Axis misalignment detection device and axis misalignment detection program

Abstract

The present invention provides an axis misalignment detection device that detects the axis misalignment of a radio wave sensor that emits radio waves toward the interior of a vehicle and receives the reflected waves that are reflected by objects inside the vehicle. [Solution] The system includes a reflection characteristic information generation unit (12, 12a, 12b, 12c) that generates reflection characteristic information indicating the reflection characteristics of a reflected wave from sensor information based on the reflected wave, which is a radio wave emitted by a radio wave sensor (2) toward the interior of the vehicle when there is no moving object inside the vehicle, and reference reflection characteristic information; an error detection unit (13) that compares the reflection characteristic information generated by the reflection characteristic information generation unit (12, 12a, 12b, 12c) with reference reflection characteristic information and detects the difference between the reflection characteristics and the reference reflection characteristics as an error; and a determination unit (14) that determines whether or not an axis misalignment has occurred based on the error detected by the error detection unit (13).

Description

Technical Field

[0001] The present disclosure relates to an axis deviation detection device and an axis deviation detection program.

Background Art

[0002] In recent years, a technique for detecting an occupant in a vehicle interior based on a reflected wave obtained by reflecting radio waves irradiated by a radio wave sensor toward the vehicle interior on an object in the vehicle interior is known. Here, the "detection of an occupant" includes detection of the presence or absence of an occupant, detection of the seating position of the occupant, or detection of the physique of the occupant. The above detection results of the occupant are utilized for various controls such as detection of abandonment of infants and the like, or airbag deployment control. By the way, in a technique for monitoring the vehicle periphery by detecting an object around the vehicle based on a reflected wave obtained by reflecting radio waves irradiated by a radio wave sensor toward the outside of the vehicle on an object outside the vehicle, there is a technique for detecting an axis deviation of the radio wave sensor. For example, in Patent Document 1, in order to detect that the mounting axis of a radar device attached to the front bumper of a vehicle has deviated from the initial state, a minute reflector such as metal is disposed on an extension in a direction deviated from a predetermined detection direction of the radar device in front of the mounting position of the radar device to create a reference reflection point, and measurement data from the reference reflection point during operation of the radar device is compared with a reference value stored in advance, thereby detecting an axis deviation of the radar device for detecting an object in front of the vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For various controls based on the detection results of occupants inside a vehicle using radio wave sensors to be performed accurately, it is necessary that occupants are detected accurately inside the vehicle. However, if the radio wave sensor is misaligned, this misalignment can reduce the accuracy of occupant detection inside the vehicle. Therefore, there was a need for a technology to detect when a radio wave sensor used to detect occupants inside a vehicle is misaligned. It should be noted that the conventional technology described above is a technology for detecting misalignment of radio wave sensors used to detect objects around a vehicle, and not for detecting misalignment of radio wave sensors used to detect occupants inside the vehicle. Even if one were to attempt to apply the conventional technology described above to detecting misalignment of radio wave sensors used to detect occupants inside the vehicle, it would be necessary to install additional minute reflective materials, and there is a possibility that the installed minute reflective materials may fall off.

[0005] This disclosure was made to solve the above-mentioned problems, and aims to provide an axial misalignment detection device that detects the axial misalignment of a radio wave sensor that irradiates radio waves toward the interior of a vehicle and receives reflected waves that are reflected by objects inside the vehicle. [Means for solving the problem]

[0006] The shaft misalignment detection device according to this disclosure is a shaft misalignment detection device that detects shaft misalignment of a radio wave sensor that irradiates radio waves toward the interior of a vehicle and receives reflected waves reflected by objects in the interior of the vehicle, and comprises: a reflection characteristic information generation unit that generates reflection characteristic information indicating the reflection characteristics of the reflected waves from sensor information based on reflected waves reflected by objects in the interior of the vehicle when the radio wave sensor irradiates radio waves toward the interior of the vehicle in a situation in which there are no moving objects in the interior of the vehicle; an error detection unit that compares the reflection characteristic information generated by the reflection characteristic information generation unit with reference reflection characteristic information indicating a reference reflection characteristic that serves as a standard for reflection characteristics, which is generated assuming a reference situation in the interior of the vehicle, and detects the difference between the reflection characteristics and the reference reflection characteristics as an error; and a determination unit that determines whether or not shaft misalignment has occurred based on the error detected by the error detection unit. [Effects of the Invention]

[0007] According to this disclosure, it is possible to detect misalignment of a radio wave sensor that emits radio waves towards the interior of a vehicle and receives reflected waves that are reflected by objects inside the vehicle. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example configuration of the axial misalignment detection device according to Embodiment 1. [Figure 2] This diagram illustrates an example of the installation location of a radio wave sensor according to Embodiment 1 and the mechanism for detecting objects. [Figure 3] This figure illustrates an example of a first reflection characteristic map generated by the reflection characteristic information generation unit in Embodiment 1. Figure 3A shows the interior of a vehicle, and Figure 3B shows an example of a first reflection characteristic map. [Figure 4] This is a flowchart illustrating the operation of the axial misalignment detection device according to Embodiment 1. [Figure 5] Figures 5A and 5B show an example of the hardware configuration of an axial misalignment detection device. [Figure 6] This figure shows an example configuration of the axial misalignment detection device according to Embodiment 2. [Figure 7] In Embodiment 2, the following diagram illustrates an example of a stationary object region that is removed from the first reflection characteristic map by the reflection characteristic information generation unit: Figure 7A shows the interior of a vehicle, and Figure 7B illustrates an example of a stationary object region that is removed from the first reflection characteristic map. [Figure 8] This is a flowchart illustrating the operation of the axial misalignment detection device according to Embodiment 2. [Figure 9] This figure shows an example configuration of an axis misalignment detection device in Embodiment 2, in which a first reflection characteristic map is generated when it is determined that the seat position is the reference position, and the first reflection characteristic map is not generated if the seat position is not the reference position. [Figure 10]This flowchart illustrates the operation of the axial misalignment detection device in Embodiment 2, which generates a first reflection characteristic map when it is determined that the seat position is the reference position, and does not generate a first reflection characteristic map if the seat position is not the reference position. [Figure 11] This figure shows an example configuration of the axial misalignment detection device according to Embodiment 3. [Figure 12] This is a flowchart illustrating the operation of the axial misalignment detection device according to Embodiment 3. [Figure 13] This figure shows an example configuration of the axial misalignment detection device according to Embodiment 4. [Figure 14] This is a flowchart illustrating the operation of the axial misalignment detection device according to Embodiment 4. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described in detail below with reference to the drawings. Embodiment 1. Figure 1 shows an example of the configuration of the axial misalignment detection device 1 according to Embodiment 1. The axial misalignment detection device 1 according to Embodiment 1 is connected to a radio wave sensor 2, and the axial misalignment detection device 1 and the radio wave sensor 2 constitute an axial misalignment detection system 100.

[0010] The axial misalignment detection device 1 detects the axial misalignment of a radio wave sensor 2, which emits radio waves toward the vehicle interior and receives reflected waves that are reflected by objects inside the vehicle interior. In Embodiment 1, the axial misalignment of the radio wave sensor 2 includes angular misalignment in the azimuth, elevation, or roll direction of the radio wave sensor 2, or positional misalignment in the depth direction of the radio wave sensor 2. More specifically, the axis deviation detection device 1 obtains sensor information from the radio wave sensor 2 based on the reflected wave obtained by irradiating radio waves into the passenger compartment when there is no moving object in the passenger compartment and the irradiated radio waves are reflected by an object in the passenger compartment. Based on the obtained sensor information, the axis deviation detection device 1 generates information indicating the reflection characteristics of the reflected wave (hereinafter referred to as "reflection characteristic information"). Then, the axis deviation detection device 1 detects the axis deviation of the radio wave sensor 2 by comparing the generated reflection characteristic information with the reference reflection characteristic information (hereinafter referred to as "reference reflection characteristic information").

[0011] The sensor information based on the reflected wave obtained by irradiating radio waves into the passenger compartment by the radio wave sensor 2 and the irradiated radio waves being reflected by an object in the passenger compartment is output to, for example, an occupant detection device (not shown), and the occupant detection device uses it to detect an occupant in the passenger compartment. The "detection of an occupant" as used here includes, for example, detection of the presence or absence of an occupant, detection of the seating position of the occupant, or detection of the physique of the occupant. The detection result of the above occupant is output from the occupant detection device to a vehicle control device (not shown), for example, and is utilized for various controls such as detection of abandonment of infants or the like or airbag deployment control by the vehicle control device. In order for these controls to be performed accurately, it is required that the occupant in the passenger compartment be accurately detected. However, if an axis deviation of the radio wave sensor 2 occurs, the axis deviation may reduce the detection accuracy of the occupant in the passenger compartment. Therefore, when such an axis deviation of the radio wave sensor 2 occurs, it is required that this be detected. The axis deviation detection device 1 according to Embodiment 1 detects such an axis deviation of the radio wave sensor 2. Details of the configuration example of the axis deviation detection device 1 according to Embodiment 1 will be described later.

[0012] In Embodiment 1, the axis deviation detection device 1 and the radio wave sensor 2 are mounted on the vehicle. The radio wave sensor 2 is a sensor that irradiates radio waves into the passenger compartment and observes a specific range in the passenger compartment based on the reflected wave, and includes a millimeter wave radar. In Embodiment 1, as an example, the radio wave sensor 2 is assumed to be a millimeter wave radar. The radio wave sensor 2 detects an object in the passenger compartment. The radio wave sensor 2 acquires sensor information based on a reflected wave obtained by reflecting radio waves irradiated toward the interior of the vehicle by an object in the vehicle interior.

[0013] Here, FIG. 2 is a diagram for explaining an example of the installation position of the radio wave sensor 2 according to the first embodiment and the mechanism for detecting an object. FIG. 2 is a diagram showing an example of the state inside the vehicle interior as viewed from the side of the vehicle. In FIG. 2, the vehicle is indicated by "C". Among the three-dimensional coordinate axes in the three-dimensional coordinate system representing the actual space inside the vehicle interior, the x-axis is an axis parallel to the vehicle width direction, the y-axis is an axis parallel to the vehicle height direction, and the z-axis is an axis parallel to the vehicle length direction. In the first embodiment, "parallel" is not limited to being strictly "parallel", but includes substantially parallel. In the three-dimensional coordinate system representing the actual space inside the vehicle interior, the origin is, for example, the installation position of the radio wave sensor 2. Note that the vehicle may be a right-hand drive vehicle or a left-hand drive vehicle. As shown in FIG. 2, the radio wave sensor 2 is installed, for example, above the vehicle interior. In FIG. 2, as an example, the radio wave sensor 2 is shown as being installed in an overhead console (not shown).

[0014] In the vehicle interior shown in FIG. 2, the radio wave sensor 2 irradiates radio waves toward the vehicle interior and receives the reflected waves of the radio waves from the objects in the vehicle interior. In FIG. 2, it is assumed that there is no occupant in the vehicle interior. Even if there is no occupant in the vehicle interior, the radio waves irradiated from the radio wave sensor 2 are reflected by the vehicle structures. The vehicle structures include, for example, the frame of the vehicle body or the frame of the seat. The frame of the vehicle body and the frame of the seat are made of metal. In FIG. 2, vehicle structures made of metal, such as the metal frame of the vehicle body or the metal frame of the seat, are indicated by "M". Also, in FIG. 2, the images of the radio waves irradiated from the radio wave sensor 2 and the reflected waves obtained by reflecting the radio waves by the vehicle structures made of metal in the vehicle interior are indicated by arrows. In Embodiment 1, as shown in Figure 2, the axial misalignment detection device 1 detects the axial misalignment of the radio wave sensor 2 from sensor information based on the reflected waves that are reflected by objects in the vehicle interior, more specifically, by the metal vehicle structure inside the vehicle interior, when the radio wave sensor 2 emits radio waves toward the vehicle interior.

[0015] In Embodiment 1, the radio wave sensor 2 is assumed to be a general-purpose radio wave sensor for detecting objects. The radio wave sensor 2 is a radio wave sensor that detects the angle and distance of an object by arranging multiple transmitting and receiving antennas using a MIMO (Multiple-Input Multiple-Output) antenna and transmitting and receiving signals frequency-modulated using the FM-CW (Frequency Modulation - Continuous Wave) method. The radio wave sensor 2 can also acquire velocity information related to the velocity of an object. Here, we will explain an example of how to acquire sensor information using the radio wave sensor 2. In this example, we will explain using the FM-CW method, which is commonly used in automotive applications, as the modulation method for the sensing signal of the radio wave sensor 2. The radio wave transmitting and receiving unit (not shown) of the radio wave sensor 2 periodically generates an FM signal (called a chirp wave) whose frequency increases and decreases. The radio wave transmitting and receiving unit amplifies the signal power to obtain the power necessary for irradiating radio waves, and irradiates the space inside the vehicle interior via a transmitting antenna (not shown). When radio waves irradiated into the vehicle interior reach a target object within the irradiation range of the radio wave transmitting / receiving unit, a portion of the waves are reflected by the surface of the target object and returned to the radio wave transmitting / receiving unit. Here, the target object refers to an object that reflects radio waves, such as the occupants inside the vehicle or the vehicle structure.

[0016] The radio wave transmitting and receiving unit receives radio waves (reflected waves) that have been reflected back from the surface of the target object via a receiving antenna (not shown). The radio wave transceiver unit receives a signal similar to the FM transmission wave as an FM received wave. This received signal is input to the radio wave transceiver unit after a time difference that is required for the radio waves to reach the target object and return. The radio wave transmitting and receiving unit extracts the frequency difference between the frequency of the generated FM signal and the frequency of the received signal, and generates an intermediate frequency (IF) signal with that frequency difference. The A / D conversion unit (not shown) of the radio wave sensor 2 converts the intermediate frequency signal from an analog signal to a digital signal, acquires the digital signal as sensor information, and outputs the acquired sensor information to the axial misalignment detection device 1.

[0017] Although Figure 1 shows only one radio wave sensor 2, this is merely an example. The type and number of radio wave sensors 2 can be single or multiple. For example, multiple radio wave sensors 2 may be installed on the vehicle, and multiple radio wave sensors 2 may be connected to the axle misalignment detection device 1. For example, one radio wave sensor 2 may be installed in a location that allows it to see the entire interior of the vehicle, such as an overhead console, so that one radio wave sensor 2 can cover the entire area of ​​the vehicle interior. Alternatively, one sensor may be installed for each area that can be seen by the radio wave sensor 2, for example, each area corresponding to a seat, or each of several pre-divided areas of the vehicle interior. In this case, the axial misalignment detection device 1 can detect the axial misalignment of each radio wave sensor 2. Furthermore, the operation control of the radio wave sensor 2 may be performed by the radio wave sensor 2 alone using an internal trigger, or it may be performed based on a trigger from outside the radio wave sensor 2.

