Mobile alarm device

Abstract

The present invention relates to a mobile alarm device. A mobile alarm device (30) according to one aspect of the present disclosure includes: a speed calculation unit (S10 to S90, S100 to S180), a position determination unit (S10 to S90, S100 to S180), and an exclusion unit (S100, S190). The speed calculation unit calculates at least one relative speed of an observation point. When multiple relative speeds are calculated, the position determination unit determines whether the observation point corresponding to each of the multiple relative speeds falls within a specified range. The exclusion unit excludes all observation points that fall within the specified range from the alarm target.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This international application claims priority based on Japanese Patent Application No. 2019-194309 filed with the Japan Patent Office on October 25, 2019, and the entire contents of Japanese Patent Application No. 2019-194309 are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a technology for detecting a moving object approaching a vehicle. Background Art

[0004] The inference device described in Patent Document 1 below estimates the movement direction and relative speed of objects around a vehicle and uses the estimated movement direction and relative speed to infer the object's trajectory. Furthermore, the inference device uses vehicle information to infer the vehicle's trajectory. Furthermore, if the estimated object's trajectory intersects the estimated vehicle's trajectory, the inference device outputs an alarm.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-201279

[0006] The inventors' detailed research has yielded the following insights: When a rotating object, such as an outdoor unit, rotates in a fixed location, the position and relative speed of the rotating object detected by the sensor may indicate that the rotating object is approaching the vehicle. Furthermore, the inventors' detailed research has revealed the potential for misidentification of the rotating object as a moving object approaching the vehicle, potentially leading to unnecessary alerts being issued for rotating objects located in fixed locations. Summary of the Invention

[0007] One aspect of the present disclosure contemplates being able to suppress unnecessary alarms.

[0008] One aspect of the present disclosure is a mobile object alarm device that detects a mobile object approaching a vehicle and outputs an alarm. The mobile object alarm device includes a speed calculation unit, a position determination unit, and an exclusion unit. The speed calculation unit is configured to calculate at least one relative speed of an observation point based on detection information from a sensor mounted on the vehicle. The position determination unit is configured to, when the speed calculation unit calculates multiple relative speeds, determine whether the observation point corresponding to each of the multiple relative speeds falls within a specified range. The exclusion unit is configured to, when the position determination unit determines that the observation point corresponding to each of the multiple speeds falls within the specified range, exclude all observation points within the specified range from the alarm target.

[0009] In one aspect of the present disclosure, a mobile object alarm device calculates multiple relative speeds based on sensor detection information, and then determines whether each observation point corresponding to each of the multiple relative speeds falls within a specified range. Because rotating objects have multiple speed components, when a sensor observes a stationary object with a rotating object, multiple relative speeds are calculated at multiple observation points that are relatively close to each other. Therefore, if each observation point corresponding to each of the multiple relative speeds is determined to fall within the specified range, it can be determined that the stationary object with a rotating object exists within the specified range. Furthermore, all observation points within the specified range can be excluded from the alarm target, suppressing unnecessary alarms. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a diagram showing the configuration of a driving assistance system according to the first embodiment.

[0011] Figure 2 This is a diagram showing an example in which the velocity vector of the outdoor unit intersects the warning line of the vehicle.

[0012] Figure 3 is a diagram showing a plurality of velocity vectors generated from a rotating body.

[0013] Figure 4 It is a diagram showing the speed spectrum of a rotating body.

[0014] Figure 5 This is a diagram showing that the relative speed of a rotating object detected by a radar device mounted on a vehicle has a spread toward a smaller azimuth direction.

[0015] Figure 6 It is a schematic diagram showing the detected orientation of a rotating body with respect to a relative speed.

[0016] Figure 7 This diagram shows that the relative speed of another vehicle detected by the radar device mounted on the vehicle has a large spread in the azimuth direction.

[0017] Figure 8 It is a schematic diagram showing the detected positions of other vehicles with respect to relative speed.

[0018] Figure 9 This is a flowchart showing the process of excluding an object from being an alarm target executed by the mobile object alarm device according to the first embodiment.

[0019] Figure 10 is a diagram showing a velocity spectrum and peaks detected from the velocity spectrum.

[0020] Figure 11 This is a diagram showing groups of detected peaks that are grouped together based on peaks that are located close to each other.

