JP2006251910A - Method and device for detecting preceding jam, and preceding jam sensitive control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for automatically and adequately detecting the occurrence of a preceding jam, and to provide its device and a preceding jam sensitive control system for appropriately performing signal control, based on the detection. <P>SOLUTION: The prescribed area of a vehicle inflow road to an intersection is photographed with a camera, so as to monitor the travelling condition of a plurality of vehicles existing on a straight lane in the prescribed area, based on the picture signal. When a stop continuing time period becomes prescribed time period concerning the whole vehicles, the occurrence of the preceding jam is determined. A green signal on the road direction concerned is eliminated, so as to reduce useless green signal time period. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and apparatus for detecting a jam at a signalized intersection, and a sensitive control system for controlling a traffic light in response to the occurrence of a jam.

Conventionally, traffic control systems have been introduced to facilitate and improve road traffic. For example, an ultrasonic vehicle detector (point sensor) is arranged at an upstream point of an intersection, and based on the traffic volume and time occupancy measured thereby, the flow of the vehicle at the intersection is estimated. Try to determine the allocation of time. There has also been proposed an apparatus that measures a traffic flow by image processing by photographing a vehicle inflow path to the intersection with a camera installed near the intersection (see, for example, Patent Document 1).
As signal control for changing the green signal time, for example, a control method is known in which the upper limit time of the green signal is increased in accordance with the traffic volume of the inflow path to the intersection and the number of waiting signals (for example, see Patent Document 2). In this case, since the green traffic time becomes longer as the traffic volume or the number of traffic signals waiting increases, the occurrence of traffic jams can be effectively prevented when the traffic volume in one direction is particularly large.

Japanese Patent No. 2917661 JP 2003-331385 A

  However, when a traffic jam occurs due to traffic demand exceeding the road capacity, road construction, a traffic accident, etc., and the traffic jam becomes a `` clogged '' state that extends to the vehicle outflow part at the upstream intersection, It is difficult to detect accurately based on information such as traffic volume at the upstream point of the intersection. In addition, when signal control based on traffic volume or the number of traffic lights is performed, the green light time will be longer even for a jammed state, and the green light will turn on unnecessarily for a long time, even though it cannot enter the intersection. There may be traffic jams in the lane.

  In view of the conventional problems as described above, it is an object of the present invention to provide a method and an apparatus for accurately automatically detecting that a clogging has occurred. It is another object of the present invention to provide a clogging sensitive control system capable of appropriate signal control based on the detection.

The clogging detection method of the present invention monitors the running status of a plurality of vehicles existing on a straight lane in a predetermined area in a vehicle inflow path to an intersection, and when the vehicle is stopped, the stop duration time is calculated. It is measured and it is determined that the clogging has occurred because the stop continuation time has reached a predetermined time for the plurality of vehicles.
Further, the pre-clogging detection device of the present invention includes a monitoring unit that monitors a traveling state of a plurality of vehicles existing on a straight lane in a predetermined area in a vehicle inflow path to an intersection, and when the vehicle is stopped, Measuring means for measuring the stop duration and determination means for determining that a clogging has occurred due to the stop duration reaching a predetermined time for the plurality of vehicles.
In the above-described pre-clogging detection method and apparatus, the clogging is detected when the stop continuation time has reached a predetermined time for a plurality of vehicles on the straight lane. Here, right turn vehicles that are not directly related to clogging are eliminated by targeting vehicles on the straight lane, and accidental stops of one vehicle are eliminated by targeting multiple vehicles. In addition, an instantaneous stop is eliminated by capturing an event that the stop duration reaches a predetermined time. As a result, it is possible to accurately detect clogging.

Further, in the above-described pre-clogging detection device, the monitoring unit may monitor a traveling state for a plurality of straight lanes within a predetermined area, and the measurement unit may measure a vehicle stop duration in the plurality of straight lanes. Good.
Here, when the straight lane is a straight / left turn lane, there is a possibility that the left turn vehicle may temporarily stop due to a pedestrian crossing or the like, so it is desirable to target a plurality of straight lanes. In this case, it is possible to accurately determine the clogging based on the continuation of the stop of each vehicle in a plurality of straight lanes.

