JP2000099877A - Image type vehicle detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exactly measure the number and speed of vehicles by every lane irrespective of a time zone by a TV camera and to reduce a maintenance work. SOLUTION: Cameras 1 to 3 are installed by every lane, pieces of video of the vehicles are digitized by every lane by an AD converter 6 and are stored in memories A1 to A3. The number of the running vehicles and vehicle speed by every lane are exactly measured by analyzing pieces of digital video by every lane by a processing part 5. Measurement in the morning and the evening are enabled by evading influence of direct sunlight by directing the cameras toward west in the morning and directing them toward east in the evening. The measurement in the morning and the evening are exactly performed by securing contrast ratio equal to or more than a fixed level by providing illumination for an object area of measurement on a road and performing the illumination only in the time zone of twilight. A cleaning work of the front glasses of the cameras is reduced by applying photocatalyst to chemically clean the surface of the glass on a photographing window.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image-type vehicle detector, and more particularly, to an image-type vehicle detector that measures the number of traveling vehicles and the speed of the traveling vehicle.

[0002]

2. Description of the Related Art One or a plurality of television cameras are used to photograph a vehicle traveling on a road, measure the speed of the vehicle to detect traffic congestion, and monitor traffic conditions at an intersection. I have. When a single TV camera monitors a road with a few lanes, a vehicle in an adjacent lane may be hidden behind a large vehicle, making accurate measurement difficult. Therefore, a method has been used in which video signals captured by a plurality of image capturing means are combined to detect the amount of movement of the moving body. For example, one disclosed in JP-A-6-333193 is known.

FIG. 8 shows an example of a conventional image type vehicle detector. In this device, video signals from nine television cameras are synthesized as nine multi-screens by an analog image synthesizer and multi-displayed in one frame. The composite image is converted to digital, a detection area is cut out, and a target vehicle is detected by image processing. It is suitable for the purpose of measuring the moving amount of the moving body.

The imaging direction of a conventional image processing camera is fixed with respect to an area to be measured. In order to avoid the effects of direct sunlight in the morning and evening, the site is selected and the angle of depression of the camera is adjusted.

[0005] Since the road surveillance camera is installed on a road with heavy traffic, the lens or the photographing window becomes dirty with exhaust gas from the vehicle. 1 so as not to interfere with shooting
They are manually cleaned about once a year.

[0006]

In a conventional image-type vehicle detector, images from nine cameras are combined into one frame with the horizontal and vertical resolutions reduced to one third respectively. Therefore, the image data is reduced to one-ninth and the accuracy is reduced, so that it is difficult to accurately measure the speed of the high-speed vehicle.

[0007] Further, since the image pickup direction of the camera is constant, the camera is installed in either east or west on a road extending in the east or west direction. In this case, even if the installation position and direction of the camera are adjusted, the direct influence of the morning and evening sunlight cannot be eliminated, so that the amount of input light to the camera becomes excessive and there are times when accurate measurement cannot be performed. There is.

Further, since no lighting is used, there is a problem that the contrast ratio between the vehicle and the road background decreases at dusk in the morning and evening, and accurate measurement cannot be performed.

In addition, in order to remove dirt and dust and the like adhering to the surface of the camera glass, there is a problem that roadside regulation must be performed and a large-scale cleaning operation using a dedicated vehicle equipped with an elevator car must be regularly performed. is there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and has as its object to provide an image-type vehicle detector that requires little maintenance while improving the measurement accuracy of the speed of each vehicle traveling on a highway. Aim.

[0011]

In order to solve the above-mentioned problems, according to the present invention, an image type vehicle detector is provided with a plurality of cameras installed for each lane and an AD for digitizing each camera image signal. The configuration includes a converter, means for cutting out a target image from the digital video signal, and analysis means for analyzing the image based on the cut-out video signal to obtain the number and speed of vehicles. With this configuration, the vehicle in each lane can be reliably captured while maintaining the resolution at the time of imaging,
It is possible to accurately measure the number of individual vehicles traveling at high speed in each lane and the speed of the vehicles.

