JP2909340B2 - Vehicle detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle detecting device used for toll collection machines on toll roads and traffic equipment such as traffic volume measurement.

[0002]

2. Description of the Related Art As a conventional method for detecting and counting passing vehicles on a road from above a road surface, the following methods (1) to (1) are used.
It is something like (3). (1) Ultrasonic method shown in FIG. 15: In this method, a vibrator 101 for oscillating and receiving an ultrasonic wave 101A is provided above a road surface, and a distance to the road surface is detected. That is, as shown in FIG. 15, when the vehicle 103 passes, the time for the reflected echo 104 to return is shortened, and the presence of the vehicle 103 is detected. (2) Microwave method (not shown): In this method, the frequency of the reflected wave with respect to the oscillated microwave is measured. That is, the wave reflected back to the passing vehicle undergoes Doppler shift (frequency shift), and the wave reflected back to the road surface does not undergo frequency shift. Therefore, the passage of the vehicle can be detected by detecting the frequency shift. (3) Optical system shown in FIG. 16: In this system, as shown in FIG. 16, the illuminance on the road surface 102 is monitored by the optical sensor 105, and when the vehicle 103 passes, the paint color of the roof is different from the road surface. Therefore, the vehicle 103 is detected. In the optical system, the field of view can be reduced by an optical lens, and multiple detection can be performed by forming an array.

[0003]

The above-mentioned conventional vehicle detection technology has the following problems.

[0004] The ultrasonic system and the microwave system have long wavelengths because of their long wavelengths, and thus cover a wide lane below the installation position on the road surface. In other words, it is possible to detect a small vehicle 103 such as a motorcycle in the lane immediately below wherever it passes. This allows 1
Although it has the advantage that one sensor can cover the entire width of one lane, conversely, when a plurality of motorcycles translate in the same lane, they cannot be counted separately. Also, it is not possible to detect a motorcycle passing by a truck on a stagnated road. As described above, in the method using the ultrasonic waves and the microwaves, there is a limit to the accurate detection of the passing vehicle. In the case of traffic measurement for the control of signal lights at intersections, miscounting in the special case as described above is not a particularly serious problem, but when applied to toll collection on toll roads, such No exceptions are allowed.

[0005] The optical system is based on the light beam 106, unlike the microwave or ultrasonic system.
If 05 is provided so that the field of view has a fine pitch in the width direction in the lane, a case such as translation of the motorcycle 103 can be separately counted as shown in FIG. However, in this case, when the altitude of the sun 107 is low in the morning or evening, a shadow 108 of one vehicle is generated on the road surface 102, so that depending on the time, the translation of two motorcycles is also detected as one vehicle. It is possible.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle detection device which is hardly affected by a traffic form such as translation or stagnation, and is hardly affected by weather conditions.

[0007]

According to the present invention, there is provided a vehicle detecting apparatus which is installed above a road surface and obtains a one-dimensional light amount signal in a lane width direction from the road surface. An optical system installed on the sensor, an intermittent marking installed on a road surface in a one-dimensional field of view of the optical array sensor, and a signal processing device for performing vehicle detection processing from an output signal of the optical array sensor. and, further, the signal processing unit from the output signal of said optical array sensor
Periodic component corresponding to the intermittent marking period has disappeared
Means for detecting whether or not the periodic component has disappeared , into a binary signal sequence consisting of a first level corresponding to the road surface and a second level corresponding to a portion other than the road surface; Vehicle in the vehicle traveling direction and the lane width direction based on the degree of the first level and the second level in the vehicle and the degree of the first level and the second level in the binary signal sequence different in time. And a means for separately detecting the

In this case, preferably, the intermittent period of the intermittent marking is longer than the period of the pixels of the optical array sensor on the road surface and shorter than the minimum width of the detection target vehicle. Alternatively, preferably, at least one of a tread having contacts buried in the road surface, a loop coil buried in the road surface, an ultrasonic transceiver installed above the road surface, and a microwave transceiver installed above the road surface The signal processing device performs a vehicle detection process based on an output signal of the sensor and an output signal of the optical array sensor.

