JP2015032153A - Control device for vehicle detection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a vehicle detection sensor using a light emitter and receiver to appropriately detect a vehicle by distinguishing from an obstacle.SOLUTION: A control device for vehicle detection comprises: a receiving part for receiving a detection signal from a vehicle detection sensor equipped with a plurality of light emitters and receivers; and a light-shielding cause determination part for starting light-shielding cause determination processing when it detects according to the detection signal the occurrence of at least one long-period light-shielding region with a period when the light is shielded exceeding the first threshold. The light-shielding cause determination part outputs vehicle determination information indicating the presence of a vehicle when the light is shielded in both of two light emitters and receivers adjacent to both sides of the long-period light-shielding region, among the plurality of light emitters and receivers.

Description

  The present invention relates to control of a device that detects a vehicle at a tollgate or the like.

  In facilities such as toll gates on toll roads, vehicle detection sensors are installed to detect the passing, entering, and leaving of vehicles. As an example of the vehicle detection sensor, an apparatus using a light projecting / receiving device may be mentioned. The projector / receiver is composed of a projector and a receiver installed on both sides of the lane. When there is no vehicle in the lane, the light beam output from the projector is detected by the light receiver. In this case, the vehicle detection sensor determines that there is no vehicle. When there is a vehicle in the lane, the light output from the projector is blocked by the vehicle and is not detected by the light receiver. In this case, the vehicle detection sensor determines that the vehicle exists.

  Hereinafter, the background art of the present invention will be described with reference to specific examples of the vehicle detection sensor. 1 to 4 are drawings showing background art (a reference technique for facilitating understanding of the present invention, and not necessarily a known technique). FIG. 1 is a perspective view showing an example of the vehicle detection sensor 2. The vehicle detection sensor 2 includes a first housing 3 and a second housing 4 that are respectively installed on both sides in the width direction across the lane R. A plurality of light projectors 5 are arranged in the first casing 3 side by side in the vertical direction.

  FIG. 2 is a front view of the second casing 4. A plurality of light receivers 6 are installed in the second casing 4 in the vertical direction. The plurality of light projectors 5 and the plurality of light receivers 6 are provided in a one-to-one correspondence with the optical axis of the light beam 7. That is, a pair of projectors 5 and light receivers 6 arranged at the same height constitute one projector / receiver.

  In each projector / receiver, a light beam 7 such as an infrared ray output from the projector 5 is detected by the receiver 6. When the light beam 7 output from the projector 5 is blocked by the vehicle 1 on the lane R, the light receiver 6 does not detect the light beam 7. The projector / receiver in such a state is hereinafter referred to as a “light-shielding optical axis” in the sense that the light beam 7 is blocked at any position on the optical axis. In the example of FIG. 2, a part of the lower side of the projector / receiver is shielded by the vehicle 1. As a result, among the plurality of light receivers 6, the light-shielded light receiver 6-1 does not detect the light beam 7.

  Each of the plurality of light receivers 6 outputs a detection signal indicating whether or not a light beam has been detected to the vehicle detection control device 8. The first casing 3, the second casing 4, and the vehicle detection control device 8 constitute a vehicle detection system. The vehicle detection control device 8 determines whether or not the vehicle 1 has been detected based on the detection signals received from each of the plurality of light projecting and receiving devices, and the determination result is sent to a host device such as a lane server or a toll booth. Output to a monitoring panel installed in

  In the example of FIGS. 1 and 2, the projector 5 is provided in the first casing 3 and the light receiver 6 is provided in the second casing 4. For example, the projector 5 and the light receiver 6 may be provided alternately on the first housing 3. In that case, the light receiving device 6 and the light projecting device 5 are alternately provided in the second housing 4 so as to form the light projecting device 5 and the light receiving device 6 of the first housing 3 and the light projecting and receiving device.

  In FIG. 1, the vehicle detection control device 8 is housed in a separate housing from the first housing 3 and the second housing 4 and installed on a roadside island. However, the vehicle detection control device 8 may be installed inside either the first housing 3 or the second housing 4, or may be installed inside a device such as a lane server.

