JP5558238B2 - Vehicle interval detection system, vehicle interval detection method, and vehicle interval detection program - Google Patents

Description

  Embodiments described herein relate generally to a vehicle interval detection system, a vehicle interval detection method, and a vehicle interval detection program.

The tollgate of a toll road such as a highway, ETC with wireless receiver ETC gantry a dedicated gate (a abbreviation for Electronic Toll Collection Syste m, hereinafter referred to as automatic toll collection system) is installed .

  The wireless receiver of the automatic toll collection system receives data related to toll collection (hereinafter referred to as toll collection data) sent by DSRC (narrow area) communication from the ETC onboard unit of the vehicle when passing through the ETC gantry. After that, it automatically collects the road usage fee from a deposit account of a vehicle manager or the like later.

  In this case, the automatic toll collection system needs to receive toll collection data sent from each vehicle connected in the vertical direction within a relatively narrow reception area by narrow area communication. It is desirable to pass through the ETC gantry while maintaining the following inter-vehicle distance.

  If the front and rear vehicles are jammed below a certain distance, the wireless receiver of the automatic toll collection system cannot communicate with the following vehicle and cannot collect tolls. It may cause an accident such as the exit gate not opening due to smooth coordination.

  In particular, when the following vehicle approaches after a small, medium, or large freight vehicle with a high loading platform, the wireless receiver is affected by the height of the last part of the small, medium, or large freight vehicle, and the ETC of the following vehicle In some cases, radio waves emitted from the vehicle-mounted device are completely blocked, and the toll collection data cannot be received.

  Therefore, in the conventional automatic toll collection system, since it is necessary to accurately grasp even in an approaching state, a laser device using laser light is used on one side of a road set in a toll gate. The laser device irradiates a laser beam in the lateral direction of the traveling vehicle, detects the distance between the front and rear vehicles from the time of the reflected signal, the level of the reflected signal, etc. If so, the automatic fee collection system is notified.

JP 2010-014706 A

  However, the laser device provided in the automatic toll collection system as described above can accurately measure various distances, but only one piece of information such as vehicle height, length, and distance between front and rear vehicles of each vehicle. I can't get it. Therefore, in order to measure the distance to be measured, a laser device or the like must be individually installed for each measurement object, which is expensive in terms of cost, and the information must be integrated. In addition, synchronization processing and the like are complicated.

  Therefore, the vehicle interval detection system, the vehicle interval detection method, and the vehicle interval detection program determine whether or not communication is possible from captured images of the front and rear vehicles when the front and rear vehicles enter the toll gate.

In order to solve the above-described problem, according to an embodiment of the present invention, when the front and rear vehicles entering the toll gate are approaching, the wireless receiver of the automatic toll collection system communicates with the ETC on-board unit of the following vehicle and the DSRC communication. A vehicle interval detection system for estimating a distance between the front and rear vehicles in order to determine whether or not data relating to toll collection can be received, wherein the front images of the forward vehicle and the following vehicle entering the toll gate Vehicle photographing means for photographing the vehicle, vehicle detection means for detecting the front and following vehicles entering the toll gate, and an image of the bottom of the windshield reflected in the front image of the front vehicle photographed by the vehicle photographing means Based on the position, the horizontal distance from the wireless receiver to the windshield bottom of the vehicle ahead is determined, and the frame rate and the image position change of the windshield bottom Distance and speed calculating means for determining the speed of the preceding vehicle from the vehicle size (vehicle length, the rear height) of the front vehicle and the vehicle size acquisition means for acquiring, the front which has been determined by the distance and speed calculating means Using the vehicle speed, the horizontal distance obtained by the distance / speed calculating means and the horizontal distance from the wireless receiver obtained from the acquired vehicle length to the rear of the front vehicle, the distance between the front and rear vehicles It is a configuration provided with a hidden occurrence presence / absence determining means for estimating distance and determining whether or not data related to fee collection by DSRC communication in the following vehicle cannot be received (hidden).

The schematic block diagram of the vehicle space | interval detection system which concerns on one Embodiment which supports the fee collection of the automatic toll collection system installed in a toll road toll gate. The figure which shows the example of the simple vehicle front part reference pattern referred when detecting a vehicle. The data array example figure which shows an example of the table for distance calculation for calculating the distance from a radio receiver to a front vehicle based on the vehicle front part image image | photographed with the vehicle imaging | photography means. The data array example figure which shows an example of a vehicle size management table. The flowchart explaining an example of the flow of the process by the operation | movement of the vehicle interval detection system which concerns on embodiment, and the vehicle interval detection method. The figure explaining the position of the windshield bottom image which appears in the vehicle front part image image | photographed with the vehicle imaging | photography means, when the vehicle windshield bottom edge reaches | attains the reference distance D0 from the radio | wireless receiver of an automatic toll collection system. Explanatory drawing for determining whether the data regarding toll collection can be received by DSRC communication from the ETC on-board unit of the succeeding vehicle in the wireless receiver of the automatic toll collection system. The image figure showing the state in which the windshield of a succeeding vehicle is partially hidden by the rear part height of a front vehicle. The data arrangement example figure of the table for simple hidden occurrence determination used for determining the presence or absence of hidden occurrence.

