JP2019197379A - Vehicle detection device, vehicle detection method, and program - Google Patents

Abstract

To provide a vehicle detection device, a vehicle detection method, and a vehicle detection program that can prevent erroneous detection of the presence/absence of a vehicle in a detection space, such as a parking space of a parking lot.SOLUTION: A control unit 12 of a vehicle detection device 10, provided that after a parking space Z1 is determined to be in a full state, a detection value of a magnetic sensor 11A changes, determines whether a second difference vector is an inverse vector of a first difference vector (S22). When the second difference vector is determined to be the inverse vector, the control unit determines that the parking space Z1 is changed from the full state to an empty state. Thus, even when a vehicle 21 is parked in the parking space Z1, the control unit can accurately determine the empty state in the parking space Z1.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a vehicle detection technique for determining the presence or absence of a vehicle in a detection space such as a parking space such as a parking lot using a magnetic sensor.

  Conventionally, a vehicle detection device that installs a magnetic sensor on a parking surface in a parking space of a parking lot and detects whether the parking space is full or empty by detecting a change in geomagnetism caused by the presence or absence of a vehicle. It is known (see Patent Document 1). The vehicle detection device installs a plurality of magnetic sensors in a vehicle width direction or the like in a parking space, and uses a difference composite value of detection levels in the respective axial directions between the magnetic sensors to determine whether or not there is a vehicle. As a result, even if a heavy vehicle such as a truck or bus passes near the magnetic sensor, the geomagnetism greatly fluctuates, or a train overhead wire or high-voltage line is installed near the magnetic sensor, resulting in a large fluctuation in geomagnetism. However, false detection is prevented.

JP 2006-164145 A

However, the conventional vehicle detection device uses a plurality of magnetic sensors to suppress the influence of disturbance caused by the passage of heavy objects, and uses a plurality of magnetic sensors, so that the configuration becomes large and the cost is high. Become high.

  In addition, there are various types of vehicles, and depending on the type of vehicle, the degree of influence on geomagnetism is high and low, and it is not easy to accurately determine whether the vehicle is full or not. Further, when a vehicle of a vehicle type having a high influence on geomagnetism (that is, a large change in geomagnetism) stops in an adjacent parking space, the possibility of erroneous detection of the own parking space increases.

  Hereinafter, with reference to FIG. 13 and FIG. 14, an example of erroneous detection in a conventional vehicle detection device that determines that the vehicle is full when the amount of change in geomagnetism after parking is equal to or greater than a predetermined fullness determination threshold Lo will be described. To do. FIGS. 13 and 14 are diagrams for explaining erroneous detection due to the magnitude of the influence on geomagnetism in the parking space Z1 of the parking lot. The upper diagram of FIG. 13 shows vehicle states P1, P2, and P3 when the vehicle 21 having a low influence on geomagnetism enters the parking space Z1, and the lower diagram shows the amount of change in the detection value of the magnetic sensor 11 (geomagnetism). A waveform W1 representing a change over time in the amount of change in (). The upper diagram of FIG. 14 shows vehicle states P11, P12, and P13 when the vehicle 22 having a high influence on geomagnetism enters the parking space Z2 adjacent to the parking space Z1, and the lower diagram shows the magnetism of the parking space Z1. A waveform W2 representing the change over time of the change amount of the detection value of the sensor 11 is shown. In FIG. 13, it is assumed that no vehicle is parked in a space adjacent to the parking space Z1, and in FIG. 14, no vehicle is parked in the parking space Z1. The vehicle 21 enters the parking space Z1, and the vehicle 22 enters the adjacent parking space Z2. The magnetic sensor 11 is installed in the parking space Z1.

  In FIG. 13, the vehicle state P1 is a state in which the vehicle 21 is approaching the parking space Z1. In this case, as indicated by the waveform W1, the amount of change in the detection value of the magnetic sensor 11 (the amount of change in geomagnetism) gradually increases. Next, when the engine portion of the vehicle 21 enters above the magnetic sensor 11 as in the vehicle state P2, the amount of change reaches a peak. When the vehicle 21 further enters and the engine portion passes the position of the magnetic sensor 11, the amount of change gradually decreases. When the vehicle 21 enters the parking space Z1 and stops as in the vehicle state P3, the amount of change is stabilized at a predetermined value less than the fullness determination threshold Lo. In this example, since the vehicle 21 is parked in the parking space Z1, that is, the parking space Z1 is full, the amount of change is less than the fullness determination threshold Lo, so the parking space Z1 is empty. Misdetected as a condition.

  Moreover, in FIG. 14, the vehicle state P11 is a state in which the vehicle 22 is approaching the parking space Z2. In this case, as shown by the waveform W2, the amount of change in the detection value of the magnetic sensor 11 rises gradually. Next, when the vehicle 22 begins to enter the parking space Z2 as in the vehicle state P12, the amount of change may exceed the fullness determination threshold Lo. When the vehicle 22 further enters, the amount of change changes side by side while maintaining a value equal to or higher than the fullness determination threshold Lo, and the vehicle 22 enters the parking space Z1 as in the vehicle state P13. Even when the vehicle stops, the amount of change maintains a value equal to or higher than the fullness determination threshold Lo. In this example, although the vehicle 21 is not parked in the parking space Z1 and the parking space Z1 is in an empty state, the amount of change is equal to or greater than the fullness determination threshold Lo, and therefore the parking space Z1 is in a full state. Misdetected.

  An object of the present invention is to provide a vehicle detection device, a vehicle detection method, and a program capable of preventing erroneous detection of the presence or absence of a vehicle in a detection space such as a parking space of a parking lot.

  A vehicle detection device according to one aspect of the present invention is configured to determine the presence or absence of a vehicle in the detection space based on a detection value of a magnetic sensor that detects a magnetic field vector including the magnitude and direction of a magnetic field in the detection space. , A first difference calculation unit, and an empty vehicle determination unit. The first difference calculation unit acquires, from the magnetic sensor, the magnetic field vectors of the first state where the vehicle enters and stops in the detection space and the second state where the vehicle leaves the detection space, respectively. A first difference vector of each magnetic field vector is calculated. The empty vehicle determination unit changes the detection space from the first state to the second state when a magnetic field fluctuation in a direction opposite to the direction of the first difference vector occurs after the vehicle stops in the detection space. Judge that it has changed.

  A vehicle detection method according to another aspect of the present invention is a method of determining the presence or absence of a vehicle in the detection space based on a detection value of a magnetic sensor that detects a magnetic field vector including the magnitude and direction of a magnetic field in the detection space. And a first difference calculating step and an empty vehicle determining step. The first difference calculating step acquires, from the magnetic sensor, the magnetic field vectors of the first state where the vehicle enters and stops in the detection space and the second state where the vehicle leaves the detection space, respectively. A first difference vector of each magnetic field vector is calculated. In the empty vehicle determination step, when a magnetic field fluctuation in a direction opposite to the direction of the first difference vector occurs after the vehicle stops in the detection space, the detection space changes from the first state to the second state. Judge that it has changed.