  In such a vehicle detection sensor 2, there may be a case where an obstacle (snow, dust, insects, etc.) adheres to the projector 5 or the light receiver 6. FIG. 3 shows a state in which an obstacle 9 is attached to one of the light receivers 6 and the light receiver 6 is shielded from light. In such a situation, even if the vehicle 1 is not present in the lane R, the light receiver 6 outputs a signal indicating that the light beam 7 is blocked. As a result, the vehicle detection sensor 2 may detect the presence of the vehicle 1 by mistake. A technique for avoiding such erroneous detection is desired.

  In order to distinguish between the vehicle 1 and the deposits such as dust, a method of determining based on the time during which the light beam 7 is shielded can be considered. A vehicle 1 such as a toll gate moves from the upstream side of the lane R to the downstream side. Therefore, the vehicle 1 detected by the vehicle detection sensor 2 is considered to run away from the vehicle detection sensor 2 after a certain amount of time. On the other hand, when the obstacle 9 adheres to the projector 5 or the light receiver 6, the light may be blocked for a long time.

  FIG. 4 shows an example of an obstacle determination method executed by the vehicle detection control device 8 based on the light blocking time of the light beam 7. When the vehicle detection sensor 2 is performing the vehicle detection operation, it is assumed that at any point in time, any of the plurality of light receivers 6 has detected the light beam 7 being blocked (step S101). When the light shielding is detected, the measurement of the time Ton during which the light shielding continues from that time is started (step S102).

  When the number of light-shielding optical axes indicating the number of light-emitters / light-receiving units that have detected light shielding among a plurality of light-emitters / receivers included in the vehicle detection sensor 2 is equal to or less than a preset value N (N is an integer of 1 or more). In step S103, a standby process is performed. If the number of light-shielding optical axes exceeds N (step S103 Yes), it is determined that the vehicle 1 has entered (step S104), the vehicle detection signal is turned on and output to the vehicle detection control device 8 (step S105). .

  Next, in order to determine the cause of light shielding, the light shielding time Ton is compared with a preset threshold value Tsh (for example, stored in the storage device of the vehicle detection control device 8). When the light blocking time Ton is less than or equal to the threshold value Tsh (step S106 No), the number of light blocking optical axes of the vehicle detection sensor 2 is confirmed (step S107). If the number of light shielding optical axes is not zero, that is, if any one of the light receivers 6 detects light shielding, the process returns to step S106 (No in step S107). If the number of light-shielding optical axes is zero (Yes in step S107), the light beam 7 of the light-shielding optical axis can be detected within a relatively short time (Tsh or less), and it is determined that the cause of light shielding is not an obstacle. . In this case, it is determined that the vehicle has exited and the light shielding optical axis has become zero (step S108), the vehicle detection signal is turned off, and the vehicle detection signal is output to the vehicle detection control device 8 (step S109).

  In step S106, when the light shielding time Ton exceeds the threshold value Tsh, the optical axis is determined to be the light shielding optical axis for a long time (step S110). It is considered that an obstacle such as dust is blocking the light beam 7 instead of the vehicle 1 in the long-time light blocking optical axis. In this case, the corresponding sensor optical axis is disconnected (step S111). In other words, the vehicle detection control device 8 outputs an identifier for identifying the projector / receiver determined as Ton> Tsh to a higher-level device such as a lane server, and outputs the detection signal of the projector / receiver to the subsequent vehicle detection. Is set not to be used. Thereafter, the vehicle detection control device 8 turns off the vehicle detection signal. The host device determines that the vehicle 1 does not exist in the lane R by turning off the vehicle detection signal (step S112).

  By the above processing, when the light beam 7 of the light projecting / receiving device is blocked for a long period of time, it is determined that the obstacle 9 is not the cause, not the vehicle 1. Therefore, it is possible to appropriately detect the vehicle by distinguishing it from the obstacle.

  Patent Document 1 shows an example of a vehicle detector using a projector / receiver.