[0018] An example configuration of the axial misalignment detection device 1 will be described. As shown in Figure 1, the axial misalignment detection device 1 comprises a motion absence detection unit 11, a reflection characteristic information generation unit 12, an error detection unit 13, a determination unit 14, a correspondence unit 15, and a reference reflection characteristic information storage unit 16.

[0019] The motion absence detection unit 11 detects whether or not there are any moving objects inside the vehicle. Here, "moving object" refers to a person, i.e., an occupant. The motion absence detection unit 11 should detect, by various means, whether or not there is a motion inside the vehicle.

[0020] For example, the motion absence detection unit 11 acquires images of the interior of the vehicle from an in-vehicle camera (not shown in Figure 1) installed in the vehicle for the purpose of monitoring the interior, and detects motion inside the vehicle by performing known image recognition processing on the captured images. If no motion is detected inside the vehicle, the motion absence detection unit 11 detects that there is no motion inside the vehicle.

[0021] Furthermore, for example, the motion absence detection unit 11 may acquire information indicating the opening and closing of a door and information indicating the state of the ignition switch from a door sensor (not shown) that detects the opening and closing of a vehicle door and an engine control unit (not shown), respectively. If it detects that the door has been opened and then closed after the engine has been turned off, it may detect that there is no motion present inside the vehicle.

[0022] Alternatively, for example, the motion absence detection unit 11 may detect whether or not there is no motion inside the vehicle by receiving information from the vehicle occupant notifying them that there is no motion inside the vehicle (hereinafter referred to as "absence notification information"). For example, after the occupant gets out of the vehicle, they operate a smart key or the like to input the absence notification information, and the motion absence detection unit 11 receives the input absence notification information from the smart key or the like.

[0023] Alternatively, for example, the motion absence detection unit 11 may acquire sensor information from the radio wave sensor 2 and detect from the sensor information whether or not there is a motion object inside the vehicle. For example, the motion absence detection unit 11 may use known techniques to analyze the sensor information in a time series and detect changes in the position or reflectance of objects to detect motion objects inside the vehicle. If no motion object is detected inside the vehicle, the motion absence detection unit 11 should determine that there is no motion object inside the vehicle. Note that in Figure 1, the arrow from the radio wave sensor 2 to the motion absence detection unit 11 is omitted.

[0024] The motion absence detection unit 11 outputs a detection result (hereinafter referred to as "motion absence detection result") indicating whether or not there is a motion object inside the vehicle interior to the reflection characteristic information generation unit 12. Furthermore, when the motion absence detection unit 11 detects that there is no motion inside the vehicle interior, it triggers the shaft misalignment detection device 1 to start detecting the shaft misalignment of the radio wave sensor 2.

[0025] The reflection characteristics information generation unit 12 generates reflection characteristics information, which indicates the reflection characteristics of the reflected waves, from sensor information based on the reflected waves that are reflected by objects inside the vehicle when the radio wave sensor 2 irradiates the vehicle interior. The process by which the reflection characteristics information generation unit 12 generates reflection characteristics information is called the "reflection characteristics information generation process."

[0026] In Embodiment 1, the reflection characteristic information is, for example, a reflection characteristic map that represents the reflection characteristics of a reflected wave as a three-dimensional spatial distribution within the vehicle interior. In Embodiment 1, the reflection characteristic represented by the reflection characteristic map is the reflection intensity. The reflection characteristic map expresses the reflection intensity in three dimensions: azimuth, elevation, and depth. In the following description, the reflective properties information will also be referred to as the reflective properties map. Furthermore, a reflective properties map that represents the reflective intensity as a reflective property, such as the reflective properties map generated by the reflective properties information generation unit 12 in Embodiment 1, will also be referred to as the "first reflective properties map."

[0027] Here, an example of how the reflection characteristic information generation unit 12 generates the first reflection characteristic map in Embodiment 1 will be described.

[0028] First, the reflection characteristic information generation unit 12 acquires sensor information from the radio wave sensor 2. The reflection characteristic information generation unit 12 then generates a first reflection characteristic map based on the sensor information output from the radio wave sensor 2. The reflection characteristics information generation unit 12 calculates the position of the reflection point of the reflected wave when the radio waves emitted from the radio wave sensor 2 are reflected by a target object inside the vehicle, based on the sensor information output from the radio wave sensor 2. The sensor information is generated from the reflected wave when the radio waves are reflected off the surface of the target object. The reflection characteristics information generation unit 12 can calculate the position of the reflection point on the surface of the target object from the sensor information. The reflection characteristic information generation unit 12 then generates a first reflection characteristic map that represents the reflection intensity of the reflected wave as a three-dimensional spatial distribution. The first reflection characteristic map generated by the reflection characteristic information generation unit 12 represents the reflection intensity of the reflected wave, which is reflected by objects in the vehicle interior from the radio wave sensor 2, using a plurality of grids that correspond to the reflection points of the radio waves in the three-dimensional space inside the vehicle interior. Each grid is assigned a dB value indicating the reflection intensity.

[0029] Here, Figure 3 is a diagram illustrating an example of a first reflection characteristic map generated by the reflection characteristic information generation unit 12 in Embodiment 1. Here, we assume that the radio wave sensor 2 is installed inside the vehicle at the location shown in Figure 2. Note that there are no occupants inside the vehicle. For clarity, Figure 3 also shows a diagram of the interior of the vehicle as seen from a rearview mirror located near the installation position of the radio wave sensor 2, as shown in Figure 3A. In Figure 3A, vehicle structures made of metal, such as the vehicle frame and seat frames, are indicated by "M". In Figure 3A, among the vehicle structures made of metal, those with particularly high reflected wave intensity are indicated by "M". For example, the edges of vehicle structures made of metal have a high reflected wave intensity from radio waves emitted from the radio wave sensor 2. Figure 3B shows an example of a first reflection characteristic map, which represents the reflection intensity of reflected waves reflected by objects inside a vehicle interior as shown in Figure 3A, when radio waves emitted from the radio wave sensor 2 are reflected by objects inside the vehicle interior, as a three-dimensional spatial distribution. Figure 3B is an xy cross-sectional view of the first reflection characteristic map, with the azimuth direction (i.e., vehicle width direction) and elevation direction (i.e., vehicle height direction) as the vertical and horizontal axes, respectively, and the depth direction (i.e., vehicle length direction) cut off at a position corresponding to the shoulder of the seat.

[0030] In the first reflection characteristics map, each grid is assigned a value, i.e., a dB value, corresponding to the reflection intensity of the reflected wave from an object located at the grid's position. More specifically, for a given grid, the greater the reflection intensity of the reflected wave from an object located at that grid's position, the larger the value assigned to that grid. In the first reflection characteristic map shown in Figure 3B, grids with larger assigned values ​​are shown darker. In other words, in the first reflection characteristic map shown in Figure 3B, grids with stronger reflection intensity are shown darker. As described above, the reflection intensity of reflected waves is higher at the edges of vehicle structures made of metal. Therefore, in the first reflection characteristic map, the grid corresponding to these edges, more specifically, the edges of the metal frame of the vehicle body and the edges of the metal frame of the seats, is shown as darker.

[0031] In this way, the reflection characteristic information generation unit 12 generates a first reflection characteristic map that represents the reflection intensity of the reflected wave as a three-dimensional spatial distribution within the vehicle interior. The reflection characteristic information generation unit 12 outputs the generated first reflection characteristic map to the error detection unit 13.

[0032] The error detection unit 13 compares the reflection characteristic information generated by the reflection characteristic information generation unit 12 with the reference reflection characteristic information and detects the difference between the reflection characteristic and the reference reflection characteristic (hereinafter referred to as "reference reflection characteristic") as an error. In other words, in Embodiment 1, the error detection unit 13 compares the first reflection characteristic map generated by the reflection characteristic information generation unit 12 with the reference reflection characteristic information and detects the difference between the reflection intensity and the reflection intensity as a reference reflection characteristic (hereinafter referred to as "reference reflection intensity") as an error. The error detection process performed by the error detection unit 13, as described above, is called the "error detection process."

[0033] In Embodiment 1, the reference reflection characteristic information is reflection characteristic information generated based on the assumption of a reference interior condition. In Embodiment 1, the reference interior condition refers to a situation in which there are no moving objects in the interior, the seats are in a reference position (hereinafter referred to as the "reference position"), and the radio wave sensor 2 is installed in the interior without any axial misalignment. The reference reflectance characteristics are shown in the reference reflectance characteristics information. Furthermore, the reference reflective properties information is information in the same form as the reflective properties information. In other words, in Embodiment 1, the reference reflective properties information is a first reflective properties map that represents the reflective intensity as the reflective properties. In Embodiment 1, the first reflective properties map as the reference reflective properties information is also called the "reference first reflective properties map". The reflective intensity represented by the reference first reflective properties map is the reference reflective intensity. The standard first reflection characteristic map is generated in advance by an administrator or the like and stored in the standard reflection characteristic information storage unit 16.

[0034] Here, the "seat position" mentioned above includes the fore-aft position, height, and backrest position of the seat. The backrest position is expressed, for example, by the angle at which the backrest is tilted (recline angle). The standard seating position refers to the standard position of a seat that is set so that, for example, a person of average build sits comfortably and naturally in the seat, the fore-aft position, height, and recline angle are optimal. This standard seating position is set in advance by the administrator or other relevant person. Furthermore, "no axial misalignment of radio wave sensor 2" means that radio wave sensor 2 is accurately positioned relative to the set position and is positioned to accurately detect objects within its detection range. In Embodiment 1, "no axial misalignment" includes axial misalignment within an acceptable range and can be considered as having no axial misalignment.

[0035] For example, an administrator or similar person may generate a reference first reflection characteristic map in advance through simulation and store the generated reference first reflection characteristic map in the reference reflection characteristic information storage unit 16. Furthermore, for example, before the vehicle leaves the factory, the administrator may install the radio wave sensor 2, which is the target of axis misalignment detection, in a predetermined installation position inside the vehicle, in other words, in an installation position where there is no axis misalignment, and operate the radio wave sensor 2 and the axis misalignment detection device 1 while no one is inside the vehicle. The first reflection characteristic map generated by the reflection characteristic information generation unit 12 is acquired as the reference first reflection characteristic map, and the acquired reference first reflection characteristic map is stored in the reference reflection characteristic information storage unit 16. Furthermore, for example, an administrator may select a representative vehicle (hereinafter referred to as the "representative vehicle") from among multiple vehicles equipped with radio wave sensors 2 to be used for detecting misalignment. The administrator may then operate the radio wave sensor 2 and the misalignment detection device 1 with the radio wave sensor 2 installed at a predetermined location on the representative vehicle and with no passengers inside, acquire the first reflection characteristic map generated by the reflection characteristic information generation unit 12 as a reference first reflection characteristic map, and store the acquired reference first reflection characteristic map in the reference reflection characteristic information storage unit 16 corresponding to the multiple vehicles.

[0036] An example of a method by which the error detection unit 13 detects the error between the reflection characteristics and the reference reflection characteristics by comparing the first reflection characteristic map with the reference first reflection characteristic map will be explained. The error detection unit 13 fixes either the first reflection characteristic map or the reference first reflection characteristic map, and while shifting the other in the angular or distance direction, it compares the first reflection characteristic map and the reference first reflection characteristic map to detect the error. Here, as an example, the error detection unit 13 is set to fix the reference first reflection characteristic map.

[0037] First, the error detection unit 13 overlays the first reflection characteristic map onto the reference first reflection characteristic map. Next, the error detection unit 13 performs the following <first error detection process> to <sixth error detection process> while keeping the position of the reference first reflection characteristic map superimposed on the first reflection characteristic map fixed.

[0038] <First Error Detection Process> The first reflection characteristic map is shifted by a predetermined angle in the azimuth direction, and the difference between the reference first reflection characteristic map and the reflection intensity values ​​assigned to each grid in the first reflection characteristic map is calculated. This calculated difference is detected as an error. This process is repeated until the angle in the azimuth direction after the shift exceeds a set range.

[0039] <Second Error Detection Process> The first reflection characteristic map is shifted by a predetermined angle in the elevation direction, and the difference between the reference first reflection characteristic map and the reflection intensity values ​​assigned to each grid in the first reflection characteristic map is calculated. This calculated difference is detected as an error. This process is repeated until the angle in the elevation direction after the shift exceeds a set range.

[0040] <Third Error Detection Process> The first reflection characteristic map is shifted by a predetermined distance in the depth direction, and the difference between the reference first reflection characteristic map and the reflection intensity values ​​assigned to each grid in the first reflection characteristic map is calculated. This calculated difference is detected as an error. This process is repeated until the distance in the depth direction after the shift exceeds a set value.

[0041] <Fourth Error Detection Process> The first reflection characteristic map is tilted in the roll direction by a predetermined angle, and while the first reflection characteristic map is tilted, it is shifted in the azimuth direction by a predetermined angle. The difference between the reference first reflection characteristic map and the reflection intensity values ​​assigned to each grid in the first reflection characteristic map is calculated, and the calculated difference is detected as an error. This is repeated while maintaining the tilt of the first reflection characteristic map by the predetermined angle until the angle in the azimuth direction after shifting exceeds a set range (this is called the first iteration). Furthermore, this first iteration is repeated until the angle tilted in the roll direction exceeds a set range.

[0042] <5th Error Detection Process> The first reflection characteristic map is tilted by a predetermined angle in the roll direction, and while the first reflection characteristic map is tilted, it is shifted by a predetermined angle in the elevation direction. The difference between the reference first reflection characteristic map and the reflection intensity values ​​assigned to each grid in the first reflection characteristic map is calculated, and the calculated difference is detected as an error. This is repeated while maintaining the first reflection characteristic map tilted by the predetermined angle until the angle in the elevation direction after the shift exceeds a set range (this is called the second iteration). Furthermore, this second iteration is repeated until the angle tilted in the roll direction exceeds a set range.

[0043] <Sixth Error Detection Process> The first reflection characteristic map is tilted in the roll direction by a predetermined angle, and while the first reflection characteristic map is tilted, it is shifted in the depth direction by a predetermined distance. The difference between the reference first reflection characteristic map and the reflection intensity values ​​assigned to each grid in the first reflection characteristic map is calculated, and the calculated difference is detected as an error. This is repeated while maintaining the tilt of the first reflection characteristic map by the predetermined angle until the distance in the depth direction after shifting exceeds a set range (this is called the third iteration). Furthermore, this third iteration is repeated until the angle tilted in the roll direction exceeds a set range.

[0044] In the above-mentioned <First Error Detection Process> to <Sixth Error Detection Process>, the error detection unit 13 can calculate the difference in the reflection intensity values ​​by, for example, subtracting the reflection intensity values ​​assigned to the grids of the first reflection characteristic map that overlap with the reference reflection intensity values ​​assigned to the grids of the reference first reflection characteristic map from the reference reflection intensity values ​​assigned to the grids of the reference first reflection characteristic map. If shifting the first reflection characteristic map results in no grid of the reference first reflection characteristic map overlapping with the first reflection characteristic map, the difference will be a negative value equal to the reflection intensity value assigned to the grid of the first reflection characteristic map. Conversely, if there is no grid of the first reflection characteristic map overlapping with the reference first reflection characteristic map, the difference will be the reference reflection intensity value assigned to the grid of the reference first reflection characteristic map.