[0021] Figure 12 This is a diagram showing the fastest relative speed within a group and relative speeds symmetrical to the fastest relative speed at 0 km / h in the speed spectrum.

[0022] Figure 13 The diagram shows the position where the fastest relative speed in the group is detected and the position where a relative speed symmetrical to the fastest relative speed is detected.

[0023] Figure 14 This diagram shows a case where the positional differences between observation points of other vehicles passing behind the vehicle are relatively large.

[0024] Figure 15 This is a diagram showing a case where the positional difference between observation points on a rotating body is relatively small.

[0025] Figure 16 This is a flowchart showing a process of excluding an object from being an alarm target, which is executed by the mobile object alarm device according to the second embodiment.

[0026] Figure 17 This is a diagram for explaining how the spread of the direction of the speed detected from the rotating object changes depending on the distance from the vehicle to the rotating object.

[0027] Figure 18 This is a diagram showing a speed spectrum and an orientation with respect to the relative speed when the distance from the vehicle to the rotating object is relatively short.

[0028] Figure 19 This is a diagram showing a speed spectrum and an orientation with respect to the relative speed when the distance from the vehicle to the rotating body is relatively long.

[0029] Figure 20 : is a graph showing theoretical values ​​of azimuth spread relative to the distance from the vehicle.

[0030] Figure 21 1 and 2 are diagrams showing the relative position of the rotating body with respect to the vehicle, where the spread width of the distance detected from the rotating body is the largest.

[0031] Figure 22 This is a graph showing the error of distance with respect to SN ratio. DETAILED DESCRIPTION

[0032] Hereinafter, exemplary embodiments for implementing the present disclosure will be described with reference to the drawings.

[0033] (First embodiment)

[0034] 1. Structure

[0035] Reference Figure 1The configuration of a driving support system 100 according to this embodiment will be described. The driving support system 100 includes a radar device 10 , a vehicle sensor group 20 , a moving object warning device 30 , a speaker 41 , a display 42 , and a vibration device 43 .

[0036] Radar device 10 is mounted on the front center, rear center, left front side, right front side, left rear side, or right rear side of vehicle 50. In this embodiment, radar device 10 is mounted on the rear center of the vehicle. Radar device 10 is a millimeter-wave radar using a modulation method such as 2FCW or FMCW. FCW stands for Frequency Continuous Wave, and FMCW stands for Frequency Modulated Continuous Wave. In this embodiment, radar device 10 is a 2FCW millimeter-wave radar.

[0037] The radar device 10 uses an array antenna to transmit and receive radar waves, acquiring a beat signal and performing frequency analysis on the beat signal to detect a spectrum. The spectrum contains information about the relative speed, distance, and direction of the observation point. The observation point here is the point where the radar wave is reflected. The radar device 10 outputs the detected spectrum as detection information to the mobile object warning device 30.

[0038] The vehicle sensor group 20 includes a vehicle speed sensor, a yaw rate sensor, etc. The vehicle speed sensor detects the speed of the vehicle 50. The yaw rate sensor detects the yaw rate of the vehicle 50. The vehicle sensor group 20 outputs various detection values ​​to the mobile object warning device 30.

[0039] The vibration device 43 is provided on the steering wheel, the seat, etc., and vibrates the steering wheel, the seat, etc. The speaker 41 and the display 42 are arranged in the vehicle cabin.

[0040] The mobile object warning device 30 is mainly composed of a microcomputer including a CPU 31, ROM 32, RAM 33, and I / O, etc. The mobile object warning device 30 realizes the functions of a speed calculation unit, a position determination unit, and an exclusion unit by the CPU 31 executing a program stored in a non-transitory physical recording medium.

[0041] like Figure 2As shown, the mobile object warning device 30 uses the acquired speed and yaw rate of the vehicle 50 to set a warning line Lw behind the vehicle 50. Furthermore, the mobile object warning device 30 uses the detection information acquired from the radar device 10 to estimate the velocity vector of the mobile object near the vehicle 50. Then, when the estimated velocity vector of the mobile object intersects the warning line Lw, the mobile object warning device 30 outputs an alarm output instruction to at least one of the speaker 41, the display 42, and the vibration device 43. The mobile object is, for example, another vehicle approaching from behind the vehicle 50.