Japanese Patent Laid-Open No. 10-334294

  However, when applied to a toll booth where there is a lot of traffic, the reference technology described above has room for further improvement in detection accuracy. When the traveling speed of the vehicle is slow due to traffic congestion or the like, the vehicle 1 may be blocking the light beam of the vehicle detection sensor 2 for a relatively long time. In such a case, in the vehicle detection method shown in FIG. 4, there is a possibility that the vehicle 1 is erroneously determined to be the obstacle 9.

  In the reference technique, if the threshold value Tsh is set to a very long value, it is possible to prevent the vehicle 1 from being erroneously determined to be the obstacle 9 even in a traffic jam. However, in such a case, if two vehicles are traveling close to each other with a short inter-vehicle distance, there is a possibility that billing processing for the second vehicle cannot be performed. Therefore, it is not desirable to set the threshold value Tsh to a very long value.

  Even when the flow of the vehicle 1 is slow as in the case of traffic congestion, a technique that can more accurately identify the vehicle 1 and the obstacle 9 is desired.

  In one aspect of the present invention, the vehicle detection control device includes: a vehicle detection sensor in which a plurality of light projectors and light receivers that detect light beams output from the light projectors are arranged in a vertical direction; And a receiving unit that receives a detection signal indicating whether or not the light receiver has detected a light beam, and based on the detection signal, the light is blocked for a long time at least at one place where the time exceeds the first threshold A light-shielding cause determination unit that starts a light-shielding cause determination process when it is detected that a region has occurred. The light-shielding cause determination unit determines whether the light beam is shielded by both of two adjacent projectors / receivers adjacent to both sides of the long-time light-shielding region among the plurality of projectors / receivers in the light-shielding cause determination process. The vehicle determination information indicating that is present is output.

  In another aspect of the present invention, a vehicle detection method includes: a vehicle detection sensor in which a plurality of light projectors and light receivers that detect light beams output from a light projector are arranged in a vertical direction; A step of receiving a detection signal indicating whether or not the light receiver has detected a light beam; and at least one long-time light-shielding region where the time during which the light beam is shielded exceeds a first threshold based on the detection signal. And a step of starting a light shielding cause determination process when it is detected that the occurrence has occurred. The step of starting the light shielding cause determination process is that the vehicle is present when the light beam is shielded by both of the plurality of light projecting / receiving devices that are adjacent to both sides of the light shielding region for a long time. Outputting vehicle determination information indicating that.

  According to the present invention, there is provided a technique capable of appropriately detecting a vehicle by distinguishing it from an obstacle in a vehicle detection sensor using a projector / receiver.

FIG. 1 is a perspective view of a vehicle detection sensor. FIG. 2 is a front view of the second housing. FIG. 3 shows a light receiver with an obstruction attached. FIG. 4 shows an example of the obstacle discrimination method. FIG. 5 is a functional block diagram showing the configuration of the control device. FIG. 6 shows the configuration of the first housing. FIG. 7 is a flowchart of the shading cause determination process. FIG. 8 shows vehicle detection of a specially shaped vehicle.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 5 shows functional blocks provided in the vehicle detection control device 8 in the present embodiment. The vehicle detection control device 8 includes a receiving unit 11, a light shielding cause determination unit 12, a light shielding region width setting unit 13, and a determination time changing unit 14.

  The receiving unit 11 receives a detection signal indicating whether or not the light receiver 6 has detected the light beam 7 output from the light projector 5 in each of the plurality of light projectors / receivers included in the vehicle detection sensor 2. The light-shielding cause determination unit 12 determines whether the light-shielding cause is the vehicle 1 or the other obstacle 9 based on the received detection signal. The determination result is transmitted to a host device such as a lane server or a monitoring board of a toll booth. The light shielding area width setting unit 13 sets the width of a light shielding area described later in response to an input operation to a device such as a monitoring panel. The determination time changing unit 14 sets a determination time to be described later in response to an input operation to a device such as a monitoring panel. Each of these functional blocks can be realized by reading and executing the program stored in the storage device by the CPU in the computer included in the vehicle detection control device 8.