Further, the jamming-sensitive control system according to the present invention includes a monitoring unit that monitors a traveling state of a plurality of vehicles existing on a straight lane in a predetermined area in a vehicle inflow path to an intersection, and when the vehicle is stopped. Measuring means for measuring the stop continuation time and determination means for outputting a clogging determination signal for stopping the blue signal when the stop continuation time reaches a predetermined time for the plurality of vehicles.
In the preload control system configured as described above, when the stop duration time reaches a predetermined time for a plurality of vehicles existing on the straight lane, a preload determination signal is output and the green signal is cut off. Green light time is reduced. Moreover, since such signal control can be performed without going through the central processing unit of the traffic control center, sensitive control based on the clogging determination can be realized even at a single control intersection that is not connected to the traffic control center.

Further, in the above-mentioned jamming-sensitive control system, the jamming judgment signal is output as a signal that does not sense the presence of the vehicle when the stop duration reaches a predetermined time even when the vehicle is present. There may be.
In this case, although the vehicle is present in the predetermined area at the time of the leading jam, a signal that does not sense the presence of the vehicle is output as the detection output signal (the leading jam determination signal) of the system. Therefore, by turning off the presence detection signal as the detection output signal, the general sensitivity control of the signal controller that cuts off the blue signal can be used as it is to perform the clogging sensitivity control. Here, it is not necessary to refer to the signal display state of the signal controller in the clogging determination, independent determination is possible, and the determination result can be output to the signal controller.

Further, in the above-mentioned jamming-sensitive control system, the jamming determination signal may be output regardless of the signal display state of the signal controller.
In this case, for example, since the vehicle is stopped at the stop line when the signal is red, when the stop continuation time reaches a predetermined time, it is determined that the vehicle is clogged even if it is actually clogged, Since the signal is red, it does not affect the operation of the signal controller. After that, even if the signal changes to blue, if a clogging has occurred, the green light is cut off after the traffic light is turned on with an initial green signal (usually longer than the stop duration). If there is no clogging, the vehicle that has stopped on the stop line during the initial green light starts immediately, so that the vehicle can travel without any trouble thereafter. If a preload occurs when the signal is blue, when the stop duration reaches a predetermined time, it is determined that there is a preload and the blue signal is cut off. In addition, when there is no clogging, the green light continues without being cut off, which can increase the traffic demand. In this way, it is possible to reduce useless green signal time based on the pre-clogging determination signal regardless of the signal display state of the signal controller.

Further, in the above-mentioned jamming-sensitive control system, the sensitivity control for the vehicle presence detection signal in the right-turning sensitivity control may be shared for the jamming determination signal.
In this case, since general sensitivity control can be used as it is for the clogging determination signal, it is convenient.

According to the pre-clogging detection method and apparatus of the present invention, it is possible to accurately and automatically detect that a clogging has occurred because a stop continuation time has reached a predetermined time for a plurality of vehicles existing on a straight lane. .
Further, according to the preload-sensitive control system of the present invention, when the stop duration time reaches a predetermined time for a plurality of vehicles existing on the straight lane, a preload determination signal is output and the blue signal is cut off. Green light time can be reduced. Further, by allocating the reduced green light time to the intersecting route, it is possible to alleviate the congestion of the intersecting route. That is, it is possible to accurately automatically detect the occurrence of the clogging and perform appropriate signal control based on the automatic detection.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preload detection method and apparatus and a preload detection control system according to an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view of an intersection with a traffic light 1. The signal device 1 is controlled by a signal controller 2. A pole 5 is installed on the sidewalk next to the stop line 4 in the vehicle inflow path 3 to the intersection, and an ITV camera (hereinafter referred to as a camera) 6 is attached to the top. A control unit 7 that performs processing described later based on a signal output from the camera 6 is attached to the bottom of the pole 5. The field of view of the camera 6 extends to all lanes of a road having, for example, four lanes, and a substantially rectangular predetermined area extending, for example, about 30 m in front of the stop line 4 is photographed as a measurement area A.

  FIG. 2 is a block diagram showing a device connected to the control unit 7 and a device configuration in the control unit 7. The control unit 7 includes an image input unit 71 that inputs an image signal acquired from the camera 6, a vehicle detection unit 72 that detects a vehicle from the image, a vehicle tracking unit 73 that tracks the detected vehicle, and a measurement processing unit. 74 and a clogging determination processing unit 75. The control unit 7 further includes a transmission unit 76 that transmits the output information of the measurement processing unit 74 to the traffic control center via a communication line, an output unit 77 that outputs an event detection signal, a warning command signal, and the like. And a power supply unit 78 to be supplied. The output unit 77 is connected to the signal controller 2. The main parts of the control unit 7 as a pre-clogging detection device are an image input unit 71, a vehicle detection unit 72, a vehicle tracking unit 73, and a clogging determination processing unit 75, which are measured when not communicating with the traffic control center. The processing unit 74 and the transmission unit 76 are not necessary.