[0045] In addition, in the above-mentioned <First Error Detection Process> to <Sixth Error Detection Process>, the amount by which the first reflection characteristic map is shifted or tilted in the azimuth direction, elevation direction, depth direction, or roll direction is predetermined by the administrator or other relevant personnel. Furthermore, the order in which the error detection unit 13 executes the above-mentioned <first error detection process> to <sixth error detection process> is predetermined by the administrator or other relevant party. When the error detection unit 13 completes one error detection process (<first error detection process>, <second error detection process>, <third error detection process>, <fourth error detection process>, <fifth error detection process>, or <sixth error detection process>), it returns to the state where the first reflection characteristic map is superimposed on the reference first reflection characteristic map before performing the next error detection process, and then performs the next error detection process from there.

[0046] Once the above-mentioned <First Error Detection Process> to <Sixth Error Detection Process> are completed, the error detection unit 13 outputs information regarding the errors detected by the <First Error Detection Process> to <Sixth Error Detection Process> (hereinafter referred to as "detected error information") to the determination unit 14. The detection error information is information that associates information indicating the error detected by the error detection unit 13 (hereinafter referred to as "error information") with information indicating the state of the first reflection characteristic map at the time the error was detected (hereinafter referred to as "map state information"). The map state information indicates the amount by which the first reflection characteristic map was shifted (how many degrees in the azimuth direction, how many degrees in the elevation direction, how far in the depth direction, and how many degrees in the roll direction it was shifted or tilted). The error detection unit 13 generates the above-mentioned detection error information each time the first reflection characteristic map is shifted in the azimuth direction, elevation direction, or depth direction, starting from a state in which the first reflection characteristic map is superimposed on the reference reflection characteristic map, or from a state in which the first reflection characteristic map is superimposed on the reference reflection characteristic map and the first reflection characteristic map is tilted by a predetermined angle in the roll direction. In other words, the error information included in the detection error information includes information indicating the error in each grid detected when the first reflection characteristic map, indicated by the map state information, is shifted in the azimuth direction, elevation direction, or depth direction. The error detection unit 13 outputs the detected error information to the determination unit 14.

[0047] In this example, the error detection unit 13 generates detection error information by performing the above-mentioned <first error detection process> to <sixth error detection process>, but this is only one example. The type of error detection process the error detection unit 13 performs and how it generates detection error information can be set in advance by an administrator or other relevant person.

[0048] The determination unit 14 determines whether or not an axial misalignment has occurred in the radio wave sensor 2 based on the error detected by the error detection unit 13. The process by the determination unit 14 to determine whether or not an axial misalignment has occurred in the radio wave sensor 2 is called the "axial misalignment determination process".

[0049] An example of a method by which the determination unit 14 determines whether or not an axial misalignment has occurred in the radio wave sensor 2 based on the error detected by the error detection unit 13 will be described. First, the determination unit 14 calculates the total error detected by the error detection unit 13 based on the detection error information output from the error detection unit 13. Specifically, the determination unit 14 calculates the total error, which is the difference in reflection intensity included in the error information of the detection error information. In other words, here the determination unit 14 calculates the total error, which is the difference in reflection intensity for each grid, in the state where the first reflection characteristic map has been shifted by the error detection unit 13 for the number of times the first reflection characteristic map has been shifted in the azimuth direction, elevation direction, or depth direction. Furthermore, the determination unit 14 calculates the total error by treating all positive and negative values ​​of the values ​​detected as errors by the error detection unit 13 as positive values. In other words, the determination unit 14 calculates the total of the values ​​detected as errors, including their absolute values.

[0050] The determination unit 14 calculates the total error for all detection error information output from the error detection unit 13, identifies the detection error information with the smallest total error, and sets the amount by which the first reflection characteristic map, indicated by the map state information included in the identified detection error information, is shifted as the axial misalignment amount of the radio wave sensor 2.

[0051] The determination unit 14 then determines that no axial misalignment has occurred in the radio wave sensor 2 if the total calculated error is less than or equal to a preset threshold (hereinafter referred to as the "total error determination threshold") and the amount of axial misalignment of the identified radio wave sensor 2 is within a preset range (hereinafter referred to as the "misalignment determination range"). On the other hand, the determination unit 14 determines that an axial misalignment has occurred in the radio wave sensor 2 if the total calculated error is greater than the threshold for determining the total error, or if the amount of axial misalignment of the identified radio wave sensor 2 is outside the range for determining misalignment. For example, if the radio wave sensor 2 is completely detached and pointing in a completely different direction than intended, the total error in the calculated reflection intensity will be very large.

[0052] The determination unit 14 outputs a determination result (hereinafter referred to as "axis misalignment determination result") to the corresponding unit 15, indicating whether or not an axis misalignment has occurred in the radio wave sensor 2. The axial misalignment detection result includes information indicating whether or not axial misalignment has occurred, and information indicating the amount of axial misalignment of the radio wave sensor 2.

[0053] If the determination unit 14 determines that an axis misalignment has occurred in the radio wave sensor 2, the response unit 15 generates information to warn about the axis misalignment (hereinafter referred to as "warning information") and outputs the generated warning information to an external device (not shown). The external device may be, for example, a display device or audio output device on a mobile terminal such as a smartphone held by a crew member, or it may be a management server managed by an administrator or the like.

[0054] If the determination unit 14 determines that an axial misalignment has occurred in the radio wave sensor 2, the response unit 15 may, for example, generate information for correcting the axial misalignment in the radio wave sensor 2 (hereinafter referred to as "correction information") and output the generated correction information to the radio wave sensor 2. The correction information is intended to allow the radio wave sensor 2 to perform corrections such as angle calculation values ​​using software functions. The correction information includes information indicating the amount of axial misalignment of the radio wave sensor 2. The corresponding unit 15 corrects the calculated angle of the radio wave sensor 2 by the amount of the angle in the azimuth direction, elevation direction, or roll direction, or the position in the depth direction, where the radio wave sensor 2 is misaligned. In this case, the response unit 15 may correct the axial misalignment amount determined by the determination unit 14 if it is within a correctable range. More specifically, the response unit 15 may output correction information to the radio wave sensor 2 to correct the axial misalignment if the axial misalignment amount determined by the determination unit 14 is within a preset range (hereinafter referred to as the "correctable range"). The correctable range is set in advance by an administrator or the like. The administrator or the like may permit the radio wave sensor 2 to correct the axial misalignment when an axial misalignment occurs, or set the amount of axial misalignment that the radio wave sensor 2 can correct within the correctable range. In this case, the corresponding unit 15 does not output correction information if the amount of axial misalignment determined by the determination unit 14 is outside the correctable range.

[0055] The corresponding unit 15 may, for example, generate warning information and correction information. Furthermore, the response unit 15 may output the generated warning information to an external device and the generated correction information to the radio wave sensor 2. The process by the response unit 15 described above, which generates and outputs warning information or correction information, is referred to as the "response process".

[0056] The reference reflection characteristic information storage unit 16 stores reference reflection characteristic information. In Figure 1, the reference reflection characteristic information storage unit 16 is located within the misalignment detection device 1, but this is merely one example. The reference reflection characteristic information storage unit 16 may be located outside the misalignment detection device 1, in a location accessible to the device 1.

[0057] The operation of the axial misalignment detection device 1 according to Embodiment 1 will be described. Figure 4 is a flowchart illustrating the operation of the axial misalignment detection device 1 according to Embodiment 1. The misalignment detection device 1, for example, when it detects that the vehicle's engine has been turned off, starts the operation shown in the flowchart of Figure 4. For example, a control unit (not shown) of the misalignment detection device 1 can obtain information indicating the state of the ignition switch from an engine control unit (not shown) and detect that the vehicle's engine has been turned off. When the control unit detects that the vehicle's engine has been turned off, it outputs instructions to start operation to each part of the misalignment detection device 1. For example, once the shaft misalignment detection device 1 starts operating, it repeats the operations shown in the flowchart of Figure 4 until the processes from step ST20 to step ST50 in the flowchart of Figure 4 are completed once. The shaft misalignment detection device 1 may also be configured to perform these operations periodically.

[0058] The motion absence detection unit 11 detects whether or not there is a motion object inside the vehicle (step ST10). The motion absence detection unit 11 outputs the motion absence detection result to the reflection characteristic information generation unit 12.

[0059] If the motion absence detection unit 11 detects in step ST10 that a motion object is present inside the vehicle (i.e., the answer to step ST10 is "YES"), the operation of the shaft misalignment detection device 1 skips the processing in steps ST20 to ST50.

[0060] In step ST10, if the motion absence detection unit 11 detects that there is no motion inside the vehicle (if the result of step ST10 is "NO"), the reflection characteristic information generation unit 12 performs a reflection characteristic information generation process to generate reflection characteristic information that shows the reflection characteristics of the reflected waves inside the vehicle from sensor information based on the reflected waves that were reflected by objects inside the vehicle from the radio wave sensor 2 that was irradiated towards the vehicle (step ST20). Here, in the reflection characteristic information generation process, the reflection characteristic information generation unit 12 generates a first reflection characteristic map that represents the reflection intensity of the reflected waves as a three-dimensional spatial distribution inside the vehicle. The reflection characteristic information generation unit 12 outputs the generated first reflection characteristic map to the error detection unit 13.

[0061] In step ST20, the error detection unit 13 compares the first reflection characteristic map generated by the reflection characteristic information generation unit 12 with the reference first reflection characteristic map and performs an error detection process to detect the difference between the reflection intensity and the reference reflection intensity as an error (step ST30). The error detection unit 13 outputs the detected error information to the determination unit 14.

[0062] The determination unit 14 performs an axis misalignment determination process (step ST40) to determine whether or not an axis misalignment has occurred in the radio wave sensor 2, based on the error detected by the error detection unit 13 in step ST30. The determination unit 14 outputs the axis misalignment determination result to the corresponding unit 15.

[0063] If the determination unit 14 determines that an axial misalignment has occurred in the radio wave sensor 2, the response unit 15 performs a corresponding process, for example, by generating warning information and outputting the generated warning information to an external device (step ST50). If the response unit 14 determines during the response process that an axial misalignment has occurred in the radio wave sensor 2, the response unit 15 may, for example, generate correction information and output the generated correction information to the radio wave sensor 2. Alternatively, the response unit 15 may, for example, generate warning information and correction information during the response process.

[0064] In this way, the misalignment detection device 1 generates a first reflection characteristic map, which shows the reflection characteristics of the reflected wave, from sensor information based on the reflected wave that was reflected by an object inside the vehicle when the radio wave sensor 2 emitted the radio wave towards the vehicle interior in a situation where there is no moving object inside the vehicle interior. The device then compares this first reflection characteristic map with reference reflection characteristic information, in other words, a reference first reflection characteristic map, and detects the difference between the reflection intensity and the reference reflection intensity as an error. Based on the detected error, the misalignment detection device 1 determines whether or not misalignment has occurred in the radio wave sensor 2. Therefore, the misalignment detection device 1 can detect the misalignment of the radio wave sensor 2, which emits radio waves toward the vehicle interior and receives the reflected waves that are reflected by objects inside the vehicle interior.

[0065] The conventional technologies described above are for detecting misalignment of radio wave sensors used to detect objects around a vehicle, but not for detecting misalignment of radio wave sensors used to detect occupants inside the vehicle. Even if one were to attempt to apply the conventional technologies described above to detecting misalignment of radio wave sensors used to detect occupants inside the vehicle, it would require the additional installation of minute reflective materials, and there is a possibility that these installed minute reflective materials may fall off. There would also be additional costs associated with adding the minute reflective materials. Furthermore, as a technique for detecting the axial misalignment of radio wave sensors used to detect objects around a vehicle, there is a known technique, such as the one disclosed in Reference 1 below, which calculates the angle of deviation of the radar beam of a radar positioned in front of the vehicle that detects the distance between the vehicle and the target, the direction of the target relative to the vehicle, and the relative speed between the vehicle and the target, with respect to the vertical direction of the vehicle, based on the relative velocity of a detected stationary structure with respect to the vehicle while the vehicle is in motion. However, such techniques cannot be used to detect the axial misalignment of the radio wave sensor 2 intended for use inside the vehicle. (Reference document 1) Patent No. 5407443

[0066] In contrast, the axial misalignment detection device 1 according to Embodiment 1 generates a reflection characteristic map showing the reflection intensity of the reflected wave from sensor information based on the reflected wave that is reflected by an object inside the vehicle when the radio wave sensor 2 irradiates the vehicle interior with radio waves when no moving object is present inside the vehicle interior. The device compares this first reflection characteristic map with a reference first reflection characteristic map, detects the difference between the reflection intensity and the reference reflection intensity as an error, and determines whether or not axial misalignment of the radio wave sensor 2 has occurred based on the detected error. Therefore, the misalignment detection device 1 can detect misalignment of the in-vehicle radio wave sensor 2, which emits radio waves towards the vehicle interior and receives reflected waves that are reflected by objects inside the vehicle interior.

[0067] The radio waves emitted from the radio wave sensor 2 are reflected by the vehicle structure, including the metal frame of the vehicle body or the metal frame of the seats. In Embodiment 1, the reflection intensity of the reflected wave represented by the first reflection characteristic map generated by the axial misalignment detection device 1 includes the reflection intensity of the reflected wave reflected by the metal frame of the vehicle body, the reflection intensity of the reflected wave reflected by the metal frame of the seat, or the reflection intensity of the reflected wave reflected by both the metal frame of the vehicle body and the metal frame of the seat. As described above, for example, the edges of vehicle structures made of metal have a high reflection intensity of the reflected waves from the radio wave sensor 2. In other words, in the first reflection characteristic map, the reflection intensity of the reflected waves from the vehicle structure made of metal appears darker. The axis misalignment detection device 1 can utilize this to detect the axis misalignment of the radio wave sensor 2 with greater accuracy.

[0068] Figures 5A and 5B show an example of the hardware configuration of the axial misalignment detection device 1 according to Embodiment 1. In Embodiment 1, the functions of the motion absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the correspondence unit 15, and the control unit (not shown) are realized by the processing circuit 1001. Specifically, the axial misalignment detection device 1 generates a reflection characteristic map showing the reflection characteristics of the reflected waves in the vehicle interior from sensor information based on the reflected waves that are reflected by objects in the vehicle interior when the radio wave sensor 2 irradiates the vehicle interior with radio waves in the vehicle interior when no motion is present in the vehicle interior. The processing circuit 1001 compares the first reflection characteristic map with a reference first reflection characteristic map, detects the difference between the reflection intensity and the reference reflection intensity as an error, and determines whether or not axial misalignment of the radio wave sensor 2 has occurred based on the detected error. The processing circuit 1001 may be dedicated hardware as shown in Figure 5A, or it may be a processor 1004 that executes a program stored in memory as shown in Figure 5B.