Also, the westward direction during the time of the rising sun and the eastward direction during the setting time of the sunset,
A means for changing the direction of the camera with time is provided. With this configuration, the number of vehicles and the vehicle speed can be stably measured while avoiding the influence of direct sunlight.

An illuminance sensor for measuring the illuminance of external light, an illuminating device for illuminating an area to be measured on a road, and an illuminance of the external light within a predetermined range based on a signal from the illuminance sensor. A means for detecting and a means for controlling to illuminate only when the illuminance of the external light is within a predetermined range are provided. With this configuration, the vehicle ratio can be reliably measured while the contrast ratio is always equal to or higher than a certain value.

Further, a transparent film in which photocatalyst particles and water-repellent particles are dispersed was applied to a photographing window glass of a camera case. With this configuration, it is possible to eliminate a large-scale on-site cleaning operation for dirt on the camera front glass.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION
A plurality of cameras installed for each lane, an AD converter for digitizing each camera video signal, a unit for cutting out a target image from the digital video signal, An image-type vehicle detector including an analysis means for determining the number and speed of vehicles, and has an operation of digitizing a video signal for each lane to accurately measure the number and speed of vehicles.

The second aspect of the present invention is the first aspect of the present invention.
In the described image type vehicle detector, means for changing the direction of the camera with time is provided so that the camera is oriented westward during the time when the morning sun rises and eastward during the time when the setting sun is set. It has the effect of preventing direct sunlight from entering.

The third aspect of the present invention is the first aspect of the present invention.
In the image type vehicle detector described in the above, an illuminance sensor for measuring illuminance of external light, an illuminating device for illuminating a measurement target area on a road, and an illuminance of external light within a predetermined range based on a signal from the illuminance sensor. Is provided, and means for controlling to illuminate only when the illuminance of the external light is within a predetermined range is provided. It has the effect of identifying.

[0018] The invention described in claim 4 of the present invention relates to claim 1.
In the image type vehicle detector according to the description, a transparent film in which photocatalyst particles and water-repellent particles are dispersed is applied to a photographing window glass of a camera case, and the photographing window is chemically cleaned and mechanically cleaned. It has the effect of making cleaning work unnecessary.

According to a fifth aspect of the present invention, there is provided an image-based vehicle detection system for obtaining the number and speed of vehicles by individually digitizing the video signals of a plurality of cameras installed in each lane and extracting the target image. The method is an image-based vehicle detection method that changes the direction of the camera to the west at a predetermined time at midnight and changes the direction of the camera to the east at a predetermined time in the daytime to prevent direct sunlight from entering the camera. Has an action.

According to a sixth aspect of the present invention, there is provided an image-type vehicle detection system which obtains the number and speed of vehicles by individually digitizing video signals of a plurality of cameras installed in each lane and cutting out target images. In the method, the illuminance of the external light is measured, and when it is detected that the illuminance of the external light is within a predetermined range, the measurement target area on the road is illuminated, and the illuminance of the external light is out of the predetermined range. This is an image-based vehicle detection method that controls to turn off the illumination when it is detected that the vehicle is illuminated only when the contrast is low and has an effect of reliably identifying the vehicle.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described in detail with reference to FIGS.

(First Embodiment) In a first embodiment of the present invention, video signals from a plurality of cameras installed for each lane are individually digitized, and a target image is cut out from the digital video signal. This is an image-based vehicle detector that analyzes the extracted video signal to determine the number and speed of vehicles.

FIG. 1 is a functional block diagram of an image type vehicle detector according to the first embodiment of the present invention. In FIG.
The camera 1 is a camera that captures the left lane. Camera 2
Is a camera that captures the center lane. The camera 3 is a camera that captures the right lane. The image synthesizing unit 4 includes the cameras 1 to 3
This is a device that converts the video signal into a digital signal and combines them. The processing unit 5 is a device that analyzes a digital video signal. A
The D converter 6 is a circuit that converts an analog video signal of the camera into a digital video signal. The control unit 7 is a circuit that supplies a control signal such as a timing signal to a circuit of each unit.