[0009]

The optical array sensor and the optical system obtain a one-dimensional light quantity signal in the width direction of the lane from the road surface. Intermittent marking on the road surface adds modulation to the one-dimensional light amount signal, and whether there is actually a vehicle on the road surface depending on the presence or absence of the modulation disturbance, or simply passing through an adjacent lane without a vehicle It is used to determine whether there is only a vehicle shadow. That is, the signal processing device processes the one-dimensional light amount signal using the presence or absence of modulation by intermittent marking, separates and discriminates a background road from passing vehicles, and performs passage detection for each vehicle. .

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a vehicle detection device according to an embodiment of the present invention. In FIG. 1, a gantry 1 is used to install a device 2 above a road surface 102 of a road. The device 2 is an optical array sensor and an optical system. In this embodiment, a one-dimensional CCD optical element is incorporated. It is a one-dimensional CCD camera. The one-dimensional CCD cameras 2 are installed so as to face directly below each lane.
A one-dimensional visual field 2A in the lane width direction is obtained. In addition, one lane width may be taken into view with a plurality of one-dimensional CCD cameras. 3 is a passing vehicle.
The output signal of the one-dimensional CCD camera 2 is transmitted to a signal processing device 5 via a cable 4, and the passing vehicle 3 is detected by the signal processing device 5. The signal processing device 5 outputs a pulse signal 5A each time one vehicle passes. The intermittent marking 6 is a periodic marking provided on the road surface 102 in the field of view of the one-dimensional CCD camera 2. In this embodiment, the marking 6 is formed by periodically applying a reflective paint on the road surface 102.

Next, the role of the intermittent marking 6 will be described with reference to FIGS. FIG. 2 shows an example of an output signal 2B obtained when the road surface is captured by the one-dimensional CCD camera 2,
The offset changes depending on the sunshine conditions, but the marking 6
A modulated signal can be obtained. Therefore, if the vehicle passes, the periodic signal is disturbed at the portion where the vehicle passes, as shown by reference numeral 2C in FIG. 3, and the position where the vehicle has passed can be known from the disturbance. For example, even if the motorcycle is translated, there are two places 2C where the periodic signal is disturbed, so that it can be separated. Also, if there is no passing vehicle in the lane immediately below the one-dimensional CCD camera 2 and a large truck passes through the adjacent lane, a shadow of the truck is formed in the field of view of the one-dimensional CCD camera 2 depending on the direction of the sun. At this time, a waveform 2D as shown in FIG. 4 is obtained. That is, in the shadow portion 2D, the offset is reduced, but the periodic signal does not disappear, so that it is understood that no vehicle exists in this lane. As described above, a vehicle can be accurately detected by detecting a portion where the periodic signal is disturbed based on the periodic signal.

Next, a specific example of the signal processing device 5 will be described with reference to FIG. The signal processing device 5 includes an amplifier 10, a band-pass filter 11, an A / D converter 12, a reference signal pattern memory 13, a matching circuit 14, and a binarizing circuit 1.
5, a reference register 16, a one-dimensional memory 17, a timing generation circuit 18, and a computer 19.