[0069] If the processing circuit 1001 is dedicated hardware, it may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof.

[0070] When the processing circuit is a processor 1004, the functions of the motion absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the response unit 15, and the control unit (not shown) are realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in memory 1005. The processor 1004 reads and executes the program stored in memory 1005 to perform the functions of the motion absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the response unit 15, and the control unit (not shown). In other words, the axis misalignment detection device 1 includes memory 1005 for storing a program that, when executed by the processor 1004, will result in the execution of steps ST10 to ST50 in Figure 4 described above. Furthermore, the program stored in memory 1005 can be said to cause the computer to execute the processing procedures or methods of the motion absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the correspondence unit 15, and the control unit (not shown). Here, memory 1005 refers to, for example, non-volatile or volatile semiconductor memory such as RAM, ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), or magnetic disks, flexible disks, optical disks, compact disks, minidiscs, DVDs (Digital Versatile Discs), etc.

[0071] Furthermore, the functions of the motion absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the response unit 15, and the control unit (not shown) may be partially implemented by dedicated hardware and partially by software or firmware. For example, the functions of the motion absence detection unit 11 and the reflection characteristic information generation unit 12 can be implemented by a processing circuit 1001 as dedicated hardware, while the functions of the error detection unit 13, the determination unit 14, the response unit 15, and the control unit (not shown) can be implemented by the processor 1004 reading and executing a program stored in the memory 1005. The storage unit, which is not shown in the diagram, is composed of, for example, memory 1005. Furthermore, the axial misalignment detection device 1 includes a device such as a radio wave sensor 2, and an input interface device 1002 and an output interface device 1003 that perform wired or wireless communication.

[0072] In the above embodiment 1, the shaft misalignment detection device 1 was equipped with a motion absence detection unit 11, but this is merely an example, and the shaft misalignment detection device 1 may be configured without a motion absence detection unit 11. For example, if it is assumed that there are always no occupants in the vehicle interior, the shaft misalignment detection device 1 is not required to have the function of a motion absence detection unit 11. Also, for example, the function of the motion absence detection unit 11 may be provided outside the shaft misalignment detection device 1, in a location accessible to the shaft misalignment detection device 1, and the reflection characteristic information generation unit 12 in the shaft misalignment detection device 1 may acquire the motion absence detection result from outside the shaft misalignment detection device 1. If the shaft misalignment detection device 1 is configured not to include a motion absence detection unit 11, the operation of the shaft misalignment detection device 1 can omit the processing of step ST10 in the operation described using the flowchart in Figure 4.

[0073] Furthermore, in the above embodiment 1, the shaft misalignment detection device 1 was equipped with a corresponding unit 15, but this is merely an example, and the shaft misalignment detection device 1 may be configured without a corresponding unit 15. For example, in the shaft misalignment detection device 1, the determination unit 14 may store the shaft misalignment determination result in a storage unit not shown. Alternatively, for example, the function of the corresponding unit 15 may be provided outside the shaft misalignment detection device 1, in a location accessible to the shaft misalignment detection device 1, and the determination unit 14 in the shaft misalignment detection device 1 may output the shaft misalignment determination result to a device outside the shaft misalignment detection device 1. If the shaft misalignment detection device 1 is configured not to include the corresponding unit 15, the operation of the shaft misalignment detection device 1 can be as described using the flowchart in Figure 4, and the processing of step ST50 can be omitted.

[0074] Furthermore, in the above embodiment 1, the axial misalignment detection device 1 is an on-board device mounted on a vehicle, and the motion absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the corresponding unit 15, and the control unit (not shown) are provided on the on-board device. The system is not limited to this, however, a portion of the motion absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the response unit 15, and the control unit (not shown) may be mounted on an in-vehicle device, while the others are provided on a server connected to the in-vehicle device via a network, thereby configuring the system with the in-vehicle device and the server. Furthermore, the motion object absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the correspondence unit 15, and the control unit (not shown) may all be provided on the server.

[0075] As described above, according to Embodiment 1, the shaft misalignment detection device 1 is configured to include: a reflection characteristic information generation unit 12 that generates reflection characteristic information indicating the reflection characteristics of a reflected wave from sensor information based on the reflected wave, which is generated when the radio wave sensor 2 irradiates the vehicle interior with the vehicle interior in a situation where there are no moving objects in the vehicle interior; an error detection unit 13 that compares the reflection characteristic information generated by the reflection characteristic information generation unit 12 with reference reflection characteristic information indicating a reference reflection characteristic that serves as a standard for reflection characteristics, which is generated assuming a reference situation inside the vehicle interior, and detects the difference between the reflection characteristics and the reference reflection characteristics as an error; and a determination unit 14 that determines whether or not shaft misalignment has occurred based on the error detected by the error detection unit 13. Therefore, the misalignment detection device 1 can detect the misalignment of the radio wave sensor 2, which emits radio waves toward the vehicle interior and receives the reflected waves that are reflected by objects inside the vehicle interior.

[0076] In the axial misalignment detection device 1, the reflection characteristic information generation unit 12 generates a reflection characteristic map (first reflection characteristic map) as reflection characteristic information, which represents the reflection characteristics (reflection intensity) of the reflected wave as a three-dimensional spatial distribution inside the vehicle cabin. The error detection unit 13 compares the reflection characteristic map generated by the reflection characteristic information generation unit 12 with a reference reflection characteristic map (reference first reflection characteristic map) as reference reflection characteristic information, and detects the difference between the reflection characteristics and the reference reflection characteristics (reference reflection intensity) as an error. Therefore, the misalignment detection device 1 can detect the misalignment of the radio wave sensor 2, which emits radio waves toward the vehicle interior and receives the reflected waves that are reflected by objects inside the vehicle interior.

[0077] Embodiment 2. In Embodiment 1, when detecting the misalignment of the radio wave sensor 2, the presence or absence of stationary objects such as passenger luggage left inside the vehicle was not considered. The presence of such stationary objects may affect the distribution of the reflected wave intensity. Embodiment 2 describes an embodiment in which the axial misalignment of the radio wave sensor 2 is detected by considering whether or not there are stationary objects such as passenger luggage left inside the vehicle.

[0078] Figure 6 shows an example of the configuration of the axial misalignment detection device 1a according to Embodiment 2. As shown in Figure 6, the axial misalignment detection device 1a is connected to the radio wave sensor 2 and the in-vehicle camera 3. The in-vehicle camera 3 is a camera installed in the vehicle for the purpose of monitoring the interior of the vehicle. The in-vehicle camera 3 is either an infrared camera or a visible light camera. The in-vehicle camera 3 may also be shared with the imaging device of a so-called "Driver Monitoring System (DMS)" that is installed in the vehicle to monitor the driver's condition inside the vehicle. Although the arrow from the in-vehicle camera 3 to the motion absence detection unit 11 is not shown in Figure 6, the motion absence detection unit 11 may detect moving objects inside the vehicle based on the image captured by the in-vehicle camera 3. Although not shown in Embodiment 1, for example, the shaft misalignment detection device 1 according to Embodiment 1 may be connected to such an in-vehicle camera 3, and the motion absence detection unit 11 in the shaft misalignment detection device 1 may detect moving objects inside the vehicle based on the image captured by such an in-vehicle camera 3.

[0079] The axis misalignment detection system 100a is composed of the axis misalignment detection device 1a and the radio wave sensor 2. Regarding the configuration example of the axial misalignment detection device 1a shown in Figure 6, the same reference numerals are used for configuration examples similar to the axial misalignment detection device 1 of Embodiment 1, which was explained using Figure 1 in Embodiment 1, and redundant explanations are omitted. The axial misalignment detection device 1a according to Embodiment 2 differs from the axial misalignment detection device 1 according to Embodiment 1, which was described using Figure 1, in that it includes a stationary object detection unit 17. Furthermore, in Embodiment 2, the specific operation of the reflection characteristic information generation unit 12a differs from the specific operation of the reflection characteristic information generation unit 12 of the axial misalignment detection device 1 according to Embodiment 1.

[0080] In Embodiment 2, the reflection characteristic information generated by the reflection characteristic information generation unit 12a is, similar to the reflection characteristic information generated by the reflection characteristic information generation unit 12 in Embodiment 1, a reflection characteristic map that represents the reflection characteristics of the reflected wave as a three-dimensional spatial distribution within the vehicle interior. Furthermore, the reflection characteristic represented by the reflection characteristic map is the reflection intensity. Specifically, in Embodiment 2, the reflection characteristic information generated by the reflection characteristic information generation unit 12a is, more specifically, a first reflection characteristic map that represents the reflection intensity in the azimuth direction, elevation direction, and depth direction of the reflected wave as a three-dimensional spatial distribution within the vehicle interior.

[0081] The stationary object detection unit 17 detects stationary objects present inside the vehicle based on images captured by the in-vehicle camera 3, which captures images of the inside of the vehicle. Here, the stationary object detected by the stationary object detection unit 17 refers to a stationary object that is a non-fixed object that can be attached to or detached from the vehicle. Examples of stationary objects that are non-fixed objects that can be attached to or detached from the vehicle include luggage, etc., and vehicle structures are not included in stationary objects that are non-fixed objects that can be attached to or detached from the vehicle. The stationary object detection unit 17 can detect stationary objects using known image recognition techniques. The stationary object detection unit 17 outputs information indicating whether or not a stationary object has been detected (hereinafter referred to as "stationary object presence / absence information") to the reflection characteristic information generation unit 12a. The stationary object presence / absence information includes information indicating whether or not a stationary object has been detected, and, if a stationary object has been detected, information indicating the area in which the stationary object exists. The area in which the stationary object exists is, for example, an area on the captured image. When the stationary object detection unit 17 detects a stationary object, for example, it identifies the smallest rectangular area containing the stationary object on the captured image as the area in which the stationary object exists. The stationary object detection unit 17 then uses the coordinates of the four corners of the identified area as information indicating the area in which the stationary object exists. Note that this is just one example, and the information indicating the area in which the stationary object exists only needs to be information that allows the area in which the detected stationary object exists to be identified on the captured image. The process of detecting stationary objects by the stationary object detection unit 17, as described above, is called the "stationary object detection process."

[0082] The reflection characteristic information generation unit 12a generates reflection characteristic information. Here, the reflection characteristic information generation unit 12a generates a first reflection characteristic map. The method for generating the first reflection characteristic map by the reflection characteristic information generation unit 12a may be the same as the method for generating the first reflection characteristic map by the reflection characteristic information generation unit 12 in Embodiment 1. In this embodiment 2, when a stationary object is detected by the stationary object detection unit 17, the reflection characteristic information generation unit 12a removes from the generated first reflection characteristic map the region in which the stationary object detected by the stationary object detection unit 17 is considered to exist (hereinafter referred to as the "stationary object region"). In Embodiment 2, "removing" the region corresponding to the stationary object region may mean that the region corresponding to the stationary object region does not exist, or it may mean that the dB value indicating the reflection intensity assigned to the grid of the region corresponding to the stationary object region is set to "0". "Removing" the region corresponding to the stationary object region means that in the first reflection characteristic map, there is no distribution of reflection intensity of reflected waves from the stationary object region.

[0083] Figure 7 is a diagram illustrating an example of a stationary object region that is removed from the first reflection characteristic map by the reflection characteristic information generation unit 12a in Embodiment 2. Here, we assume that the radio wave sensor 2 is installed inside the vehicle at the position shown in Figure 2. There are no occupants inside the vehicle. However, we assume that a bag has been left behind on the passenger seat. For clarity, Figure 7 also shows a diagram of the interior of the vehicle as seen from the rearview mirror located near the installation position of the radio wave sensor 2, as shown in Figure 7A. The interior of the vehicle shown in Figure 7A differs from the interior of the vehicle shown in Figure 3A in Embodiment 1 in that a bag is present on the passenger seat. In Figure 7A, the bag is indicated by the letter "S". Figure 7B is a diagram illustrating an example of a stationary object region that is removed from the first reflection characteristic map, which represents the three-dimensional spatial distribution of the reflected wave intensity of the reflected waves, which are emitted from the radio wave sensor 2 and reflected by objects inside the vehicle interior as shown in Figure 7A. Figure 7B is a diagram illustrating an example of the interior of the vehicle as seen from the side. For convenience, Figure 7B shows two in-vehicle cameras 3: one located near the overhead console (also referred to as "in-vehicle camera 3A") and another located near the dashboard (also referred to as "in-vehicle camera 3B").

[0084] For example, the reflection characteristics information generation unit 12a identifies the range in the azimuth and elevation directions of the three-dimensional space inside the vehicle where a stationary object exists, based on the presence or absence information of a stationary object output from the stationary object detection unit 17. Since the installation position, orientation, and field of view of the in-vehicle camera 3 are known in advance, the reflection characteristics information generation unit 12a can identify the range in the azimuth and elevation directions of the three-dimensional space inside the vehicle where a stationary object exists, provided that it knows the range in which a stationary object exists on the captured image. Then, the reflection characteristics information generation unit 12a sets the range within the imaging range of the in-vehicle camera 3 that includes the stationary object, with the installation position of the in-vehicle camera 3 as the vertex, in the three-dimensional space inside the vehicle. For example, if the in-car camera 3 is in-car camera 3A, the reflection characteristic information generation unit 12a sets the area shown as "exclusion range for camera 3A" in Figure 7B as the stationary object region. Also, for example, if the in-car camera 3 is in-car camera 3B, the reflection characteristic information generation unit 12a sets the area shown as "exclusion range for camera 3B" in Figure 7B as the stationary object region.

[0085] Note that the method for setting the stationary object region as explained using Figure 7 is merely one example. The reflection characteristic information generation unit 12a only needs to set the region containing the stationary object in the three-dimensional space inside the vehicle interior as the stationary object region.

[0086] The reflection characteristic information generation unit 12a removes the region corresponding to the set stationary object region from the first reflection characteristic map. The reflection characteristic information generation unit 12a then outputs the first reflection characteristic map (hereinafter referred to as the "excluded map"), which is obtained by removing the region corresponding to the stationary object region, to the error detection unit 13 as the generated first reflection characteristic map. The excluded map is obtained by removing the reflection intensity of reflected waves from the stationary object region from the reflection intensity shown in the first reflection characteristic map. In other words, this excluded map is the excluded reflection characteristic information from the reflection characteristic information, with the reflection characteristics of reflected waves from the stationary object region removed.

[0087] Furthermore, if the stationary object detection unit 17 does not detect a stationary object, the reflection characteristic information generation unit 12a outputs the generated first reflection characteristic map directly to the error detection unit 13.