  The present invention can also be understood as a program for causing a computer to execute each step of the vehicle detection method, or a computer-readable recording medium in which such a program is recorded non-temporarily.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to prevent the erroneous detection of the parking state of the vehicle with respect to the parking space of a parking lot.

FIG. 1 is a schematic diagram illustrating a connection configuration between a vehicle detection device and a magnetic sensor according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of the vehicle detection device. FIG. 3 is a diagram showing an example of the degree of influence on the geomagnetism on the ground surface with respect to the part in the traveling direction of the vehicle, and (A) is a figure showing the amount of change in the geomagnetism in each part of the vehicle having a low degree of influence. (B) is a figure which shows the variation | change_quantity of the geomagnetism in each site | part of a vehicle with a high influence degree. FIG. 4 is a diagram illustrating the parking state of the vehicle and the amount of change in the detection value of the magnetic sensor according to each parking state. FIG. 5 is a vector diagram showing an example of a magnetic field vector corresponding to each parking state at the installation position of the magnetic sensor. FIG. 6 is a vector diagram illustrating an example of the first difference vector and the second difference vector. FIG. 7 shows changes over time in the vehicle state when the vehicle enters the parking space Z1 in a forward direction and leaves in the reverse direction, and the amount of change in the detected value detected by the magnetic sensor in the parking space Z1 while the vehicle enters and leaves the vehicle. It is a figure which shows the waveform to represent. FIG. 8 shows changes over time in the amount of change in the detected value detected by the magnetic sensor in the parking space Z1 when the vehicle leaves the parking space Z1 in the middle of the forward approaching vehicle and moves backward. It is a figure which shows the waveform showing. FIG. 9 shows changes over time in the vehicle state when the vehicle enters the parking space Z1 backward and leaves the parking space, and the amount of change in the detection value detected by the magnetic sensor in the parking space Z1 while the vehicle enters and leaves the vehicle. It is a figure which shows the waveform to represent. FIG. 10 shows the vehicle state when the vehicle enters the parking space Z1 in a forward direction and leaves the parking space Z1 in the adjacent parking space Z2, and the parking space Z1 while the vehicle enters and leaves the vehicle. It is a figure which shows the waveform showing a time-dependent change of the variation | change_quantity of the detected value which the magnetic sensor detected. FIG. 11 shows a state in which the vehicle is parked in the adjacent parking space Z2, the vehicle enters the parking space Z1 in a forward direction, and then the vehicle leaves the parking space Z2 in the reverse direction, and then the parking space Z1. FIG. 6 is a diagram illustrating a vehicle state when the vehicle leaves in reverse, and a waveform representing a change over time in the amount of change in the detected value detected by the magnetic sensor in the parking space Z1 while each vehicle enters and leaves the vehicle. FIG. 12 is a flowchart illustrating an example of a procedure of a vehicle detection process executed by the control unit of the vehicle detection device. FIG. 13 is a diagram for explaining erroneous detection caused by the magnitude of the influence on geomagnetism in the parking space Z1, and the upper figure shows that a vehicle having a low influence on geomagnetism enters the parking space Z1. Vehicle state P1, P2, P3 at the time, and the lower figure shows a waveform W1 representing a temporal change in the amount of change in geomagnetism detected by the magnetic sensor in the parking space Z1 while entering the parking space Z1. FIG. 14 is a diagram for explaining false detection due to the magnitude of the influence on geomagnetism in the parking space Z1, and the upper figure shows that a vehicle having a high influence on geomagnetism enters the parking space Z2. Vehicle state P11, P12, P13 at the time, and the lower figure shows a waveform W2 representing the change over time of the amount of change in geomagnetism detected by the magnetic sensor in the parking space Z1 while entering the parking space Z2.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. In addition, embodiment described below is only an example which actualized this invention, and does not limit the technical scope of this invention.

[Vehicle detection device 10]
FIG. 1 is a schematic diagram illustrating a connection configuration between a vehicle detection device 10 and a magnetic sensor 11 according to an embodiment of the present invention.

  The vehicle detection device 10 determines the presence / absence of a vehicle in each of a plurality of parking spaces Z partitioned into a parking lot 20. As shown in FIG. 1, a magnetic sensor 11 is installed in each parking space Z. The magnetic sensor 11 is a known sensor capable of detecting the strength (magnetic flux density) of a magnetic field including the geomagnetism at the installation position. In the present embodiment, the vehicle detection device 10 determines the presence or absence of a vehicle in the parking space Z based on the change amount G of the detection value of the magnetic sensor 11 installed on the parking surface of the parking space Z. Further, the vehicle detection device 10 determines whether or not the parking space Z is empty based on the magnetic field vector obtained from the detection value of the magnetic sensor 11. Note that the magnetic sensor 11 detects the strength of the geomagnetism at the installation position unless there is anything in the parking space Z that forms a magnetic field other than geomagnetism.

  The magnetic sensor 11 is installed in the parking space Z. As shown in FIG. 1, the magnetic sensor 11 is installed at a position closer to the vehicle entrance / exit 17 than the central portion of the parking space Z. In the present embodiment, the magnetic sensor 11 is embedded in the parking surface in the parking space Z. The installation position of the magnetic sensor 11 is, for example, a rear having a cargo compartment or the like when a vehicle (front engine vehicle) such as an FR vehicle or FF vehicle equipped with an engine on the front side is parked in the parking space Z in a forward direction. This is the position where the part is arranged, and is the position where the engine part on which the engine is mounted is arranged when the vehicle is parked in the parking space Z in reverse. The installation position of the magnetic sensor 11 is a position where the engine portion is arranged when a vehicle such as an RR vehicle (rear engine vehicle) equipped with an engine on the rear side is parked in the parking space Z in a forward direction. This is a position where a front portion having a luggage compartment or the like is disposed when the vehicle is parked in the parking space Z in reverse. The magnetic sensor 11 is installed at a position other than the engine portion when a vehicle (midship vehicle) such as an MR vehicle mounted with an engine between the front and rear axles parks in the parking space Z forward or backward. It is a position to be done.

The magnetic sensor 11 is of a three-axis type and detects the magnetic field vector amount at the installation position, that is, the magnetic field magnitude (scalar amount) and the magnetic field direction (magnetic field direction).
The magnetic sensor 11 may be of a biaxial type, and may detect the magnitude and direction of the magnetic field on the XY plane including the X axis and the Y axis.

  FIG. 2 is a block diagram illustrating a configuration of the vehicle detection device 10.

  A magnetic sensor 11 is connected to the vehicle detection device 10. The magnetic sensor 11 uses, for example, a magnetic sensor element such as a coil, a Hall element, a magnetoresistive element (MR element), or a magnetic impedance element (MI element) to detect the vector quantity of the magnetic field including the geomagnetism near the installation position. Is. More specifically, the magnetic sensor 11 detects a vector quantity of the detected magnetic field vector, that is, a scalar quantity as a magnitude component and a magnetic field direction (magnetic field direction), and detects the scalar quantity and the magnetic field direction as a detected value. To the control unit 12 described later. The magnetic sensor 11 is electrically connected to the vehicle detection device 10 by wire or wireless. The magnetic sensor 11 includes an amplification circuit, an AD conversion circuit, and the like in addition to the magnetic sensor element. When the magnetic sensor 11 is a two-axis type, the magnetic sensor 11 controls the detected magnetic field vector using the scalar amount and magnetic field direction of the component force on the XY plane including the X-axis and the Y-axis as detection values. Send to part 12.