The operation of the signal processing device 5 will be described. First,
The signal 2B from the one-dimensional CCD camera 2 is amplified by the amplifier 10, and the amplified signal a passes a frequency component centered on the periodic component of the marking 6 to remove low-frequency components due to sunlight or shadow. This signal b is further digitized by an A / D converter 12 through a band pass filter 11. The reference signal pattern memory 13 stores a standard periodic pattern when there is no vehicle on the road surface and all the intermittent markings 6 are in the field of view. The capacity is for a one-dimensional field of view. The matching circuit 14 receives the road surface signal from the A / D converter 12 and the reference pattern c from the reference signal pattern memory 13 and removes the periodic component from the road surface signal of the A / D converter 12. The signal d from which the periodic component has been removed is applied to the binarization circuit 15. In the reference register 16, a reference value which is one input of the binarization circuit 15 is set.
Therefore, for example, the binarizing circuit 15 divides the portion where the vehicle is present into the level “1” and the road surface portion into the level “0”. The binarized signal e is stored in the one-dimensional memory 17. Is stored in Thus, when the contents of the one-dimensional memory 17 are all "0", no vehicle exists. The timing generation circuit 18 controls the entire timing inside the signal processing device 5. As this timing, for example, a synchronization signal of the one-dimensional CCD camera 2 or
The conversion command signal of the A / D converter 12 and the one-dimensional memory 17
, And notification to the computer 19. The signal processing device 5 generates a vehicle entry output when the content of the one-dimensional memory 17 changes from “0” to non- “0”. The contents of the one-dimensional memory 17 are updated one after another based on the signal of the timing generation circuit 18. The computer 19 controls and determines the entire apparatus. Further, the computer 19 checks the content of the one-dimensional memory 17 every time the content is updated, as described above, to determine whether or not the content is non-zero.
When it is not "0", the presence of the vehicle is detected. FIG. 6 shows the waveforms of the signals a, b, c, d, and e of the respective parts in FIG.

Next, a vehicle detection procedure in the computer 19 will be described with reference to FIGS. FIG. 7 shows the contents of the one-dimensional memory 17 over time, and FIG. 8 shows a flowchart.

[0015] As shown in FIG. 7 may be unsubstituted as t = 1, t = 2 for the contents of the one-dimensional memory 17 of one vehicle 3 "0", t = 3 one-dimensional memory as When the area of “1” occurs with “0” placed at another location of No. 17, the approach of another vehicle 3A is detected. However, the computer 19 checks the contents of the one-dimensional memory 17 each time it is updated, and there is a lump of "1" divided into two areas, and this is reduced to one area later as t = 4 . If this is found, it is determined again that this is one vehicle 3A. That is, the determination is completed not when the one-dimensional memory 17 changes from all "0" to non- "0" but when the vehicle leaves. If the non- "0" portion becomes "0" as a result of successive updating, it is determined that the vehicle has passed from the detection area, and the output signal is dropped. That is, the detection of the entry of the vehicle includes the detection of the first vehicle and the detection of the second vehicle, and also detects the exit for each detected vehicle. As described above, the computer 19 determines the content of the one-dimensional memory 17 while comparing it with the content of the one-dimensional memory 17 at the time of the previous scan. This is performed by performing a labeling process such as attaching a label to each vehicle.

The output from the computer 19 is obtained through a passing number counter 20 and a presence counter 21. The passing number counter 20 is counted up next when a vehicle is detected. Therefore, this counter 20 specifies the number of passing vehicles. In addition, the presence counter 21 sets the CC
The number of vehicles existing in the field of view of the D camera 2 is specified. Therefore, when there is a motorcycle to be translated, the counter 21 displays, for example, two.

Here, the size of the one-dimensional memory 17 is determined in relation to the number of pixels of the optical sensor constituting the one-dimensional CCD camera 2. In principle, when a 1000 pixel CCD camera is used, the one-dimensional memory 17 also has a capacity of 1000 bits. When the number of pixels of the one-dimensional CCD camera 2 is 1000 and the road width is 5000 mm,
One pixel corresponds to 5 mm on the road surface.

Accordingly, the cycle of the intermittent marking 6 is set to a cycle larger than 5 mm corresponding to one pixel and smaller than the width of a small vehicle such as a motorcycle. In the present invention, the vehicle is detected based on the disturbance of the cycle in the output signal of the optical array sensor. Therefore, if a vehicle having a minimum width of 500 mm is to be detected, about 2 to 5 marks are required for 500 mm. Assuming five periods, the period of the marking 6 on the road surface is 100 mm. In other words, the period of the marking 6 is larger than one pixel of the CCD camera 2 on the road surface and smaller than the minimum width of the passing vehicle.