Hereinafter, an embodiment will be described with reference to the drawings.
FIG. 1 is a block diagram showing an embodiment of a vehicle interval detection system connected to an automatic toll collection system at a toll road toll gate.

In the figure, 1 is an automatic fee collection system equipped with a wireless receiver (not shown),
For example, it is attached to the ETC gantry 3 installed at the toll gate of the toll road 2. The ETC gantry 3 is not limited to the arch shape as shown in the figure, and may be a support having various shapes, for example, an inverted L-shaped support.

  Various forward vehicles 4 and following vehicles 4 '(small cars, ordinary passenger cars, small ordinary freight cars, medium and large freight cars) enter the toll road toll gate, but when passing through the ETC gantry 3, Toll collection data is transmitted to the automatic toll collection system 1 sequentially from an ETC on-board unit (not shown) mounted on the preceding vehicle 4 among a plurality of vehicles connected in the direction.

  The wireless receiver of the automatic toll collection system 1 receives toll collection data by DSRC (narrow area) communication when the preceding vehicle 4 enters a predetermined receivable area, and automatically sets the toll for the vehicle manager. Billing is possible.

  The vehicle interval detection system 10 is received by a vehicle imaging means 11 having an imaging camera, a vehicle interval detection processing unit 12 including a CPU, a database 13, a data buffer memory 14, and a succeeding vehicle 4 '. It is the structure containing the warning generation | occurrence | production part 15 which issues a warning when approaching the back of the front vehicle 4 to such an extent that it becomes impossible.

  Further, the vehicle interval detection system 10 may include a program memory 16 that stores a vehicle interval detection program as necessary, or stores and stores a vehicle interval detection program from a server on a network.

  The vehicle photographing means 11 is installed in the ETC gantry 3 as in the automatic toll collection system 1 or installed upstream of the ETC gantry 3 as shown, and when the vehicle 4 approaches the ETC gantry 3, The front part of the vehicle is photographed with an angle of view such that the front image of the vehicle including the windshield falls within the field of view. The reason why the windshield is included in the field of view is that various vehicles are often characterized by the windshield, and the vehicle type can be identified from the shape of the windshield. As will be described later, if the vehicle type can be specified, the vehicle height and the vehicle length can be known.

  The vehicle photographing means 11 shoots a front image of the preceding front vehicle 4 among the vehicles 4 that are arranged in the column direction according to a predetermined frame rate, and uses the photographed vehicle front image data as a vehicle interval detection processing unit. 12 are sequentially transmitted. The succeeding vehicle 4 'also takes a front image.

  Note that the installation position of the vehicle imaging means 11 and the horizontal distance from the installation position of the vehicle imaging means 11 to the installation point of the wireless receiver are stored as fixed values in the database 13 as necessary (see FIG. 6).

  The vehicle interval detection processing unit 12 functionally includes, for example, a vehicle detection unit 21 that detects only the front vehicle 4 or the front vehicle 4 and the subsequent vehicle 4 ′ from the vehicle front image data captured by the vehicle imaging unit 11. The image position on the bottom of the windshield when the front portion of the vehicle 4 or the succeeding vehicle 4 'reaches the reference distance from the predetermined wireless receiver and the vehicle front image data actually captured by the vehicle photographing means 11 Distance calculating means 22 for calculating the distance from the image position on the bottom of the vehicle windshield to the front of the vehicle, and the front image data of the vehicle 4 (light, license plate, front grill shape (radiator shape) Etc.)) vehicle size acquisition means 23 for obtaining the vehicle size such as the vehicle type name, the length of the preceding vehicle, the rear height of the preceding vehicle, the hiding occurrence determination means 24, and an alarm Output means 25.

  The hidden occurrence determination unit 24 is related to the vehicle size of the front vehicle acquired by the vehicle size acquisition unit 23, particularly the rear height of the front vehicle 4, the windshield bottom position of the subsequent vehicle, the installation height of the wireless receiver, and the like. Thus, the inter-vehicle distance between the front and rear vehicles 4 and 4 ′ is estimated, and the wireless receiver has a function of determining whether toll collection data generated from the succeeding vehicle 4 ′ cannot be received due to the rear height of the front vehicle 4.

  The warning output means 25 has a function of outputting a warning message from the warning generation unit 15 to the subsequent vehicle 4 ′ when the subsequent vehicle 4 ′ is determined to be unreceivable (hidden occurrence) due to the rear height of the preceding vehicle 4. Have. An alarm output may be used to notify the vehicle that is actually traveling, or to the system administrator.