The image input unit 71, the vehicle detection unit 72, and the vehicle tracking unit 73, together with the camera 6, monitor means for monitoring the traveling status of a plurality of vehicles existing in the measurement area A based on the image signal output from the camera 6. Is configured.
Specifically, the image input unit 71 includes M × M sample points in the transverse direction of the road and N sample points in the traveling direction of the vehicle so as to include all lanes of the road having four lanes. An image signal output from the camera 6 corresponding to N coordinates is taken in every fixed measurement cycle, and each luminance value is stored. The vehicle detection unit 72 performs feature extraction of the vehicle by performing image processing such as edge extraction on the sample point image every time an image signal is captured, and detects a vehicle head position and a body region candidate.

  The vehicle tracking unit 73 associates the vehicle candidate information in the current measurement cycle with the vehicle candidate information in the current measurement cycle from the information on the vehicle head position and the vehicle body area determined in the previous measurement cycle, and tracks each vehicle. In addition, the vehicle tracking unit 73 that also functions as a measurement unit divides the movement distance from the vehicle head position in the previous measurement cycle to the vehicle head position in the current measurement cycle by the measurement cycle to obtain the instantaneous speed. calculate. When the instantaneous speed is 0, that is, when the vehicle is stopped, the stop duration is measured. Further, the vehicle tracking unit 73 fully tracks the movement distance from the vehicle head position to the vehicle head position in the current measurement cycle that is tracked from the vehicle head position when the vehicle head is detected for the first time when the vehicle head position enters the measurement area A. Divide by elapsed time to find the average speed. When the vehicle reaches a sensing measurement position set in advance on the downstream side of the measurement region, the measurement processing unit 74 outputs the presence of the passing vehicle and the average speed as a traffic flow measurement result. The traffic flow measurement output information obtained by the measurement processing unit 74 is transmitted to the traffic control center via the transmission unit 76.

  Next, the operation of the clogging determination processing unit 75 as a determination unit will be described. Here, the basic idea of the clogging determination is that when no clogging occurs, all the vehicles existing in the straight lane in the measurement area A shown in FIG. 1 stop for a predetermined time or more despite the green signal. On the other hand, if a clogging occurs as shown in FIG. 4, the vehicle existing in the straight lane in the measurement area A can enter the intersection in spite of the green light. However, the state of the stop continues.

  Hereinafter, the operation of the clogging determination processing unit 75 will be specifically described with reference to the flowchart of FIG. In FIG. 3, the clogging determination processing unit 75 sets the number of vehicles tracked by the vehicle tracking unit 73 to N by the start of the determination operation, and further sets the initial values of P, Q, and R required for the following processing to 0. (Step S1). Next, in step S2, it is determined whether a vehicle exists, that is, whether N> 0. Here, if there is no vehicle, the process ends. On the other hand, when the vehicle exists, R is counted by 1 in step S3, and the first vehicle information among the tracked vehicles is read. Subsequently, in step S4, it is determined whether or not the first vehicle is on a straight lane. Here, when the vehicle is not on the straight lane (when the vehicle is on the right turn lane), the process jumps to step S9 to determine whether or not R = N, that is, the value of R has reached the number of vehicles tracked. Is called. If the value of R has not reached the tracked number of vehicles, the process returns to step S3. In step S3, the second vehicle information is read this time, and in step S4, it is determined whether or not the vehicle is on a straight lane. Similarly, steps S5 to S8 are not executed for vehicles that are not on the straight lane, and steps S5 to S8 are executed only for vehicles that are on the straight lane.

  In the case of a vehicle on a straight lane, P is counted by 1 in step S5. That is, P represents the number of vehicles determined to be on the straight lane. Next, in step S6, it is determined whether or not the Rth vehicle is a stopped vehicle. If it is not stopped, the process jumps to step S9. On the other hand, if the vehicle is a stopped vehicle, the process proceeds to step S7, and it is determined whether or not the stop duration time of the R-th vehicle has reached a threshold value. This threshold value is set to a predetermined time that is recognized as a stop continuation time due to clogging. If the threshold is not reached, the process jumps to step S9. On the other hand, when the stop duration has reached the threshold, Q is counted by 1 in step S8. That is, Q represents the number of vehicles whose stop duration has reached the threshold on the straight lane.