As described above, the use of the one-dimensional CCD camera 2 and the intermittent marking 6 allows the vehicle to be collected using the wireless IC card in the main lane of the toll road, and in addition to the vehicle detection device for measuring traffic volume. As a result, the vehicle can be accurately detected even under special conditions such as translation in the lane of the vehicle, overtaking of the motorcycle during a stagnation, or occurrence of a shade.

Next, a vehicle detecting apparatus according to another embodiment of the present invention will be described with reference to FIGS.

In the vehicle detecting device shown in FIG. 9, in addition to the one-dimensional CCD camera 2, the signal processing device 5, and the intermittent marking 6 shown in FIG. One or more vehicle type discriminating treads 30 are provided as auxiliary sensors for vehicle detection. The signal processing device 5 detects a vehicle using not only the signal from the one-dimensional CCD camera 2 but also the signal from the vehicle type discriminating treads 30. Perform processing.

FIG. 10 shows the structure of the vehicle type discrimination tread plate 30.
The vehicle type discrimination tread 30 is used by being buried on the road 109 as described above. Inside the vehicle type discrimination tread, conductive contacts 3
A plurality of 1, 32 are arranged in the vehicle width direction. Then, when the tire 33 of the vehicle passes over the contact, a pressure 34 is generated, the conductor contacts 31 and 32 come into contact, and a current flows. When this contact information is mapped on the memory, the contact information 35 to 38 and 4 shown in FIG.
Map information consisting of 0 and 41 is obtained. That is, 35
When the four contact information items of ~ 38 are obtained, the contact information group indicated by 39 is recognized based on the arrangement and the vehicle is determined to be a passenger car. When the two contact information items 40 to 41 are obtained, the contact information group indicated by 42 is obtained. Can be recognized as a motorcycle.

FIG. 12 shows an example of a schematic configuration of the signal processing device 5. The memory 43 for the vehicle type discriminating tread plate 30, the line sensor memory 44 for the one-dimensional CCD camera 2, and the synthesizing memory 4
5 and a matching device 46. The more detailed configuration is as shown in FIG. 13, and when compared with FIG. 5, the one-dimensional memory 17 in FIG. 5 corresponds to the line sensor memory 44 in FIG.
5 corresponds to the one-dimensional memory 17 of FIG. The function of the matching device 46 is taken over by the computer 19.

Referring to FIG. 12, the vehicle detecting device according to the present embodiment will be described. In FIG. 12, first, a tire of a passing vehicle applies a pressing force to a vehicle type determining tread plate 30, and the vehicle type determining tread plate 3
The 0 contact is made conductive. Then, in synchronization with the synchronization signal 47 sent from the one-dimensional CCD camera 2, the conduction / non-conduction state of each contact in the vehicle width direction, that is, contact information is transmitted to the vehicle type discriminating tread board memory 43. Then, as time elapses, map information 49 as shown in FIG. 14 can be obtained in the vehicle type discriminating treadboard memory 43. 49A is contact ON information.

Using the one-dimensional CCD camera 2, the contour of the image of the vehicle passing from the gantry 1 to the vehicle type discrimination tread plate 30 is cut out in the same manner as in the previous embodiment, and stored in the line sensor memory 44. In this manner, map information 50 as shown in FIG. 14 can be obtained in the line sensor memory 44 as time passes. 44A is non- "0"
Area. At this time, the vehicle type discrimination tread plate 30 and the CC
To match the time axis of the D camera 2,
The synchronization signal 47 is output from the D camera to the vehicle type discrimination tread plate 30.

Then, the contents of the two memories 43 and 44 are superimposed and stored in the synthesizing memory 45. Based on the contents of the synthesizing memory 45, the matching device 46
First, the areas indicated by 51 and 52 are recognized as two motorcycles instead of passenger cars, and the area indicated by 54 is recognized as a large vehicle. Further, the vehicle which cannot be seen by the one-dimensional CCD camera 2 behind the shadow of the large vehicle, such as the region indicated by 53 in FIG. By comparison,
Recognize as a motorcycle.