  As shown in FIG. 2, the vehicle detection device 10 includes a control unit 12, a storage unit 13, and a communication unit 14.

  The communication unit 14 is a communication interface, connects the vehicle detection device 10 to the network N1 by wire or wirelessly, and executes data communication with the management server 15 via the network N1 according to a predetermined communication protocol. The communication part 14 transmits the determination result (full state or empty state) of the presence or absence of the vehicle in the vehicle detection apparatus 10 to the management server 15 via the network N1. Here, the empty state is a state where there is no vehicle 21 in the parking space Z (detection space) to be determined, and is an example of a second state of the present invention. The full state is a state where the vehicle 21 is present in the parking space Z and is an example of the first state of the present invention. The management server 15 is a server device that manages the presence or absence of a vehicle in the parking lot 20. In the present embodiment, the configuration in which the vehicle detection device 10 is connected so as to be communicable with the management server 15 is illustrated, but the configuration in which the vehicle detection device 10 is realized by the management server 15 may be used.

  The storage unit 13 is a non-volatile storage medium including an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The storage unit 13 stores control programs for causing the control unit 12 to execute various processes, threshold values used for vehicle detection processing described later executed by the vehicle detection device 10, and magnetic field vectors detected by the magnetic sensor 11. Coordinate information, each determination result by the vehicle detection process, status information indicating the full state of the parking space Z1, a reference value for calculating a change amount G described later, and the like are stored.

  The control unit 12 includes control devices such as a CPU, a ROM, and a RAM. The ROM is a nonvolatile storage medium in which control programs such as BIOS and OS for causing the CPU to execute various processes are stored in advance. The RAM is a volatile or non-volatile storage medium that stores various types of information, and is used as a temporary storage memory (working area) for various processes executed by the CPU. The control unit 12 controls the vehicle detection device 10 by executing various control programs stored in advance in the ROM or the storage unit 13 with the CPU.

  As shown in FIG. 2, the control unit 12 includes a change amount calculation unit 121, a threshold determination unit 122, a vehicle determination unit 123, a first empty vehicle determination unit 124, a fluctuation determination unit 125 (an example of a detection value fluctuation determination unit of the present invention). ), A first difference calculation unit 126, a second difference calculation unit 127, and a second empty vehicle determination unit 128 (an example of an empty vehicle determination unit of the present invention). The control unit 12 functions as the various processing units by executing various processes such as a vehicle detection process in the CPU according to the control program. Note that some or all of the processing units included in the control unit 12 may be configured by an electronic circuit. The control program may be a program for causing a plurality of processors to function as the various processing units.

  The change amount calculation unit 121 calculates the change amount G based on the detection value (the value of magnetic flux density indicating the strength of the magnetic field) sent from the magnetic sensor 11. The change amount G is an absolute value of a difference between a scalar amount included in the detection value of the magnetic sensor and a predetermined reference value. The reference value is detected when the vehicle is not parked in any of the parking space Z1 (an example of the detection space of the present invention) in which the magnetic sensor 11 is installed and the parking space Z2 (adjacent space) adjacent thereto. The detected value of the magnetic sensor 11 is stored in the storage unit 13 in advance. The magnetic field including the geomagnetism in each of the plurality of parking spaces Z in the parking lot 20 is the influence of the magnetic field formed by the surrounding electric wires, the strength of the reinforcing bars used in the surrounding buildings or the reinforcing bars used in the three-dimensional parking lot, etc. Influenced by magnetic material. Therefore, the reference value is different for each parking space Z. For this reason, the reference value for each parking space Z is acquired in advance and stored in the storage unit 13.

  In general, a ferromagnetic material that affects geomagnetism is often used in vehicles such as automobiles. Therefore, when a vehicle such as an automobile enters the parking space Z and is parked, the detected value of the magnetic sensor 11, that is, the vector amount of the magnetic field vector fluctuates during the parking process. For this reason, the presence / absence of a vehicle in the parking space Z is calculated by calculating the amount of change G, which is the difference between the detected value of the magnetic sensor 11 that fluctuates due to the presence of the vehicle and the reference value. It is possible to determine by comparing.

  By the way, there are various types of vehicles, and the degree of influence on geomagnetism varies depending on the type of vehicle. FIG. 3 is a diagram showing an example of the degree of influence on the geomagnetism on the ground surface with respect to a part in the traveling direction of the vehicle. FIG. 3A shows the amount of change in geomagnetism in each part of the vehicle 21 having a low degree of influence on the geomagnetism. It is a figure which shows distribution, (B) is a figure which shows distribution of the variation | change_quantity of geomagnetism in each site | part of the vehicle 22 with a high influence degree to geomagnetism. The vehicle 21 is, for example, a front engine vehicle, and the exterior is made of an aluminum alloy or a resin instead of a sheet metal such as steel in order to reduce the weight. In this vehicle 21, a ferromagnetic material is often used in the engine part. Therefore, as shown in FIG. 3A, a relatively large distortion is applied to the geomagnetism under the engine part, The amount of change in the magnitude (scalar amount) of the corresponding geomagnetism on the ground surface is large. On the other hand, since the amount of ferromagnetic material used is small in portions other than the engine portion, the amount of change in the magnitude of the earth's magnetic field (scalar amount) corresponding to the portion is relatively small compared to the engine portion. . On the other hand, the vehicle 22 is, for example, a hybrid vehicle in which an engine is mounted on the front side and a motor and a battery are mounted between the front and rear axles. The vehicle 22 uses a lot of ferromagnetic material not only in the engine part but also in other parts. Therefore, as shown in FIG. 3B, the geomagnetic field of the ground surface corresponding to the entire area of the vehicle 22 is obtained. The change amount is larger than the change amount of the vehicle 21. It should be noted that vehicles such as trucks and buses that use a large amount of ferromagnetic material in the entire region in the traveling direction also have a high degree of influence on geomagnetism. Becomes larger.

  Hereinafter, the change amount G of the scalar amount included in the detection value of the magnetic sensor 11A according to the parking state of the vehicles 21 and 22 in the adjacent parking spaces Z1 and Z2 will be described with reference to FIG. Each threshold used for the vehicle detection process will be described. Here, the magnetic sensor 11A is installed in the parking space Z1, and the same applies to the following description. The parking space Z2 is a parking space adjacent to the parking space Z1. In addition, in FIG. 4, illustration of the magnetic sensor 11 of the parking space Z2 is abbreviate | omitted.

