JPH11353584A - Traffic signal controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-precision traffic signal controller capable of predictive control based on a vehicle traffic state. SOLUTION: Cameras 211 to 214 pick up the number Wn of vehicles 3, which stop in the rear of stop lines 221 to 224 set on intersection entrance roads R1 to R4, on a plane and output their picture signals. A signal processor 1 obtains the number Wn of stopping vehicles 3 from picture signals supplied from cameras 211 and 214, and a green time Tg of signals 41 to 44 is extended by a unit extension time T1 if the number Wn of stopping vehicles 3 exceeds a threshold Wtm, and the green time Tg of the signal 41 which controls traffic in the intersection entrance road R1 is shortened by the unit extension time T1 if the number Wn is smaller than the threshold Wtm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a traffic signal control device.

[0002]

2. Description of the Related Art Traffic signal control systems at intersections are roughly classified into point traffic signal control systems and centralized traffic signal control systems. As point traffic signal control systems, there are a fixed period control system and a point sensitive control system. Are known.

The fixed-period control method is mainly used independently of a traffic control center at an independently controlled intersection, and prepares several time tables for setting a signal time based on a local traffic condition survey made in advance. A morning switch, a daytime pattern, a nighttime pattern, and the like are selected by a time switch. The problem with this fixed-cycle control method is that the time table is created in advance based on a local traffic situation survey performed by a person, and the control pattern is switched by a time switch, so that the actual traffic that changes Inability to cope with the situation, inability to follow changes in traffic conditions over time, and the like. As a result, a long green indication time may be given in a direction in which no vehicle arrives, a signal switching cycle may be short in spite of a heavy traffic, or a time ratio of a green indication given between roads in a master-slave relationship may be inappropriate. This causes a drawback that it becomes dull.

In the point-sensitive control system, a vehicle sensor is installed at each inflow channel at an intersection where traffic fluctuations are severe, that is, at an intersection where traffic demand on the main and subordinate roads is unpredictable, and in response to a gap time of the vehicle, It is to extend the blue presentation time. This traffic signal control method uses the actual traffic entity,
It can be reflected in traffic control. However, when the traffic volume increases, both the main and subway roads operate with the extension limit time, so that the operation is the same as that of the periodic control method, and the problem described in the periodic control method becomes apparent. When the fixed-cycle control method is entered, the vehicle driver says, "If the green time of the secondary road is extended for another 5 seconds, the secondary road will not be difficult and crowded."
Such a simple question arises.

In the centralized control system, a signal control device is connected to a control center using a communication line such as a telephone line.
Centralized control of the signal time is performed remotely, and system control with an adjacent intersection or the like or macro control that reflects the traffic situation in the control area is performed. Micro-control at each intersection extends or shortens the blue-indicating time in response to vehicles entering each of the inflows at the intersection. Therefore, in a critical situation that causes traffic congestion, the same problem as in the point-sensitive control method. Produces a point.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a traffic signal control device capable of performing highly accurate and reliable signal control at an intersection.

Another object of the present invention is to provide a highly accurate and highly reliable traffic signal control device capable of performing predictive control based on a vehicle traffic condition.

[0008]

In order to solve the above-mentioned problems, a traffic signal control device according to the present invention includes a camera and a signal processing device. The camera takes a planar image of the number of stopped vehicles that are stopped behind a stop line set on the intersection inflow road, and outputs an image signal thereof.

[0009] The signal processing device is supplied with the image signal from the camera, determines the number of stopped vehicles from the image signal, and when the number of stopped vehicles is larger than a predetermined threshold number, The green time of the traffic light controlling the traffic on the intersection inflow is extended by a unit time, and if the number of stopped vehicles is less than the threshold number, the green time of the traffic light controlling the traffic on the intersection inflow is united. Reduce time.

[0010] In the traffic signal control device according to the present invention,
The camera includes a camera, and the camera captures a planar image of the number of stopped vehicles that are stopped behind a stop line set on the intersection inflow road, and outputs an image signal of the image. Therefore, on the inflow path to the intersection, the number of stopped vehicles stopped behind the stop line can be grasped in a two-dimensional manner.

The signal processing device is supplied with an image signal from the camera, determines the number of stopped vehicles from the image signal, and, if the number of stopped vehicles is larger than a preset threshold number,
The green time of the traffic light controlling the traffic of the intersection inflow road,
Extend unit time. As a result, accumulation of remaining vehicles can be prevented, and traffic congestion can be avoided.

When the number of stopped vehicles is smaller than the threshold number, the signal processor reduces the green time of the traffic light controlling the traffic on the intersection inflow by a unit time. Therefore,
Eliminating the waste of continuing to spend time without a vehicle,
In the other intersection inflow road, the red time for vehicle traffic can be reduced, and traffic congestion can be avoided.

Other objects, configurations and advantages of the present invention will be described in detail below with reference to the accompanying drawings which are embodiments.