If the vehicle does not move due to traffic congestion on the road, the vehicle type discriminating treadboard memory 43 and the line sensor memory 44 may store only the same information. At this time, the memory capacity becomes insufficient, and a memory overflow occurs. In order to prevent this, in this embodiment, the matching circuit device 46 cuts out the vehicle width information from the vehicle type discriminating treadboard memory 43, and predicts the length of the vehicle based on the ratio of the vehicle width to the length direction of a general vehicle. If memory contents longer than the predicted length continue, a delete signal 48 is output to store unnecessary memory data in the direction of elapsed time in each of the memories 43 and 4.
4 will be deleted. Thus, for example, even if the passenger car is stopped due to traffic congestion, it is not erroneously determined that the vehicle is a trailer truck. If the data input to the vehicle type discriminating treadboard memory 43 or the line sensor memory 44 does not change for a certain period of time, a similar deletion signal 48 is output,
We are going to delete monotonous memory data. This eliminates memory overflow.

In the vehicle detecting apparatus of the above embodiment, the vehicle type and the number of axes of the tires of the vehicle are detected by the vehicle type determining tread plate 30, the contact information thereof is stored in the vehicle type determining tread plate memory 43, and the one-dimensional CCD camera 2 is used. Captures an image of the vehicle, and stores the image information in the line sensor memory 44. At this time,
From the one-dimensional CCD camera 2, a scanning signal is
The contact information of the vehicle type discrimination tread 30 is sampled in synchronization with the synchronizing signal 47. The contents of these two memories 43 and 44 are combined in the combining memory 45, and the matching device 46 determines the type and number of passing vehicles to detect the vehicle. Therefore, a case where the motorcycles are running in parallel is not erroneously determined to be a passenger car, and a motorcycle or the like that is hidden in the shadow by approaching a large vehicle is not overlooked. In addition, by outputting the delete signal 48 from the matching device 46, it is possible to prevent the memory from overflowing due to unnecessary information during a traffic jam. As described above, by using the vehicle type discriminating tread 30 as an auxiliary sensor for vehicle detection, the type and number of passing vehicles can be accurately grasped, and unmanned toll collection on toll roads and the like can be greatly accelerated.

In the above embodiment, the vehicle type discrimination tread plate 30 is used as an auxiliary sensor for vehicle detection. However, a loop coil, an ultrasonic transceiver, or a microwave transceiver (not shown) may be used. it can. (1) An appropriate number of loop coils are embedded in the road surface below the intermittent marking 6 so as to be sensitive to the vehicle. Thereby, the cardboard box, the person,
Alternatively, even if a vehicle is present for the one-dimensional CCD camera 2 because it is hidden by dust or dirt, the loop coil does not respond to these, so that the vehicle is not detected unless there is a detection output of the loop coil. Is given to the signal processing device 5. (2) The ultrasonic transmitter / receiver is installed, for example, in the gantry 1 so that the area above the intermittent marking 6 is set as a detection area so that a passing vehicle can be detected. When an ultrasonic handset is used, a person is detected in addition to the vehicle. However, even if there is dust or dirt, the detection signal is the same as that of a road surface. Therefore, the intermittent marking 6 is hidden by dust and dirt, and the one-dimensional CC
Even if a vehicle is present for the D camera 2, since the ultrasonic handset does not respond to these, a determination function for not detecting the vehicle unless there is a vehicle detection output of the ultrasonic handset is signaled. The processing device 5 has the information. (3) The microwave handset is also installed, for example, on the gantry 1 so that the area above the intermittent marking 6 is set as a detection area so that a passing vehicle can be detected. When using a microwave handset, it detects moving objects such as vehicles,
Even if there is a person, a cardboard box, dust or dirt, there is no Doppler shift, so that these become the same detection signal as the road surface. Therefore, even if the intermittent marking 6 is hidden by dust and dirt, and further by a cardboard box or a person and a vehicle exists for the one-dimensional CCD camera 2, the microwave handset is insensitive to these. In addition, the signal processing device 5 is provided with a determination function of preventing the vehicle from being detected unless the vehicle detection output of the microwave handset is present.