  FIG. 6 shows the configuration of the first housing 3. As already drawn in FIG. 1, the first housing 3 includes a plurality of projectors 5 arranged side by side in the vertical direction. On the other hand, the second casing 4 has the configuration described in FIG.

  A region 20 illustrated in FIG. 6 illustrates an example of a region determined by the light shielding region width set by the light shielding region width setting unit 13. The area 20 is an area defined by a plurality of light emitters / receivers lined up and down (instead of jumping) on the basis of the position of each light emitter / receiver, and has a width that may be blocked by an obstacle. It is determined based on.

  For example, in the vehicle detection sensor 2 installed in an area where there is a lot of snow, since the snowflake is small, one optical axis of the vehicle detection sensor 2 (the optical axis of a pair of light projectors and receivers) is set as the region 20. Alternatively, in an area where there are many relatively large obstacles such as a piece of paper, several continuous optical axes may be blocked, so a plurality of optical axes (optical axes of M consecutive projectors / receivers, M is The integer 20 is set as the area 20. In the example of FIG. 6, M = 3, that is, the region 20 is set by three projectors / receivers including the projectors / receivers adjacent above and below with reference to the position of each projector / receiver.

  The number M of light projectors / receivers included in one region 20 is not limited to these, and may be 2 or 4 or more. The light-shielding area width setting unit 13 sets the widths of these areas 20 based on, for example, an input operation on the monitoring board of the toll booth.

  The lower adjacent projector / receiver 21 and the upper adjacent projector / receiver 22 shown in FIG. 6 indicate the projector / receiver adjacent to the lower side and the upper side of the shielded area 20, respectively. The detection results of these projectors / receivers are also used for the light shielding cause determination process.

  The determination time changing unit 14 sets a threshold value Tsh1 (hereinafter referred to as a first threshold value) that serves as a reference for determining that there is a possibility of light blocking by an obstacle. The first threshold value Tsh1 is a value corresponding to the threshold value Tsh in step S106 of FIG. The first threshold value Tsh1 is set to a large value for the vehicle detection sensor 2 installed at a location where the flow of the vehicle 1 tends to stagnate, such as a toll gate where traffic congestion frequently occurs. For example, the determination time changing unit 14 sets the first threshold value Tsh1 in response to an input operation on the monitoring board of the toll booth.

  Tsh1 is specifically set to 720 ms, for example. This value is the time required for a typical ordinary passenger car (vehicle length: 4 m) to pass through the ETC lane at 20 km / h. Actually, since the vehicle length, the vehicle speed, the time when the signal changes, and the like vary depending on the local situation, the threshold value Tsh1 is appropriately set according to the local situation. However, generally, it is considered that the value is often set to about 100 ms to 1000 ms.

  The determination time changing unit 14 can further change the first threshold value Tsh1 according to the time zone. For example, in the case of a toll gate whose traffic volume fluctuates greatly depending on the time zone, such as heavy traffic congestion in the morning and evening and traffic volume decreasing during the day, the first threshold value Tsh1 is changed according to the time zone. In the morning time zone and the evening time zone set in advance, the first threshold value Tsh1 is set to a large value. In other time zones, the first threshold Tsh1 is set to a small value based on the traffic speed of the vehicle 1 when no traffic jam occurs. The determination time changing unit 14 can automatically change the first threshold value Tsh1 based on the time output by the built-in clock.

  With reference to FIG. 7, the shading cause determination process will be described. Steps S1 to S9 are the same as steps S101 to S109 in FIG. However, the value N, which is a criterion for determining the number of light-shielding optical axes in step S3, is a value set by the light-shielding area width setting unit 13. In step S3, all of the N light emitters / receivers arranged in succession are shielded. It is determined whether or not it has become an axis.