[0014]

FIG. 1 is a diagram schematically showing a configuration of a traffic signal control device according to the present invention. Referring to the drawing, a traffic signal control device according to the present invention includes a signal processing device 1.
And cameras 211 to 214. The embodiment shows an example in which the present invention is applied at the crossroads CR.
Cameras 211 to 214 are individually arranged for each of the four inflow paths R1 to R4.

The cameras 211 to 214 are provided with inflow paths R1 to R
4, the number Wn of the stopped vehicles 3 stopping behind the stop lines 221 to 224 is imaged in a plane, and the image signal is output.

A typical example of the cameras 211 to 214 is a CCD.
Camera. The cameras 211 to 214 are provided with
It is arranged at an appropriate height position so as to face the stopped vehicle 3 flowing into the intersection CR through R4. Camera 2
The imaging area by 11 to 214 is set by one camera so as to cover, for example, an area with a road length of 20 to 25 m. The imaging area having such an area includes cameras 211 to 21.
4 can be obtained by setting it at a height of about 5 m from the ground.

Considering the capabilities of current cameras, the area (length) that can be covered by one camera is limited to about 25 m. If an attempt is made to cover an area larger than this, individual positions of the stopped vehicle 3 cannot be individually measured. When the resolution of the camera is improved, the area that can be covered by one camera naturally extends to more than 25 m.

The cameras 211 to 214 are provided with inflow paths R1 to R
4, the camera 211 provided in the inflow path R1 will be representatively referred to below. The camera 211 images an area including the vehicle stop line 221. Although only one camera 211 is shown in the figure, more cameras may be provided at intervals. Thereby, the area that can be covered by the entire camera can be enlarged.

FIG. 2 shows a camera 21 in the inflow path R1.
1 is a diagram schematically showing a state of a stopped vehicle 3 imaged by 1. In the figure, the inflow path R1 has three lanes La1 to La.
3 is illustrated. Lanes La1-L
a3 is set in the horizontal axis direction, and the inflow path R is set in the vertical axis direction.
One length direction is taken. The imaging area shown is
It covers a length Xm = 25 m and is divided into lengths L1 to L5 in units of X1m = 5 m. The lane La1 is divided into five cells L11 to L15. The lane La2 is also divided into five cells L21 to L5, and the lane La3 is also divided into five cells L21 to L5.
Cells L31 to L35. From the number of vehicles stopped in these cells L11 to L35, the number Wn of stopped vehicles 3 is detected. In the example of FIG.
a1 includes three stopped vehicles 311 to 313, lane La2 includes two stopped vehicles 321 and 322, and lane La3 includes two stopped vehicles 331 and 312.
32, and the number of stopped vehicles 3 is Wn = 7.

The means for detecting the stopped vehicle 3 includes detecting the stopped vehicle 3 by comparing the road luminance pattern and the vehicle luminance pattern in the daytime, and detecting the vehicle by the headlight luminance pattern pair of the stopped vehicle 3 in the nighttime. Can be.

As another means, a light emitting element may be individually provided in each of the cells L11 to L35. According to such a configuration, the number Wn of the stopped vehicles 3 can be detected by the camera 211 with a probability of almost 100% as the interruption of the light emitting element.

The signal processing device 1 is supplied with an image signal from the camera 211 and, based on the image signal, determines the number Wn of stopped vehicles 3.
When the number Wn of the stopped vehicles 3 is larger than the preset threshold number Wtm, the green time Tg of the traffic light 41 controlling the traffic on the inflow path R1 is extended by the unit extension time T1. As a result, accumulation of remaining vehicles can be prevented, and traffic congestion can be avoided.

The signal processing device 1 determines the number Wn of stopped vehicles 3
Is smaller than the threshold number Wtm, the inflow path R1
The green time Tg of the traffic light 41 for controlling the traffic is reduced by the unit extension time T1. Therefore, it is possible to eliminate waste such as continuing the blue time even when there is no vehicle, and to shorten the red time Tr at the other intersection inflow roads R3 and R4, thereby avoiding traffic congestion.

FIG. 3 is a diagram exemplifying the relationship between the signal display of the traffic signals 41 to 44 and the number of stopped vehicles Wn, and FIG. 4 is a flowchart showing the processing in the signal processing device 1. In FIG. 3, the signal indications of the traffic lights 41 and 42 become blue (G) at t0. Since the operations of the traffic lights 41 and 42 are completely the same, the traffic light 41 will be representatively described below.

In the signal processing device 1, the initial green time T0
Is determined. When the initial green time T0 has not elapsed, the progress of the initial green time T0 is continuously monitored. In the case of FIG. 3, it is determined that the initial green time T0 has elapsed at the time t1 when the initial green time T0 has elapsed from the time t0.

When it is determined that the initial green time T0 has elapsed, it is determined whether or not the camera 211 monitoring the inflow path R1 has vehicle sensitivity. In the case of the example of FIG. 3, at the time t1, the stopped vehicle 3 disappears in the inflow path R1 controlled by the traffic light 41 and the vehicle becomes insensitive to the inflow path R1 (N), so that after the initial green time T0 has elapsed. t1
At times, the signal indication of the traffic light 41 changes from blue (G) to yellow (Y).

