JP3375409B2 - Right turn 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 right turn vehicle detection device for detecting a right turn vehicle at an intersection.

[0002]

2. Description of the Related Art In traffic signal control at intersections, at present, the signal time of a right-turning blue arrow is fixed for a fixed period of time, and while usefulness is known, a blue arrow is displayed in response to the presence or absence of a right-turning vehicle. There are few intersections that variably control the time. One of the reasons for this is that conventionally there is no suitable sensor for detecting a right-turning vehicle at an intersection, including cost.

As conventional sensors for detecting a right-turn vehicle, there are (a) ultrasonic type, (b) loop type, (c) visible light image type, (d) thermal image type, etc. ) Ultrasonic method cannot be applied to large intersections. At large intersections, the distance from the roadside to the right-turn lane is 20 m or more, and it is impossible to install with long arms because of its strength. (B) The loop type requires a loop coil to be embedded in the road surface and must dig up the road surface at the right turn of the intersection, and is not suitable as a sensor for an intersection with heavy traffic.

(C) Since the visible light image type is remote sensing, there is no problem in installation as in the above (a) and (b), but since the nighttime headlight is seen as an image obliquely, detection is not possible. In some cases, it may be possible, and there may be cases where the straight ahead vehicle and the image overlap each other, and it is difficult to separate the two by image processing. In the thermal image type of (d), there is no problem in installation by remote sensing and the vehicle image can be recognized even at night, but as in (c) above, the straight ahead vehicle and the right turn vehicle are superimposed on the image. The separation is difficult. Also, since the infrared light receiving element section must be electronically cooled, in terms of cost,
It cannot be expected to be commercialized for vehicle detection. As described above, there is no suitable sensor for detecting a right-turning vehicle in the related art, which is inexpensive and can operate day and night.

[0005]

As described above, there is no suitable sensor for detecting a right-turning vehicle in the related art, which is inexpensive and can be operated day and night. As a result, an appropriate right-turning vehicle is detected. The device has not been realized, and as a result, the utility of the well-known right turn vehicle response control of intersection traffic lights has not spread. The present invention has been made in view of such circumstances, and in order to promote the right turn response control of an intersection traffic light, it can be used all day and night, and at a low price.
The object is to provide a right turn vehicle detection device at an intersection.

[0006]

In order to solve the above-mentioned problems, in the first invention of the present application, a right turn vehicle detection device images a linear field of view substantially matched with a right turn lane at an intersection from a roadside high place and outputs a luminance distribution. A line sensor camera, a laser light irradiating means for irradiating a laser beam by sequentially scanning the linear field of view from a roadside height, and processing the output from the line sensor camera to be present in the linear field of view. An image processing unit for detecting a right-turn vehicle is included, and the image processing unit is provided for each laser beam scanning position, and the line sensor is obtained in response to irradiation of the laser beam when no vehicle is present on the right-turn lane. The position of the laser spot image on the camera is stored as a reference position, and the position of the laser spot image on the line sensor camera obtained in response to the scanning / irradiation of the laser light is stored as the reference position. If there is a difference compared to the vehicle position, it is detected that there is a vehicle at the laser beam scanning position, and the difference is
Right-turn vehicle when it is within the predetermined range corresponding to the existence
It is configured to determine that there is.

Further, in the second invention of the present application, the right turn vehicle detection device is provided with a line sensor camera for picking up a linear field of view substantially coincident with a right turn lane at an intersection from a roadside height position and outputting a luminance distribution, and a roadside height position camera. A laser light irradiation unit that sequentially scans the linear visual field and radiates a laser beam, and an image processing unit that processes an output from the line sensor camera and detects a right-turn vehicle existing in the linear visual field. The image processing unit includes the position of the laser spot image on the line sensor camera obtained corresponding to the irradiation of the laser light when a vehicle is present on the right turn lane for each laser light scanning position. The position of the laser spot image on the line sensor camera, which is stored as the reference position data and is obtained in response to the scanning / irradiation of the laser light, is compared with the reference position data and there is a difference. The laser beam scanning position
Is detected, and the difference corresponds to the case where there is a vehicle making a right turn.
It is also configured to determine that there is a right-turn vehicle when it is within the predetermined range .