  The database 13 stores a vehicle front reference pattern 31, a distance calculation table 32, a vehicle size management table 33, alarm message data 34, a hidden occurrence determination table 35, and the like.

  The vehicle front reference pattern 31 is a pattern necessary for the vehicle detection means 21 to detect the vehicle 4 (see FIG. 2).

  The distance calculation table 32 is a vehicle front portion photographed by the vehicle photographing means 11 in view of the fact that the bottom of the windshield of vehicles 4, 4 'such as small ordinary cargo vehicles, medium-sized and large cargo vehicles is substantially equal to the front surface of the vehicle. It is a table used when calculating | requiring the distance from the installation position of a wireless receiver (ETC gantry 3) to the front vehicle 4 based on the image position of the vehicle windshield bottom in image data (refer FIG. 3).

  The vehicle size management table 33 is a table for managing the size of the vehicle (see FIG. 4). Updates such as deletion and addition at regular intervals. In addition, it has a learning function related to the vehicle front pattern, for example, the company name mark in the front image data of the photographed vehicle, the characteristic front design of each company, the part arrangement, etc. are ruled, for example, the front part of the photographed vehicle Based on the company name mark, front feature design, and parts layout of the image data, the front image data of the vehicle is sequentially added as a new vehicle front pattern for each company, and the model name and vehicle size are added later by the operator. The vehicle size management table 33 for large-scale pattern matching may be created.

  The alarm message data 34 is, for example, message data such as “occurrence of vehicle hiding”, “please secure a sufficient inter-vehicle distance”, “please stop approaching the vehicle”, and the like.

  The hidden occurrence determination table 35 is a table that defines a relationship among a plurality of data related to hidden occurrences (see FIG. 9).

  The data buffer memory 14 stores necessary images and data being processed.

  Next, an operation of the vehicle interval detection system configured as described above and an embodiment of the vehicle interval detection method will be described with reference to FIG.

  First, when the vehicle interval detection system operates, the vehicle interval detection processing unit 12 transmits an activation command to the vehicle photographing means 11. Here, the vehicle photographing means 11 photographed the front part of the vehicle such as a light, a license plate, a front grill, etc. including at least the bottom of the front glass of the forward vehicle 4 entering the toll gate according to a predetermined frame rate. The vehicle front image data is transmitted, or the vehicle front image data from the outside is waited for.

  At this time, the vehicle interval detection processing unit 12 executes the vehicle detection means 21. The vehicle detecting means 21 executes an initialization process for erasing unnecessary data stored in the data buffer memory 14 or the like (S1), and then captures vehicle front image data transmitted from the vehicle photographing means 11. Alternatively, after directly capturing the vehicle front image data temporarily stored in the vehicle photographing means 11 and storing it in the data buffer memory 14 (S2), pattern matching is performed based on the vehicle front image data. Using the method or the background difference method, it is determined whether a vehicle has entered (S3).

  The pattern matching method is used when the photographed vehicle front image data matches at least one vehicle front reference pattern 31 in FIGS. 2A to 2C or the similarity exceeds a predetermined threshold. Detecting that the vehicle has entered. For example, in FIG. 2A, when the radiator 4a and the light 4b exist in the vehicle front image data, or the light 4b and the license plate 4c exist in the vehicle front image data as shown in FIG. 2B. When it does, it detects that the vehicle has entered.

  In the background subtraction method, only a fixed background image is shown in the previous / previous frame image data, but when a front image corresponding to a vehicle is shown in the current image, it is detected that a vehicle has entered. In addition, the process of step S1-S3 is corresponded to the vehicle detection step in a vehicle space | interval detection method.

  Subsequently, the vehicle interval detection processing unit 12 starts from the position of the wireless receiver (ETC gantry 3) from the image position of the windshield bottom where the vehicle front image data is reflected and the data of the distance calculation table 32 shown in FIG. The distance calculating means 22 for obtaining the distance to the head of the preceding vehicle 4 is executed.

  Before describing the operation of the distance calculation means 22, the relationship between the distance calculation table 32 shown in FIG. 3 and FIG. 6 will be described.

  In view of the fact that the bottom of the windshield 4d of the vehicle 4 such as a small-sized ordinary freight vehicle, medium-sized or large-sized freight vehicle is substantially the same height from the ground and is substantially at the top portion of the vehicle 4, the bottom of the windshield of the vehicle 4 is When the distance from the wireless receiver (ETC gantry 3) installation position to the windshield bottom side position (vehicle top) is D0 when the reception center line by the narrow band communication of the radio receiver is reached, the windshield bottom picture is The vehicle photographing means 11 is installed at an inclination angle so as to exist in the upper and lower center portions of the vehicle front image data photographed by the vehicle photographing means 11. At this time, if the height from the bottom of the windshield 4d of the vehicle 4 to the wireless receiver is H0, the reception angle θ0 is obtained from the distance D0 and the height H0.