FIG. 2 is a diagram of a photographed image. FIG. 2 (a)
Is an image of the third lane, FIG. 2B is an image of the second lane,
FIG. 2C is an image of the first lane. FIG. 2 (d)
It is a composite image.

Next, the operation of the image type vehicle detector according to the first embodiment of the present invention configured as described above will be described.
TV cameras will be installed in each lane of the three-lane road.
The camera 1 is a camera mounted on the left lane, and projects a vehicle in the left lane straight on the center of the screen as shown in FIG. The center lane and right lane are reflected diagonally. The camera 2 is a camera mounted on the center lane, and a vehicle in the center lane is projected straight on the center of the screen as shown in FIG. 2 (b). The camera 3 is a camera mounted on the right lane, and a vehicle in the right lane is projected straight in the center of the screen as shown in FIG. The cameras 2 and 3 synchronize with the frames of the three cameras by moving with the synchronization signal of the camera 1,
The consistency between the memory transfer data and the frame of the editing process is ensured.

The imaging data of each camera is digitized,
The data is temporarily stored in memories A1 to A3 corresponding to the camera. The video signals from each camera are stored in memories A1 to A3 corresponding to the cameras after AD conversion by the AD converter 6.

From the memories A1 to A3 corresponding to the camera, only the vehicle running state and background data of the target lane are digitally cut out. The extracted image data of each lane is edited and stored in the memory B. The memory A is operated by the operation from the control unit 7.
The target lanes of A1, A2 and A3 are extracted and transferred to the memory B.
The target lane images of a plurality of cameras are synthesized into one frame while the resolution at the time of imaging is secured.

When the data in the memory B is DA-converted and visualized, as shown in FIG. 2D, images of the left lane, the center lane, and the right lane are projected straight on the screen from the left. The data stored in the memory B is subjected to image processing by the processing unit 5 to analyze the vehicle for each lane. The resolution of the synthesized video signal is the same accuracy as that of one screen, and much more image signals can be used as compared to the case of synthesizing one screen at the stage of an analog video signal. Therefore, the speed and number of individual vehicles traveling at high speed can be measured with extremely high accuracy.

Since the image of each camera is converted into a digital signal and processed, the number of vehicles and the speed of the vehicle can be accurately measured without being affected by adjacent lanes. Since a signal synthesized on one screen with a digital signal is output, the conventional image processing apparatus can be used as it is, and the resources of the conventional image processing can be effectively used.

As described above, in the first embodiment of the present invention, the image type vehicle detector is provided with a plurality of cameras installed for each lane and an AD for digitizing each camera video signal.
A converter, a control unit that cuts out the target image from the digital video signal, and a processing unit that analyzes the clipped video signal and obtains the number and speed of the vehicles, so that the vehicles for each lane are cut out individually. Thus, the number and speed can be accurately measured.

(Second Embodiment) In a second embodiment of the present invention, the camera is oriented so that it faces westward during the time when the sun rises and eastward during the time when the sunset sets. It is an image type vehicle detector provided with a means for changing with time.

FIG. 3 is a functional block diagram of an image type vehicle detector according to a second embodiment of the present invention. In FIG.
The clock 8 is a clock that outputs signals at midnight and noon. The control unit 9 is a circuit that controls the measurement unit and the motor based on the signal of the clock 8. The measurement unit 10 is a device that measures the speed of a vehicle and the like by image processing. The motor preset control unit 11 is a circuit that controls the motor according to the control of the control unit. The motor A12 is a motor for moving the camera in the left-right direction. The motor B13 is a motor for moving the camera up and down.

FIG. 4 is a diagram showing the control timing.
In FIG. 4, the time signals are the AM12 signal at noon and the midnight signal.
PM12 signal. The measurement control instruction is a signal for issuing an instruction to stop measurement according to the time signal. The camera direction control instruction is a signal for instructing the camera direction according to the time signal. The motor A and B controls are signals for operating the motor. The motor operation completion signal is a signal indicating that the change of the camera direction has been completed.