[0008]

In the first aspect of the invention, the right turn lane is irradiated with the laser light by the laser light irradiating means, and this is scanned in the lane direction. The laser light image forming position on the line sensor, which has a linear visual field in the region matched with the laser light scanning range, is a fixed position (reference position) when there is no vehicle at the scanning position.
Therefore, if there is a right-turning vehicle, the position is different, and if an image of a spot with the laser light is obtained at a position within a certain range different from the reference position, it is determined that the right-turning vehicle is at the laser light scanning position. Note that this determination can absolutely detect a right-turning vehicle that is stopped (presence operation).

In the second invention, the image processing section stores the position of the laser spot image on the line sensor camera corresponding to the case where the vehicle is on the right turn lane as reference position data. Then, the laser light irradiation means irradiates the right turn lane with laser light, and scans this in the lane direction. The laser light image forming position on the line sensor at this time is compared with the reference position, and if the difference is within a predetermined range, it is determined that there is a right-turn vehicle at the laser light scanning position. In other cases, that is, when the difference is outside the predetermined range, there is no vehicle or there is a straight ahead vehicle. Of course, this determination absolutely detects a vehicle that is turning right.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments with reference to the accompanying drawings. The right-turn vehicle detection device of the present invention uses a line sensor camera that uses a low-cost, high-resolution CCD line sensor, scans and irradiates infrared laser light along the right-turn lane, and forms a laser spot on the line sensor. The vehicle on the right turn lane (right turn vehicle) is absolutely detected by calculating the distance from the image position to the laser spot by a method similar to triangulation and comparing it with the reference value.

FIG. 1 is a schematic block diagram showing the configuration of a right turn vehicle detection apparatus according to an embodiment of the present invention. The right-turn vehicle detection device of FIG. 1 includes a line sensor camera 10 that captures a linear field of view that substantially matches the right-turn lane of an intersection from a high point on the roadside and outputs a luminance distribution. From a laser light irradiation unit 20 including a plurality of laser light irradiation devices, and an image processing unit 30 that processes the output from the line sensor camera 10 to detect a right-turn vehicle existing in the linear field of view (right-turn lane). It is configured. The line sensor camera 10 and the laser light irradiation means 20 are provided on the head (see FIG. 2).
It is housed together.

The line sensor camera 10 includes a lens 12 that is appropriately housed and fixed in a housing, a line sensor 13 disposed near the focal point of the lens 12, and a line signal reading circuit 14 that reads the photoelectric conversion result of the line sensor 13. It is configured. An infrared pass filter 11 is arranged in front of the lens 12 so as to remove visible light and increase the S / N ratio. The line sensor 13 senses an infrared ray and obtains an electric signal corresponding to the amount of light. For example, 5000 pixels are linearly arranged. High-resolution line sensors (one-dimensional elements) of this type are supplied at low cost.

In the line sensor camera 10, the photoelectric conversion field of view (imaging range) is a linear field of view and has no resolution in the pixel continuous direction and the orthogonal direction, and the image processing unit 30 described later is used.
From the read clock generation circuit 31 to the line signal read circuit 14
A voltage corresponding to the amount of light received by consecutive pixels is sequentially output in accordance with the synchronization signal input to. Line sensor camera 10
Is installed with the linear field of view aligned with the right turn lane.

The laser light scanning means 20 is a laser diode 21 which is controlled and driven by the image processing section 30 to generate laser light.
And a plurality of sets of light-transmitting lenses 22 (hereinafter, referred to as laser irradiators) for arranging the laser light into a predetermined beam.
In the figure, five laser irradiators are shown. The respective laser irradiators are installed so that the laser light irradiation positions are distributed along the above-described linear visual field on the right turn lane, and are sequentially driven. Therefore, the laser light irradiation means 20 sequentially scans and irradiates the laser light on the linear visual field.

The image processing section 30 includes the laser beam scanning means 20.
In addition to controlling and driving the
The part that processes the output from the above is entirely controlled by the CPU 35. The image processing unit 30 has a laser drive circuit 41 that drives the plurality of laser diodes 21, and is controlled by the CPU 35 to sequentially drive each laser diode 21 to sequentially monitor a predetermined position on the right turn lane. Are sequentially irradiated (scanned).

In the same image processing unit 30, a read clock generating circuit 31 for sending a read clock to the line sensor camera 10, and an output signal from the line sensor camera 10 (corresponding to a brightness level corresponding to the amount of light received for each pixel) A / D converter 32 for converting the generated voltage) into digital data, and a dual port RAM (DPR) 33 for temporarily holding the data group converted by the A / D converter 32. Dual port R
The data held in the AM 33 is fetched into the CPU 35 via the CPU bus as needed.