On the other hand, when there is a vehicle response,
That is, when there is a remaining vehicle after the elapse of the initial green time T0, a unit extension green time T1 is added to the initial green time T0, and the green time is extended from the initial green time T0 to (T0 + T1). Then, it is determined whether or not the extended green time (T0 + T1) has elapsed. If it is determined that the extended green time (T0 + T1) has not elapsed, the green time is extended. When it is determined that the extended blue time (T0 + T1) has elapsed, the signal indication of the traffic light 41 changes to yellow (Y) and red (R).
become.

The signal indication of the traffic light 41 is red (R) at t2 when a predetermined time given to the yellow (Y) signal indication has elapsed.
, And the number of stopped vehicles 3 in the inflow path R1 controlled by the traffic light 41 increases with time.

The red (R) signal display of the traffic light 41 continues from t2 to t4, and switches to blue (G) from t4. Between the time t1 and the time t4, the number Wn of the stopped vehicles 3 accumulated by the stop line 221 is determined by the camera 21
1 and an image signal is supplied to the signal processing device 1. The signal processing device 1 obtains the number Wn of the stopped vehicles 3 from the image signal. And the number W of stopped vehicles 3
n and a predetermined threshold number Wtm,
If Wn> Wtm, the green time Tg of the traffic light 41 controlling the traffic on the inflow path R1 is extended by the unit extension time T1. In the case of FIG. 3, the number of stopped vehicles Wn accumulated during the red (R) signal presentation from t2 to t4 is greater than the threshold number Wtm, and the blue time is
The unit is extended by the unit extension time T1 from t5 to t6 when the initial green time T0 ends. In the case of FIG. 3, the unit extension time T
The case where the stopped vehicle 3 becomes zero as a result of extending by one is shown. As a result, accumulation of remaining vehicles can be prevented, and traffic congestion can be avoided.

The extension of the unit extension time T1 is as follows: Wn> Wtm
Are repeatedly executed until the condition is not satisfied. If Wn> Wtm continues for more than the basic extension time limit Tex given in one lock-in cycle, the basic extension time limit EX1 is further extended by the unit extension time T1. Then, the basic extension limit time EX1 is compared with the sum of the unit extension time T1 (Tex + T1) and the maximum extension limit time Tm. If (Tex + T1)> Tm is not satisfied, the blue time is extended by the unit extension time T1, and then the signal indication of the traffic light 41 controlling the inflow path R1 is switched from yellow (Y) to red (R). If (Tex + T1)> Tm holds, the unit extension time T1 is not added,
The signal indication of the traffic light 41 is switched to red (R) via yellow (Y). The lock-in cycle is defined as Wn> Wtm
Means a processing cycle.

When Wn> Wtm no longer holds,
The number Wn of stopped vehicles in the inflow path R1 is equal to the minimum threshold value WtL.
It is determined whether it is smaller than. If Wn <WtL is satisfied and it continues for one lockout cycle or more, the signal extension of the traffic light 41 is switched to red (R) via yellow (Y) by reducing the unit extension time T1.

When Wn <WtL does not hold, and when W
If n <WtL holds but does not continue for one lockout cycle or more, the signal indication of the traffic light 41 is changed to yellow (Y) and red (R) without shortening the unit extension time T1.
Switch to

Although the description is omitted, the inflow paths R1 to R4R2
Is also controlled in the same manner as the traffic light 41.
The control timing theory of the traffic light 41 described above is applied to the control timing of the traffic lights 43 and 44 provided in the inflow paths R1 to R4.

[0034]

As described above, according to the present invention, the following effects can be obtained. (A) It is possible to provide a traffic signal control device capable of performing high-precision signal control at an intersection. (B) It is possible to provide a high-precision traffic signal control device capable of performing predictive control based on vehicle traffic conditions.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of a traffic signal control device according to the present invention.

FIG. 2 is a diagram schematically showing a state of a vehicle captured by any of the cameras in any of the inflow paths.

FIG. 3 is a diagram exemplifying a relationship between a signal display of a traffic light and the number of stopped vehicles.

FIG. 4 is a flowchart showing processing in the signal processing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Signal processing device 211-214 Camera 41-44 Traffic light 3 Vehicle 311-313 Vehicle 321 322 Vehicle 331, 332 Vehicle R1-R4 Inflow route CR intersection

Claims (1)

[Claims] 1. A traffic signal control device including a camera and a signal processing device, wherein the camera planarly counts the number of stopped vehicles stopped behind a stop line set at an intersection inflow path. Imaging, and outputting the image signal, the signal processing device is supplied with the image signal from the camera, obtains the number of stopped vehicles from the image signal, the number of stopped vehicles is a preset threshold number of vehicles If the number is more, the green time of the traffic light controlling the traffic on the intersection inflow is extended by a unit time, and if the number of stopped vehicles is less than the threshold number, the traffic light controlling the traffic on the intersection inflow is extended Traffic signal control device that shortens the green time of a unit time.