Next, the operation of the image type vehicle detector according to the second embodiment of the present invention configured as described above will be described.
During the control for changing the camera direction, the vehicle cannot be measured. Therefore, it is necessary to change the direction of the camera during a time when the traffic volume is small during the day so as not to affect the overall measurement accuracy. Here, 12
I decide to turn the camera at time and at 12:00 at night.

The control unit 9 constantly monitors the time information of the clock 8, and when a preset camera direction control time has come, a stop instruction to the measuring unit 10 and an instruction to the motor preset control unit 11 are issued. Outputs direction control instruction. At 12 o'clock in the daytime, a control instruction is issued to turn the camera to the east to avoid the effect of the sunset, and at 12 o'clock in the night, a control instruction is issued to turn the camera to the west to avoid the influence of the sunrise. The motor preset control unit 11 outputs motor A and B control signals to the motor A12 and the motor B13 under the control of the control unit. Since the motor operation completion signal is output when the motor operation is completed, the control unit 11 issues a measurement restart instruction and causes the measurement unit 10 to restart measurement. The measurement stop time is several minutes. The camera direction control instruction signal is connected to the measurement unit 10 in order to reset the measurement area.

As described above, the direction of the camera is changed by stopping the measurement for a few minutes during a time period when the traffic volume is relatively small, thereby preventing the measurement failure due to the direct sunlight caused by the morning sun and sunset. In order to avoid the effects of direct sunlight in the morning and evening, the camera direction is automatically changed to the direction opposite to the direction of direct sunlight regardless of the selection of the installation point and the depression angle adjustment of the camera, so the measurable time is Can be significantly increased. Further, since the influence of direct sunlight is eliminated, the measurement accuracy is greatly improved.

As described above, in the second embodiment of the present invention, the image-type vehicle detector is directed westward during the time of the rising sun and eastward during the time of the setting sun. Since the means for changing the direction of the camera according to time is provided, it is possible to prevent direct sunlight from entering the camera and accurately measure the number and speed of vehicles.

(Third Embodiment) A third embodiment of the present invention is an image-type vehicle detector that illuminates an area to be measured on a road only when the illuminance of external light is within a predetermined range. .

FIG. 5 is a diagram showing a lighting control method in the image type vehicle detector according to the third embodiment of the present invention. In FIG. 5, a graph 14 is a graph showing the illuminance on the road. The illumination control signal 15 is a signal indicating the timing of turning on the illumination.

FIG. 6 is a functional block diagram of an image type vehicle detector according to the third embodiment of the present invention. In FIG.
The illuminance sensor 16 is a sensor that detects illuminance. The AD converter 17 is a circuit that converts a signal of the illuminance sensor into a digital signal. The control unit 18 is a circuit for turning on / off the lighting based on the digitized illuminance signal. The power switch control unit 19 turns on / off the lighting according to the control of the control unit.
It is a circuit to turn off. The lighting fixture 20 is a lamp that illuminates the road and the vehicle.

Next, the operation of the image type vehicle detector according to the third embodiment of the present invention configured as described above will be described.
Lighting is required only in the morning and evening twilight hours, so lighting is turned on only when the illuminance of external light is within a certain range. At night, the vehicle can be accurately identified by detecting the vehicle lights and tail lamps, so that nighttime illumination is unnecessary. The illuminance is measured by the illuminance sensor 16 for external light, and when the illuminance reaches a value within a certain range, it is determined to be dusk, and the illumination power is turned on only during this period.

The signal from the illuminance sensor 16 is AD-converted by the AD converter 17, and the illuminance is measured by the control unit 18. When the measured illuminance is within a preset range, the control unit 18 gives a lighting instruction signal to the power switch control unit 19 to turn on the illumination of the lighting fixture 20. The lighting fixture 20 illuminates all the lanes to be measured, and the illuminance is equal to or more than the upper limit of the dusk illuminance range. In addition, power control is performed in consideration of a preheating time from when the lighting apparatus 20 is turned on until the illuminance reaches a predetermined illuminance.