The CPU bus also has a clock circuit 36, RO
M37, RAM38, E to the line sensor camera 10
A D / A converter 39 for transmitting an E electronic aperture control signal is connected to exchange data with the CPU 35. Reference numeral 34 is a D / A converter, which can externally monitor the operation in an analog manner. In addition to the above, the CPU 35 has an input switch 40 for setting up at the start of operation and an output I / O (4) for outputting the output from the CPU such as parking vehicle detection information to the outside.
1) is connected. DC stabilized power supply 44
More power is being supplied.

Each of the above-mentioned parts is used by being fixed to an appropriate column provided near the intersection as shown in FIG. A head in which the line sensor camera 10 and the laser light irradiation means 20 are integrated is fixed to the upper portion of the column.
The line sensor camera 10 and the laser light irradiation means 20 are connected to an image processing unit 30 attached to the lower part of the support.

The line sensor camera 10 converts the luminance of the road portion, which is subdivided by being individually associated with the pixels along a predetermined length portion of the right-turn lane (a linear visual field in the lane direction), and outputs the voltage in order. become. That is, the line sensor camera 10 outputs the distribution of the brightness level for each minute portion of the linear visual field along the right turn lane. On the other hand, the laser light irradiation means 20 is installed so that its scanning range substantially coincides with the linear visual field, and sequentially irradiates a predetermined portion determined at appropriate intervals along the right turn lane with laser light. .

Then, in the image processing unit 30, the position of the image on the line sensor 13 obtained in response to the irradiation of the laser light when there is no right-turning vehicle in the right-turning lane is stored as a reference position (data). , The position of the image corresponding to the laser light sequentially obtained by scanning the laser light in a predetermined cycle is compared with the reference position, and if there is a difference, it is detected that there is a vehicle at the laser light scanning position, and this difference indicates that the vehicle is turning right. When it is within the predetermined range corresponding to the case where it exists, it is determined that there is a right-turn vehicle (first invention of the present application).

The principle of detection of a right-turn vehicle in this case will be described (see FIG. 3). The image formation position of the laser spot on the CCD line sensor by the laser scanning is different when the vehicle is making a right turn and when it is not.

When there is no vehicle in the right turn lane, the emitted laser light strikes the road surface A and becomes a laser spot.
An image corresponding to the laser spot on the road surface is formed at the position A '(reference position) on the line sensor Ls in FIG.
A high level signal is obtained from the corresponding pixel.

However, if there is a right-turning vehicle CA on the right-turning lane, the irradiated laser light hits the upper surface or the side surface of the right-turning vehicle CA and becomes a laser spot. The image corresponding to this laser spot is formed at the position B'on the line sensor Ls of FIG. 3, and a high level signal is obtained from the corresponding pixel. Therefore, it is possible to determine the presence / absence of a right-turn vehicle based on the difference in the image forming position (deviation amount Δd in FIG. 3).

The head height h = 10 m and Lg = 10 are calculated by the equation (1) in FIG. 3 to find how many pixels are different on the CCD line sensor between when the vehicle is actually turning right and when it is not. (M) = 100
0 (cm), Lc = 7 (m) = 700 (cm), a = 5
(Cm) and f = 2 (cm), Δd = (1 / 700-1 / 1000) 5 × 2 = 3/70
(Mm), and it can be seen that the image forming position is displaced by (3/70) mm. With a commercially available 5000-bit (pixel) CCD line sensor (length 30 mm), the amount of this deviation is
This corresponds to 7 pixels, and it can be seen that sufficient discrimination (detection) is possible.

Even when there is a straight ahead vehicle, the image forming position is still displaced from the reference position. However, in the case of a straight ahead vehicle, there is a larger deviation than the deviation due to the vehicle making a right turn, so it is easy to distinguish between the two. In addition, since a straight-ahead vehicle normally passes through an intersection without stopping, it can be distinguished from a right-turn vehicle based on a temporal characteristic.

To detect an actual right-turn vehicle, five laser irradiators share the right-turn lane and irradiate laser light.
The image-forming position (reference position: li in FIG. 5) on the line sensor when there is no vehicle due to the five laser spots generated by this is calculated in advance and stored as the position of the road surface. It suffices to monitor whether or not a high-level signal is obtained at the pixel corresponding to the position. If not, first determine that there is a right-turn vehicle or a straight-ahead vehicle,
Furthermore, if the amount of deviation is within a predetermined range, it may be determined that there is a right-turn vehicle.