[0088] The error detection unit 13 compares the first reflection characteristic map generated by the reflection characteristic information generation unit 12a with the reference first reflection characteristic map and detects the difference between the reflection intensity and the reference reflection intensity as an error. In Embodiment 2, if a stationary object is detected by the stationary object detection unit 17, the error detection unit 13 compares the excluded map with the reference first reflection characteristic map and detects the difference between the reflection intensity and the reference reflection intensity as an error. When a stationary object is detected by the stationary object detection unit 17, that is, when the first reflection characteristic map generated by the reflection characteristic information generation unit 12a is an excluded map, the error detection unit 13 may, for example, remove the region corresponding to the stationary object region from the reference first reflection characteristic map, and compare the reference first reflection characteristic map after removing the region corresponding to the stationary object region (hereinafter referred to as the "excluded reference map") with the excluded map to detect the error.

[0089] The operation of the axial misalignment detection device 1a according to Embodiment 2 will be described. Figure 8 is a flowchart illustrating the operation of the axial misalignment detection device 1a according to Embodiment 2. The misalignment detection device 1a, for example, when it detects that the vehicle's engine has been turned off, starts the operation shown in the flowchart of Figure 8. For example, a control unit (not shown) of the misalignment detection device 1a can obtain information indicating the state of the ignition switch from an engine control unit (not shown) and detect that the vehicle's engine has been turned off. When the control unit detects that the vehicle's engine has been turned off, it outputs instructions to start operation to each part of the misalignment detection device 1a. For example, once the shaft misalignment detection device 1a starts operating, it repeats the operations shown in the flowchart of Figure 8 until the processes from step ST13 to step ST50 in the flowchart of Figure 8 are completed once. The shaft misalignment detection device 1a may also perform these operations periodically.

[0090] Regarding the operation of the axial misalignment detection device 1a shown in the flowchart of Figure 8, the processes of steps ST10 and ST30 to ST50 are the same as the processes of steps ST10 and ST30 to ST50 by the axial misalignment detection device 1, which were explained using the flowchart of Figure 4 in Embodiment 1, so redundant explanations will be omitted.

[0091] In step ST10, if the motion absence detection unit 11 detects that there is no motion inside the vehicle (if the result of step ST10 is "NO"), the stationary object detection unit 17 performs stationary object detection processing to detect stationary objects present inside the vehicle based on the image captured by the in-vehicle camera 3 (step ST13). The stationary object detection unit 17 outputs information about the presence or absence of a stationary object to the reflection characteristic information generation unit 12a.

[0092] In step ST13, if the stationary object detection unit 17 detects a stationary object, the reflection characteristic information generation unit 12a performs a reflection characteristic information generation process to generate a first reflection characteristic map showing the reflection intensity of the reflected waves inside the vehicle, based on sensor information derived from the reflected waves that were reflected by an object inside the vehicle when the radio wave sensor 2 irradiated the vehicle interior. Here, if the stationary object detection unit 17 detects a stationary object in step ST13, the reflection characteristic information generation unit 12a removes the region corresponding to the stationary object from the generated first reflection characteristic map. Then, the reflection characteristic information generation unit 12a uses the map after the region corresponding to the stationary object has been removed as the generated first reflection characteristic map (step ST20a). The reflection characteristic information generation unit 12a outputs the generated first reflection characteristic map to the error detection unit 13. On the other hand, if the stationary object detection unit 17 does not detect a stationary object in step ST13, the reflection characteristic information generation unit 12a outputs the generated first reflection characteristic map as is to the error detection unit 13.

[0093] In this example, the reflection characteristic information generation unit 12a removes the region corresponding to the stationary object region from the generated first reflection characteristic map and outputs the resulting map to the error detection unit 13 as the generated first reflection characteristic map. However, this is merely one example. For example, the error detection unit 13 may have a function to remove the region corresponding to the stationary object region from the first reflection characteristic map. In this case, even if the stationary object detection unit 17 detects a stationary object, the reflection characteristic information generation unit 12a does not remove the region corresponding to the stationary object region from the first reflection characteristic map, but outputs the generated first reflection characteristic map as is, along with the stationary object presence / absence information, to the error detection unit 13. Furthermore, if the stationary object detection unit 17 detects a stationary object, the error detection unit 13 may set a stationary object region based on the presence or absence of stationary objects, remove the region corresponding to the stationary object region from the first reflection characteristic map generated by the reflection characteristic information generation unit 12a, and then compare the excluded map with the reference first reflection characteristic map to detect the difference between the reflection intensity and the reference reflection intensity as an error. When a stationary object is detected by the stationary object detection unit 17, the error detection unit 13 should, as a result, compare the first reflection characteristic map (i.e., the map after exclusion) which has been removed from the reflection intensity shown in the first reflection characteristic map by removing the reflection intensity of the reflected wave from the stationary object region where a stationary object is considered to be present in the vehicle interior, in other words, after excluding it, with the reference first reflection characteristic map, and detect the difference between the reflection intensity and the reference reflection intensity as an error.

[0094] In this way, the misalignment detection device 1a detects stationary objects present in the vehicle interior based on the images captured by the in-vehicle camera 3, which captures images of the vehicle interior. When a stationary object is detected, the misalignment detection device 1a compares the excluded map, which is obtained by removing the reflection intensity of the reflected wave from the region where a stationary object is considered to be present in the vehicle interior from the reflection intensity shown in the first reflection characteristic map, with the reference first reflection characteristic map, and detects the difference between the reflection intensity and the reference reflection intensity as an error. Therefore, the axial misalignment detection device 1a can improve the accuracy of detecting axial misalignment of the radio wave sensor 2 by taking into account the effect of reflection from stationary objects.

[0095] <Modified example of Embodiment 2 (1)> In the above embodiment 2, when the axial misalignment detection device 1a detects a stationary object, it removes the region corresponding to the stationary object from the generated first reflection characteristic map, compares the map after exclusion with the reference first reflection characteristic map, and detects the difference between the reflection characteristics and the reference reflection characteristics as an error. However, this is merely one example. For example, the misalignment detection device 1a may not generate a first reflection characteristic map when it detects a stationary object; that is, it may not determine whether or not misalignment has occurred in the radio wave sensor 2. In this case, in the axial misalignment detection device 1a, the reflection characteristic information generation unit 12a generates a first reflection characteristic map when no stationary object is detected by the stationary object detection unit 17, and the error detection unit 13 compares the first reflection characteristic map generated by the reflection characteristic information generation unit 12a with a reference first reflection characteristic map and detects the difference between the reflection intensity and the reference reflection intensity as an error. When a stationary object is detected by the stationary object detection unit 17, the reflection characteristic information generation unit 12a, the error detection unit 13, and the corresponding unit 15 do not operate. In this case, regarding the operation of the axis misalignment detection device 1a as explained using the flowchart in Figure 8, if the stationary object detection unit 17 does not detect a stationary object in step ST13, the axis misalignment detection device 1a will perform the processes from step ST20a to step ST50. If the stationary object detection unit 17 detects a stationary object in step ST13, the axial misalignment detection device 1a will not perform the processing in steps ST20a to ST50.

[0096] <Modification of Embodiment 2 (2)> Furthermore, in the second embodiment described above, the axial misalignment detection device 1a' (see Figure 9 below) may be configured to generate a first reflection characteristic map when it determines that the seat position is the reference position, and not generate a first reflection characteristic map if the seat position is not the reference position. As mentioned above, "seat position" includes the front-to-back position, height, and backrest position of the seat. The backrest position is represented, for example, by the angle (reclining angle) of how much the backrest is tilted.

[0097] Figure 9 shows an example of the configuration of the axial misalignment detection device 1a' in Embodiment 2, namely, an example of the configuration of the axial misalignment detection device 1a' in which a first reflection characteristic map is generated when it is determined that the seat position is the reference position, and the first reflection characteristic map is not generated if the seat position is not the reference position. Regarding the configuration example of the axial misalignment detection device 1a' shown in Figure 9, the same reference numerals are used for configuration examples similar to the axial misalignment detection device 1a shown in Figure 6, and redundant explanations are omitted. The configuration example of the axis misalignment detection device 1a' differs from the configuration example of the axis misalignment detection device 1a in that it includes a seat position determination unit 18.

[0098] The seat position determination unit 18 detects the position of a seat in the vehicle based on information used for determining the seat position (hereinafter referred to as "seat position determination information") and determines whether the seat position is deviating from the reference position. Here, the seat position determination unit 18 acquires, for example, the image captured by the in-vehicle camera 3 as seat position determination information. Furthermore, information indicating the reference position of the seats (hereinafter referred to as "seat reference position information") is stored in a memory unit (not shown) or the like. The seat reference position information may be, for example, an image captured by the in-vehicle camera 3 of an unoccupied vehicle interior with the seats set to their reference positions. The seat position determination unit 18 uses known image recognition technology to determine whether the current seat position in the vehicle is deviating from the reference position, based on the captured image obtained from the in-vehicle camera 3 and the seat reference position information. Even if the current seat position in the vehicle differs from the reference position, if the difference is within a preset tolerance range, the seat position determination unit 18 can consider the current seat position as the reference position and determine that it is not deviating from the reference position. The seat position determination unit 18 outputs a determination result (hereinafter referred to as "seat position determination result") to the stationary object detection unit 17, indicating whether or not the seat position is deviating from the reference position. The process described above, in which the seat position determination unit 18 determines whether or not the seat position is deviating from the reference position, is called the "seat position determination process."

[0099] When the seat position determination unit 18 determines that the seat position in the vehicle is the reference position, the stationary object detection unit 17 detects stationary objects present in the vehicle based on the image captured by the in-vehicle camera 3 that captures images of the vehicle interior. In this case, the stationary object detection unit 17 only needs to acquire the captured image from the in-vehicle camera 3 via the seat position determination unit 18. If the seat position determination unit 18 determines that the position of the seat in the vehicle is not the reference position, that is, that the position of the seat in the vehicle is deviating from the reference position, the stationary object detection unit 17 will not detect stationary objects present in the vehicle. The stationary object detection unit 17 will then output the seat position determination result, which indicates that the position of the seat in the vehicle is not the reference position, output from the seat position determination unit 18, to the reflection characteristic information generation unit 12a. In this case, the first reflection characteristic map will not be generated by the reflection characteristic information generation unit 12a.

[0100] Figure 10 is a flowchart illustrating the operation of the axial misalignment detection device 1a' according to <Modification (2) of Embodiment 2>, that is, the axial misalignment detection device 1a' which generates a first reflection characteristic map when it is determined that the seat position is the reference position, and does not generate a first reflection characteristic map if the seat position is not the reference position. Regarding the operation of the axial misalignment detection device 1a' shown in the flowchart of Figure 10, the processes of steps ST10 and ST13 to ST50 are the same as the processes of steps ST10 and ST13 to ST50 of the axial misalignment detection device 1a, which have already been explained using the flowchart of Figure 8, so redundant explanations will be omitted.

[0101] In step ST10, if the motion absence detection unit 11 detects that there is no motion inside the vehicle (if the result is "NO" in step ST10), the seat position determination unit 18 detects the position of the seats inside the vehicle based on the seat position determination information and performs a seat position determination process to determine whether the seat position is deviating from the reference position (step ST11). The seat position determination unit 18 outputs the seat position determination result to the stationary object detection unit 17.

[0102] In step ST11, if the seat position determination unit 18 determines that the seat is in the reference position, the stationary object detection unit 17 performs a stationary object detection process to detect stationary objects present in the vehicle interior based on the image captured by the in-vehicle camera 3 which captures images of the vehicle interior (step ST13). Subsequently, the axial misalignment detection device 1a' performs the processing described in steps ST20a to ST50.

[0103] On the other hand, if the seat position determination unit 18 determines in step ST11 that the seat position is not the reference position, the stationary object detection unit 17 does not detect stationary objects present in the vehicle interior. The stationary object detection unit 17 then outputs the seat position determination result, which indicates that the seat position in the vehicle interior is not the reference position, output from the seat position determination unit 18, to the reflective characteristics information generation unit 12a. Furthermore, the operation of the axial misalignment detection device 1a' skips the processing of steps ST20a to ST50.

[0104] Thus, the axial misalignment detection device 1a' may have a function to detect the position of a seat in the vehicle based on seat position determination information, and to determine whether the seat position is deviated from the reference position. If it is determined that the seat position is the reference position, it may generate a first reflection characteristic map, compare the first reflection characteristic map with the reference first reflection characteristic map, and detect the difference between the reflection intensity and the reference reflection intensity as an error. For example, if the seat position is not at the reference position, this may result in the calculation of an unnecessary difference in reflectivity between the first reflectivity map and the reference first reflectivity map. The axial misalignment detection device 1a' is configured as described above, which allows for improved detection accuracy of the axial misalignment of the radio wave sensor 2 by taking into account the effects of reflection from stationary objects.

[0105] An example of the hardware configuration of the axial misalignment detection devices 1a and 1a' according to Embodiment 2 is the same as the example configuration shown using Figures 5A and 5B in Embodiment 1. The functions of the motion object absence detection unit 11, the reflection characteristic information generation unit 12a, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18, and the control unit (not shown) are realized by the processing circuit 1001. When the processing circuit is a processor 1004, the functions of the motion absence detection unit 11, the reflection characteristic information generation unit 12a, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18, and the control unit (not shown) are realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in memory 1005. The processor 1004 reads and executes the program stored in memory 1005 to perform the functions of the motion absence detection unit 11, the reflection characteristic information generation unit 12a, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18, and the control unit (not shown). In other words, the axis misalignment detection devices 1a and 1a' include a memory 1005 for storing a program that, when executed by the processor 1004, will result in the execution of the processes of steps ST10 to ST50 in Figure 8, or the processes of steps ST10 to ST50 in Figure 10. Furthermore, the program stored in the memory 1005 can be said to cause the computer to execute the procedures or methods of the processes of the motion object absence detection unit 11, the reflection characteristic information generation unit 12a, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18, and the control unit (not shown). Furthermore, the axial misalignment detection devices 1a and 1a' include a radio wave sensor 2 or an in-vehicle camera 3, and an input interface device 1002 and an output interface device 1003 that perform wired or wireless communication.

[0106] In the above embodiment 2, the axis misalignment detection devices 1a and 1a' were equipped with a motion absence detection unit 11, but this is merely an example, and the axis misalignment detection devices 1a and 1a' may be configured without a motion absence detection unit 11. If the shaft misalignment detection device 1a is configured not to include a motion absence detection unit 11, the operation of the shaft misalignment detection device 1a can be as described using the flowchart in Figure 8, and the processing of step ST10 can be omitted. Furthermore, if the shaft misalignment detection device 1a' is configured not to include the motion absence detection unit 11, the operation of the shaft misalignment detection device 1a' can be as described using the flowchart in Figure 10, and the processing of step ST10 can be omitted.

[0107] Furthermore, in the above embodiment 2, the shaft misalignment detection devices 1a and 1a' were equipped with corresponding parts 15, but this is merely an example, and the shaft misalignment detection devices 1a and 1a' may be configured without corresponding parts 15. If the shaft misalignment detection device 1a is configured not to include the corresponding unit 15, the operation of the shaft misalignment detection device 1a can be as described using the flowchart in Figure 8, and the processing of step ST50 can be omitted. Furthermore, if the shaft misalignment detection device 1a' is configured not to include the corresponding unit 15, the operation of the shaft misalignment detection device 1a' can be as described using the flowchart in Figure 10, and the processing of step ST50 can be omitted.

