R. Therefore, the vehicle speed can be measured from the time difference between the output signals of the two photodiode arrays 7.

FIG. 9 schematically shows the structure of a device according to claim 7, wherein a plurality of light emitting and receiving means 5, 8 are provided at intervals in the longitudinal direction of the road surface R (here, two). Are located. Also in this case, the position information detecting means can measure the vehicle speed of the vehicle 70 from the time difference between the output signals from the two light receiving means 8. When three or more light emitting and receiving means 5 and 8 are arranged, a change in vehicle speed within the detection range can be measured.

8 and FIG. 9, a comparison of FIG.
Since there is a plurality of one-dimensional photodiode arrays 7 in the light receiving means 8 and only one light emitting means 5 and one light receiving means 8,
Although the size and cost of the vehicle type identification device can be reduced, the interval between the light receiving fields of the two photodiode arrays 7 is narrow.
Accuracy of speed detection of a high-speed vehicle is not very good, and the projection spot of the light beam must be enlarged. on the other hand,
In FIG. 9, although the accuracy of speed detection of a high-speed vehicle is high, since a plurality of light emitting and receiving means 5 and 8 are required, the size of the vehicle type discriminating apparatus becomes large and the cost is high. As described above, each of them has advantages and disadvantages, and therefore, it is preferable to appropriately select them.

FIG. 10 shows a schematic configuration of an apparatus according to claim 8. Here, the light projecting means 5 synchronizes the light beam scanning with the light beam. Specifically, two light emitting and receiving means 5, 8 are arranged at intervals in the longitudinal direction of the road surface R,
The light beams are emitted from the light projecting means 5 in synchronization with each other so that the light beams are scanned in opposite directions. That is, one of the light emitting means 5
When the light beam from the light source irradiates one side of the road surface R, the light beam from the other light projecting means 5 is set to irradiate the other side of the road surface R. Thereby, the vehicle 7
When 0 passes at high speed, even if one of the light emitting and receiving means 5 and 8 cannot detect the vehicle 70 due to the light emitting scanning timing, the other light emitting and receiving means 5 and 8 detect the vehicle 70.
, And the high-speed vehicle 70 can be reliably detected. The number of the light emitting and receiving means 5 and 8 need not be two, and three or more light emitting and receiving means may be used for more completeness.

FIG. 11 schematically shows the structure of the device according to the ninth aspect. In the apparatus shown here, the light scanning of the light beam of the light projecting means 5 and the light receiving scanning of the reflected light of the light receiving means 8 are performed by the same optical scanning mechanism 9. The optical scanning mechanism 9
It comprises a long polygon mirror 3 and a motor 4 for driving the polygon mirror 3 to rotate. The light beam and the reflected light from the light projecting means 5 are both scanned by the polygon mirror 3. As described above, when the light-receiving field of view is scanned in the same manner as the light beam, there is an advantage that the width of the one-dimensional photodiode array 7 may be reduced while the influence of noise such as disturbance light and sunlight is reduced. Is obtained.

Further, there are various modes, and the interval between the emission pulses of the light beam of the light projecting means may be changed according to the condition of the vehicle. For example, when no vehicle is present in the detection range, the life span of the LD 1 can be extended and the temperature of the device can be prevented from increasing by increasing the interval between the light projection pulses of the light beam. Conversely, when the traffic volume of the vehicle is large, the detection response becomes faster by shortening the light emission pulse interval. Note that whether or not a vehicle exists in the detection range can be easily detected by a separately provided ultrasonic device or imaging device, and the light projecting means may be operated based on the detection signal.

When the light beam scanning of the light beam is stopped when the vehicle is not within the detection range (claim 11), ie, when the movement of the motor 4 and the polygon mirror 3 is stopped, the motor 4. It is also possible to prolong the service life and prevent the temperature of the apparatus from rising. Further, assuming that the time during which the vehicle exists within the detection range is t and the vehicle speed is v, the vehicle length l is represented by l = vt, so that the vehicle length l can be easily calculated.
2).

The vehicle type can be determined from the obtained vehicle length l and the vehicle width d and the vehicle height h (claim 13, FIG. 1).
4). That is, the relationship between the vehicle width, the vehicle height, the vehicle length, and the vehicle type is as shown in the table of FIG. 12, and if such a table is stored in advance, the vehicle type can be determined using the table. FIG. 13 is a diagram for explaining the principle of vehicle shape measurement in the device according to claim 14. Position information detection means obtains a vehicle speed determined as described above, the optical scanning lines C _1, C _2, ..., more and series manner determined cross-sectional shape when in accordance with C _n, the entire car type vehicle 70. Then, the obtained vehicle shape is collated with the vehicle shape data of the existing vehicle type stored in advance to determine the vehicle type (claim 15).

[0024]

The vehicle type discriminating apparatus of the present invention has the following effects because it is configured as described above. (1) High-speed vehicles can be detected. (2) Hardly affected by surrounding environment (illuminance). (3) It may be installed above the vehicle passage area, the installation work is easy, and it is hardly affected by dirt such as mud.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus according to claim 2;

FIG. 2 is a schematic configuration diagram showing a modified example of FIG.

FIG. 3 is a view for explaining the measurement principle of the apparatus shown in FIGS. 1 and 2;

FIG. 4 is a schematic configuration diagram of an apparatus according to claim 3.