FIG. 4 shows a timing chart of a series of operations. In the embodiment, each laser irradiator is irradiated with an intermittent pulse. For example, a laser beam of several 100 mW with a pulse width of 0.1 μsec is irradiated so as to form a spot light of several tens cm 10 m ahead. In this way, since the duty ratio is extremely small, there is no actual harm even if the laser light directly hits the skin or eyes of the human body.

As shown in (A), the laser drive signal is sequentially generated, and the five laser irradiators are sequentially driven at the scanning cycle T (for example, 1 second). That is, the right turn lane is scanned at the scanning cycle T. The first line sensor read out of T / 5 is to read the image forming position of the laser spot light, and the rest is the reset read operation of the line sensor.

When there is no right turn vehicle, etc. (FIG. 4 (B): CC
An image of a laser spot on the road surface is obtained by the line sensor in response to each scanning (see the read signal from the D line sensor). The position of the laser spot is compared with the stored reference position, and when there is no deviation or when the deviation amount is equal to or more than a predetermined value, it is determined that there is no right-turn vehicle. Similar comparisons are made for all zones and a final no right turn vehicle signal is issued if there is no right turn vehicle in any zone.

FIG. 4C shows an example of a read signal from the CCD line sensor when a right-turn vehicle is present. In this figure, a right-turn vehicle is present in the first and second zones, and a straight ahead vehicle is present in the fifth zone. Due to the presence of each vehicle, the image forming position of the corresponding laser spot on the line sensor is deviated from the reference position. Each position is compared with the stored reference position, and it is detected that a right-turn vehicle is present in the first zone and the second zone where the deviation is within a predetermined range (see FIG. 4 (E)). Although there is a deviation from the reference position in the fifth zone as well, it is determined that the vehicle is a straight ahead vehicle because there is a large amount of deviation, and it is determined that there is no right-turn vehicle.

When a right-turn vehicle is detected in any of the zones, a signal indicating that the right-turn vehicle is present is sent to the signal control device. The information on the presence / absence of the right-turn vehicle is reflected in the response control of the right-turn blue arrow signal.

In the embodiment, the sensitivity of the line sensor camera is automatically controlled so as to reflect the illuminance of the outside world and follow the illuminance change. That is, on the line sensor,
The EE point is set in advance, and the average value La of the brightness data at this point is calculated. The electronic aperture control value of the EE lens is calculated so that this value becomes the specified value, and the D / A conversion of FIG. 1 is performed. It outputs to the EE lens via the device 39.

As shown in FIG. 5, the window Dw
The average value La of the brightness values of the line sensor in the section is obtained, the binarization detection level T's is set to a value which is a constant value ΔT from this La, and the brightness value is determined by the binarization detection level T's. Is binarized to perform stable laser spot position detection that follows changes in illuminance in the external environment.

In addition to the structure shown in the embodiment, the laser light irradiating means includes a scan mirror which is rotatable so that only one laser irradiator can reflect the laser beam at an arbitrary angle. A configuration may be adopted in which the laser light itself is scanned by combining a galvano motor that rotates the scan mirror at a predetermined angle to scan the laser light, and the linear visual field can also be sequentially scanned and irradiated with the laser light.

The case where the image processing unit 30 stores the position of the laser spot image when there is no vehicle on the right turn lane as the reference position (first invention of the present application) has been described above. It is also possible to store the laser spot image position on the line sensor camera obtained corresponding to the irradiation of the laser light when is on the right turn lane (second invention of the present application).

That is, the right turn vehicle detection device of the second invention of the present application has the same structure as that of the first invention described above,
The image processing unit stores the laser spot image position on the line sensor camera obtained in response to the irradiation of the laser light when a standard vehicle is present on the right turn lane as the reference position, and the corresponding laser Compare the position of the laser spot image on the line sensor obtained in response to light scanning / irradiation with the reference position, and if the difference is within a predetermined range, determine that there is a right turn vehicle at the laser light scanning position. Has become. Since the processing and the like are very similar to those of the first invention and are easy to analogize, the description thereof is omitted.