  As shown in FIG. 4, in the parking state P21 in which the vehicle 21 enters only the parking space Z1, the change amount G of the detection value of the magnetic sensor 11A is a waveform W11 (see the solid line waveform in FIG. 4). Thus, the amount of change G gradually increases as the vehicle 21 enters. When the engine portion of the vehicle 21 passes above the magnetic sensor 11A, the amount of change G reaches the peak value SP1, then gradually decreases, converges to the stable value AV1, and completely enters the parking space Z1. In the full state in which the vehicle 21 is parked, the change amount G maintains the stable value AV1.

  Further, in the parking state P22 in which the vehicle 22 enters only the parking space Z2 in a forward direction, the change amount G of the detection value of the magnetic sensor 11A in the parking space Z1 is as shown by a waveform W12 (see the broken line waveform in FIG. 4). Moreover, as the vehicle 22 enters, the amount of change G increases gradually. This is because the vehicle 22 is a vehicle having a large influence on the geomagnetism, and thus when the vehicle 22 is parked in the adjacent parking space Z2, the geomagnetism in the parking space Z1 is also affected. In this case, the amount of change G does not increase to the peak value SP1, but may increase to a stable value AV2 that is greater than the stable value AV1, and the change occurs when the vehicle 22 is completely parked in the parking space Z2. The quantity G maintains a stable value AV2.

  Further, in the parking state P23 where the vehicle 22 is already parked in the parking space Z2 and the vehicle 21 enters the parking space Z1 in a forward direction, the change amount G is from before the vehicle 21 enters the parking space Z1. The stable value AV2 has already been reached. That is, the change amount G when the parking space Z1 is empty and the parking space Z2 is full is the stable value AV2. Then, as the waveform W13 (see the dotted line waveform in FIG. 4), the amount of change G gradually increases as the vehicle 21 enters, and the peak value is obtained when the engine portion passes above the magnetic sensor 11A. The peak value SP2 that is larger than SP1 is reached. Thereafter, the change amount G gradually decreases and converges to a stable value AV3 larger than the stable value AV1, and when the vehicle 21 is completely parked in the parking space Z1, the change amount G decreases to the stable value AV3. maintain.

  In the present embodiment, in view of a plurality of parking states of the vehicles 21 and 22 with respect to the parking spaces Z1 and Z2 and a plurality of waveform patterns of the amount of change G according to the parking state, each threshold used for the vehicle detection process is It has been established.

  Specifically, the trigger threshold value H1 for determining whether or not a parking determination process described later by the vehicle determination unit 123 is started is used in a first empty determination process described later by the first empty determination unit 124. It is set to a numerical value larger than the empty threshold value L1. Specifically, the trigger threshold H1 is set to a numerical value that is larger than the first empty threshold L1 and smaller than the peak value SP1.

  Here, the first empty threshold L1 is set to a value larger than the stable value AV2 so that the empty state in the parking space Z1 can be reliably determined even when the vehicle 22 is parked in the adjacent parking space Z2. It has been. For example, the first empty threshold L1 is set to a numerical value obtained by multiplying the stable value AV2 by a reliability coefficient (for example, 1.2) obtained from an experiment or the like.

  The full threshold H2 used for the parking determination process is a numerical value between the first empty threshold L1 and the trigger threshold H1, that is, greater than the first empty threshold L1 and smaller than the trigger threshold H1. It is set to a numerical value.

  The threshold determination unit 122 shown in FIG. 2 determines whether or not the change amount G calculated by the change amount calculation unit 121 exceeds the trigger threshold H1 that is larger than the first empty threshold L1 used in the first empty vehicle determination process. Determine whether.

  When the threshold determination unit 122 determines that the amount of change G has exceeded the trigger threshold H1, the vehicle determination unit 123 determines whether there is a vehicle in the determination target parking space Z (detection space). Start processing. Specifically, the vehicle determination unit 123 determines a time point T32 (see FIG. 7) after a predetermined set time Ta has elapsed from a time point T31 (see FIG. 5) when it is determined that the amount of change G has exceeded the trigger threshold value H1. ) Is determined whether the change amount G is equal to or greater than the full threshold value H2. Here, when the change amount G is equal to or greater than the full threshold value H2, the vehicle determination unit 123 determines that the vehicle is present in the determination target parking space Z, that is, the parking space Z. It is determined that the vehicle is parked. The set time Ta is set based on an average time required for the vehicle to enter the parking space Z and park in the parking space Z.

  The first empty vehicle determination unit 124 performs a first empty determination process for determining whether or not the determination target parking space Z (detection space) is empty based on the change amount G and the first empty threshold L1. Specifically, the first empty vehicle determination unit 124 determines that the determination target parking space Z is an empty state in which no vehicle exists when the amount of change G is less than the first empty threshold L1.

  The fluctuation determination unit 125 performs processing for determining whether or not the detection value of the magnetic sensor 11 has fluctuated. This determination process is started after the vehicle is parked in the parking space Z. Specifically, when the vehicle determination unit 123 determines that the vehicle is parked in the parking space Z, the determination process is started.

  The first difference calculation unit 126 calculates a difference vector (hereinafter, referred to as a first difference vector) of magnetic field vectors before and after parking of the vehicle with respect to the parking space Z. The first difference vector is a vector indicating a difference between the magnetic vector detected by the magnetic sensor 11 before parking and the magnetic vector detected by the magnetic sensor 11 after parking, and the fluctuation of the magnetic field vector changed before and after parking. Indicates the amount. Specifically, the first difference calculation unit 126 stores the vector amount of the magnetic field vector detected by the magnetic sensor 11 before the vehicle is parked in the storage unit 13 and determines that the vehicle is parked. Sometimes, the vector quantity of the magnetic field vector detected by the magnetic sensor 11 is stored in the storage unit 13, and the difference between these vectors is calculated as the first difference vector.

  FIG. 5 is a vector diagram showing magnetic field vectors R1 to P3 at the installation position Q of the magnetic sensor 11A in the parking space Z1. FIG. 5A shows the magnetic field vector R1 when the vehicle is not parked in any of the parking spaces Z1, Z2. FIG. 5B shows the magnetic field vector R2 when the vehicle is parked only in the parking space Z1. FIG. 5C shows a magnetic field vector R3 when the vehicle is parked only in the parking space Z2. In FIG. 5, the X-axis direction is north, the Y-axis direction is east, and the Z-axis direction is vertical. In each figure, the installation position Q is the origin of the X, Y, and Z axes.

  For example, the magnetic sensor 11A of the parking space Z1 detects the magnetic field vector R1 (see FIG. 5A) when the vehicle is not parked in any of the adjacent parking spaces Z1, Z2, and only the parking space Z1. When the magnetic sensor 11A detects the magnetic field vector R2 (see FIG. 5B) when the vehicle is parked, a first difference vector RS11 (see FIG. 6A) that is a difference vector between the vectors R1 and R2. ) Is calculated by the first difference calculation unit 126. In this case, the first difference calculation unit 126 stores the coordinates [X0, Y0, Z0] of each axis of the magnetic field vector R1 in the storage unit 13, and coordinates [X1, Y1, Z1] of each axis of the magnetic field vector R2. ] Is stored in the storage unit 13, and the first difference vector RS11 is calculated from each coordinate.