  In step S6, when the time when the light shielding is detected exceeds the first threshold value Tsh1 in at least one light shielding region (the region 20 where the light shielding is detected in step S3) (Yes in step S6), the light shielding cause determination unit 12 Then, it is detected that a light blocking area has been generated for a long time, and the light blocking cause determination process from steps S10 to S18 is started. This light blocking cause determination process is performed by all the light blocking optical axes determined to be Yes in step S6 (or all the continuous light blocking regions determined to be Yes in step S6 (all of the N or more consecutive light emitters / receivers are shielded). This is done individually for the region that became the optical axis)).

  In step S10, the light shielding cause determination unit 12 confirms the sensor states of the two projectors / receivers (the lower adjacent projector / receiver 21 and the upper adjacent projector / receiver 22) that are adjacent to both sides of the long-time light-shielding region. Step S10). When both the lower adjacent projector / receiver 21 and the upper adjacent projector / receiver 22 are shielded from light, it is determined that the vehicle 1 is present because the obstacle is large. In this case, the light shielding cause determination unit 12 outputs vehicle determination information indicating the possibility that the vehicle 1 stays at the position of the vehicle detection sensor 2 for a long time due to traffic jam or the like (step S11), and performs the process of step S7. Transition.

  In step S10, one of the two adjacent projectors / receivers (the lower adjacent projector / receiver 21 and the upper adjacent projector / receiver 22) is shielded from light, and the other is not shielded (the receiver 6 detects the light beam 7). ) Is detected, the process proceeds to step S12. In step S12, the detection state of the adjacent projector / receiver on the non-light-shielding side is monitored for the second threshold value Tsh2. The second threshold value Tsh2 is set, for example, by an input operation on the monitoring board installed in the toll booth. Furthermore, as with the first threshold value Tsh1, the value may be automatically changed according to the time zone.

  Specifically, Tsh2 is set to 60 s, for example. This value is a value assuming that the time when the signal changes is 1 minute (60 s). This value is also set as appropriate according to the local situation, as in Tsh1. However, generally, it is considered that the value is often set to about 10 s to 100 s.

  When the one-side light-shielding is detected, the light-shielding cause determination unit 12 compares the time Toff during which the adjacent projector / receiver is not shielded with the second threshold value Tsh2. When Toff ≦ Tsh2, that is, when the non-shielded optical axis is shielded within Tsh2 (No in step S12), it is determined that the vehicle 1 has entered, and vehicle determination information is output (step S11). When Toff> Tsh2, it is determined that there is a possibility that the light-shielding cause is an obstacle, and obstacle determination information is output (step S12 Yes), and the process proceeds to step S14.

  When it is determined in step S10 that the light is received on both sides (both two adjacent projectors and receivers are not light-shielded), it is considered that the vehicle detection sensor 2 is shielded from light by a small object. In such a case, as shown in FIG. 3, small obstacles such as snow, dust, and insects may cause the light shielding. Therefore, the obstacle determination information may be output in such a case.

  However, in the case of the double-sided light receiving state in step S10, as shown in FIG. 8, there may be a possibility that it is caused by a specially shaped vehicle 23 such as a car carrier. In a specially shaped vehicle 23 such as a car carrier, since the carrier is constituted by the frame 24, the vehicle detection sensor 2 is shielded from light with a relatively small width, for example, the thickness of the beam-like member forming the frame 24. There is.

  In order to discriminate between the specially shaped vehicle 23 and the obstacle 9, the processes of steps S14 and S15 are executed. In step S14, the number of light shielding optical axes in the vehicle detection sensor 2 is confirmed. When the number of light-shielding optical axes is equal to or greater than a predetermined number n (n is a preset integer equal to or greater than 2) (No in step S14), the light-shielded light receivers 6-1 shown in FIG. 8 are separated from each other. Since there are a plurality of light shielding optical axes, it is determined that there is a specially shaped vehicle 23 such as a car carrier (step S15). When the number of light-shielding optical axes is less than n (Yes at Step S14), it is determined that the obstacle 9 such as dust, snow, and insects is not shielded from the vehicle 1 (Step S16).