  Under the above conditions, when the front vehicle 4 is traveling in the direction indicated by the arrow (A), the vehicle photographing means 11 captures the front of the front vehicle 4 a plurality of times according to the frame rate. It is assumed that the image position of the glass bottom changes from the upper side to the lower side of the vehicle front image data.

  Therefore, as the distance calculating means 22, a predetermined windshield bottom image position in the vehicle front image data photographed by the vehicle photographing means 11 or the upper and lower central portions of the vehicle front image data photographed by the vehicle photographing means 11. When the windshield bottom image is reflected at the pixel position closest to the vehicle, it is determined that the preceding vehicle 4 has entered the reception area (S4), and the position of the windshield bottom (vehicle top) is determined from the position where the wireless receiver (ETC gantry 3) is installed. ) Is obtained (S5).

  That is, the distance calculating means 22 predetermines a pixel conversion distance ΔD (see FIG. 5) that is determined in advance as the number of shift pixels between the upper and lower center parts of the vehicle front image data photographed by the vehicle photographing means 11 and the image position where the windshield bottom image is reflected. 3), and the distance D0 ′ can be calculated by the following equation (1) by adding or subtracting from the center of the image according to the vertical position of the glass bottom image.

D0 ′ = D0 ± (number of shifted pixels × ΔD) (1)
Note that the position of the bottom of the windshield 4d of the vehicle 4 such as a small ordinary freight vehicle, a medium-sized or large freight vehicle, etc. is not a complete top portion of the vehicle 4, so that a predetermined distance correction value is added to the equation (1). Good.

  If the distance D0 ′ is obtained as described above and the height H0 from the bottom of the windshield 4d of the vehicle 4 to the wireless receiver is known, the reception angle θ can be easily determined from the distance D0 ′ and the height H0. Can be sought.

  Further, based on the movement change of the glass bottom image in the vehicle front image data of the two frames and the number of moved pixels, the traveling speed V of the vehicle 4 was obtained using the pixel conversion distance ΔD and the frame rate. Thereafter, the distance D0 ′ and the traveling speed V of the corresponding vehicle are stored in the data buffer memory 14.

  Note that the pixel conversion distance ΔD is not necessarily one, and the conversion distance by pixels varies as the distance from the center of the image increases. Therefore, when accurately obtaining the distance, a different pixel conversion distance is set for each of a plurality of pixels in advance. May be.

  Note that the processing of steps S4 to S5 corresponds to a vehicle distance / speed calculation step in the vehicle interval detection method.

  Subsequently, the vehicle interval detection processing unit 12 executes the vehicle size acquisition means 23. The vehicle size acquisition means 23 is the vehicle shown in FIG. 4 that is already stored in the database 13 based on the vehicle front image data (light, license plate, front grill shape (radiator shape, etc.)) including the already taken company name mark. With reference to the size management table 33, when the vehicle front image data matches the vehicle front pattern of the vehicle size management table 33 (S6) or when the similarity exceeds a predetermined threshold value by pattern matching (S7), A vehicle type name corresponding to the vehicle front pattern is specified, and a vehicle size (vehicle length, rear height, etc.) corresponding to the vehicle type name is acquired (S8). If none of Steps S6 and S7 corresponds, it is determined that the vehicle is not the target vehicle (for example, a small car, a normal passenger car, or other vehicle), and the subsequent processing is not executed.

  As a result, by obtaining the vehicle size (vehicle length, rear height, etc.) corresponding to the car model name, the horizontal distance D from the position where the wireless receiver (ETC gantry 3) is installed to the rear part of the front vehicle 4 is obtained by the following equation. Can be sought.

D = D0 + (number of misaligned pixels × ΔD) + vehicle length (2)
Then, in correspondence with the vehicle model name, necessary data such as the horizontal distance D, the rear height, the vehicle speed described above, the height from the vehicle rear height to the wireless receiver, and the like obtained in this manner are stored in the data buffer memory 14. Store (S9). Since the bottom position of the windshield 4d of the vehicle 4 such as a small-sized ordinary freight vehicle, a medium-sized or large-sized freight vehicle, etc. may not be the complete top portion of the vehicle 4, from the bottom position of the windshield 4d to the top portion depending on the model name in advance. If the distance correction value is associated, the accurate vehicle length can be obtained by subtracting the distance correction value from the expression (2) vehicle length.

  The processes in steps S6 to S9 correspond to a vehicle size acquisition step in the vehicle interval detection method.

  Further, the vehicle interval detection processing unit 12 executes a hidden occurrence presence determination unit 24.

  As described above, when the succeeding vehicle 4 ′ approaches the high cargo bed, for example, after the small / medium / large freight vehicle 4, the wireless receiver is affected by the rear height of the small / medium / large freight vehicle 4 that precedes. The radio wave between the following vehicle 4 'and the ETC on-board unit is completely blocked, and the toll collection data cannot be received.

  Therefore, the hidden occurrence determination unit 24 detects the distance (inter-vehicle distance) d from the bottom of the windshield 4d of the following vehicle 4 ′ to the rear part of the preceding vehicle 4 in the same manner as S1 to S3 (S10).

  Since the hidden occurrence determination unit 24 obtains the speed V0 of the preceding vehicle 4 and obtains the length D of the preceding vehicle 4 as described above, the speed V0 of the preceding vehicle 4 is obtained from the data buffer memory 14. When the distance D to the rear portion is read out, and the time when the preceding vehicle 4 is detected is T0, and the time when the succeeding vehicle 4 'is detected from the vehicle captured images of the next and subsequent frames is T1, the preceding and following vehicles 4-4' The estimated inter-vehicle distance d can be obtained from the following equation (3).

d = V0. (T1-T0) -D <ε (3)
However, although the threshold value ε is determined by the positional relationship of FIG. 7 described later, it may be determined from experiments, experiences, and the like.

  Further, as the vehicle interval detection processing unit 12, the estimated inter-vehicle distance d obtained by the above equation (3) is affected by the height of the rearmost part of the preceding vehicle 4 when the ETC onboard unit of the succeeding vehicle 4 ′ is affected by the automatic toll collection. Consider the possibility of obstructing communication with the system 1 side radio receiver.

  In general, if the depression angle of the vehicle photographing means 11 installed in the ETC gantry 3 is made shallow, the number of frames of the vehicle front image data in which the windshield 4d is reflected increases, but on the other hand, the distance between the front and rear vehicles 4, 4 'is increased. When approaching, a phenomenon occurs in the vehicle photographing means 11 such that the windshield 4d ′ of the following vehicle 4 ′ is partially hidden and cannot be seen.

  Therefore, assuming that the vehicle photographing means 11 is installed in the ETC gantry 3 similarly to the wireless receiver, the viewing angle of the vehicle photographing means 11 is set to correspond to the reception range of the wireless receiver, and the windshield 4d of the succeeding vehicle 4 ′ is set. The conditions for hiding 'will be described with reference to FIG.

  As shown in FIG. 7, the vehicle photographing means 11 is configured such that the windshield 4d ′ is within the range of θ ± (θ ′ / 2), where θ is the depression angle of the vehicle photographing means 11 and θ ′ is the viewing angle. For example, it is possible to photograph the windshield 4d ′ that is the subject.

  Therefore, when the distance d between the windshield 4d ′ (S) of the following vehicle 4 ′ and the rear portion of the front vehicle 4 is changed, the hiding occurs under the condition shown in the following formula (4). FIG. 8 shows a state in which the windshield 4d ′ (S) of the following vehicle 4 ′ is hidden by the rear vehicle 4 rear height.

Θ = tan ⁻¹ {(H−Hs) / d}> θ + (θ ′ / 2) (4)
In the above equation, θ: the depression angle of the vehicle photographing means 11, θ ′: the viewing angle of the vehicle photographing means 11, S: the windshield 4d ′, d: the distance between the windshield 4d ′ (S) and the rear part of the front vehicle 4, H Is the rear height of the front vehicle 4, Hs is the height from the ground to the windshield 4d ′ (S), and θ is an angle formed by d and (H−Hs).

For this reason, the boundary condition for hiding the windshield 4d ′ (S) is:
tan ⁻¹ {(H−Hs) / d} = θ + (θ ′ / 2) (5)
It becomes.

Therefore, the hidden occurrence determination unit 24 determines whether or not tan ⁻¹ {(H−Hs) / d}> θ + (θ ′ / 2) based on the equation (4), that is, the subsequent vehicle 4 ′ is ahead. It is determined whether or not the vehicle 2 is hidden behind the vehicle 2 (S11).

  Incidentally, the presence / absence of hidden occurrence will be described with a specific example. Now, assuming that the angle of view is set so that θ = 45 ° and θ ′ = 20 °, d and Θ are shown in FIG. 9 when Hs = 1000 mm in a general car and the bus height H = 3000 mm. It becomes a relationship.

  Accordingly, a plurality of hidden occurrence determination tables 35 as shown in FIG. 9 may be facilitated in the database 13 in advance, and the presence / absence of hidden occurrences may be determined from θ = 45 °, θ ′ = 20 °, and the vehicle size.

  In addition, the process of step S10-S11 is corresponded to the hidden occurrence presence determination step in the vehicle space | interval detection method.

  Further, in step S11, when it is determined that the hidden vehicle 4 'is hidden, the alarm output means 25 is executed. Here, when it is determined that the hidden vehicle 4 'is hidden, the vehicle front image data stored in the data buffer memory 14 is associated with the vehicle type name, the distance, the rear height, the vehicle speed described above, the vehicle The rear height, the estimated inter-vehicle distance d and the data with occurrence of hiding are stored and accumulated in, for example, the database 13 or further stored in a database (not shown) corresponding to the automatic toll collection system 1 (S12).

  Subsequently, the vehicle interval detection processing unit 12 reads out the voice warning message data 34 from the database 13 based on the determination of the occurrence of hiding, and generates the voice warning message data 34 from the warning generation unit 15 toward the following vehicle 4 ′ ( S13). Steps S12 and S13 correspond to an alarm output step in the vehicle interval detection method.

  Then, if it is a continuation process (S14), it will return to step S1, erase | eliminate the acquisition data related to the front vehicle 4, replace the necessary data etc. which were acquired by the following vehicle 4 'as the front vehicle 4, and update, Repeat a series of processes.

  Therefore, according to the embodiment as described above, when the front and rear vehicles approach and pass the toll gate, especially by the rear height of a small ordinary truck, medium-sized / large-sized cargo, large-sized bus, etc., which becomes the front vehicle, The radio wave emitted from the ETC on-board device of the following vehicle is blocked, and data related to toll collection cannot be received. In such a case, the inter-vehicle distance between the front and rear vehicles is estimated. In consideration of the rear height of the vehicle, the height position of the bottom of the windshield, the reception area of the wireless receiver, etc., it is determined that data reception is impossible (occurrence of hiding). An alert message can be generated to call attention.

  Further, when it is determined that data reception is not possible (hidden occurrence), for example, the front image and necessary data including the vehicle number and the like are stored and accumulated, so that necessary billing measures can be taken later.

  If a computer is used as the vehicle interval detection processing unit 12, the operation flow shown in FIG. 5 is stored in the program memory 16 as a vehicle interval detection program, and is read by the computer. A function similar to that of the alarm output means 25 can be realized, and the same effect obtained by the vehicle interval detection system can be obtained.

(Other embodiments)
(1) In the above embodiment, the presence / absence of the vehicle is detected from the vehicle front image data photographed by the vehicle photographing means 11 on the basis of the pattern matching or the background difference method. Any one of a sensor, a line sensor, and a distance sensor may be installed in the vicinity of the toll gate entrance, and the vehicle may be detected from the passage of the vehicle.

  The laser sensor can detect the presence of a vehicle approaching a toll gate by, for example, irradiating a laser beam, detecting the laser beam reflected from the entering vehicle side, and calculating the distance to the side of the vehicle. The line sensor is a light receiving means arranged so as to face the light projecting means arranged on one shoulder of the toll gate, and can detect the passage of the vehicle by shading due to the passage of the vehicle.

(2) In the above embodiment, the vehicle size management table 33 is referred to based on the vehicle front image data photographed by the vehicle photographing means 11 to obtain the vehicle size (vehicle length, rear height). However, for example, a vehicle size (vehicle length, rear height) can be acquired from a reflected wave that is emitted from a radar device and reflected from a traveling vehicle ahead.

(3) In addition, the vehicle license plate numbers “1: normal freight car”, “2: large passenger bus”, “4: light / small / medium / large freight car”, “8: special purpose car” Even if the relationship between the vehicle size (vehicle length, vehicle rear height) is tabulated and the vehicle length and vehicle rear height are extracted from the vehicle number in the vehicle front image data photographed by the vehicle photographing means 11 Good.

(4) Further, the vehicle speed is obtained from the frame rate and the number of pixels (pixel conversion distance) of the image change on the bottom of the windshield in the photographed vehicle front image data, for example, for speed control. It is also possible to measure the vehicle speed from the radar reflected wave, or to obtain the inter-vehicle distance between the front and rear vehicles using a radar device installed on the front side or the rear side of the front and rear vehicles. .

(5) Further, the vehicle photographing means 11 is installed on one shoulder side of the toll booth before the installation position of the automatic toll collection system 1 equipped with the wireless receiver, and the front and rear vehicles 4 passing in front of the vehicle photographing means 11 , 4 ′ may be measured from moving images of a plurality of frames, and the wireless receiver may determine that the toll collection data transmitted from the succeeding vehicle 4 ′ cannot be received.

(6) Furthermore, as another embodiment, it can be implemented in combination with various measurement sensors as much as possible, and in that case, the effect of the combination can be obtained. Further, each of the above embodiments includes various higher-level and lower-level inventions, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, when an invention is extracted because some constituent elements can be omitted from all the constituent elements described in the means for solving the problem, the omitted part is used when the extracted invention is implemented. Is appropriately supplemented by well-known conventional techniques.

  DESCRIPTION OF SYMBOLS 1 ... Automatic toll collection system provided with wireless receiver, 2 ... Toll road, 3 ... ETC gantry, 4 ... Forward vehicle, 4 '... Subsequent vehicle, 10 ... Vehicle interval detection system, 11 ... Vehicle photographing means, 12 ... Vehicle Interval detection processing unit, 13 ... database, 14 ... data buffer memory, 15 ... alarm generating unit, 16 ... program memory, 21 ... vehicle detection means, 22 ... distance calculation means, 23 ... vehicle size acquisition means, 24 ... hidden occurrence Presence / absence determination means, 25 ... alarm output means, 31 ... simple vehicle front reference pattern, 32 ... distance calculation table, 33 ... vehicle size management table, 34 ... alarm message data, 35 ... hiding occurrence determination table.

Claims (15)

To determine whether the wireless receiver of the automatic toll collection system can receive data related to toll collection with the ETC on-board unit of the following vehicle and DSRC communication when the front and rear vehicles entering the toll gate are approaching A vehicle interval detection system for estimating an inter-vehicle distance between the front and rear vehicles,
Vehicle photographing means for photographing front images of the preceding vehicle and the following vehicle entering the toll gate;
Vehicle detection means for detecting the forward and subsequent vehicles entering the toll gate;
A horizontal distance from the wireless receiver to the front windshield bottom of the front vehicle is obtained based on the image position of the windshield bottom taken in the front image of the front vehicle photographed by the vehicle photographing means, and the frame rate and the front Distance / speed calculation means for determining the speed of the vehicle ahead from the image position change of the glass bottom,
Vehicle size acquisition means for acquiring the vehicle size (vehicle length, rear height) of the preceding vehicle;
Horizontal speed from the wireless receiver obtained from the speed of the preceding vehicle obtained by the distance / speed computing means, the horizontal distance obtained by the distance / speed computing means and the obtained vehicle length to the rear portion of the preceding vehicle. And a hidden occurrence presence / absence determining means for estimating an inter-vehicle distance between the preceding and following vehicles using a distance and determining whether or not to receive data related to toll collection by DSRC communication in the following vehicle (hidden). Vehicle spacing detection system. In the vehicle interval detection system according to claim 1,
The vehicle detection means includes a front image including at least a light, a license plate, a front grill and the like of a preceding vehicle photographed by the vehicle photographing means, and a vehicle including at least one of a light, a license plate and a front grill stored in advance. A vehicle interval detection system that detects a vehicle from pattern matching with a front reference pattern, or from previous and current image changes of the preceding vehicle imaged by the vehicle imaging means for each frame rate. In the vehicle interval detection system according to claim 1,
The vehicle detecting means includes one of a laser sensor, a line sensor, and a distance sensor in the vicinity of a toll gate entrance side, and detects that the vehicle is a vehicle from a detection target passing state. Interval detection system. In the vehicle interval detection system according to claim 1 or 2,
The distance calculating means is arranged such that when the bottom portion of the windshield of the front vehicle reaches a reference distance from a predetermined installation position of the wireless receiver, the front of the front image of the front image of the front vehicle is captured. When the vehicle photographing means is provided so that an image of the bottom of the glass is reflected, and the image of the bottom of the windshield is changing from the vertical center in the front image actually photographed by the vehicle photographing means, A vehicle distance detection system, wherein a conversion distance corresponding to the number of changed pixels is added to or subtracted from the reference distance to obtain a horizontal distance from an installation position of the wireless receiver to the preceding vehicle. In the vehicle interval detection system according to claim 1 or 2,
The vehicle size acquisition means stores in advance vehicle front pattern data and vehicle sizes corresponding to a plurality of vehicle model names, and stores each vehicle based on a front image of the front vehicle taken by the vehicle photography means. A vehicle interval detection system characterized by referring to front pattern data and acquiring a vehicle size (vehicle length, rear height) of a specific vehicle type name. In the vehicle interval detection system according to claim 1 or 2,
The vehicle size acquisition means emits a radio wave from a radar device and acquires a vehicle size (vehicle length, rear height) from a reflected wave reflected from a traveling front vehicle. . In the vehicle interval detection system according to claim 1 or 2,
Estimate d of the distance to the vehicle front, the speed V0, the distance D from the radio receiver to the forward vehicle rear portion, the forward vehicle detection time TO, when the T1 of the detection time of the following vehicle,
d = V0 · (T1−T0) −D In the vehicle space | interval detection system as described in any one of Claim 1, Claim 2, Claim 5 thru | or 7,
DSRC of data related to toll collection transmitted from the succeeding vehicle by the wireless receiver according to a predetermined calculation formula using the estimated value of the inter-vehicle distance between the front and rear vehicles, the rear height of the preceding vehicle and the windshield height of the following vehicle A vehicle interval detection system characterized by determining whether or not reception by communication is possible (hidden). In the vehicle interval detection system according to any one of claims 1 to 8,
An alarm generator installed at an appropriate location in the toll gate;
When it is determined that reception is impossible by the hidden occurrence determination means, necessary data among various types of acquired data is accumulated and a warning message indicating that the vehicle is approaching is generated from the warning generation unit A vehicle interval detection system, further comprising an alarm output means. To determine whether the wireless receiver of the automatic toll collection system can receive data related to toll collection with the ETC on-board unit of the following vehicle and DSRC communication when the front and rear vehicles entering the toll gate are approaching A vehicle interval detection method for estimating an inter-vehicle distance between the front and rear vehicles,
A vehicle detection step of detecting a forward vehicle and a subsequent vehicle entering the toll gate;
The horizontal distance from the wireless receiver to the front windshield bottom of the front vehicle from the image position of the windshield bottom reflected in the front image of the vehicle in front of the front vehicle entering the toll gate, the frame rate, and the front A distance / speed calculating step for determining the speed of the preceding vehicle from the image position change of the glass bottom;
A vehicle size acquisition step of acquiring a vehicle size (vehicle length, rear height) of the preceding vehicle;
Horizontal to said front vehicle rear portion from the radio receiver obtained from the horizontal distance and the acquired vehicle length determined by the speed and the distance and speed calculation step of the front vehicle which has been determined by the distance and speed calculating step A hidden occurrence determination step for estimating an inter-vehicle distance between the preceding and following vehicles using a distance and determining whether or not to receive data related to toll collection by DSRC communication in the subsequent vehicle (hidden);
And a warning output step of generating a warning message from a warning generation unit in the succeeding vehicle when it is determined that reception is impossible. At least a vehicle front reference pattern, a vehicle size management table in which a vehicle front pattern and vehicle size data (vehicle length, rear height) are associated with each vehicle type name, and a storage unit for storing alarm message data are provided. Whether the wireless receiver of the automatic toll collection system can receive data related to toll collection by DSRC communication with the ETC on-board unit of the succeeding vehicle when the front and rear vehicles entering the toll gate are approaching by the computer A vehicle interval detection program for estimating an inter-vehicle distance between the front and rear vehicles for determination,
In the computer,
A front vehicle and a succeeding vehicle are detected by pattern matching between a vehicle front image captured by a photographing camera installed in the toll gate and the vehicle front reference pattern or background difference processing based on a plurality of vehicle front images. A vehicle detection function, a horizontal distance from the image position of the windshield bottom reflected in the front image of the vehicle to the windshield bottom of the front vehicle from the wireless receiver, a frame rate, and an image position change of the windshield bottom The vehicle front pattern of the vehicle size management table based on the distance / speed calculation function for determining the speed of the preceding vehicle from the front image of the front vehicle captured by the imaging camera, and a specific vehicle type name vehicle size (vehicle length, the rear height) of the vehicle size acquiring function of acquiring, the front which has been determined by the distance and speed calculation function The obtained horizontal distance and the acquired vehicle length determined by the distance and speed calculation function and both of the speed by using the horizontal distance to said front vehicle rear portion from the wireless receiver, vehicle of the front and rear vehicle A hidden occurrence presence / absence determination function for estimating distance and determining whether or not to receive data related to toll collection by DSRC communication in the subsequent vehicle, and that the subsequent vehicle is approaching when it is determined that reception is impossible A vehicle interval detection program for realizing an alarm output function for generating the alarm message data from an alarm generator. Vehicle photographing means for photographing the front image of the preceding vehicle and the following vehicle entering the toll gate of the automatic toll collection system;
A horizontal distance from a wireless receiver of the automatic toll collection system to a windshield included in the front image of the preceding vehicle is obtained from a front image of the preceding vehicle photographed by the vehicle photographing means, and the vehicle photographing means A distance / speed calculating means for determining the speed of the preceding vehicle based on either the photographed front image and the detection result of the preceding vehicle by a vehicle detection device;
Vehicle size acquisition means for acquiring the vehicle size of the preceding vehicle;
The inter-vehicle distance between the preceding vehicle and the following vehicle is estimated using the vehicle size of the preceding vehicle acquired by the vehicle size acquiring unit, the speed of the preceding vehicle obtained by the distance / speed calculating unit, and the horizontal distance. And a hidden occurrence presence / absence generating means for determining whether the subsequent vehicle and the automatic toll collection system cannot communicate with each other.
A vehicle interval detection system comprising: The vehicle interval detection system according to claim 12,
The distance / speed calculating means is based on the image position of the front glass bottom of the front image of the front vehicle photographed by the vehicle photographing means from the wireless receiver of the automatic toll collection system to the windshield bottom of the front vehicle. A vehicle distance detection system characterized by obtaining a horizontal distance of the vehicle. The vehicle interval detection system according to claim 12,
The distance / speed calculating means obtains the speed of the front vehicle from a frame rate and an image position change of a windshield bottom side of the front image of the front vehicle. The vehicle interval detection system according to claim 12,
The vehicle size acquisition means acquires a vehicle length and a rear height as the vehicle size,
The hiding occurrence presence / absence judging means includes a speed obtained by the distance / speed computing means, a horizontal distance obtained by the distance / speed computing means, and a horizontal distance from the wireless receiver obtained from the vehicle length to the rear portion of the front vehicle. An inter-vehicle distance between the preceding vehicle and the following vehicle is estimated using a distance, and communication between the following vehicle and the automatic toll collection system is determined to be impossible.

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