  Here, the first difference vector RS11 is a unique vector of the vehicle parked in the parking space Z1. Therefore, for example, when the vehicle is parked only in the parking space Z2, even when the vehicle is further parked in the parking space Z1, the first difference calculation unit 126 calculates the first difference vector RS11. For example, as shown in FIG. 5B, when the vehicle is parked only in the parking space Z2, the magnetic sensor 11A in the parking space Z1 detects the magnetic field vector R3 (coordinates [X2, Y2, Z2]). Suppose. In this case, the magnetic field vector R4 detected by the magnetic sensor 11A after the vehicle is parked in the parking space Z1 is a composite vector obtained by adding the first difference vector RS11 to the magnetic field vector R3 as shown in FIG. Become.

  A magnetic object or the like that affects the magnetic field may be arranged around the installation position of the magnetic sensor 11. For example, a magnetic object is installed in a space adjacent to the determination target parking space Z1 (detection space), another vehicle having a high influence on geomagnetism passes through the vicinity of the parking space Z1, or the adjacent parking space Z2 In some cases, other vehicles having high influence on geomagnetism are parked. In any case, the magnetic object and the other vehicle arranged outside the parking space Z1 that is the determination target are factors that distort the magnetic field including the geomagnetism at the installation position of the magnetic sensor 11A in the parking space Z1. The vector amount of the magnetic field vector at the installation position varies depending on the factor. However, the amount of change in the magnetic field vector detected by the magnetic sensor 11A differs between when the vehicle is parked in the determination target parking space Z1 and when another vehicle or a magnetic object is arranged in the parking space Z2. This is because the position of the vehicle parked in the parking space Z1 is different from the positions of other vehicles and magnetic objects arranged in the parking space Z2. That is, the vector quantity of the magnetic field vector detected by the magnetic sensor 11A differs depending on whether the magnetic sensor 11A is affected from the vertical upper side or the lateral direction. For this reason, the magnetic field direction of the magnetic field vector R3 described above does not coincide with the magnetic field direction of the magnetic field vector R2, and the magnitudes of the vectors do not become the same.

  When the fluctuation determination unit 125 determines that the detection value of the magnetic sensor 11 has fluctuated, the second difference calculation unit 127 calculates a difference vector (hereinafter referred to as a first difference vector) of the magnetic field vectors before and after the fluctuation of the detection value of the magnetic sensor 11. 2 difference vector). The second difference vector is a vector indicating a difference between the magnetic vector detected before the change of the detection value of the magnetic sensor 11 and the magnetic vector which is the detection value after the change, and the magnetic field before and after the change of the detection value. Indicates the amount of vector variation. Specifically, the second difference calculation unit 127 stores the coordinates of the magnetic field vector detected by the magnetic sensor 11 before the detection value fluctuates in the storage unit 13, and after the fluctuation occurs, the magnetic sensor 11 stores the coordinates of the magnetic field vector detected by the storage unit 13 and calculates a difference between the magnetic field vectors obtained from the coordinates as the second difference vector.

  The fluctuation of the detection value of the magnetic sensor 11 fluctuates, for example, when the vehicle leaves (leaves) from the parking space Z1 (detection space) to be determined. In this case, the detection value of the magnetic sensor 11A returns from the magnetic field vector R2 to the magnetic field vector R1 if it is not affected by other magnetic objects or other vehicles. Therefore, in this case, the second difference calculation unit 127 calculates the second difference vector RS21 (see FIG. 6) having the same size as the first difference vector RS11 and in the reverse direction.

  Moreover, even if the detection value of the magnetic sensor 11 is in a full state in which the vehicle is parked in the parking space Z1, it also varies when the vehicle leaves the adjacent parking space Z2. For example, when the vehicle leaves the parking space Z2, the magnetic field vector R5 detected by the magnetic sensor 11A after leaving the vehicle becomes a combined vector obtained by adding a later-described difference vector RS22 to the magnetic field vector R4. Therefore, in this case, the difference vector RS22 is calculated as the second difference vector. Here, the difference vector RS22 is a vector having the same magnitude and the reverse direction as the difference vector RS12 of the magnetic field vector R1 and the magnetic field vector R3 described above.

  The second empty vehicle determination unit 128 determines whether or not the parking space Z has changed from the full state to the empty state after the vehicle is parked in the determination target parking space Z. For example, the second empty vehicle determination unit 128 changes the parking space Z from the full state to the empty state when a magnetic field fluctuation in a direction opposite to the direction of the first difference vector calculated by the first difference calculation unit 126 occurs. Judge that it has changed.

  For example, when a vehicle parked in the parking space Z1 leaves, the detection value of the magnetic sensor 11A in the parking space Z1 returns from the magnetic field vector R2 to the magnetic field vector R1 (see FIG. 6A). In this case, in the installation position Q of the magnetic sensor 11A, a magnetic field fluctuation having the same magnitude occurs in the opposite direction to the first difference vector RS1. On the other hand, when the vehicle parked in the parking space Z2 leaves, the detection value of the magnetic sensor 11A in the parking space Z1 returns from the magnetic field vector R3 to the magnetic field vector R1. In this case, in the installation position Q of the magnetic sensor 11A, a magnetic field fluctuation (magnetic field fluctuation in the opposite direction of the second difference vector RS2) that is different in direction and magnitude from the first difference vector RS1 occurs.

  Therefore, the second empty vehicle determination unit 128 compares the direction of the second difference vector calculated by the second difference calculation unit 127 with the direction of the first difference vector, and the direction of the second difference vector is When it is determined whether or not the direction of the first difference vector coincides with the opposite direction, and it is determined that the direction of the second difference vector coincides with the opposite direction, the parking space Z changes from the full state to the empty state. It is determined that That is, it is determined that the vehicle has left the determination target parking space Z.

  In the present embodiment, the second empty vehicle determination unit 128 determines whether or not the second difference vector is an inverse vector of the first difference vector, and when the parking space Z is in a full state when the second difference vector is an inverse vector. It is determined that the state has changed to an empty state. In other words, the second empty vehicle determination unit 128 determines that the direction of the second difference vector coincides with the opposite direction of the direction of the first difference vector, and the magnitude of the second difference vector and the first difference vector. It is determined that the parking space Z has changed from the full state to the empty state.

[Vehicle detection processing]
Hereinafter, an example of the vehicle detection method of the present invention will be described together with the procedure of the vehicle detection process executed by the control unit 12 with reference to FIGS. 7 to 11 and the flowchart of FIG. 12, S11, S12,... Indicate processing procedure numbers (step numbers). In the following description, it is assumed that the detection value of the magnetic sensor 11A of the parking space Z1 is stored in the storage unit 13.

  First, as shown in FIG. 7, a vehicle detection process in the case where the vehicle 21 enters the parking space Z1 in a forward direction and exits in the reverse direction will be described. Here, FIG. 7 shows vehicle states P31 to P35 when entering and leaving the vehicle, and a waveform W31 that represents a change over time in the change amount G of the detected value of the magnetic sensor 11A while entering and leaving the vehicle.