[0108] Furthermore, in the above embodiment 2, the axis misalignment detection devices 1a and 1a' are in-vehicle devices mounted on the vehicle, and the motion absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18, and the control unit (not shown) are provided on the in-vehicle device. The system is not limited to this, however, a system may be configured with the on-board device and the server, in which some of the moving object absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the corresponding unit 15, the stationary object detection unit 17, the seat position determination unit 18, and the control unit (not shown) are mounted on the on-board device of the vehicle, and the others are provided on a server connected to the on-board device via a network. Furthermore, the server may also be equipped with the motion object absence detection unit 11, the reflection characteristic information generation unit 12, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18, and a control unit (not shown).

[0109] As described above, according to Embodiment 2, the axial misalignment detection device 1a includes a stationary object detection unit 17 that detects stationary objects present in the vehicle interior based on images captured by an in-vehicle camera 3 that images the interior of the vehicle. The error detection unit 13 is configured to detect the difference between the reflective characteristics (reflection intensity) and the reference reflective characteristics (reference first reflective characteristics map) when a stationary object is detected by the stationary object detection unit 17. This difference is obtained by removing the reflective characteristics (reflection intensity) of the reflected waves from the area of ​​stationary objects that are considered to be present in the vehicle interior from the reflective characteristics information (first reflective characteristics map) shown in the reflective characteristics information (first reflective characteristics map). Therefore, the axial misalignment detection device 1a can improve the accuracy of detecting axial misalignment of the radio wave sensor 2 by taking into account the effect of reflection from stationary objects.

[0110] Furthermore, according to Embodiment 2, the axial misalignment detection device 1a' may be configured to include a stationary object detection unit 17 that detects stationary objects present in the vehicle interior based on images captured by an in-vehicle camera 3 that captures images of the vehicle interior, a reflection characteristic information generation unit 12a that generates reflection characteristic information (first reflection characteristic map) when no stationary object is detected by the stationary object detection unit 17, and an error detection unit 13 that compares the reflection characteristic information generated by the reflection characteristic information generation unit 12a with reference reflection characteristic information (reference first reflection characteristic map) and detects the difference between the reflection characteristic (reflection intensity) and the reference reflection characteristic (reference reflection intensity) as an error. This allows the axial misalignment detection device 1a to improve the accuracy of detecting axial misalignment of the radio wave sensor 2 by taking into account the effect of reflection from stationary objects.

[0111] Furthermore, according to Embodiment 2, the axial misalignment detection device 1a' is equipped with a seat position determination unit 18 that detects the position of a seat in the vehicle based on seat position determination information and determines whether the seat position is deviated from a reference position. The stationary object detection unit 17 detects a stationary object when the seat position determination unit 18 determines that the seat position is the reference position. The error detection unit 13, when the stationary object detection unit 17 detects a stationary object, compares the excluded reflection characteristics information (excluded map), which is obtained by removing the reflection characteristics (reflection intensity) of the reflected wave from the area of ​​a stationary object that is considered to be present in the vehicle, from the reflection characteristics (reflection intensity) shown in the reflection characteristics information (first reflection characteristics map), with the reference reflection characteristics information (reference first reflection characteristics information), and detects the difference between the reflection characteristics (reflection intensity) and the reference reflection characteristics (reference reflection intensity) as an error. Alternatively, the axis misalignment detection device 1a' may be configured to include a seat position determination unit 18 in addition to the stationary object detection unit 17, wherein the stationary object detection unit 17 detects a stationary object when the seat position determination unit 18 determines that the seat position is the reference position, the reflection characteristic information generation unit 12a generates reflection characteristic information (first reflection characteristic map) when the stationary object detection unit 17 does not detect a stationary object, and the error detection unit 13 compares the reflection characteristic information generated by the reflection characteristic information generation unit 12a with the reference reflection characteristic information (reference first reflection characteristic map) and detects the difference between the reflection characteristic (reflection intensity) and the reference reflection characteristic (reference reflection intensity) as an error. This allows the axial misalignment detection device 1a' to improve the accuracy of the radio wave sensor 2's detection of axial misalignment by taking into account the effects of reflection from stationary objects and the positional misalignment of the seat.

[0112] Furthermore, the <Modified Example (2) of Embodiment 2> described above may be applied to the axial misalignment detection device 1 according to Embodiment 1. In other words, in the example configuration of the shaft misalignment detection device 1 described with reference to Figure 1 in Embodiment 1, the shaft misalignment detection device 1 may be connected to, for example, an in-vehicle camera 3 and include a seat position determination unit 18. In this case, for example, the axis misalignment detection device 1 includes a seat position determination unit 18 that detects the position of a seat in the vehicle based on seat position determination information and determines whether or not the seat position is deviated from a reference position. In the axis misalignment detection device 1, the reflection characteristic information generation unit 12 generates reflection characteristic information (first reflection characteristic map) when the seat position determination unit 18 determines that the seat position is the reference position, and the error detection unit 13 compares the reflection characteristic information (first reflection characteristic map) generated by the reflection characteristic information generation unit 12 with reference reflection characteristic information (reference first reflection characteristic map) and detects the difference between the reflection characteristic (reflection intensity) and the reference reflection characteristic (reference reflection intensity) as an error. As a result, the axis misalignment detection device 1 can take into account the positional misalignment of the seat and improve the accuracy of the detection of axis misalignment by the radio wave sensor 2.

[0113] Embodiment 3. As described in <Modification of Embodiment 2 (2)>, for example, if the seat position is not at the reference position, this may result in the calculation of an unnecessary difference in reflective properties between the reflective property information and the reference reflective property information. Embodiment 3 describes an embodiment that makes it possible to return the seat position to the reference position when the seat position in the vehicle interior is not in the reference position. Furthermore, Embodiment 3 assumes that the seat has a power seat function.

[0114] Figure 11 shows an example of the configuration of the axial misalignment detection device 1b according to Embodiment 3. As shown in Figure 11, the axial misalignment detection device 1b is connected to the radio wave sensor 2 and the power sheet 4. Power Seat 4 is a vehicle seat system that uses an electric motor to adjust the position of the seat.

[0115] The axis misalignment detection system 100b is composed of the axis misalignment detection device 1b and the radio wave sensor 2. Regarding the configuration example of the axial misalignment detection device 1b shown in Figure 11, the same reference numerals are used for configuration examples similar to the axial misalignment detection device 1 of Embodiment 1, which was explained using Figure 1 in Embodiment 1, and redundant explanations are omitted. The axial misalignment detection device 1b according to Embodiment 3 differs from the axial misalignment detection device 1 according to Embodiment 1, which was described using Figure 1, in that it includes a seat position determination unit 18a and a seat drive control unit 19. Furthermore, in Embodiment 3, the specific operation of the reflection characteristic information generation unit 12b differs from the specific operation of the reflection characteristic information generation unit 12 of the axial misalignment detection device 1 according to Embodiment 1.

[0116] In Embodiment 3, the reflection characteristic information generated by the reflection characteristic information generation unit 12b is, similar to the reflection characteristic information generated by the reflection characteristic information generation unit 12 in Embodiment 1, a reflection characteristic map that represents the reflection characteristics of the reflected wave as a three-dimensional spatial distribution within the vehicle interior. The reflection characteristic represented by the reflection characteristic map is the reflection intensity. Specifically, in Embodiment 3, the reflection characteristic information generated by the reflection characteristic information generation unit 12b is, more specifically, a first reflection characteristic map that represents the reflection intensity in the azimuth direction, elevation direction, and depth direction of the reflected wave as a three-dimensional spatial distribution within the vehicle interior.

[0117] The seat position determination unit 18a detects the position of the seat in the vehicle based on the seat position determination information and determines whether the seat position is deviating from the reference position. Here, the seat position determination unit 18a acquires information indicating the current position of each adjustment mechanism (hereinafter referred to as "seat position information") from, for example, a position sensor (not shown) provided by the power seat 4, as seat position determination information. The seat position determination unit 18a then determines whether the seat position is deviating from the reference position based on the acquired seat position determination information and the seat reference position information stored in a storage unit (not shown) or the like. For example, if the control unit (not shown) of the power seat 4 stores seat reference position information, the seat position determination unit 18a may obtain this information from the power seat 4 along with the seat position information as seat position determination information, and determine whether the seat position is deviating from the reference position. Although the seat position determination unit 18a and the seat position determination unit 18 described in Embodiment 2 differ in the content of the seat position determination information used to determine whether the seat position is deviating from the reference position and the determination method, both the seat position determination unit 18a and the seat position determination unit 18 determine whether the current seat position is deviating from the reference position. The seat position determination unit 18a outputs a seat position determination result, indicating whether or not the seat position is deviating from the reference position, to the reflection characteristic information generation unit 12b and the seat drive control unit 19.

[0118] The seat drive control unit 19 has the function of changing the position of the seats in the vehicle interior. More specifically, the seat drive control unit 19 has the function of changing the front-to-back position, height, or backrest position of the seats in the vehicle interior. In Embodiment 3, if the seat position determination unit 18a determines that the position of the seat in the vehicle interior is deviating from the reference position, the seat drive control unit 19 returns the seat to the reference position. For example, the seat drive control unit 19 outputs an instruction to the power seat 4 to return the seat to its reference position. As a result, the seat drive control unit 19 returns the seat to its reference position. When the seat drive control unit 19 returns the seat to its reference position, it outputs information indicating that the seat has been returned to its reference position (hereinafter referred to as "seat instruction completion information") to the reflection characteristic information generation unit 12b. Furthermore, it is desirable for the seat drive control unit 19 to return the seat to its reference position when there are no occupants in the vehicle cabin. In other words, it is desirable for the seat drive control unit 19 to acquire the motion absence detection result from the motion absence detection unit 11, and to return the seat to its reference position only after the motion absence detection unit 11 has detected that there are no moving objects in the vehicle cabin. Note that in Figure 11, the arrow from the motion absence detection unit 11 to the seat drive control unit 19 is not shown.

[0119] The reflective properties information generation unit 12b generates reflective properties information after the seat drive control unit 19 returns the seat to the reference position when the seat position determination unit 18a determines that the seat position is deviated from the reference position. Here, the reflective properties information generation unit 12b generates a first reflective properties map after the seat drive control unit 19 returns the seat to the reference position when the seat position determination unit 18a determines that the seat position is deviated from the reference position. The method for generating the first reflective properties map by the reflective properties information generation unit 12b may be the same as the method for generating the first reflective properties map by the reflective properties information generation unit 12 in Embodiment 1. The reflective properties information generation unit 12b can determine from the seat position determination result output from the seat position determination unit 18a that the seat position determination unit 18a has determined that the seat position is deviating from the reference position. Furthermore, the reflective properties information generation unit 12b can determine from the seat instruction completion information output from the seat drive control unit 19 that the seat position has been returned to the reference position by the seat drive control unit 19.

[0120] The operation of the axial misalignment detection device 1b according to Embodiment 3 will be described. Figure 12 is a flowchart illustrating the operation of the axial misalignment detection device 1b according to Embodiment 3. The misalignment detection device 1b, for example, when it detects that the vehicle's engine has been turned off, begins the operation shown in the flowchart of Figure 12. For example, a control unit (not shown) of the misalignment detection device 1b can obtain information indicating the state of the ignition switch from an engine control unit (not shown) and detect that the vehicle's engine has been turned off. When the control unit detects that the vehicle's engine has been turned off, it outputs instructions to start operation to each part of the misalignment detection device 1b. For example, once the shaft misalignment detection device 1b starts operating, it repeats the operations shown in the flowchart of Figure 12 until the processes from step ST11a to step ST50 in the flowchart of Figure 12 are performed once. The shaft misalignment detection device 1b may also perform these operations periodically.

[0121] Regarding the operation of the axial misalignment detection device 1b shown in the flowchart of Figure 12, the processes of steps ST10 and ST30 to ST50 are the same as the processes of steps ST10 and ST30 to ST50 by the axial misalignment detection device 1, which were explained using the flowchart of Figure 4 in Embodiment 1, so redundant explanations will be omitted.

[0122] In step ST10, if the motion absence detection unit 11 detects that there is no motion in the vehicle interior (if the result of step ST10 is "NO"), the seat position determination unit 18a obtains seat position determination information from the power seat 4, detects the position of the seat in the vehicle interior based on the obtained seat position determination information, and performs a seat position determination process to determine whether the seat position is deviating from the reference position (step ST11a). The seat position determination unit 18a outputs a seat position determination result, indicating whether or not the seat position is deviating from the reference position, to the reflection characteristic information generation unit 12b and the seat drive control unit 19.

[0123] In step ST11a, if the seat position determination unit 18a determines that the position of the seat in the vehicle interior is deviated from the reference position, the seat drive control unit 19 causes the seat to return to the reference position (step ST17). The seat drive control unit 19 outputs seat instruction completion information to the reflective characteristic information generation unit 12b.

[0124] In step ST11a, if the seat position determination unit 18a determines that the position of the seat in the vehicle interior is deviated from the reference position, the reflection characteristic information generation unit 12b waits until seat instruction completion information is output from the seat drive control unit 19. Once seat instruction completion information is output from the seat drive control unit 19, the unit performs a reflection characteristic information generation process to generate a first reflection characteristic map showing the reflection intensity of the reflected wave in the vehicle interior from sensor information based on the reflected wave that was reflected by an object in the vehicle interior from the radio wave sensor 2 irradiated toward the vehicle interior (step ST20b). In step ST11a, if the seat position determination unit 18a determines that the seat position in the vehicle interior is not deviating from the reference position, the reflection characteristic information generation unit 12b generates the first reflection characteristic map without waiting for the seat drive control unit 19 to output seat instruction completion information.

[0125] In this manner, the axis misalignment detection device 1b detects the position of the seats in the vehicle interior based on seat position determination information and determines whether the seat position is deviated from the reference position. If the axis misalignment detection device 1b determines that the seat position is deviated from the reference position, it causes the seat position to return to the reference position. If the axis misalignment detection device 1b determines that the seat position is deviated from the reference position, it generates a reference first reflection characteristic map after the seat position has been returned to the reference position. Therefore, the misalignment detection device 1b can improve the accuracy of the radio wave sensor 2 in detecting misalignment by taking into account the effect of reflection due to the seats in the vehicle interior not being in the reference position.