[0030]

As described above, according to the present invention, the use of the optical array sensor and the intermittent marking makes it possible to translate the vehicle in the lane, pass the motorcycle when the vehicle is stagnant, or perform special conditions such as shading. Even below, the vehicle can be detected accurately.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a vehicle detection device according to one embodiment of the present invention.

FIG. 2 is a diagram showing a waveform example of input light.

FIG. 3 is a diagram showing a waveform example of input light.

FIG. 4 is a diagram showing a waveform example of input light.

FIG. 5 is a block diagram illustrating a configuration example of a signal processing device.

FIG. 6 is a diagram showing a waveform example of each part of the signal processing device.

FIG. 7 is a diagram showing a state of one-dimensional memory contents.

FIG. 8 is a flowchart illustrating an example of a signal processing procedure.

FIG. 9 is a schematic diagram of a vehicle detection device according to another embodiment of the present invention.

FIG. 10 is a diagram showing a configuration example of a vehicle type discrimination tread plate.

FIG. 11 is a diagram showing an example of a map of contact information.

FIG. 12 is a block diagram illustrating a configuration example of a signal processing device.

FIG. 13 is a block diagram showing a configuration example corresponding to FIG. 5 of the signal processing device.

FIG. 14 is an explanatory diagram of the operation of the signal processing device.

FIG. 15 is a diagram showing a conventional ultrasonic vehicle detection device.

FIG. 16 is a diagram showing a conventional optical vehicle detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gantry 2 One-dimensional CCD camera 3 Passing vehicle 4 Cable 5 Signal processor 6 Intermittent marking 30 Model discrimination tread

Continued on the front page (72) Inventor Riichiro Yamashita 2-1-1, Shinhama, Arai-machi, Takasago-shi, Hyogo Mitsubishi Heavy Industries, Ltd. Inside Takasago Research Laboratory (72) Inventor Ichiro Fujita 1-1-1, Wadazakicho, Hyogo-ku, Kobe-shi, Hyogo No. 1 Inside Kobe Shipyard of Mitsubishi Heavy Industries, Ltd. (72) Inventor Hideo Uehara 1-1-1, Wadazakicho, Hyogo-ku, Kobe-shi, Hyogo Prefecture Inside Kobe Shipyard of Mitsubishi Heavy Industries, Ltd. (56) References JP-A-54- 106263 (JP, A) JP-A-4-188005 (JP, A) JP-A-4-49498 (JP, A) JP-A-53-124482 (JP, A) JP-A-5-264744 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01V 9/00-9/04

Claims (3)

(57) [Claims] 1. An optical array sensor installed above a road surface to obtain a one-dimensional light amount signal in a lane width direction from the road surface, an optical system installed in the optical array sensor, and a one-dimensional optical system of the optical array sensor. An intermittent marking installed on a road surface in a field of view, and a signal processing device for performing a vehicle detection process from an output signal of the optical array sensor, further comprising: a signal processing device, the output signal of the optical array sensor Intermittent ma
Whether or not the periodic component corresponding to the
Detects the presence or absence of the periodic component and determines whether the first
Consisting of the level of the road and the second level other than the road surface 2
Means for converting to a sequence of value signals;
The vehicle is separated and detected in the vehicle traveling direction and the lane width direction on the basis of the connection level and the second level, and the connection level of the first level and the second level between the binary signal sequences different in time. A vehicle detection device comprising: 2. The intermittent cycle of the intermittent marking is longer than a cycle of pixels of the optical array sensor on a road surface and shorter than a minimum width of a detection target vehicle.
The vehicle detection device according to any one of the preceding claims. 3. A tread having contacts buried in the road surface,
The apparatus further comprises at least one sensor of a loop coil embedded in a road surface, an ultrasonic transmitter / receiver installed above the road surface, and a microwave transmitter / receiver installed above the road surface, and the signal processing device outputs the output of the sensor. The vehicle detection device according to claim 1, wherein vehicle detection processing is performed based on a signal and an output signal of the optical array sensor.