[0037]

As described above, the vehicle detection device according to the first invention of the present application includes a line sensor camera that captures a linear field of view that substantially coincides with the right lane of an intersection from a roadside height position and outputs a luminance distribution, and a roadside camera. A laser light irradiating unit that sequentially scans the linear visual field from a location to irradiate a laser beam, and an image processing unit that processes an output from the line sensor camera and detects a right-turning vehicle existing in the linear visual field. And includes,
The image processing unit stores, for each laser beam scanning position, a position of a laser spot image on the line sensor camera obtained corresponding to the irradiation of the laser beam when a vehicle does not exist on the right turn lane as a reference position. The position of the laser spot image on the line sensor camera obtained in response to the scanning / irradiation of the laser light is compared with the reference position, and the difference is a predetermined value corresponding to the case where the vehicle is on the right turn lane. Since it is configured to detect that there is a right-turn vehicle at the laser light scanning position when it is within the range, it is suitable for use in right-turn sensitive control of intersection traffic lights, can be used day and night, and is low in price. It leads to promotion of dissemination. The absolute stop of the vehicle can be detected.

Further, the vehicle detection device of the second invention of the present application comprises substantially the same structure as that of the first invention described above, but the image processing unit has a vehicle on the right turn lane for each laser beam scanning position. The position of the laser spot image on the line sensor camera obtained in response to laser beam irradiation is stored as reference position data, and the laser on the line sensor camera obtained in response to laser beam scanning and irradiation is also stored. The position of the spot image is compared with the reference position data, and when the difference is within a predetermined range, it is detected that there is a right-turn vehicle at the laser light scanning position, and the effect is exactly the same as in the first invention. It can be used over a long period of time and is inexpensive, and can detect an absolute stop of the vehicle. Therefore, it is suitable for right turn sensitive control of an intersection traffic light.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a right turn vehicle detection device of the present invention.

FIG. 2 is a diagram illustrating an installation state of the right turn vehicle detection device of the present invention.

FIG. 3 is a diagram illustrating the principle of the right turn vehicle detection device of the present invention.

FIG. 4 is a timing chart illustrating the operation of the apparatus according to the embodiment.

FIG. 5 is a diagram illustrating a process of determining a laser spot image formation position of the apparatus according to the embodiment.

FIG. 6 is a diagram showing an example of an actual analog output for distance measurement obtained by the device of the embodiment, together with set values of the device.

[Explanation of symbols]

10 ... Line sensor camera, 20 ... Laser light irradiation means, 30 ... Image processing unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A 63-8898 (JP, A) JP-A 5-143887 (JP, A) JP-A 55-162200 (JP, A) JP-A 61- 278981 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G08G 1/04 G01S 17/88 G01V 8/10 G06T 1/00

Claims (2)

(57) [Claims] 1. A line sensor camera (10) that captures a linear field of view that is substantially aligned with the right-turning lane of an intersection from a high point on the roadside and outputs a luminance distribution, and sequentially scans the linear field of view from a high point on the roadside. Laser light irradiating means (20) for irradiating a laser beam with a laser beam, and an image processing unit (3) for processing an output from the line sensor camera (10) to detect a right-turn vehicle existing in the linear visual field.
0) and, the image processing unit (30), for each laser light scanning position, the line sensor camera (10 obtained in response to the irradiation of the laser light when there is no vehicle on the right turn lane The position of the laser spot image on the above is stored as a reference position, and the position of the laser spot image on the line sensor camera (10) obtained in response to scanning and irradiation of the laser light is compared with the reference position. If there is a difference, it is detected that there is a vehicle at the laser beam scanning position, and if there is a right-turn vehicle , the difference is detected.
It is determined that there is a right-turn vehicle when it is within the predetermined range corresponding to the case
A right turn vehicle detection device characterized by: 2. A line sensor camera (10) for imaging a linear field of view substantially coincident with the right-turning lane at an intersection from a high point on the roadside and outputting a luminance distribution, and sequentially scanning the linear field of view from a high point on the roadside. Laser light irradiating means (20) for irradiating a laser beam with a laser beam, and an image processing unit (3) for processing an output from the line sensor camera (10) to detect a right-turn vehicle existing in the linear visual field.
0) and, the image processing unit (30), for each laser light scanning position, the line sensor camera obtained corresponding to the irradiation of the laser light when the vehicle is on the right turn lane ( The position of the laser spot image on 10) is stored as reference position data, and the position of the laser spot image on the line sensor camera (10) obtained in response to the scanning / irradiation of the laser light is the reference position. Compared with the data, if there is a difference, the laser light
It is detected that there is a vehicle at the scanning position, and the difference is that there is a right-turn vehicle.
There is a right-turn vehicle when it is within the predetermined range corresponding to the case
Turn right, characterized in that determining that the vehicle sensing device.