As described above, according to the third embodiment of the present invention, the illuminance sensor for measuring the illuminance of the external light and the illuminating device for illuminating the area to be measured on the road are provided. And means for detecting that the illuminance of the external light is within a predetermined range based on a signal from the illuminance sensor, and means for controlling to illuminate only when the illuminance of the external light is within a predetermined range. With the configuration, when the contrast is low, the vehicle can be illuminated and accurate measurement can be performed.

(Fourth Embodiment) In a fourth embodiment of the present invention, a surface containing transparent photocatalytic oxide particles, silicone, and a water-repellent fluororesin is provided on the surface of a photographic window glass of a camera case. It is an image type vehicle detector in which a layer was formed.

FIG. 7 is a diagram showing a camera unit of an image-type vehicle detector according to a fourth embodiment of the present invention. FIG. 7A is a diagram illustrating the entire camera unit, and FIG. 7B is a cross-sectional view of a shooting window. The camera case has a shooting window, and the glass of the shooting window is coated with a silicone resin in which particles of a photocatalyst and a water-repellent fluororesin are dispersed. These are transparent to the extent that the imaging window does not interfere with imaging.

Next, the function of the photographing window of the image-type vehicle detector according to the fourth embodiment of the present invention will be described. When the photocatalyst is excited by sunlight, the organic group bonded to the silicon atom in the silicone molecule is partially replaced by a hydroxyl group, and becomes hydrophilic. Both the hydrophilic part exposed to the outside air and the water-repellent fluororesin exposed to the outside have a microscopically dispersed structure on the surface.

In such a structure, since the hydrophilic surface and the water-repellent surface are adjacent to each other, the hydrophilic deposit which easily adapts to the hydrophilic surface does not adapt to the adjacent water-repellent portion. Conversely, hydrophobic deposits that are easily adapted to the water-repellent surface do not adapt to adjacent hydrophilic portions. Therefore, neither the hydrophilic deposit nor the hydrophobic deposit is fixed to the member surface, and the surface is maintained in a clean state.

Dirt such as combustion products in exhaust gas of automobiles, abrasion powder of tires, and dust and soot floating in the air does not adhere to the photographing window. Dangerous and time-consuming cleaning work at high places on the road is greatly reduced, and maintenance costs are also reduced. In addition, it can help to reduce traffic congestion and reduce traffic accidents.

As described above, in the fourth embodiment of the present invention, a film coated with a photocatalyst to which dirt due to exhaust gas does not adhere is formed on the photographing window glass of the camera case of the image-type vehicle detector. Cleaning work can be reduced.

[0050]

As described above, according to the present invention, the image type vehicle detector is provided by a plurality of cameras installed for each lane, an AD converter for digitizing each camera video signal, and a digital video signal. Since it is configured to include means for cutting out the target image and analysis means for analyzing the image based on the cut out video signal to obtain the number and speed of vehicles, the video signal of the vehicle is digitized for each lane and analyzed. Thus, it is possible to obtain the effect that the vehicle can be reliably grasped, and the number of vehicles traveling in each lane and the vehicle speed can be accurately measured.

Also, the westward direction during the time of the rising sun and the eastward direction during the setting time of the sunset,
Since the means for changing the direction of the camera with time is provided, the effect of avoiding the influence of direct sunlight and performing stable vehicle measurement can be obtained.

Further, an illuminance sensor for measuring the illuminance of the external light, an illuminating device for illuminating an area to be measured on the road, and an illuminance of the external light within a predetermined range based on a signal from the illuminance sensor. Since the detection means and the control means for illuminating only when the illuminance of the external light is within a predetermined range are provided, it is possible to ensure a constant or more contrast ratio and perform stable vehicle measurement. The effect is obtained.