<Steps S11 and S12>
As shown in FIG. 12, in step S11, the control unit 12 determines whether or not the change amount G of the detection value of the magnetic sensor 11A is smaller than the first empty threshold L1. A vehicle state P31 shown in FIG. 7 shows a state in which the front side of the vehicle 21 is approaching the parking space Z1, and in this vehicle state P31, the vehicle 21 has little influence on the magnetic field at the installation position of the magnetic sensor 11A. For this reason, the change amount G in the vehicle state P31 is smaller than the first empty threshold value L1. Therefore, when the vehicle 21 is in the vehicle state P31, the control unit 12 determines that the amount of change G is smaller than the first empty threshold L1 (Yes in S11). In this case, in the next step S12, the control unit 12 determines that the parking space Z1 is empty, stores status information indicating that the parking space Z1 is empty in the storage unit 13, and the status. Information is output to the management server 15. Thereafter, the process returns to step S11. If it is determined in step S11 that the change amount G is equal to or greater than the first empty threshold L1, the process proceeds to the next step S13.

<Step S13>
In step S13, the control unit 12 determines whether or not the change amount G has exceeded the trigger threshold value H1. When the vehicle 21 enters the parking space Z1 and enters the vehicle state P32 in which the engine portion of the vehicle 21 is disposed above the magnetic sensor 11A, the influence of the vehicle 21 on the magnetic field at the installation position of the magnetic sensor 11A is abrupt. growing. Therefore, in the vehicle state P32, the change amount G is larger than the trigger threshold value H1. Therefore, when the vehicle 21 is in the vehicle state P32, the control unit 12 determines that the change amount G is larger than the trigger threshold value H1 (Yes in S13). In this case, the process proceeds to the next step S14. If it is determined in step S13 that the change amount G is equal to or less than the trigger threshold value H1 (No in S13), the process returns to step S11.

<Step S14>
In step S14, the control unit 12 determines whether or not the set time Ta has elapsed from time T31 (see FIG. 7) when it is determined in step S13 that the change amount G has exceeded the trigger threshold value H1. If it is determined that the set time Ta has elapsed, the process proceeds to step S15.

<Step S15>
In step S15, the control unit 12 determines whether or not the change amount G at the time T32 (see FIG. 7) when the set time Ta has elapsed is smaller than the trigger threshold value H1. As the vehicle 21 further enters the parking space Z1 and the vehicle 21 moves to the vehicle state P33, the influence of the vehicle 21 on the magnetic field at the installation position of the magnetic sensor 11A gradually decreases, and the vehicle 21 enters the vehicle state P33. Then, the amount of change G becomes smaller than the trigger threshold value H1. Here, the vehicle state P33 is a state in which the engine portion of the vehicle 21 passes above the magnetic sensor 11A and the rear portion of the vehicle 21 is disposed above the magnetic sensor 11A, and the vehicle 21 enters the parking space Z1. You are parked. Therefore, when the vehicle 21 is in the vehicle state P33, the control unit 12 determines that the change amount G is smaller than the trigger threshold value H1 (Yes in S15). In this case, the process proceeds to the next step S16. If it is determined in step S15 that the amount of change G at time T32 (see FIG. 7) is greater than or equal to the trigger threshold value H1 (No in S15), the process proceeds to step S17 described later.

  Information relating to the detection value (magnetic field vector) of the magnetic sensor 11A at time T32 (see FIG. 7) is stored in the storage unit 13. As specific information to be stored, coordinate information of each axis of the magnetic field vector can be considered.

<Step S16>
In step S16, the control unit 12 determines whether or not the amount of change G (determination value G1) at time T32 (see FIG. 7) is greater than the full threshold value H2. As described above, in the vehicle 21, the portion other than the engine portion has a low influence on the magnetic field, but the change amount G indicates a numerical value higher than the full threshold value H <b> 2. Therefore, when the vehicle 21 is in the vehicle state P33, the control unit 12 determines that the amount of change G is larger than the full threshold value H2 (Yes in S16). In this case, the process proceeds to the next step S17. On the other hand, if it is determined in step S17 that the amount of change G at time T32 (see FIG. 7) is less than or equal to the full threshold H2 (No in S16), the process returns to step S11.

<Step S17>
If it is determined in step S16 that the amount of change G at time T32 (see FIG. 7) is less than or equal to the full threshold value H2, the controller 12 determines that the parking space Z1 is full in the next step S17. judge. And the control part 12 memorize | stores the status information which shows that the parking space Z1 is a full state in the memory | storage part 13, and outputs the said status information to the management server 15. FIG.

<Step S18>
In the next step S18, the control unit 12 calculates the first difference vector. Step S18 is an example of a first difference calculation step of the present invention. Specifically, based on the magnetic field vector at time T32 stored in the storage unit 13 and the magnetic field vector that is the detected value detected by the magnetic sensor 11A before the vehicle 21 enters the parking space Z1, the first One difference vector is calculated. Information on the calculated first difference vector is stored in the storage unit 13. In the example of entry / exit shown in FIG. 7, the first difference vector RS11 shown in FIG. 6 is calculated.

<Step S19>
In the next step S18, the control unit 12 determines whether or not the detection value of the magnetic sensor 11A has changed. When the vehicle 21 starts to leave the parking space Z1 and the vehicle 21 moves from the vehicle state P33 to the vehicle state P34, the detection value of the magnetic sensor 11A changes. Here, the vehicle state P34 is a state in which the vehicle 21 starts to leave the parking space Z1 and the engine portion of the vehicle 21 is disposed above the magnetic sensor 11A. The controller 12 determines whether or not the detected value has changed by monitoring the detected value of the magnetic sensor 11A.

<Step S20>
If it is determined in step S19 that the detection value of the magnetic sensor 11A has changed, the control unit 12 determines whether or not the detection value of the magnetic sensor 11A has converged to a constant value. Specifically, when the detection value of the magnetic sensor 11A shows the same value for a certain time, it is determined that the detection value of the magnetic sensor 11A has converged to a certain value. For example, when the vehicle state P35 where the vehicle 21 has completely left the parking space Z1 is detected, the detection value of the magnetic sensor 11A is not affected by not only the vehicle 21 but also surrounding magnetic objects and other vehicles. For this reason, the detection value of the magnetic sensor 11A converges to the magnetic field vector R1 shown in FIG.

<Step S21>
If it is determined in step S20 that the detection value of the magnetic sensor 11A has converged to a constant value (see time point T33 in FIG. 7), in the next step S21, the control unit 12 calculates the second difference vector. In the example of entry / exit shown in FIG. 7, the second difference vector RS21 shown in FIG. 6 is calculated.

<Steps S22 to S24>
Thereafter, in step S22, the control unit 12 determines whether or not the second difference vector calculated in step S21 is an inverse vector of the first difference vector calculated in step S18. This determination is performed to determine whether or not the parking space Z1 has changed from a full state to an empty state. Step S22 is an example of an empty vehicle determination step of the present invention. Here, if it is determined that the second difference vector is not an inverse vector, it is determined that the parking space Z1 is full, the status information in the storage unit 13 is not changed, and in the next step S24, the control unit 12 After the detection value (convergence value) of the magnetic sensor 11A is stored in the storage unit 13, the process returns to step S19. On the other hand, if it is determined that the second difference vector is an inverse vector, the control unit 12 determines that the parking space Z1 has returned to an empty state. In the example of entry / exit shown in FIG. 7, since the second difference vector RS21 is an inverse vector of the first difference vector RS11, the control unit 12 determines that the second difference vector is an inverse vector. In this case, status information indicating that the parking space Z1 is empty is stored in the storage unit 13, and the status information is output to the management server 15 (S23). Then, a series of vehicle detection processes are complete | finished.

  Next, as shown in FIG. 8, a vehicle detection process in the case where the vehicle 21 moves backward in the middle of entering the parking space Z1 in the forward direction and leaves the vehicle will be described. In the following, description of procedures common to the procedures of the process detection process described above will be omitted. Here, FIG. 8 shows vehicle states P31, P32, and P35 when entering and leaving the vehicle, and a waveform W32 that represents a change over time in the change amount G of the detected value of the magnetic sensor 11A while entering and leaving the vehicle.

  When the vehicle 21 moves backward from the vehicle state P32 described above and leaves the vehicle state P35, the change amount G temporarily becomes larger than the trigger threshold H1 in the vehicle state P32, but in the vehicle state P35, The change amount G is smaller than the first empty threshold value L1. Therefore, even if it is determined in step S15 described above that the change amount G is smaller than the trigger threshold value H1, in the next step S16, the control unit 12 determines that the change amount G is greater than the first empty threshold value L1. Is also determined to be small (No in S16). In this case, the process returns to step S11 while the determination result of the parking space Z1 is maintained in the empty state.

  Next, as shown in FIG. 9, a vehicle detection process in the case where the vehicle 21 enters the parking space Z1 backward and leaves the parking space Z1 will be described. Here, FIG. 9 shows vehicle states P41 to P45 when entering and leaving, and a waveform W33 that represents a change with time in the change amount G of the detected value of the magnetic sensor 11A while entering and leaving the vehicle. The vehicle states P41 to P45 differ from the vehicle states P31 to P35 described above only in the direction in which the vehicle 21 enters the parking space Z1, and the other operation states are the same.

  A vehicle state P41 shown in FIG. 9 shows a state in which the rear side of the vehicle 21 is approaching the parking space Z1, and in this vehicle state P41, the influence of the vehicle 21 on the magnetic field at the installation position of the magnetic sensor 11A is small. For this reason, the change amount G in the vehicle state P41 is smaller than the first empty threshold value L1. Therefore, when the vehicle 21 is in the vehicle state P41, the control unit 12 determines that the change amount G is smaller than the first empty threshold L1 (Yes in S11), and the parking space Z1 is in an empty state. Determine (S12).

  When the vehicle 21 further enters the parking space Z1 and enters the vehicle state P42 in which the rear portion of the vehicle 21 is disposed above the magnetic sensor 11A, the influence of the vehicle 21 on the magnetic field at the installation position of the magnetic sensor 11A is slightly. growing. However, in the vehicle state P42, the change amount G does not exceed the trigger threshold value H1. Although the change amount G may exceed the full threshold value H2, the presence / absence of the vehicle 21 in the parking space Z1 is not determined unless the change amount G exceeds the trigger threshold value H1. Therefore, the determination result of the parking space Z1 remains maintained in an empty state.

  When the vehicle 21 further enters the parking space Z1 and enters the vehicle state P43 in which the engine portion of the vehicle 21 is disposed above the magnetic sensor 11A, the influence of the vehicle 21 on the magnetic field at the installation position of the magnetic sensor 11A is abrupt. Become bigger. Here, the vehicle state P43 is a state in which the engine portion of the vehicle 21 is disposed above the magnetic sensor 11A and the vehicle 21 is parked in the parking space Z1. In the vehicle state P43, the change amount G is greater than the trigger threshold value H1. Therefore, when the vehicle 21 is in the vehicle state P43, the control unit 12 determines that the change amount G is larger than the trigger threshold value H1 (Yes in S13), and then the process proceeds to the next step S14.

  When it is determined in step S14 that the set time Ta has elapsed, in step S15, as described above, the control unit 12 determines that the change amount G at time T32 (see FIG. 9) when the set time Ta has elapsed. It is determined whether or not the trigger threshold value H1 is smaller. In the vehicle state P43 shown in FIG. 9, the vehicle 21 is parked with the engine portion disposed above the magnetic sensor 11A. Therefore, when the vehicle 21 is in the vehicle state P43, the control unit 12 determines that the change amount G is larger than the trigger threshold value H1 (No in S15). In this case, the process proceeds to the next step S17, and the processes after step S17 described above are performed.

  In the example of entry / exit shown in FIG. 9, in the above-described step S18, the first difference vector RS11 shown in FIG. 6A is calculated as the first difference vector. In step S21 described above, the second difference vector RS21 shown in FIG. 6A is calculated as the second difference vector.

  Next, as shown in FIG. 10, a vehicle detection process when the vehicle 21 enters the parking space Z1 in a forward direction and leaves the parking space Z1 in the reverse direction while the vehicle 22 is parked will be described. Here, FIG. 10 shows vehicle states P51 to P56 when entering and leaving the vehicle, and a waveform W34 representing a change over time in the change amount G of the detected value of the magnetic sensor 11A while entering and leaving the vehicle.

  A vehicle state P51 shown in FIG. 10 shows a state in which the front side of the vehicle 22 is approaching the parking space Z2, and in this vehicle state P51, the influence of the vehicle 22 on the magnetic field at the installation position of the magnetic sensor 11A is small. For this reason, the change amount G in the vehicle state P51 is smaller than the first empty threshold value L1. The vehicle state P52 is a state in which the vehicle 22 is parked in the parking space Z2. Even when the vehicle 22 is in the vehicle state P52, the change amount G is smaller than the first sky threshold L1. Therefore, in a state where the vehicle 21 has not entered the parking space Z1, the control unit 12 determines that the change amount G is smaller than the first empty threshold L1 regardless of the presence or absence of the vehicle 22 in the parking space Z2. (Yes in S11), it is determined that the parking space Z1 is empty (S12).

  In the example of entering / exiting shown in FIG. 10, in step S18 described above, the first difference vector RS11 shown in FIG. 6B is calculated as the first difference vector.

  Moreover, the vehicle state P55 of FIG. 10 shows a state in which the vehicle 22 is parked in the parking space Z2, and the vehicle 21 has left the parking space Z1 in reverse. When the vehicle state P55 is changed to the vehicle state P56, the control unit 12 determines in step S19 that the detection value of the magnetic sensor 11A has changed. Thereafter, when the detection value of the magnetic sensor 11A converges to a constant value, the second difference vector is calculated in step S21. The second difference vector calculated at this time is shown in FIG. This is the second difference vector RS21. Therefore, in the next step S22, it is determined that the second difference vector is an inverse vector of the first difference vector. That is, the control unit 12 determines that the parking space Z1 is empty.

  Next, as shown in FIG. 11, with the vehicle 22 parked in the parking space Z2, the vehicle 21 enters the parking space Z1 in a forward direction, and then the vehicle 22 leaves the parking space Z2 in the reverse direction. Then, vehicle detection processing when the vehicle 21 leaves the parking space Z1 backward will be described. Here, FIG. 11 shows vehicle states P51 to P55, P57, and P58 during entry / exit, and a waveform W35 that represents a change over time in the change amount G of the detected value of the magnetic sensor 11A during entry / exit.

  A vehicle state P57 shown in FIG. 11 shows a state in which the vehicle 21 is parked in the parking space Z1, and the vehicle 22 leaves the parking space Z2 in the reverse direction. When the vehicle state P54 is changed to the vehicle state P57, the vehicle 22 has no influence on the magnetic field at the installation position of the magnetic sensor 11A, and the detection value of the magnetic sensor 11A varies. Therefore, in step S19, the control unit 12 determines that the detection value of the magnetic sensor 11A has changed. Thereafter, when the detection value of the magnetic sensor 11A converges to a constant value, the second difference vector is calculated in step S21. The second difference vector calculated at this time is shown in FIG. This is the second difference vector RS22. Therefore, in the next step S22, it is determined that the second difference vector is not an inverse vector of the first difference vector. That is, in the vehicle state P57, it is determined that the parking space Z1 is still full.

  On the other hand, when the vehicle 21 changes from the vehicle state P57 to the vehicle state P58, the control unit 12 again determines in step S19 that the detection value of the magnetic sensor 11A has changed. Thereafter, the second difference vector is calculated in step S21. The second difference vector calculated at this time is the second difference vector RS21 shown in FIG. 6C. Therefore, in the next step S22, it is determined that the second difference vector is an inverse vector of the first difference vector. That is, in the vehicle state P58, it is determined that the parking space Z1 has changed from the full state to the empty state.

  As described above, in the vehicle detection device 10 according to the present embodiment, when the change amount G of the detection value of the magnetic sensor 11A in the parking space Z1 exceeds the trigger threshold value H1 larger than the first empty threshold value L1. A parking determination process for determining whether or not the vehicle 21 is parked in the parking space Z1 by the vehicle determination unit 123 is started. Then, it is determined that the amount of change G has exceeded the trigger threshold value H1, the amount of change G (determination value G1) after the set time Ta has elapsed from the time point T31 of the determination is less than the trigger threshold value, and When it is equal to or greater than the full threshold value H2, it is determined that the vehicle 21 is parked in the parking space Z1. Further, after the parking space Z1 is determined to be full, it is determined whether or not the second difference vector is an inverse vector of the first difference vector on the condition that the detection value of the magnetic sensor 11A has changed. Is done. When it is determined that the second difference vector is an inverse vector, it is determined that the parking space Z1 has changed from the full state to the empty state. For this reason, even when the vehicle 21 is parked in the parking space Z1, the full state or the empty state in the parking space Z1 can be accurately determined.

  Even if the magnetic field including the geomagnetism in the parking space Z1 fluctuates due to the influence of the vehicle 22 parked in the adjacent parking space Z2, it is possible to accurately determine the full state and the empty state in the parking space Z1. It is.

  In the above-described embodiment, it is determined in step S22 whether or not the second difference vector is an inverse vector of the first difference vector. If the second difference vector is the inverse vector, the parking space Z1 is empty from the full state. Although the example which determines with having changed into the state was demonstrated, this invention is not limited to this process example. What is necessary is just to determine that the parking space Z1 has changed from the full state to the empty state when it is determined that the direction of the second difference vector coincides with the opposite direction of the direction of the first difference vector.

  Moreover, although the above-mentioned embodiment demonstrated the structure which determines the presence or absence of the vehicle 21 parked in the parking space Z which is an example of detection space, this invention is not limited to such a structure. For example, parking spaces and parking spaces established near the entrance of buildings, parking spaces defined on roadside belts, one or more parking spaces defined within the site of a house, vehicle inspection sites, etc. The vehicle detection device 10 can also be applied to discriminating the presence or absence of a vehicle parked or stopped in a stop space (all other examples of the detection space).

DESCRIPTION OF SYMBOLS 10: Vehicle detection apparatus 11, 11A: Magnetic sensor 12: Control part 13: Storage part 14: Communication part 15: Management server 17: Entrance / exit 20: Parking lot 21, 22: Vehicle 121: Change amount calculation part 122: Threshold determination part 123: Vehicle determination unit 124: First empty determination unit 125: Fluctuation determination unit 126: First difference calculation unit 127: Second difference calculation unit 128: Second empty determination unit

Claims (6)

A vehicle detection device that determines the presence or absence of a vehicle in the detection space based on a detection value of a magnetic sensor that detects a magnetic field vector including the magnitude and direction of a magnetic field in the detection space,
The magnetic field vectors of the first state in which the vehicle enters and stops in the detection space and the second state in which the vehicle leaves the detection space are acquired from the magnetic sensor, and a first difference vector of each magnetic field vector A first difference calculating unit for calculating
An empty vehicle that determines that the detection space has changed from the first state to the second state when a magnetic field fluctuation in a direction opposite to the direction of the first difference vector occurs after the vehicle stops in the detection space. A vehicle detection device comprising: a determination unit. A detection value fluctuation determination unit that determines whether or not the detection value of the magnetic sensor has changed after the vehicle has stopped in the detection space;
A second difference calculation unit that calculates a second difference vector of the magnetic field vector before and after the fluctuation of the detected value,
The empty vehicle determination unit determines whether the direction of the second difference vector matches the reverse direction of the first difference vector, and determines that the direction of the second difference vector matches the reverse direction. The vehicle detection device according to claim 1, wherein the detection space determines that the detection space has changed from the first state to the second state.   The empty vehicle determination unit determines whether the magnitude of the second difference vector matches the magnitude of the first difference vector, determines that the direction of the second difference vector matches the reverse direction, and The vehicle detection device according to claim 2, wherein when it is determined that the magnitudes of both difference vectors match, it is determined that the detection space has changed from the first state to the second state. A vehicle determination unit that determines that the vehicle has entered and stopped in the detection space based on a change amount of the detection value of the magnetic sensor;
The vehicle according to any one of claims 1 to 3, wherein the empty vehicle determination unit determines whether or not the detection space has changed from the first state to the second state after the determination by the vehicle determination unit. Detection device. A vehicle detection method for determining the presence or absence of a vehicle in the detection space based on a detection value of a magnetic sensor that detects a magnetic field vector including the magnitude and direction of a magnetic field in the detection space,
The magnetic field vectors of the first state in which the vehicle enters and stops in the detection space and the second state in which the vehicle leaves the detection space are acquired from the magnetic sensor, and a first difference vector of each magnetic field vector A first difference calculating step of calculating
An empty vehicle that determines that the detection space has changed from the first state to the second state when a magnetic field fluctuation in a direction opposite to the direction of the first difference vector occurs after the vehicle stops in the detection space. A vehicle detection method including a determination step.   The program for making a computer perform each step of the vehicle detection method of Claim 5.

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