FIG. 5 is a view for explaining the measurement principle of the apparatus of FIG.

FIG. 6 is a schematic configuration diagram of an apparatus according to claim 4.

FIG. 7 is a diagram for explaining the device according to claim 5, and is an operation diagram (a) when one light emitting and receiving means is used, and an operation diagram (b) when three light emitting and receiving means are used.

FIG. 8 is a schematic configuration diagram of an apparatus according to claim 6;

FIG. 9 is a schematic configuration diagram of an apparatus according to claim 7;

FIG. 10 is a schematic configuration diagram of an apparatus according to claim 8;

FIG. 11 is a schematic configuration diagram of an apparatus according to claim 9;

FIG. 12 is a table showing a relationship between a vehicle length, a vehicle width, a vehicle height, and a vehicle type.

FIG. 13 is a view for explaining the measurement principle of the device according to claim 14;

FIG. 14 is a diagram illustrating an operation of determining a vehicle type from a vehicle cross-sectional shape, a vehicle height, a vehicle width, and a vehicle speed / time (vehicle length).

[Explanation of symbols]

REFERENCE SIGNS LIST 1 laser diode 2 light emitting lens 3 polygon mirror 4 motor 5 light emitting means 6 light receiving lens 7 one-dimensional photodiode array (one-dimensional light receiving element array) 8 light receiving means 9 light scanning mechanism 70 vehicle R road surface C light scanning line

Claims (15)

[Claims] 1. A light projecting means for projecting and scanning a light beam in a direction transverse to a road surface, a light receiving means having a one-dimensional light receiving element array for receiving light reflected by the light beam, and a signal on the road surface based on a signal from the light receiving means. A vehicle type discriminating device, comprising: information on a vehicle passing through the vehicle; and position information detecting means for determining a vehicle type of the vehicle based on the obtained vehicle information. 2. The light projecting means and the light receiving means are arranged above a road surface, project and scan a light beam from above the road surface toward the road surface, receive reflected light above the road surface, and receive the position information. The vehicle type discriminating apparatus according to claim 1, wherein the detecting means measures a vehicle width, a vehicle height, and a cross-sectional shape as viewed from above. 3. The light projecting means and the light receiving means are disposed on a side of a road surface, project a light beam toward the road surface from the side of the road surface, scan the light beam, and receive reflected light on the side of the road surface. The vehicle type discriminating apparatus according to claim 1, wherein the position information detecting means measures a cross-sectional shape viewed from a side of the vehicle. 4. The vehicle according to claim 3, wherein said light projecting means and said light receiving means are respectively arranged on both sides of a road surface, and measure a vehicle width and a cross-sectional shape viewed from the side. Car type identification device. 5. A vehicle type discriminating apparatus according to claim 2, wherein a plurality of said light projecting means and said light receiving means are arranged at intervals in a transverse direction of a road surface. . 6. The one-dimensional light-receiving element array includes a plurality of one-dimensional light-receiving element arrays disposed at intervals in a longitudinal direction of a road surface. The vehicle speed of the vehicle is measured based on a signal from the control unit (1), (2), (3), (4), or (5).
The described vehicle type identification device. 7. A plurality of said light projecting means and a plurality of light receiving means are arranged at intervals in a longitudinal direction of a road surface, and said position information detecting means detects a vehicle speed and a vehicle speed of a vehicle based on signals from said plurality of light receiving means. 7. The vehicle type discriminating apparatus according to claim 2, wherein the change of the vehicle type is measured. 8. The light-emitting device according to claim 5, wherein the plurality of light-projecting means are synchronized with each other in light beam scanning.
A vehicle type discriminating apparatus according to claim 7. 9. The light scanning mechanism according to claim 1, wherein the light beam scanning of the light projecting means and the light receiving scanning of the reflected light of the light receiving means are performed by the same optical scanning mechanism. The vehicle type discriminating apparatus according to claim 3, claim 4, claim 5, claim 6, claim 7, claim 7, or claim 8. 10. The light projecting means changes an emission pulse interval of a light beam according to a condition of a vehicle. 9. The vehicle type discriminating apparatus according to claim 6, 7 or 8. 11. The light emitting means according to claim 1, wherein said light emitting means stops light emission scanning of a light beam depending on a condition of a vehicle.
Claim 2, Claim 3, Claim 4, Claim 5, Claim 6,
The vehicle type discriminating apparatus according to claim 7. 12. The vehicle according to claim 11, wherein said position information detecting means includes:
The vehicle length is measured from the time when the vehicle is in the light beam projection area and the vehicle length is measured. The vehicle type discriminating apparatus according to claim 7, claim 8, claim 9, claim 10, or claim 11. 13. The position information detecting means includes: a vehicle width;
The vehicle type is determined based on the vehicle height and the vehicle length, and the vehicle type is determined. 9. Claim 10,
The vehicle type discrimination device according to claim 11 or 12. 14. The position information detecting means includes: a vehicle speed of a vehicle;
And measuring a vehicle shape of the entire vehicle from the cross-sectional shape in time series. 8, Claim 9, Claim 10, Claim 11, Claim 12, or Claim 1
3. The vehicle type identification device according to 3. 15. The vehicle type according to claim 14, wherein said position information detecting means determines the vehicle type by comparing the obtained vehicle shape with vehicle shape data of an existing vehicle type stored in advance. Discriminator.