[0126] An example of the hardware configuration of the axial misalignment detection device 1b according to Embodiment 3 is the same as the example configuration shown using Figures 5A and 5B in Embodiment 1. The functions of the motion object absence detection unit 11, the reflection characteristic information generation unit 12b, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18a, the seat drive control unit 19, and the control unit (not shown) are realized by the processing circuit 1001. When the processing circuit is a processor 1004, the functions of the motion absence detection unit 11, the reflection characteristic information generation unit 12b, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18a, the seat drive control unit 19, and the control unit (not shown) are realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in memory 1005. The processor 1004 reads and executes the program stored in memory 1005 to perform the functions of the motion absence detection unit 11, the reflection characteristic information generation unit 12b, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18a, the seat drive control unit 19, and the control unit (not shown). In other words, the axis misalignment detection device 1b includes a memory 1005 for storing a program that, when executed by the processor 1004, will result in the execution of the processes shown in steps ST10 to ST50 of Figure 12 above. The program stored in the memory 1005 can also be said to cause the computer to execute the procedures or methods of processing of the motion absence detection unit 11, the reflection characteristic information generation unit 12b, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18a, the seat drive control unit 19, and a control unit (not shown). Furthermore, the axial misalignment detection device 1b includes a device such as a radio wave sensor 2 or a power sheet 4, and an input interface device 1002 and an output interface device 1003 that perform wired or wireless communication.

[0127] In the above embodiment 3, the axis misalignment detection device 1b was equipped with a motion absence detection unit 11, but this is merely one example, and the axis misalignment detection device 1b may be configured without a motion absence detection unit 11. If the shaft misalignment detection device 1b is configured not to include the motion absence detection unit 11, the operation of the shaft misalignment detection device 1b can omit the processing of step ST10 in the operation described using the flowchart in Figure 12.

[0128] Furthermore, in the above embodiment 3, the shaft misalignment detection device 1b was equipped with a corresponding part 15, but this is merely an example, and the shaft misalignment detection device 1b may be configured without a corresponding part 15. If the shaft misalignment detection device 1b is configured not to include the corresponding part 15, the operation of the shaft misalignment detection device 1b can be performed as described using the flowchart in Figure 12, and the processing of step ST50 can be omitted.

[0129] Furthermore, in the above embodiment 3, the shaft misalignment detection device 1b is an on-board device mounted on a vehicle, and the motion absence detection unit 11, the reflection characteristic information generation unit 12b, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18a, the seat drive control unit 19, and a control unit (not shown) are provided in the on-board device. The system is not limited to this, however, a system may be configured with the on-board device and the server, in which some of the following components—the motion absence detection unit 11, the reflection characteristic information generation unit 12b, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18a, the seat drive control unit 19, and a control unit (not shown)—are mounted on the on-board device of the vehicle, and the others are provided on a server connected to the on-board device via a network. Furthermore, the motion absence detection unit 11, the reflection characteristic information generation unit 12b, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18a, the seat drive control unit 19, and a control unit (not shown) may all be provided on the server.

[0130] As described above, according to Embodiment 3, the axial misalignment detection device 1b includes a seat position determination unit 18a that detects the position of a seat in the vehicle interior based on seat position determination information and determines whether or not the seat position is deviated from a reference position, and a seat drive control unit 19 that returns the seat position to the reference position if the seat position determination unit 18a determines that the seat position is deviated from the reference position, and the reflective characteristic information generation unit 12b is configured to generate reflective characteristic information (first reflective characteristic map) after the seat position is returned to the reference position by the seat drive control unit 19 when the seat position determination unit 18a determines that the seat position is deviated from the reference position. Therefore, the misalignment detection device 1b can improve the accuracy of the radio wave sensor 2 in detecting misalignment by taking into account the effect of reflection due to the seats in the vehicle interior not being in the reference position.

[0131] Embodiment 4. In embodiments 1 to 3, the reflective properties represented by the reflective properties information were defined as the reflective intensity. Embodiment 4 describes an embodiment in which the reflective properties represented by the reflective properties information are defined as the motion component.

[0132] Figure 13 shows an example of the configuration of the axial misalignment detection device 1c according to Embodiment 4. As shown in Figure 13, the axial misalignment detection device 1c is connected to the radio wave sensor 2 and the power sheet 4.

[0133] The axial misalignment detection system 100c is composed of the axial misalignment detection device 1c and the power seat 4. Regarding the configuration example of the axial misalignment detection device 1c shown in Figure 13, the same reference numerals are used for configuration examples similar to the axial misalignment detection device 1 of Embodiment 1, which was explained using Figure 1 in Embodiment 1, and redundant explanations are omitted. The shaft misalignment detection device 1c according to Embodiment 4 differs from the shaft misalignment detection device 1 according to Embodiment 1, which was described using Figure 1, in that it includes a seat drive control unit 19a. Furthermore, in Embodiment 4, the specific operation of the reflection characteristic information generation unit 12c differs from the specific operation of the reflection characteristic information generation unit 12 of the axial misalignment detection device 1 according to Embodiment 1.

[0134] In Embodiment 4, the reflection characteristic information generated by the reflection characteristic information generation unit 12c is, similar to the reflection characteristic information generated by the reflection characteristic information generation unit 12 in Embodiment 1, a reflection characteristic map that represents the reflection characteristics of a reflected wave as a three-dimensional spatial distribution within the vehicle interior. However, while the reflection characteristic represented by the reflection characteristic map in Embodiment 1 was the reflection intensity, the reflection characteristic represented by the reflection characteristic map in Embodiment 4 is the presence or absence of motion, or the velocity of the object. A reflection characteristic map that represents the presence or absence of motion or the velocity of an object as a reflection characteristic, such as the reflection characteristic map generated by the reflection characteristic information generation unit 12c in Embodiment 4, is also called a "second reflection characteristic map." In the following description, the presence or absence of motion or the velocity of an object as a reflection characteristic represented in the second reflection characteristic map is referred to as the "motion component." Details of the reflection characteristic information generation unit 12c in Embodiment 4 will be described later.

[0135] The seat drive control unit 19a, like the seat drive control unit 19 according to Embodiment 2, has the function of changing the position of the seat in the vehicle interior. More specifically, the seat drive control unit 19a has the function of changing the front-to-back position, height, or backrest position of the seat in the vehicle interior. In Embodiment 4, the seat drive control unit 19a changes the position of the seat according to a preset condition (hereinafter referred to as the "position change condition"). The position change conditions define how the seat position should be changed (for example, the range and speed within which the backrest position should be moved forward and backward, and how many times this movement should be performed, etc.). The position change conditions are set in advance by an administrator or other designated person. Once the administrator or other designated person sets the position change conditions, they store information indicating the position change conditions (hereinafter referred to as "position change condition information") in a memory unit (not shown). The administrator or other designated person can update the position change condition information as needed. The seat drive control unit 19a outputs an instruction to the power seat 4 to change the seat position to a position according to the position change conditions. As a result, the seat drive control unit 19a changes the seat position according to the position change conditions. In other words, as a result, the seat drive control unit 19a generates movement in the seat according to the position change conditions. When the seat drive control unit 19a outputs an instruction to the power seat 4 to change the position of the seat, it outputs information indicating that movement has been generated in the seat (hereinafter referred to as "movement instruction information") to the reflection characteristic information generation unit 12c. Furthermore, the seat drive control unit 19a outputs movement instruction information to the power seat 4 when the motion absence detection unit 11 detects that there is no motion present inside the vehicle.

[0136] The reflection characteristic information generation unit 12c generates reflection characteristic information, in this case a second reflection characteristic map, from sensor information based on reflected waves from objects inside the vehicle interior, which were emitted by the radio wave sensor 2 toward the vehicle interior during the period when the seat drive control unit 19a changed the position of the seat according to the position change conditions (hereinafter referred to as the "first period"). The first period is set in advance by the administrator or the like. The reflective characteristics information generation unit 12c only needs to detect that the seat drive control unit 19a has started the process of changing the seat position based on the movement instruction information output from the seat drive control unit 19a.

[0137] Here, an example of a method for generating a second reflection characteristic map by the reflection characteristic information generation unit 12c in Embodiment 4 will be described.

[0138] First, the reflection characteristic information generation unit 12c acquires time-series sensor information for a first period output from the radio wave sensor 2. For example, the reflection characteristic information generation unit 12c can acquire time-series sensor information for a first period by storing the sensor information acquired from the radio wave sensor 2 in a time-series memory unit (not shown) each time it is acquired. Then, the reflection characteristic information generation unit 12c generates a second reflection characteristic map based on the time-series sensor information for the first period output from the radio wave sensor 2. In detail, the reflective characteristics information generation unit 12c detects movement inside the vehicle based on time-series sensor information. The movement detected here includes seat movement caused by the seat drive control unit 19a changing the seat position. For example, the reflection characteristic information generation unit 12c detects, based on time-series sensor information for the first period, the change in the reflection intensity of the reflected wave, which is reflected by a target object inside the vehicle from a radio wave sensor 2 irradiated inside the vehicle, as motion. The reflection characteristic information generation unit 12c then generates a second reflection characteristic map that represents the movement inside the vehicle as a three-dimensional spatial distribution. The second reflection characteristic map generated by the reflection characteristic information generation unit 12c represents the movement inside the vehicle using a plurality of grids that correspond to the reflection points of radio waves in the three-dimensional space inside the vehicle. Each grid is assigned a value (for example, "1" or "0") that indicates whether or not there is movement, in other words, whether or not there has been a change in reflection intensity at that reflection point. That is, the second reflection characteristic map is a three-dimensional so-called "zero-one (0 / 1) map" that shows the movement in the three-dimensional space inside the vehicle. In the second reflection characteristic map, for example, each grid is assigned a "1" if there is movement at the grid position, and a "0" if there is no movement.

[0139] In the above description, the reflection characteristic information generation unit 12c is described as detecting as motion the change in the reflection intensity of the reflected wave when the radio waves emitted from the radio wave sensor 2 in the vehicle interior are reflected by a target object in the vehicle interior, based on the time-series sensor information for the first period. However, this is merely one example, and the reflection characteristic information generation unit 12c may detect motion by other methods. For example, the reflection characteristic information generation unit 12c may detect movement inside the vehicle by detecting the velocity of an object based on the time-series sensor information of the first period using a known technique that utilizes the Doppler effect to detect velocity in relation to reflected waves. In this case, the second reflection characteristic map generated by the reflection characteristic information generation unit 12c may represent, for example, the velocity of an object inside the vehicle interior using a plurality of grids that correspond to the reflection points of radio waves in the three-dimensional space inside the vehicle interior. In the second reflection characteristic map, each grid is assigned a numerical value corresponding to the velocity of the object located at that grid. More specifically, for a given grid, the greater the velocity of the object located at that grid, the larger the numerical value assigned to that grid.

[0140] In this way, the reflection characteristic information generation unit 12c generates a second reflection characteristic map that represents the motion component (presence or absence of motion or the velocity of an object) as a three-dimensional spatial distribution within the vehicle interior. The reflection characteristic information generation unit 12 outputs the generated second reflection characteristic map to the error detection unit 13.

[0141] In Embodiment 4, the error detection unit 13 compares the reflection characteristic information generated by the reflection characteristic information generation unit 12c, i.e., the second reflection characteristic map, with the reference reflection characteristic information and detects the difference between the reflection characteristic and the reference reflection characteristic as an error. In Embodiment 4, the reference reflection characteristic information is a second reflection characteristic map that represents the motion component as a reflection characteristic. In Embodiment 4, the second reflection characteristic map as reference reflection characteristic information is also called the "reference second reflection characteristic map." Furthermore, the motion component represented by the reference second reflection characteristic map is also called the "reference motion component." The reference second reflection characteristic map is generated in advance by an administrator or the like and stored in the reference reflection characteristic information storage unit 16. The administrator or the like can generate the reference second reflection characteristic map in the same manner as the reference first reflection characteristic map, as described in Embodiment 1. The error detection unit 13 can detect the difference between the motion component and the reference motion component as an error by comparing the second reflection characteristic map and the reference second reflection characteristic map, in the same manner as described in Embodiment 1, where the first reflection characteristic map and the reference first reflection characteristic map are compared and the difference between the reflection intensity and the reference reflection intensity is detected as an error.

[0142] The operation of the axial misalignment detection device 1c according to Embodiment 4 will be described. Figure 14 is a flowchart illustrating the operation of the axial misalignment detection device 1c according to Embodiment 4. The shaft misalignment detection device 1c starts the operation shown in the flowchart of Figure 14, for example, when it detects that the vehicle's engine has been turned off. For example, a control unit (not shown) of the shaft misalignment detection device 1c can obtain information indicating the state of the ignition switch from an engine control unit (not shown) and detect that the vehicle's engine has been turned off. When the control unit detects that the vehicle's engine has been turned off, it outputs instructions to start operation to each part of the shaft misalignment detection device 1c. For example, once the shaft misalignment detection device 1c starts operating, it repeats the operations shown in the flowchart of Figure 8 until the processes from step ST19 to step ST50 in the flowchart of Figure 14 are performed once. The shaft misalignment detection device 1c may also perform these operations periodically.

[0143] Regarding the operation of the axial misalignment detection device 1c shown in the flowchart of Figure 14, the processes of steps ST10 and ST40 to ST50 are the same as the processes of steps ST10 and ST40 to ST50 by the axial misalignment detection device 1, which were explained using the flowchart of Figure 4 in Embodiment 1, so redundant explanations will be omitted.

[0144] In step ST10, if the motion absence detection unit 11 detects that there is no motion in the vehicle interior (if the result is "NO" in step ST10), the seat drive control unit 19a outputs an instruction to the power seat 4 to change the seat position to a position according to the position change conditions. As a result, the seat drive control unit 19a changes the seat position according to the position change conditions (step ST19). The seat drive control unit 19a outputs the motion instruction information to the reflection characteristic information generation unit 12c.

[0145] In step ST19, when the seat drive control unit 19a changes the seat position according to the position change conditions, the reflection characteristic information generation unit 12c performs a reflection characteristic information generation process to generate a second reflection characteristic map showing the motion component inside the vehicle from sensor information based on the reflected waves of radio waves irradiated by the radio wave sensor 2 toward the vehicle interior and reflected by objects inside the vehicle interior during the first period (step ST21). The reflection characteristic information generation unit 12c outputs the generated second reflection characteristic map to the error detection unit 13.

[0146] In step ST30, the error detection unit 13 compares the second reflection characteristic map generated by the reflection characteristic information generation unit 12c in step ST21 with the reference second reflection characteristic map and performs error detection processing to detect the difference between the motion component and the reference motion component as an error.

[0147] Thus, the misalignment detection device 1c has the function of changing the position of the seats in the vehicle cabin. The misalignment detection device 1c generates a second reflection characteristic map showing the motion component from sensor information based on the reflected waves during the first period in which the position of the seats was changed according to the position change conditions, and compares the generated second reflection characteristic map with a reference second reflection characteristic map to detect the difference between the motion component and the reference motion component as an error. Therefore, the misalignment detection device 1c can detect the misalignment of the radio wave sensor 2, which emits radio waves toward the vehicle interior and receives the reflected waves that are reflected by objects inside the vehicle interior.

[0148] <Modified example of Embodiment 4 (1)> In the above embodiment 4, the axial misalignment detection device 1c generates movement within the vehicle by changing the position of the seat in the vehicle, and the reflection characteristic information generation unit 12c detects the movement generated by the seat drive control unit 19 and generates a second reflection characteristic map. This is just one example; the reflection characteristic information generation unit 12c may also detect motion generated by other means and generate a second reflection characteristic map. A detailed explanation follows.