  The straight lane may be a single lane or a plurality of lanes. When there are a plurality of straight lanes as shown in FIG. 1, the vehicles in the plurality of straight lanes are to be tracked, and the stop duration is measured. Accordingly, it is possible to accurately determine the clogging based on the continuation of the stop of each vehicle in a plurality of straight lanes. When the straight lane is a straight / left turn lane, there is a possibility that the left turn vehicle may temporarily stop due to a pedestrian crossing or the like. Therefore, it is desirable to target a plurality of straight lanes.

  Thus, when the read vehicle information reaches the number of tracked vehicles, R = N, and the process proceeds to step S10. In step S10, P = Q, that is, it is determined whether or not all of the vehicles determined to be on the straight lane have reached the threshold value and have been stopped. If the determination is no, the process ends. That is, when no clogging has occurred, P = Q cannot be satisfied, and the determination is no. On the other hand, if the determination is yes, it is determined that there is a clogging in step S11, and the presence detection signal is turned off. As a result, the process ends. In other words, the vehicle actually exists in a stopped state due to clogging, but the presence detection signal is intentionally turned off.

As described above, it is possible to determine that the vehicle is clogged when the stop continuation time has reached a predetermined time for all of the plurality of vehicles existing on the straight lane. Here, right turn vehicles that are not directly related to clogging are eliminated by targeting vehicles on the straight lane, and accidental stops of one vehicle are eliminated by targeting multiple vehicles. In addition, an instantaneous stop can be eliminated by capturing an event that the stop duration reaches a predetermined time. As a result, it is possible to accurately detect clogging.
The steps up to here are the method for detecting the leading jam, and the operation of the leading jam detection device. Next, an operation as a clogging sensitive control system by the camera 6, the control unit 7, and the signal controller 2 will be described.

In general, traffic sensitivity control is performed based on a presence detection signal from a vehicle detector. For example, in the case of right turn sensitive control, the signal controller receives the presence detection ON signal detected by the vehicle detector while the vehicle is on the right turn lane, and extends the lighting time of the right turn blue arrow. On the contrary, when the vehicle no longer exists on the right turn lane, the presence detection off signal is received from the vehicle detector and the right turn blue arrow is terminated. In the same way as in the case of the preloading sensitivity control system, if the preload detection signal is used as the presence detection on / off signal, the general control of the signal controller that cancels the green signal without detecting the presence of the vehicle remains unchanged. It can be used (shared) to perform the clogging sensitivity control. That is, it is convenient because general sensitivity control can be used as it is for the clogging determination signal.
Therefore, when the presence detection signal is turned off in the clogging determination processing unit 75, the output unit outputs the presence detection off signal to the signal controller 2. As a result, the signal controller 2 stops the green signal and reduces the unnecessary green signal time. Further, by allocating the reduced green light time to the intersecting route, it is possible to alleviate the congestion of the intersecting route.

  That is, the control unit 7 outputs the presence detection ON signal while the vehicle is traveling in the measurement area A. Even if the vehicle stops, it does not change that it is present, so a presence detection ON signal is output. However, when there are vehicles on the straight lane and the stop duration time of all of these vehicles reaches a predetermined time, the straight blue signal is cut off by transmitting a presence detection off signal to the signal controller 2. . In this way, it is possible to eliminate the inconvenience that the green light time is reduced by abruptly judging that it is a clogging by waiting for a predetermined time and determining that it is clogging. For example, even at the timing when the clogging has started to be resolved on the vehicle outflow path from the intersection, the driver recognizes the clogging with the vehicle stopped for a while and then slightly (several seconds) before starting the vehicle. Even in such a case, if the time delay is within the predetermined time, the green signal is not interrupted and the vehicle can start.

For example, when the signal is red, the vehicle is stopped at the stop line 4 by performing the above-described control for detecting the leading end, so that when the stop duration reaches a predetermined time, the leading end may not be stopped. Is detected and the vehicle is present, but the presence detection signal is turned off. This presence sensing signal does not affect the operation of the signal controller because the signal is red. After that, if there is a clogging even if the signal turns blue, the initial blue signal (usually longer than the stop duration) is lit on the traffic light 1 and then the blue signal is cut off because the presence detection signal is off. It is done. When there is no clogging, the vehicle that has stopped at the stop line 4 during the initial green light starts to start immediately, and thereafter, the presence detection is turned on and the vehicle can travel. When a clog occurs when the signal is blue, when the stop duration reaches a predetermined time, it is determined as a clog, the presence detection signal is turned off, and the signal changes from blue to red. When there is no clogging, the green light continues and traffic demand can be increased.
In this way, by transmitting the presence detection on / off signal from the control unit 7 to the signal controller 2 regardless of the signal display state of the signal apparatus 1 and the signal controller 2 that controls the signal apparatus 1, a useless blue signal is obtained. Time can be saved.