  The vehicle detection control device 8 disconnects the sensor optical axis determined to be shielded from light by the obstacle, and sets the sensor optical axis not to be used in the subsequent vehicle detection (step S17). Thereafter, the vehicle detection control device 8 turns off the vehicle detection signal. The host device determines that the vehicle 1 does not exist in the lane R by turning off the vehicle detection signal (step S18).

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Vehicle detection sensor 3 1st housing 4 2nd housing 5 Light projector 6 Light receiver 6-1 Light receiver 7 Light beam 8 Vehicle detection control apparatus 9 Obstacle 11 Receiver 12 Light-shielding cause determination part 13 Light-shielding area width setting part 14 Determination time changing unit 20 Region 21 Lower adjacent projector / receiver 22 Upper adjacent transmitter / receiver 23 Special shape vehicle 24 Frame R Lane

Claims (8)

Whether or not the light receiver has detected the light beam in each of the plurality of light projectors and light receivers from a vehicle detection sensor in which a plurality of light projectors and light receivers that are arranged in the vertical direction are detected by the light receivers. A receiving unit for receiving a detection signal indicating
Based on the detection signal, when it is detected that at least one long-time light-shielding region where the time during which the light ray is shielded exceeds the first threshold has occurred, a light-shielding cause determination process that starts a light-shielding cause determination process And comprising
In the light shielding cause determination unit, in the light shielding cause determination process, the light beam is shielded in both of the plurality of light projectors / receivers adjacent to both sides of the long-time light shielding region. A vehicle detection control device that outputs vehicle determination information indicating that a vehicle is present when the vehicle is present. The vehicle detection control device according to claim 1,
The light-blocking cause determination unit further detects a one-side light-blocking when the light beam is blocked by one of the adjacent projectors and the other side and the light beam is not blocked by the second threshold value in the light-blocking cause determination process. The vehicle determination information is output when both of the adjacent projectors and receivers are shielded from light within a period of time, and there is an obstacle that is not a vehicle when the one-side shading continues beyond the second threshold. A vehicle detection control device that outputs obstacle determination information. The vehicle detection control device according to claim 1 or 2,
The light blocking cause determination unit further includes obstacle determination information indicating that there is an obstacle that is not a vehicle when the light beam is not blocked by both of the adjacent projectors and receivers in the light blocking cause determination process. A vehicle detection control device. The vehicle detection control device according to claim 1 or 2,
The light-shielding cause determination unit further includes, in the light-shielding cause determination process, out of the at least one long-time light-shielding region, a predetermined number of both-side light-receiving regions where the light beam is not shielded by both of the adjacent projectors and receivers. When it is below, the obstacle determination information indicating that there is an obstacle that is not a vehicle is output, and when the both side light receiving areas are equal to or more than the predetermined number, the special shape vehicle determination indicating that a vehicle having a special shape is present A vehicle detection control device that outputs information. The vehicle detection control device according to any one of claims 1 to 4,
Each of the at least one long-time light-shielding region is defined by a light emitter / receiver in which M (M is an integer of 1 or more) are continuously arranged among the plurality of light emitters / receivers.
The vehicle detection control device further includes a light shielding region width setting unit that sets the value of M based on the received signal. The vehicle detection control device according to any one of claims 1 to 5,
Furthermore, the control apparatus for vehicle detection which comprises the determination time change part which changes the said 1st threshold value according to a time slot | zone. A vehicle detection control device according to any one of claims 1 to 6,
A vehicle detection system comprising the vehicle detection sensor. Whether or not the light receiver has detected the light beam in each of the plurality of light projectors and light receivers from a vehicle detection sensor in which a plurality of light projectors and light receivers that are arranged in the vertical direction are detected by the light receivers. Receiving a detection signal indicating
A step of starting a shading cause determination process when it is detected that at least one long-time light-shielding region where the time during which the light ray is shielded exceeds a first threshold is generated based on the detection signal; Equipped,
The step of starting the light shielding cause determination process is performed when the light beam is shielded in both of the plurality of light projecting / receiving devices adjacent to both sides of the long-time light shielding region. A vehicle detection method comprising a step of outputting vehicle determination information indicating that a vehicle exists.

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