[0149] For example, the reflection characteristic information generation unit 12c may generate a second reflection characteristic map that indicates the presence or absence of movement inside the vehicle or the velocity of an object, i.e., the motion component, from sensor information based on reflected waves during a preset period (hereinafter referred to as the "second period") after the vehicle door is closed. The second period is set in advance by an administrator or the like. The second period may be the same length as the first period or a different length. In this case, the reflective properties information generation unit 12c acquires information indicating the opening and closing of a door from, for example, a door sensor (not shown), and detects that the door was opened and then closed based on the acquired information indicating the opening and closing of the door. Then, the reflective properties information generation unit 12c detects the motion component inside the vehicle interior based on the time-series sensor information for the second period and generates a second reflective properties map. For example, when a vehicle door is opened for an occupant to disembark and then closed, the force of the door opening and closing causes the seat to vibrate. In this modified example (1) of Embodiment 4, the reflection characteristic information generation unit 12c captures the movement caused by the vibration of the seat due to the force of the door opening and closing and generates a second reflection characteristic map. In this case, however, the axial misalignment detection device 1c is not required to be connected to the power seat 4, nor is it required to be equipped with the seat drive control unit 19a.

[0150] An example of the hardware configuration of the axial misalignment detection device 1c according to Embodiment 4 is the same as the example configuration shown using Figures 5A and 5B in Embodiment 1. The functions of the motion object absence detection unit 11, the reflection characteristic information generation unit 12c, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat position determination unit 18, the seat drive control unit 19a, and the control unit (not shown) are realized by the processing circuit 1001. When the processing circuit is a processor 1004, the functions of the motion absence detection unit 11, the reflection characteristic information generation unit 12c, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat drive control unit 19a, and the control unit (not shown) are realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in memory 1005. The processor 1004 reads and executes the program stored in memory 1005 to perform the functions of the motion absence detection unit 11, the reflection characteristic information generation unit 12c, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat drive control unit 19a, and the control unit (not shown). In other words, the axis misalignment detection device 1c includes memory 1005 for storing a program that, when executed by the processor 1004, will result in the execution of the processes in steps ST10 to ST50 of Figure 14 described above. Furthermore, the program stored in memory 1005 can be said to cause the computer to execute the procedures or methods of processing of the motion object absence detection unit 11, the reflection characteristic information generation unit 12c, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat drive control unit 19a, and the control unit (not shown). Furthermore, the axial misalignment detection device 1c includes a device such as a radio wave sensor 2 or a power sheet 4, and an input interface device 1002 and an output interface device 1003 that perform wired or wireless communication.

[0151] In the above embodiment 4, the shaft misalignment detection device 1c was equipped with a motion absence detection unit 11, but this is merely one example, and the shaft misalignment detection device 1c may be configured without a motion absence detection unit 11. If the shaft misalignment detection device 1c is configured not to include the motion absence detection unit 11, the operation of the shaft misalignment detection device 1c can be as described using the flowchart in Figure 14, and the processing of step ST10 can be omitted.

[0152] Furthermore, in the above embodiment 4, the shaft misalignment detection device 1c was equipped with a corresponding part 15, but this is merely an example, and the shaft misalignment detection device 1c may be configured without a corresponding part 15. If the shaft misalignment detection device 1c is configured not to include the corresponding part 15, the operation of the shaft misalignment detection device 1c can be as described using the flowchart in Figure 14, and the processing of step ST50 can be omitted.

[0153] Furthermore, in the above embodiment 4, the shaft misalignment detection device 1c is an on-board device mounted on the vehicle, and the motion absence detection unit 11, the reflection characteristic information generation unit 12c, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat drive control unit 19a, and a control unit (not shown) are provided in the on-board device. The system is not limited to this, however, a system may be configured with the on-board device and the server, in which some of the moving object absence detection unit 11, the reflection characteristic information generation unit 12c, the error detection unit 13, the determination unit 14, the corresponding unit 15, the stationary object detection unit 17, the seat drive control unit 19a, and the control unit (not shown) are mounted on the on-board device of the vehicle, and the others are provided on a server connected to the on-board device via a network. Furthermore, the motion object absence detection unit 11, the reflection characteristic information generation unit 12c, the error detection unit 13, the determination unit 14, the correspondence unit 15, the stationary object detection unit 17, the seat drive control unit 19a, and a control unit (not shown) may all be provided on the server.

[0154] As described above, according to Embodiment 4, the axial misalignment detection device 1c includes a seat drive control unit 19a that changes the position of a seat in the vehicle cabin, the reflection characteristic information generation unit 12c generates reflection characteristic information (second reflection characteristic map) showing the motion component from sensor information based on the reflected wave during the first period in which the seat drive control unit 19a changes the position of the seat according to the position change conditions, and the error detection unit 13 is configured to compare the reflection characteristic information generated by the reflection characteristic information generation unit 12c with reference reflection characteristic information (reference second reflection characteristic map) and detect the difference between the reflection characteristic (motion component) and the reference reflection characteristic (reference motion component) as an error. Therefore, the misalignment detection device 1c can detect the misalignment of the radio wave sensor 2, which emits radio waves toward the vehicle interior and receives the reflected waves that are reflected by objects inside the vehicle interior.

[0155] Furthermore, according to Embodiment 4, in the axial misalignment detection device 1c, the reflection characteristic information generation unit 12c generates reflection characteristic information (second reflection characteristic map) showing the motion component from sensor information based on the reflected wave during the second period after the vehicle door is closed, and the error detection unit 13 is configured to compare the reflection characteristic information generated by the reflection characteristic information generation unit 12c with reference reflection characteristic information (reference second reflection characteristic map) and detect the difference between the reflection characteristic (motion component) and the reference reflection characteristic (reference motion component) as an error. As a result, the misalignment detection device 1c can detect the misalignment of the radio wave sensor 2, which emits radio waves toward the vehicle interior and receives the reflected waves that are reflected by objects inside the vehicle interior.

[0156] In the above embodiment 2, in <Modification of Embodiment 2 (2)>, the seat position determination unit 18 acquires the image captured by the in-vehicle camera 3 as seat position determination information, and determines whether the seat position is deviated from the reference position based on the image. This is merely one example, and in the above <Modification of Embodiment 2 (2)>, for example, if the axis misalignment detection device 1a' is connected to the power seat 4, the seat position determination unit 18 may acquire seat position information from the power seat 4 as seat position determination information, and determine whether the seat position is deviated from the reference position based on the seat position information.

[0157] Furthermore, in the above embodiment 3, the seat position determination unit 18a acquires seat position information from the power seat 4 as seat position determination information and determines whether the seat position is deviated from the reference position based on the seat position information. This is merely one example, and in the above embodiment 3, for example, if the axis misalignment detection device 1b is connected to the in-vehicle camera 3, the seat position determination unit 18a may acquire the image captured by the in-vehicle camera 3 as seat position determination information and determine whether the seat position is deviated from the reference position based on the image.

[0158] Furthermore, this disclosure allows for free combination of each embodiment, modification of any component in each embodiment, or omission of any component in each embodiment. [Explanation of Symbols]

[0159] 1,1a,1b,1c Axis misalignment detection device, 2 Radio wave sensor, 3 In-car camera, 4 Power seat, 11 Motion object absence detection unit, 12,12a,12b,12c Reflection characteristic information generation unit, 13 Error detection unit, 14 Judgment unit, 15 Correspondence unit, 16 Reference reflection characteristic information storage unit, 17 Stationary object detection unit, 18,18a Seat position determination unit, 19,19a Seat drive control unit, 100,100a,100b,100c Axis misalignment detection system, 1001 Processing circuit, 1002 Input interface device, 1003 Output interface device, 1004 Processor, 1005 Memory.

Claims

1. A misalignment detection device for detecting misalignment of a radio wave sensor that emits radio waves toward the interior of a vehicle and receives reflected waves that are reflected by objects inside the vehicle, A reflection characteristic information generation unit generates reflection characteristic information indicating the reflection characteristics of the reflected wave from sensor information based on the reflected wave, which is generated when the radio wave emitted by the radio wave sensor toward the interior of the vehicle is reflected by an object in the interior of the vehicle when no moving object is present in the vehicle interior. An error detection unit compares the reflective characteristic information generated by the reflective characteristic information generation unit with reference reflective characteristic information that represents the reference reflective characteristic of the reflective characteristic, which is generated assuming the conditions inside the vehicle interior, and detects the difference between the reflective characteristic and the reference reflective characteristic as an error. A determination unit determines whether or not the axial misalignment has occurred based on the error detected by the error detection unit. A misalignment detection device equipped with the following.

2. The aforementioned standard conditions inside the vehicle are those in which the moving object is not present inside the vehicle, the seats are in their standard positions, and the radio wave sensor is installed inside the vehicle without any axial misalignment. The axial misalignment detection device according to claim 1.

3. The reflection characteristic information generation unit, As the reflection characteristic information, a reflection characteristic map is generated that represents the reflection characteristics of the reflected wave as a three-dimensional spatial distribution within the vehicle interior. The error detection unit, The reflection characteristic map generated by the reflection characteristic information generation unit is compared with the reference reflection characteristic map used as reference reflection characteristic information, and the difference between the reflection characteristic and the reference reflection characteristic is detected as the error. The axial misalignment detection device according to claim 1.

4. The aforementioned reflection characteristics are the reflection intensity or motion component of the reflected wave. The axial misalignment detection device according to claim 1.

5. The aforementioned reflection characteristics are the reflection intensity of the reflected wave, and include the reflection intensity of the reflected wave reflected by the metal frame of the vehicle body. The axial misalignment detection device according to claim 1.

6. The aforementioned reflection characteristics are the reflection intensity of the reflected wave, and include the reflection intensity of the reflected wave reflected by the metal frame of the seat. The axial misalignment detection device according to claim 1.

7. The aforementioned reflection characteristics are the reflection intensity of the reflected wave, and include the reflection intensity of the reflected wave reflected by the metal frame of the vehicle body and the metal frame of the seat. The axial misalignment detection device according to claim 1.

8. The aforementioned reflection characteristic is the reflection intensity of the reflected wave, A seat position determination unit detects the position of the seats in the vehicle interior based on seat position determination information and determines whether the seat position is deviating from the reference position, The seat drive control unit, when it determines that the seat position is deviating from the reference position, causes the seat position to return to the reference position. The reflection characteristic information generation unit, If the seat position determination unit determines that the seat position is deviated from the reference position, the seat drive control unit returns the seat position to the reference position, and then generates the reflective characteristics information. The axial misalignment detection device according to claim 1.

9. The aforementioned reflection characteristics are a motion component, The vehicle includes a seat drive control unit that changes the position of the seats in the vehicle interior, The reflection characteristic information generation unit, The seat drive control unit generates the reflection characteristic information indicating the motion component from the sensor information based on the reflected wave during the first period in which the seat position was changed according to the position change conditions. The error detection unit, The reflection characteristic information generated by the reflection characteristic information generation unit is compared with the reference reflection characteristic information, and the difference between the motion component and the reference motion component is detected as the error. The axial misalignment detection device according to claim 1.

10. The aforementioned reflection characteristics are a motion component, The reflection characteristic information generation unit, From the sensor information based on the reflected wave during the second period after the vehicle door is closed, the reflection characteristic information indicating the motion component is generated. The error detection unit, The reflection characteristic information generated by the reflection characteristic information generation unit is compared with the reference reflection characteristic information, and the difference between the motion component and the reference motion component is detected as the error. The axial misalignment detection device according to claim 1.

11. The aforementioned reflection characteristic is the reflection intensity of the reflected wave, The vehicle is equipped with a stationary object detection unit that detects stationary objects present in the vehicle based on images captured by an in-vehicle camera that captures images of the vehicle interior. The error detection unit, When the stationary object detection unit detects the stationary object, the system compares the excluded reflection characteristics information, which is obtained by removing the reflection intensity from the region of the stationary object where the stationary object is considered to be present within the vehicle interior, with the reference reflection characteristics information, and detects the difference between the reflection intensity and the reference reflection intensity as the error. The axial misalignment detection device according to claim 1.

12. The aforementioned reflection characteristic is the reflection intensity of the reflected wave, The vehicle is equipped with a stationary object detection unit that detects stationary objects present in the vehicle based on images captured by an in-vehicle camera that captures images of the vehicle interior. The reflection characteristic information generation unit, If the stationary object is not detected by the stationary object detection unit, the reflection characteristic information is generated. The error detection unit, The reflection characteristic information generated by the reflection characteristic information generation unit is compared with the reference reflection characteristic information, and the difference between the reflection intensity and the reference reflection intensity is detected as the error. The axial misalignment detection device according to claim 1.

13. The aforementioned reflection characteristic is the reflection intensity of the reflected wave, The system includes a seat position determination unit that detects the position of a seat in the vehicle interior based on seat position determination information and determines whether the seat position is deviating from a reference position. The reflection characteristic information generation unit, When the seat position determination unit determines that the seat is at the reference position, the reflective characteristics information is generated. The error detection unit, The reflection characteristic information generated by the reflection characteristic information generation unit is compared with the reference reflection characteristic information, and the difference between the reflection intensity and the reference reflection intensity is detected as the error. The axial misalignment detection device according to claim 1.

14. If the determination unit determines that the axial misalignment has occurred, the corresponding unit outputs warning information to warn that the axial misalignment has occurred. The axial misalignment detection device according to claim 1, comprising:

15. If the determination unit determines that the axial misalignment has occurred, the corresponding unit outputs correction information to the radio wave sensor to correct the axial misalignment. The axial misalignment detection device according to claim 1, comprising:

16. The determination unit, If the error detection unit determines that the axial misalignment has occurred based on the error it has detected, it determines the amount of the axial misalignment. The corresponding part is, If the determination unit determines that the axial misalignment has occurred, and the amount of axial misalignment determined by the determination unit is within the correctable range, the unit outputs the correction information to the radio wave sensor. The axial misalignment detection device according to claim 15, characterized in that it is a feature of the device described in claim 15.

17. A program for detecting misalignment of a radio wave sensor that emits radio waves toward the interior of a vehicle and receives reflected waves that are reflected by objects inside the vehicle, Computers, A reflection characteristic information generation unit generates reflection characteristic information indicating the reflection characteristics of the reflected wave from sensor information based on the reflected wave, which is generated when the radio wave emitted by the radio wave sensor toward the interior of the vehicle is reflected by an object in the interior of the vehicle when no moving object is present in the vehicle interior. An error detection unit compares the reflective characteristic information generated by the reflective characteristic information generation unit with reference reflective characteristic information that represents the reference reflective characteristic of the reflective characteristic, which is generated assuming the conditions inside the vehicle interior, and detects the difference between the reflective characteristic and the reference reflective characteristic as an error. A determination unit determines whether or not the axial misalignment has occurred based on the error detected by the error detection unit. A program for detecting axis misalignment to function as such.

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