In the above embodiment, the clogging determination process is performed in the control unit 7. However, this is not necessarily performed in the control unit 7, and may be performed in the signal controller 2, the traffic control center, or other devices. Good. Moreover, the functional means of each part in the control part 7 can be arrange | positioned in another apparatus, without being restricted by the frame called the control part 7. FIG.
Moreover, the threshold value of the stop duration used in the above determination condition may be set to a fixed time, or may be set individually for each point and for each lane.
Further, in the above embodiment, it is determined that the clogging has occurred because the stop state continues for all the vehicles existing in the straight lane in the measurement area A. A determination not limited to “vehicle” is also possible. For example, assuming that there are n vehicles per one straight lane in the measurement area A, it is determined that the clogging has occurred because m vehicles (m <n) from the top continue to be stopped. It is also possible.

In the above embodiment, the vehicle traveling state is monitored based on the image signal output from the camera 6. However, instead of the camera 6, a plurality of vehicle detectors (for example, ultrasonic vehicle detection) are provided for each lane. Or a microwave type vehicle sensor) may be arranged in the vehicle traveling direction. However, in this case, one vehicle is not always recognized separately from other vehicles. In the case where they are not recognized separately, the “vehicle” to be sensed is not a single vehicle but several vehicles. And it can detect that the vehicle has stopped because the state which has detected the existence of some vehicles with the vehicle detector for every lane does not change for a definite period of time. Further, if the stop continuation time reaches a predetermined time, it can be determined that a clogging has occurred.
On the other hand, for example, if a sensor array is configured by arranging a number of vehicle detectors having a narrow detection area relative to the total length of the vehicle for each lane so that adjacent detection areas do not overlap, the output of each vehicle detector can be obtained. By synthesizing, it is possible to recognize one vehicle separately from other vehicles.

It is a perspective view of an intersection with a traffic light. It is a block diagram which shows the apparatus connected to the apparatus connected to a control part, and a control part. It is a flowchart of the process performed in the clogging determination process part in a control part. It is a perspective view which shows a state when a clogging generate | occur | produced in the intersection of FIG.

Explanation of symbols

2 Signal Controller 3 Vehicle Inflow Path 6 ITV Camera 7 Control Unit 71 Image Input Unit 72 Vehicle Detection Unit 73 Vehicle Tracking Unit 75 Point Clogging Determination Processing Unit A Measurement Area (Predetermined Area)

Claims (7)

Monitoring the driving situation of a plurality of vehicles existing on a straight lane in a predetermined area in the vehicle inflow path to the intersection,
When the vehicle is stopped, measure the stop duration,
A pre-clogging detection method, wherein it is determined that a clogging has occurred due to the stop duration time reaching a predetermined time for the plurality of vehicles. Monitoring means for monitoring the traveling status of a plurality of vehicles existing on a straight lane in a predetermined area in the vehicle inflow path to the intersection;
A measuring means for measuring the stop duration when the vehicle is stopped;
A pre-clogging detection device comprising: a determination unit that determines that clogging has occurred due to the stop continuation time reaching a predetermined time for the plurality of vehicles.   The clogging detection device according to claim 2, wherein the monitoring unit monitors the traveling state of a plurality of straight lanes in the predetermined area, and the measurement unit measures a stop duration time of the vehicle in the plurality of straight lanes. Monitoring means for monitoring the traveling status of a plurality of vehicles existing on a straight lane in a predetermined area in the vehicle inflow path to the intersection;
A measuring means for measuring the stop duration when the vehicle is stopped;
A pre-clogging sensitive control system, comprising: a judging unit that outputs a clogging judgment signal for cutting off a green signal when a stop continuation time reaches a predetermined time for the plurality of vehicles.   The pre-clogging sensitive control system according to claim 4, wherein the clogging judgment signal is output as a signal that does not sense the presence of the vehicle when the stop continuation time reaches a predetermined time even when the vehicle is present.   5. The pre-clogging sensitive control system according to claim 4, wherein the clogging judgment signal is output regardless of a signal display state of the signal controller.   5. The leading jam sensing control system according to claim 4, wherein the sensing control for the vehicle presence sensing signal in the right turn sensing control is shared with the leading jam judgment signal.

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