Further, since a transparent film in which photocatalyst particles and water-repellent particles are dispersed is applied to the photographing window glass of the camera case, it is possible to eliminate the necessity of a large-scale cleaning operation on site.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an image type vehicle detector according to a first embodiment of the present invention;

FIG. 2 is a diagram of a captured image of the image-type vehicle detector according to the first embodiment of the present invention;

FIG. 3 is a functional block diagram of an image type vehicle detector according to a second embodiment of the present invention;

FIG. 4 is a timing chart of an image type vehicle detector according to a second embodiment of the present invention;

FIG. 5 is an explanatory diagram of an operation of the image-type vehicle detector according to the third embodiment of the present invention;

FIG. 6 is a functional block diagram of an image type vehicle detector according to a third embodiment of the present invention;

FIG. 7 is a sectional view of an imaging window of an image-type vehicle detector according to a fourth embodiment of the present invention;

FIG. 8 is a functional block diagram of a conventional image-type vehicle detector.

[Explanation of symbols]

 1-3 Camera 4 Image synthesis unit 5 Processing unit 6 A / D converter 7 Control unit 8 Clock 9 Control unit 10 Measurement unit 11 Motor preset control unit 12 Motor A 13 Motor B 14 Illuminance graph 15 Illumination control signal 16 Illuminance sensor 17 AD conversion Unit 18 Control unit 19 Power switch control unit 20 Lighting equipment

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Mitsuaki Ota 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Inside Matsushita Communication Industrial Co., Ltd. (72) Yosuke Kyotoku Tsunashima-Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Matsushita Communication Industrial Co., Ltd. 4-3-1, Matsushita Communication Industrial Co., Ltd. (72) Inventor Tatsuro Iku 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama, Kanagawa Prefecture Inside Matsushita Communication Industrial Co., Ltd. (72) Masaichi Toyama Yokohama, Kanagawa Prefecture Matsushita Communication Industrial Co., Ltd. (4-1) Tsunashima Higashi 4-chome, Kohoku-ku, Tokyo (72) Inventor Tokio Chiba 4-3-1 Tsunashima Higashi, Kohoku-ku, Yokohama, Kanagawa Prefecture Matsushita Communication Industrial Co., Ltd. (72) Inventor Yamakatsu 4-3-1, Tsunashima Higashi, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Inside Matsushita Communication Industrial Co., Ltd. Matsushita Communication Industrial Co., Ltd.

Claims (6)

[Claims] 1. A plurality of cameras installed for each lane, an AD converter for digitizing each camera video signal, a unit for cutting out a target image from the digital video signal, and an image processing unit based on the cut-out video signal. An image-type vehicle detector, comprising: analysis means for analyzing the number and speed of vehicles. 2. The westward direction during the time when the sun rises,
2. The image-type vehicle detector according to claim 1, further comprising means for changing the direction of the camera with time so that the camera faces eastward during a sunset. 3. An illuminance sensor for measuring illuminance of external light, an illuminating device for illuminating an area to be measured on a road, and determining that the illuminance of external light is within a predetermined range based on a signal from the illuminance sensor. 2. The image-type vehicle detector according to claim 1, further comprising means for detecting, and means for controlling to illuminate only when the illuminance of the external light is within a predetermined range. 4. The image-type vehicle detector according to claim 1, wherein a transparent film in which photocatalyst particles and water-repellent particles are dispersed is applied to a photographing window glass of the camera case. 5. An image-based vehicle detection method for obtaining the number and speed of vehicles by individually digitizing video signals of a plurality of cameras installed for each lane and extracting a target image. An image-type vehicle detection method, wherein the direction of the camera is changed to the west and the direction of the camera is changed to the east at a predetermined time in the daytime. 6. An image-type vehicle detection method for obtaining the number and speed of vehicles by individually digitizing video signals of a plurality of cameras installed for each lane and then extracting a target image to measure the illuminance of external light. Then, when it is detected that the illuminance of the external light is within a predetermined range, the illumination is applied to the measurement target area on the road, and when it is detected that the illuminance of the external light is out of the predetermined range, the illumination is turned off. An image-type vehicle detection method comprising: