JP2013145530A - Road-vehicle communication system and vehicle position detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a road-vehicle communication system capable of accurately estimating a distance between a street light and a vehicle and to provide a vehicle position detection device capable of correcting a vehicle position using an existing facility.SOLUTION: A street light 1 blinks an LED lump 6. Blinking of the LED lump 6 is modulated by communication data including an ID number of the street light 1 as well as height information on the street light 1. An on-vehicle device 11: captures a blinking state of the street light 1 with a video camera 12; obtains the communication data by demodulating the same from a captured image; and estimates a distance D between a vehicle 10 and the street light 1. In a vehicle position detection device 17 on the vehicle 10, a GPS positioning section 18 obtains present information on a present position of the vehicle 10. A vehicle position information correction section 20 corrects the present position of the vehicle 10 obtained by the GPS positioning section 18 using the position information of the street light 1 specified from the ID number thereof obtained through the on-vehicle device 11 as well as the distance D between the vehicle 10 and the street light 1 estimated by the on-vehicle device 11.

Description

  The present invention relates to a road-to-vehicle communication system between a light emitting structure and a vehicle installed in the vicinity of a traveling road of the vehicle, and a vehicle position detecting device using the same.

  Japanese Patent Application Laid-Open No. 2007-85845 describes a target distance detection device. In this apparatus, an image acquired by the image sensor is displayed on the operation display, and an operator selects a distance measurement target from the displayed image, and inputs an assumed target size to the operation display. The target plane display range calculator calculates the target display range from the total number of pixels of the image, the number of pixels occupied by the selected target, and the assumed target size, and the distance calculator calculates the target display range and the image sensor. Calculate the angle of view obtained from and the distance from the target. When the operator inputs only the target type, the distance to the target is calculated using the general size of the target stored in advance in the apparatus.

  Japanese Unexamined Patent Application Publication No. 2010-276583 describes a vehicle position measuring device. In this apparatus, an optical beacon is attached to a bar extending laterally above a road from a pillar installed on the side of the road, and a near infrared signal is transmitted toward an obliquely downward direction where the vehicle approaches. The near-infrared signal includes position information in which the installation position of the optical beacon is indicated by latitude and longitude. The vehicle includes position detection means for detecting the position of the vehicle using a global positioning system (GPS), vehicle-mounted communication means, imaging means, position correction means, and the like. When the vehicle enters a predetermined area close to the optical beacon, the in-vehicle communication means receives the near infrared signal from the optical beacon to acquire the installation position information of the optical beacon, and the imaging means captures the optical beacon obliquely above the vehicle. Start. When the imaging means detects that the vehicle has passed directly under the optical beacon, the position correcting means adjusts the position of the vehicle so that the position of the vehicle detected by the position detecting means matches the installation position information of the optical beacon. By correcting, the vehicle position is accurately measured.

JP 2007-85845 A JP 2010-276583 A

  In the target distance detection device described in Patent Document 1, the operation is complicated because the operator must manually input the target selection and target size, and if there is an erroneous input, the target is detected. There is a possibility that the distance up to is erroneously calculated. In addition, when the operator inputs only the type of target, the distance to the target is calculated using the general size of the target, and the distance calculation accuracy may be reduced.

  Moreover, in the apparatus described in Patent Document 2, it is necessary to newly install a dedicated optical beacon on each of a large number of columns installed on the side of the road.

  Therefore, the present invention can provide a road-to-vehicle communication system that can accurately estimate the distance to the target without requiring complicated work, and can correct the vehicle position using existing equipment. An object of the present invention is to provide a simple vehicle position detection device.

  In order to achieve the above object, a road-to-vehicle communication system according to the present invention includes a light emitting structure installed in the vicinity of a traveling road of a vehicle and an on-vehicle device mounted on the vehicle.

  The light emitting structure includes an LED light emitting unit, an LED drive unit, and an LED drive control unit. The LED light emitting unit emits light using the LED as a light source. The LED driving unit causes the LED light emitting unit to blink to emit light. The LED drive control means controls the LED drive unit and modulates the blinking state of the LED light emitting unit in correspondence with communication data including light emitting structure height information indicating the height of the light emitting structure. The vehicle-mounted device includes an imaging unit, a light emitting structure image extraction unit, a communication data acquisition unit, and a distance estimation unit. The imaging means continuously captures the traveling road ahead of the traveling direction of the vehicle and outputs image information. The light emitting structure image extracting unit extracts an image of the light emitting structure from each of the continuous image information output by the imaging unit, and detects the blinking state of the LED light emitting unit from the extracted image of the light emitting structure. The communication data acquisition means demodulates and acquires the communication data from the blinking state of the LED light emitting unit detected by the light emitting structure image extraction means. The distance estimation unit is configured to determine the distance between the vehicle and the light emitting structure based on the light emitting structure image extracted by the light emitting structure image extracting unit and the light emitting structure height information included in the communication data acquired by the communication data acquiring unit. Estimate the distance.

  In the above configuration, on the light emitting structure side of the road-to-vehicle communication, the flashing light emission state of the LED light emitting unit of the light emitting structure is modulated by the communication data including the light emitting structure height information. On the vehicle side, when each of the image information continuously captured and output by the imaging unit includes an image of the light emitting structure, the light emitting structure image extracting unit extracts the light emitting structure from each output image information. An image is extracted and the blinking state of the LED light emitting unit is detected. The communication data acquisition means acquires communication data from a series of blinking states detected continuously, and the distance estimation means includes the extracted light emitting structure image and the light emitting structure height information included in the acquired communication data. Based on the above, the distance between the vehicle and the light emitting structure is estimated.

  In this way, the light emitting structure height information is acquired from the image information continuously captured and output by the image pickup means, and the distance between the vehicle and the light emitting structure is estimated, so information on the height of the light emitting structure is input each time. There is no need for complicated operations such as Moreover, since the light emitting structure height information is directly acquired from each light emitting structure, the distance between the light emitting structure and the vehicle can be estimated with high accuracy. Furthermore, since it is only necessary to provide an LED drive control means for an existing light emitting structure such as a street light provided with an LED light emitting unit, the distance between the vehicle and the light emitting structure is estimated by effectively using the existing equipment. Can do.

  Further, the LED driving unit causes the LED light emitting unit to emit light at a blinking cycle that is 1/2 of the commercial AC power supply cycle of the area where the light emitting structure is installed, and the LED drive control unit converts the communication data into bit string data. The blinking state of the LED light-emitting unit may be modulated by associating two blinking periods of the LED light-emitting unit with each bit of the bit string data, and the imaging unit may pick up an image with a cycle substantially the same as the commercial AC power supply cycle. .

  In addition, the LED drive control means controls the LED light emitting unit according to the blinking cycle of the LED light emitting unit corresponding to the bit in which one of the two states set alternatively to each bit of the bit string data is set. Blinking twice, corresponding to the bit in which the other of the two states is set, causing the LED light emitting part to blink once in the first half or second half of the blinking period of the LED light emitting part, You may modulate so that a LED light emission part may be light-extinguished in 1 period of the second half or the first half.

  In the above configuration, the LED driving unit on the light emitting structure side causes the LED light emitting unit to blink and emit light at a blinking cycle that is ½ of the commercial AC power supply cycle (60 Hz or 50 Hz). The LED drive control means associates two blinking periods of the LED light emitting unit with each bit of the bit string data of the data, and modulates the blinking state according to the bit string data. For example, when the bit is “0”, modulation is performed so that both of the two periods flash, and when the bit is “1”, only the first half of the period flashes and the latter half of the period turns off. Such a blinking state of the LED light emitting unit can be easily modulated by the LED drive control means when the light emitting structure includes a full-wave rectifying type LED driving unit, for example, a blinking driving process on the light emitting structure side, etc. Is simplified.

  On the vehicle side, the light emitting structure is imaged by the imaging means. Since the blinking state of the LED light emitting unit is modulated in correspondence with the commercial AC power supply cycle, the blinking state of the LED light emitting unit can be easily detected by imaging the light emitting structure at substantially the same cycle as the commercial AC power supply cycle. Is done. That is, when the commercial AC power supply is 60 Hz, for example, an NTSC system camera is used as the imaging unit, so that the light emitting structure image extraction unit blinks the LED light emitting unit from approximately 60 images output per second by the camera. The state can be detected. When the commercial AC power supply is 50 Hz, the light emitting structure image extraction means can detect the blinking state of the LED light emitting unit from 50 images per second output by the camera by using a PAL camera. The communication data acquisition means demodulates to a bit string that is “0” when the latter half of the two blinking cycles of the detected LED light emitting unit blinks, and “1” when it is extinguished. The communication data is acquired by By using a standardized camera, image processing on the vehicle side is simplified. Thus, according to the said structure, in the road-vehicle communication between a light emission structure and a vehicle, the process of both the light emission structure side and a vehicle side can be simplified.

  Further, a vehicle position detection device including a vehicle position information acquisition unit and a vehicle position information correction unit may be mounted on a vehicle including the on-vehicle device of the road-to-vehicle communication system. The communication data includes structure position information that can identify the position of the light emitting structure. The vehicle position information acquisition means acquires vehicle position information specifying the current position of the vehicle from the outside by communication. The vehicle position information correcting means includes a position of the light emitting structure specified by the structure position information included in the communication data acquired by the communication data acquiring means, and a distance between the vehicle and the light emitting structure estimated by the distance estimating means. And the current position of the vehicle specified by the vehicle position information acquired by the vehicle position information acquisition means is corrected.

  In the said structure, a vehicle position detection apparatus is mounted in the vehicle provided with the onboard equipment of the said road-vehicle communication system. The vehicle-mounted device acquires structure position information that specifies the position of the light emitting structure, and estimates the distance between the vehicle and the light emitting structure. In the vehicle position detection device, the vehicle position information acquisition means acquires the vehicle position information specifying the current position of the vehicle from the outside by communication, the position of the light emitting structure acquired by the in-vehicle device, the vehicle estimated by the in-vehicle device, and Based on the distance from the light emitting structure, the vehicle position information correction unit corrects the acquired current position of the vehicle. That is, both the position information of the light emitting structure necessary for correcting the current position of the vehicle and the distance between the vehicle and the light emitting structure are supplied from the road-to-vehicle communication system. Therefore, the current position of the vehicle can be corrected using existing equipment without requiring new dedicated equipment such as an optical beacon.

  According to the present invention, it is possible to accurately estimate the distance to the target without requiring complicated work in the road-to-vehicle communication system. Further, the vehicle position can be corrected using existing equipment in the vehicle position detection device.

1 is a system configuration diagram of a road-to-vehicle communication system in the present embodiment. It is a schematic diagram which shows the principal part of a street lamp. It is a figure which shows the structure of bit sequence data. It is a figure which shows the modulation / demodulation of the bit string data using blinking of an LED lamp. It is a flowchart which shows a communication data transmission process. It is a flowchart which shows a communication data reception process. It is a flowchart which shows a vehicle position detection process.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the road-to-vehicle communication system according to this embodiment includes a street light (light emitting structure) 1 and an on-vehicle device 11 mounted on a vehicle 10. The street lamp 1 is installed in the vicinity of the traveling path of the vehicle 10 and includes a power supply unit 2, an LED drive unit 3, an LED lamp 6, an ECU 7, and the like.

  The LED lamp 6 emits light using an LED (light emitting diode) as a light source.

  The power supply unit 2 supplies the LED driving unit 3 with commercial AC power (50 Hz or 60 Hz) in the area where the street light 1 is installed.

  The LED driving unit 3 includes a rectifying circuit unit 4 and a blinking control relay 5. The rectifier circuit unit 4 rectifies the AC voltage supplied from the power supply unit 2 and supplies the voltage to the LED lamp 6. The LED lamp 6 does not emit light when the output voltage value of the rectifier circuit unit 4 is lower than the predetermined voltage V1, and the LED lamp 6 emits light when the output voltage value of the rectifier circuit unit 4 is equal to or higher than the predetermined voltage V1. As shown in FIG. 2, the blinking control relay 5 is arranged in the circuit of the rectifier circuit unit 4, and when the exciting coil 5a is excited, the contact 5b is closed and the circuit is turned on, and the exciting coil 5a is turned on. By de-energization, the contact 5b is opened and the circuit is opened. The blinking control relay 5 may be a solid state relay using a semiconductor. In the state where the blinking control relay 5 is on, the rectifier circuit unit 4 has a positive side in which the voltage of the U terminal of the rectifier circuit unit 4 becomes positive and the voltage of the V terminal becomes negative in one cycle of the commercial AC power supply cycle. The LED lamp functions as a full-wave rectifier circuit that outputs a rectified voltage for both the ½ cycle and the ½ cycle on the negative side where the voltage at the U terminal of the rectifier circuit unit 4 becomes negative and the voltage at the V terminal becomes positive. 6 blinks (turns on and off) at a blinking cycle that is 1/2 the commercial AC power supply cycle. When the blinking control relay 5 is off, the rectifier circuit unit 4 outputs a voltage rectified only in the positive 1/2 cycle of the commercial AC power supply cycle, and outputs a rectified voltage in the negative 1/2 cycle. Since the LED lamp 6 functions as a half-wave rectification circuit that does not, the LED lamp 6 blinks once in the positive half cycle of the commercial AC power supply cycle and is turned off in the negative half cycle. That is, the LED lamp 6 repeats blinking at a blinking cycle (100 Hz or 120 Hz) that is ½ of the commercial AC power supply cycle.

  The ECU 7 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU functions as the LED drive control unit 8 by reading the communication data transmission processing program stored in the ROM and executing the communication data transmission processing. The RAM functions as a storage area for communication data including the ID number of the street lamp 1, which will be described later, and the height information of the street lamp 1, and a bit counter C.

  The LED drive control unit (LED drive control means) 8 controls the blinking control relay 5 provided in the LED drive unit 3 to modulate the blinking of the LED lamp 6 in accordance with the communication data. The communication data includes ID number data (structure position information) indicating the ID number of the street lamp unique to the street lamp 1 and street lamp height data (light emitting structure height information) indicating the height of the street lamp 1. It is configured, converted into bit string data for transmission from the street light 1 side to the vehicle 10 side, and stored in the storage area. As shown in FIG. 3, the bit string data has a total data length of 25 bits composed of a 21-bit data part A and a 4-bit delimiter code part B each bit corresponding to “0” or “1”. . The delimiter code part B is provided to identify one-time transmission data from transmission data transmitted continuously. In this embodiment, the delimiter code part B is composed of a 4-bit continuous “0” code. In addition, the data portion A is assigned a bit of “1” for every 3 bits. Since the last bit of the data part A at the boundary between the data part A and the delimiter code part B is set to “1”, when the transmission data is received on the vehicle-mounted device 11 side, it is composed of “0” that is 4 bits continuous. Can be identified. FIG. 3 shows bit string data in a no-signal state. In the bit string data, a bit number from 1 to 25 is assigned to each bit from left to right in FIG. Communication data of ID number data is assigned to bit numbers 1 to 9, street lamp height data is assigned to bit numbers 10 to 21, and delimiter code part B is assigned to bit numbers 22 to 25. Since a bit of “1” is allocated for every 3 bits of the data part A, some invalid combinations occur in the bit combinations of the data part A, and the effective number of numerical values represented by the bit string data is reduced. For example, in the case of ID number data with a bit string data length of 9 bits, numerical values such as 0, 1, 9, 73, etc. are invalid, and therefore there are 216 effective numbers excluding combinations of these numerical values. In the case of street light height data with a bit string data length of 12 bits, there are 1296 effective numbers. In the ID number data, one ID number is assigned to one street lamp. The ID numbers need not be duplicated in the areas described in the street lamp position information table Q, which will be described later, and it is not necessary to assign unique ID numbers to all street lamps nationwide. Is enough. The height (cm) of the street lamp 1 is represented by the height from the road surface to the LED lamp 8. The street lamp height data is expressed as a deviation value between the street lamp 1 height and the street lamp reference height (for example, 6 m). By using the deviation value, the height of the necessary range of the street lamp 1 can be represented with a small number of bits. The height of the street lamp may be represented by, for example, the height from the road surface to the tip of the street lamp. Further, the height of the street lamp 1 may be expressed not by a deviation value from the reference height but by an absolute value of the height of the street lamp 1. Since there are invalid numbers in the bit string data as described above, each communication data is converted into bit string data according to a conversion table P in which the correspondence relationship between the communication data and the effective number of bit string data is determined in advance.

  The LED drive control unit 8 modulates blinking of the LED lamp 6 in accordance with the bit string data. That is, when the bit string data bit is “0”, the blinking control relay 5 is turned on for a period of one cycle starting from the plus side of the commercial AC power supply voltage. As a result, the rectifier circuit unit 4 of the LED drive unit 3 is in the full-wave rectification mode, and the LED lamp 6 blinks twice in a period corresponding to one cycle of the commercial AC power supply cycle. When the bit is “1”, the blinking control relay 5 is turned off over a period of one cycle starting from the positive side of the commercial AC power supply voltage. As a result, the rectifier circuit unit 4 of the LED drive unit 3 is in the half-wave rectification mode, and the LED lamp 6 blinks once in the period of the first half of the positive side of the commercial AC power supply voltage. Is turned off during the latter half period of the negative side (see FIGS. 4A, 4B, and 4C).

  Next, communication data transmission processing executed by the ECU 7 will be described based on the flowchart of FIG. This process is repeatedly executed at a rate of 50 times or 60 times per second in synchronization with the commercial AC power supply cycle (50 Hz or 60 Hz) of the power supply unit 2. The ECU 7 first determines whether or not the bit counter C is greater than 25 (step S1). If the bit counter C is 25 or less, the process proceeds to step S3. If the bit counter C is greater than 25, transmission of one communication data has been completed, so the bit counter C is set to the initial setting value 1 (step S2) and the process proceeds to step S3. In step S3, the bit string data is read, the blinking of the LED lamp 6 is controlled in correspondence with the bit having the same bit number as the count value of the bit counter C, and the blinking state is modulated. That is, when the bit having the same bit number as the count value of the bit counter C is “0”, the blinking control relay 5 is turned on and the rectifier circuit unit 4 is set to the full-wave rectification mode. When the bit is “1”, the blinking control relay 5 is turned off and the rectifier circuit unit 4 is set to the half-wave rectification mode. Next, 1 is added to the count value of the bit counter C (step S4), and this process ends. In this way, the blinking of the LED lamp 6 is modulated in ascending order of the bit number of the data part A of the bit string data, and finally the modulation by the delimiter code part B is executed to complete one transmission. In this embodiment, since transmission of one transmission data is made to correspond to 25 commercial AC power supply cycles, transmission is executed twice per second when the commercial power supply frequency is 50 Hz.

  The vehicle 10 includes an in-vehicle device 11, a vehicle position detection device 17, a display device 21, and the like. The vehicle-mounted device 11 includes a video camera 12 (imaging means) and an ECU 13.

  The video camera 12 is disposed in the front part of the vehicle 10 and images a traveling path ahead in the traveling direction of the vehicle 10 and outputs continuous image information to the ECU 13. The video camera 12 can switch between a standardized imaging system, the NTSC system and the PAL system. In the NTSC system, approximately 60 interlaced images are captured per second, and in the PAL system, 50 interlaced images are captured per second and output to the ECU 13. The video camera 12 starts imaging when the engine is started, and ends imaging when the engine is stopped or power supply from the backup power source (battery) is stopped. Further, the imaging is continued when the engine is stopped at an intersection or the like.

  The ECU 13 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU functions as the street lamp image extraction unit 14, the communication data acquisition unit 15, and the distance estimation unit 16 by reading the communication data reception processing program stored in the ROM and executing the communication data reception processing. The RAM functions as a storage area for an image acquired by the ECU 13 from the video camera 12, bit string data, conversion table P, street lamp 1 ID number, distance D between the vehicle 10 and the street light 1 described later, a distance flag F, and the like. .

  A street lamp image extraction unit (street lamp image extraction means) 14 extracts an image of the street lamp 1 from continuous image information in front of the vehicle imaged by the video camera 12, and the LED lamp 6 of the street lamp 1 being captured is extracted. Detect blinking continuously. The street light 1 is extracted by pattern matching between a captured street light image and a preset street light template image. The blinking state of the LED lamp 6 can be identified by detecting the lighting or extinguishing of the latter half of the two blinking periods, so that the imaging cycle of the video camera 12 is the power supply of the street lamp 1. It is substantially synchronized with the AC power supply cycle of the unit 2. That is, when the power supply unit 2 is 50 Hz, 50 continuous images are acquired per second by the PAL method, and when the power supply unit 2 is 60 Hz, the NTSC system is switched to acquire approximately 60 continuous images per second.

  The communication data acquisition unit 15 (communication data acquisition means) demodulates the blinking state of the LED lamp 6 detected by the street lamp image extraction unit 14 into bit string data, and converts the bit string data into communication data. That is, the detected image of the LED lamp 6 is demodulated into a bit string that is “0” when the LED lamp is lit and “1” when the LED lamp is extinguished, and a bit string is attached to create bit string data (FIG. 4). (See (c) to (f)). From the demodulated bit string data, a delimiter code part B consisting of “0” that continues for 4 bits is detected. Bit string data is converted into communication data as street lamp height data. When converting from bit string data to communication data, a conversion table P that predetermines the correspondence between communication data and the effective number of bit string data is referred to. Further, since the street lamp height information is transmitted as a deviation value between the height of the street lamp 1 and the reference height, the reference height is added to obtain the height of the street lamp 1.

  The distance estimation unit (distance estimation unit) 16 is configured to calculate the vehicle 10 and the street light 1 from the street light 1 image extracted by the street light image extraction unit 14 and the height data of the street light 1 acquired by the communication data acquisition unit 15. Estimate the distance between.

  Here, the total number of pixels in the vertical direction of the imaging surface on which the video camera 12 images the street lamp 1 is N, the number of pixels in the height direction of the image of the street lamp 1 extracted by the street lamp image extraction unit 14 is n, Assuming that the height of the street lamp 1 is h, the distance L in the vertical direction of the imaging surface on which the video camera 12 images the street lamp 1 is expressed by Expression (1).

    L = (N / n) × h (1)

  Further, when the distance from the vehicle 10 to the street lamp 1 is D, the relationship between the distance L and the distance D uses an angle of view in the vertical direction of the video camera 12 (an angle representing an imaging range viewed from the video camera 12) θ. This is expressed by equation (2).

    tan (θ / 2) = (L / 2) / D (2)

  By substituting equation (1) into equation (2), the distance D can be obtained by equation (3).

    D = (N × h) / (2n × tan (θ / 2)) (3)

  The distance estimating unit 16 obtains the total number N of pixels in the vertical direction from the image captured by the video camera, and the number n of pixels in the height direction of the street lamp 1 from the image of the street lamp 1 extracted by the street lamp image extracting unit 14. The distance D from the vehicle 10 to the street lamp 1 is estimated by substituting the height h of the street lamp 1 acquired by the communication data acquisition unit 15 and the angles of view θ, N, and n of the video camera 12 into Equation (3). To do.

  Next, communication data reception processing executed by the ECU 13 will be described based on the flowchart of FIG. This process is repeatedly executed in synchronization with the imaging timing of the video camera 12. In the video camera 12, the imaging frame rate, aperture value, and shutter speed are set to predetermined values in advance. The NTSC system is initially set as the frame rate of the video camera 12, and approximately 60 interlaced images are captured per second. Accordingly, this processing is repeatedly executed at a cycle of approximately 60 times per second. However, when the imaging method of the video camera 12 is switched to the PAL method, the processing is performed 50 times per second in synchronization with the imaging timing of the video camera 12. It is executed repeatedly in a cycle. The ECU 13 first acquires an image in front of the vehicle imaged by the video camera 12 (step S10). Next, extraction processing of the image of the street lamp 1 is performed from the images acquired this time (step S11). It is determined whether or not an image of the street lamp 1 has been extracted. If not, the process ends (step S12). When the image of the street light 1 is extracted, it is determined whether or not there are a plurality of extracted street lights (step S13). When a plurality of street lights are extracted, the street light closest to the vehicle 10 is extracted. Is selected (step S14). For selection of the extracted street lamp, for example, the size of a plurality of captured street lamps is compared, and the largest street lamp is determined as the closest street lamp 1 and selected. Next, the extracted blinking state of the LED lamp 6 of the street lamp 1 is demodulated into bit string data. That is, when the LED lamp 6 of the street lamp 1 extracted from the current imaging screen is in the lit state, the current value of the bit string data is “0”, and when it is in the unlit state, the current bit string data is Is set to “1”, a bit number is assigned, and bit string data is stored in the storage area (step S15). Next, the presence or absence of blinking of the LED lamp 6 is detected (step S16). Since the blinking state of the LED lamp 6 changes depending on the modulated bit string data, the presence / absence of blinking is determined with reference to bit string data stored in the storage area and having a bit number smaller than the demodulated bit number. When the bit demodulated this time is “0” (the LED lamp 6 is lit), when the bit demodulated including the current demodulated bit exceeds 4 bits of the delimiter code part B and is continuously “0” Or, when the bit demodulated this time is 1 (LED lamp 6 is off), blinking of LED lamp 6 is detected when it is 1 over 22 bits beyond 21 bits of data part A. It is determined that it is not performed (NO in step S16). As shown in FIG. 4D, the timing of imaging of the street lamp 1 by the video camera 12 is preferably near the center of one period of the second half of the period corresponding to two blinking periods. If the blinking of the LED lamp 6 cannot be detected correctly, the imaging timing may be shifted from the vicinity of the center of the period. Therefore, the imaging timing of the video camera 12 is adjusted, and the aperture value and shutter speed are adjusted as necessary. Adjustment is made (step S23). If the blinking state is detected (YES in step S16), the delimiter code portion B is detected from the bit string data. That is, it is determined whether or not the bit string data is “0” for four consecutive bits (step S17). If it is not “0” for four consecutive bits (NO in step S17), the process proceeds to step S21. Then, it is determined whether or not bit string data for one transmission data has already been detected. If the determination in step S21 is YES, the delimiter code portion B is not detected in the bit string data for one transmission data, and the blinking cycle of the LED lamp 6 and the imaging cycle of the video camera 12 may be inconsistent. In this case, the imaging method of the video camera 12 is switched from the NTSC method to the PAL method, or from the PAL method to the NTSC method (step S22). A process is complete | finished when determination of step S21 is NO. When a delimiter code part B that is “0” for 4 consecutive bits is detected, the conversion table P is referred to and the 21-bit bit string data of the data part A is used for each of ID number data and street light height data. It converts into communication data (step S18). Next, the ECU 13 assigns the total number of pixels N of the captured image, the number of pixels n of the street lamp 1, the street lamp height h, and the angle of view θ of the video camera 12 to the equation (3). A distance D to the street lamp 1 is estimated (step S19). Next, the distance flag F indicating that the estimation of the distance D has been completed is turned on (step S20), and this process ends.

  The indicator 21 is provided on, for example, an instrument panel (not shown) in the passenger compartment, and displays the current position of the vehicle 10 output by the vehicle position detection device 17 to assist the driver in driving.

  The vehicle position detection device 17 includes a GPS positioning unit 18, an ECU 19 and the like.

  The GPS positioning unit 18 receives a radio signal from a GPS satellite (not shown), and acquires position information that specifies the current position of the vehicle 10 by latitude, longitude, and the like.

  The ECU 19 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The CPU functions as the vehicle position information correction unit 20 by reading the vehicle position detection processing program stored in the ROM and executing the vehicle position detection processing. The RAM functions as a storage area for a street lamp position information table Q described later.

  The vehicle position information correction unit (vehicle position information correction means) 20 includes a street lamp position information table Q that can specify the position of the street lamp 1 based on the street lamp ID number. In the street lamp position information table Q, area information for specifying an area where the street lamp is installed, an ID number of the street lamp installed in the area, and a position of the street lamp specified by the ID number Is associated with street lamp position information that specifies the latitude, longitude, and the like. The vehicle position information correction unit 20 specifies an area on the street lamp position information table Q including the current vehicle position based on the current position information of the vehicle 10 acquired by the GPS positioning unit 18, and an ID number in the area. Are compared with the ID number of the street lamp 1 acquired by the communication data acquisition unit 15 of the vehicle-mounted device 11, and the street lamp position information of the street lamp with the matching ID number is used as position information for specifying the position of the street lamp 1. get. The current position of the vehicle 10 acquired by the GPS positioning unit 18 using the acquired street lamp position information of the street lamp 1 and the distance D between the street lamp 1 and the vehicle 10 estimated by the distance estimation unit 16 of the vehicle-mounted device 11. Correct.

  Next, vehicle position detection processing executed by the ECU 19 will be described based on the flowchart of FIG. This process is repeatedly executed at a predetermined cycle. The ECU 19 first determines whether or not the distance flag F of the vehicle-mounted device 11 is on (step S30). When the distance flag F is OFF, since the estimation of the distance between the vehicle 10 and the street light 1 has not been completed on the vehicle-mounted device 11 side, the present process ends. If the distance flag F is on, the distance flag F is turned off (step S31), and the current position information of the vehicle 10 is acquired from the GPS positioning unit 18 (step S32). Subsequently, the ID number of the street light 1, the vehicle 10, the street light 1, and the distance D are acquired from the vehicle-mounted device 11 (step S33). Next, with reference to the street lamp position information table Q, the position information of the street lamp 1 specified by the ID number of the street lamp 1 is acquired (step S34). Next, the current position of the vehicle 10 is corrected using the position information of the street light 1 and the distance D between the vehicle 10 and the street light 1 (step S35), and the current position of the vehicle 10 is displayed on the display 21. (Step S36).

  In the present embodiment, on the street lamp 1 side, the flashing light emission state of the LED lamp 6 of the street lamp 1 is modulated by communication data including the ID number of the street lamp 1 and the height information of the street lamp 1. On the vehicle 10 side, when the image of the street lamp 1 is included in each piece of image information that the video camera 12 continuously captures and outputs, the street lamp image extraction unit 14 calculates the street lamp from each output image information. 1 image is extracted, and the blinking state of the LED lamp 6 is detected. The communication data acquisition unit 15 acquires communication data from a series of blinking states that are continuously detected, and the distance estimation unit 16 calculates the street lamp height included in the extracted image of the street lamp 1 and the acquired communication data. Based on the information, the distance D between the vehicle 10 and the street lamp 1 is estimated. As described above, since the street lamp height information is obtained from the image information continuously captured and output by the video camera 12 and the distance between the vehicle 10 and the street lamp 1 is estimated, information on the height of the street lamp 1 is obtained. There is no need for complicated operations such as input each time. Further, since the street lamp height information is directly acquired from each street lamp 1, the distance D between the street lamp 1 and the vehicle 10 can be estimated with high accuracy. Furthermore, since it is only necessary to provide the LED drive control unit 8 or the like in the existing street light 1 having the LED lamp 6, the distance D between the vehicle 10 and the street light 1 is estimated using the existing equipment effectively. Can do.

  Further, in the present embodiment, the LED lamp 6 is blinked at a blinking cycle that is ½ of the commercial AC power supply cycle, and the blinking state is modulated so that two blinking cycles correspond to each bit of the bit string of transmission data. That is, when the bit is “0”, the two cycles are blinked, and when the bit is “1”, the first half cycle is blinked and the latter half cycle is turned off. The blinking state of the LED lamp 6 can be easily modulated by the LED drive control unit 8 when the street lamp 1 includes a full-wave rectification type LED drive unit, and the blinking drive process on the street lamp 1 side is performed. Etc. are simplified. On the vehicle 10 side, the video camera 12 is used to detect the blinking state of the LED lamp 6. Since the blinking state of the LED lamp 6 of the street light 1 is modulated in accordance with the commercial AC power supply cycle, the blinking state of the LED lamp 6 can be easily detected by taking an image with a period substantially the same as the commercial AC power supply cycle. Is done. That is, standardized video cameras of the PAL system can be used when the commercial AC power supply is 50 Hz, and the NTSC system can be used when the commercial AC power source is 60 Hz. In the present embodiment, by using the video camera 12 capable of switching between the PAL system and the NTSC system, it is possible to deal with any commercial AC power supply of 50 Hz or 60 Hz. The detected blinking state of the LED lamp 6 is demodulated into bit string data by the communication data acquisition unit 15 and converted into communication data. By using the standardized video camera 12 of the imaging method, image processing for acquiring communication data is simplified. Thus, according to this embodiment, in the road-to-vehicle communication between the street light 1 and the vehicle 10, the processing on both the street light 1 side and the vehicle 10 side can be simplified.

  In addition, a vehicle position detection device 17 is mounted on the vehicle 10. The vehicle-mounted device 11 mounted on the vehicle 10 acquires the ID number of the street lamp 1 and the street lamp height information, and estimates the distance D between the vehicle 10 and the street lamp 1. In the vehicle position detection device 17, the GPS positioning unit 18 acquires vehicle position information that specifies the current position of the vehicle 10 through communication with a GPS satellite. The vehicle position information correction unit 20 identifies the position of the street light 1 from the ID number of the street light 1 acquired by the vehicle-mounted device 11. Based on the position of the identified street light 1 and the distance D between the vehicle 10 and the street light 1 estimated by the vehicle-mounted device 11, the vehicle position information correction unit 20 obtains the current position of the vehicle 10 acquired by the GPS positioning unit. to correct. That is, both the position information of the street lamp 1 necessary for correcting the current position of the vehicle 10 and the distance D between the vehicle 10 and the street lamp 1 are supplied from the road-to-vehicle communication system of the present embodiment. Therefore, the current position of the vehicle 10 can be corrected using existing equipment without requiring new dedicated equipment such as an optical beacon.

  In the present embodiment, when the bit of the bit string data is “0”, the blinking control relay 5 is turned on for one period of the commercial AC power cycle, and when the bit is “1”, the blinking control relay 5 is turned on. Although turned off, when the bit string data bit is “0”, the blinking control relay 5 is turned off for a period of one commercial AC power cycle, and when the bit is “1”, the blinking control relay 5 is turned on. May be. In this case, when the bit of the bit string data is “0”, the LED lamp 6 blinks once in the first half of the commercial AC power supply cycle, and turns off during the latter half of the cycle. When the bit string data bit is “1”, the LED lamp 6 blinks twice in one period of the commercial AC power supply period. When the LED lamp 6 blinks once in a period of one commercial AC power cycle, the first half of the period may be turned off and the second half of the period may be turned on. . In this case, it is desirable that the imaging timing of the video camera 12 be in the vicinity of the center of the first half of the commercial AC power cycle.

  Further, the bit string data of one communication data is not limited to 25 bits in the present embodiment, and may be expanded or shortened from 25 bits as necessary. Further, the format of the bit string of the delimiter code part B and the data part A of the communication data is the present embodiment (the delimiter code part B is “0” for four consecutive bits, and the data part A sets “1” for every three bits). However, the present invention is not limited to this as long as the data portion of the communication data can be identified by the delimiter code portion. For example, a special bit pattern that can be distinguished from the data portion may be used, and a delimiter code portion may be provided at a plurality of locations such as a start portion and an end portion of the data portion.

  Further, the blinking cycle of the LED lamp 6 of the street light 1 is not limited to a blinking cycle that is ½ of the commercial AC power cycle, and for example, it may blink at a cycle earlier than a blinking cycle that is ½ of the commercial AC power cycle. Good. In this case, the communication speed of road-to-vehicle communication can be increased.

  Further, the light emitting structure is not limited to a street light, and may be a traffic signal device having an LED light emitting unit, for example. Moreover, the kind of light-emitting structure is not limited to one kind of street light, For example, multiple types, such as a street light and a traffic signal, may be mixed.

  Further, the street lamp position information included in the communication data for specifying the position of the street lamp 1 is not limited to the ID number of the street lamp 1, but for example, latitude, longitude information, etc. directly indicating the position of the street lamp 1 There may be.

  In addition, the vehicle position detection device 17 displays the current position of the vehicle 10 on the display 21, but other devices (for example, a driving support device for the vehicle 10) that execute predetermined processing using these pieces of information are used. It may be output.

  In the present embodiment, the vehicle-mounted device 11 and the vehicle position detection device 17 are separate devices, but the function of the vehicle-mounted device 11 may be added to the vehicle position detection device 17. In this case, in the existing vehicle equipped with the vehicle position detection device, the vehicle position can be corrected by easily applying road-to-vehicle communication between the street light 1 and the vehicle.

  As mentioned above, although the embodiment to which the invention made by the present inventor is applied has been described, the present invention is not limited by the discussion and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it is needless to say that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

  The present invention can be widely applied as a road-to-vehicle communication system between a light emitting structure including an LED light emitting unit and a vehicle.

DESCRIPTION OF SYMBOLS 1 Street lamp 2 Power supply part 3 LED drive part 4 Rectification circuit part 5 Flashing control relay 6 LED lamp (LED light emission part)
7 ECU
8 LED drive control unit (LED drive control means)
DESCRIPTION OF SYMBOLS 10 Vehicle 11 Onboard equipment 12 Video camera (imaging means)
13 ECU
14 Street lamp image extraction unit (light emitting structure image extraction means)
15 Communication data acquisition unit (communication data acquisition means)
16 Distance estimation part (distance estimation means)
17 Vehicle position detection device 18 GPS positioning unit (vehicle position information acquisition means)
19 ECU
20 Vehicle position information correction unit (vehicle position information correction means)

Claims (4)

A road-to-vehicle communication system comprising a light emitting structure installed in the vicinity of a traveling path of a vehicle and an in-vehicle device mounted on the vehicle,
The light emitting structure is:
An LED light-emitting unit that emits light using an LED as a light source;
An LED driving unit that causes the LED light emitting unit to blink and emit light; and
LED driving control means for controlling the LED driving unit and modulating the blinking state of the LED light emitting unit in correspondence with communication data including light emitting structure height information indicating the height of the light emitting structure,
The in-vehicle device is
Imaging means for continuously imaging the traveling road ahead of the traveling direction of the vehicle and outputting image information;
A light emitting structure image extracting means for extracting an image of the light emitting structure from each of continuous image information output by the imaging means, and detecting a blinking state of the LED light emitting unit from the extracted image of the light emitting structure;
Communication data obtaining means for demodulating and obtaining the communication data from the blinking state of the LED light emitting unit detected by the light emitting structure image extracting means;
The vehicle and the light emitting structure based on the image of the light emitting structure extracted by the light emitting structure image extracting unit and the light emitting structure height information included in the communication data acquired by the communication data acquiring unit. A road-to-vehicle communication system comprising: distance estimation means for estimating a distance between the vehicle and the vehicle. The road-vehicle communication system according to claim 1,
The LED driving unit causes the LED light emitting unit to emit light at a blinking cycle that is ½ of a commercial AC power cycle in an area where the light emitting structure is installed,
The LED drive control means converts the communication data into bit string data, modulates the blinking state of the LED light emitting unit by corresponding two bits of the blinking cycle of the LED light emitting unit to each bit of the bit string data,
The road-to-vehicle communication system, wherein the image pickup means picks up images at a cycle substantially the same as the commercial AC power supply cycle. The road-to-vehicle communication system according to claim 2,
The LED drive control means corresponds to a bit in which one of two states set alternatively to each bit of the bit string data is set, and the LED light emission is performed according to the blinking cycle of the LED light emitting unit. The LED light-emitting part is blinked twice, and the LED light-emitting part is turned on in the first half or the latter half of the blinking period of the LED light-emitting part corresponding to the bit in which the other state of the two states is set. A road-to-vehicle communication system, wherein the LED light-emitting section is modulated so as to blink once and turn off the LED light emitting section in one cycle of the second half or the first half. A vehicle position detection device mounted on the vehicle including the on-vehicle device of the road-vehicle communication system according to claim 1,
The vehicle position detection device includes vehicle position information acquisition means and vehicle position information correction means,
The communication data includes structure position information capable of specifying the position of the light emitting structure,
The vehicle position information acquisition means acquires vehicle position information specifying the current position of the vehicle from outside by communication,
The vehicle position information correction means includes: the position of the light emitting structure specified by the structure position information included in the communication data acquired by the communication data acquisition means; the vehicle estimated by the distance estimation means; A vehicle position detection device that corrects the current position of the vehicle specified by the vehicle position information acquired by the vehicle position information acquisition means using a distance between the light emitting structure and the light emitting structure.

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