[0042] Speaker 41, display 42, and vibrator 43 output warnings according to the output instructions from mobile object warning device 30, alerting the driver to the approaching mobile object. Speaker 41 outputs warnings through sound and warning sounds. Display 42 outputs warnings through display. Vibrator 43 outputs warnings through vibration.

[0043] Furthermore, the mobile object alarm device 30 performs an exclusion process of excluding observation points that are not suitable as alarm targets from the alarm targets.

[0044] like Figure 2 As shown, when the outdoor unit 70 is present near the vehicle 50, the radar device 10 may receive reflected waves reflected by a plurality of parts of the fan 75 included in the outdoor unit 70. Figure 3 As shown, since fan 75 is a rotating body, it has speeds in multiple directions. Therefore, the relative speed detected based on the multiple reflected waves generated by fan 75 also includes the relative speed in the direction approaching vehicle 50.

[0045] The position of the observation point having such a relative speed in the approaching direction deviates in each observation cycle due to observation error, and the observation point appears to move toward the vehicle 50. In such a case, an unnecessary warning may be output for the observation point that appears to move toward the vehicle 50.

[0046] Therefore, the mobile object warning device 30 performs an exclusion process to identify a fixed rotating object such as the fan 75 and exclude the identified rotating object from the alarm target. Specifically, the mobile object warning device 30 uses the characteristics of the rotating object to exclude the observation point corresponding to the rotating object from the alarm target.

[0047] <2. Characteristics of Rotating Objects>

[0048] exist Figure 4The figure shows the speed spectrum detected from fan 75. In the 2FCW method, since the frequency corresponds to the relative speed at the observation point, the spectrum corresponds to the speed spectrum. Fan 75 has speeds in multiple directions. Therefore, in the speed spectrum observed from fan 75, the power exceeds the detection threshold over a wide speed range, and multiple relative speeds are detected.

[0049] like Figure 5 As shown in FIG. 1 , a relative velocity VA in a direction approaching the vehicle 50 and a relative velocity VB in a direction away from the vehicle 50 are observed from the fan 75. Figure 7 As shown, the other vehicle 80 has only a constant direction of vehicle speed. The relative speed of the other vehicle 80 detected by the radar device 10 corresponds to a speed based on a projection component of the vehicle speed at each of the plurality of observation points.

[0050] Here, if Figure 5 and Figure 7 As shown, fan 75 has a smaller spread than other vehicles 80 approaching vehicle 50 from behind, and exists within a relatively narrow range. The position here refers to the position as viewed from vehicle 50. That is, as viewed from vehicle 50, fan 75 has a smaller spread in direction and distance than other vehicles 80, which are the original targets of the alarm.

[0051] Therefore, if Figure 6 As shown, the relative velocities of the multiple observation points observed from fan 75 include both relative velocities in the direction of departure and relative velocities in the direction of approach, thus having a relatively large spread. However, the azimuths of the multiple observation values ​​observed from fan 75 have a relatively small spread. The observation points observed from fan 75 include observation point α, which has an azimuth θo and a relative velocity Vα, and observation point β, which has an azimuth θo and a relative velocity -Vα. In other words, the observation points observed from fan 75 include observation point α and observation point β, which has the same azimuth as observation point α but a relative velocity with the opposite sign.

[0052] On the other hand, Figure 8 As shown, the other vehicle 80 has a relatively large position spread, and therefore the directions of the plurality of observation points observed from the other vehicle 80 have a relatively large spread. Therefore, the observation points observed from the other vehicle 80 do not include observation points having the same direction and opposite relative velocities.

[0053] Therefore, the mobile object alarm device 30 excludes the stationary rotating object from the alarm target based on the difference between the information of the observation point of the stationary rotating object such as the fan 75 and the information of the observation point of the original alarm target.

[0054] <3. Exclusion Process>

[0055] Next, refer to Figure 9 The following describes the exclusion process performed by the mobile object alarm device 30 with reference to the flowchart of FIG. The mobile object alarm device 30 repeatedly performs this process in a predetermined cycle.

[0056] First, in S10, as Figure 10 As shown, a peak is detected from the speed spectrum detected by the radar device 10. The peak is a maximum point having a power value greater than or equal to a set detection threshold.

[0057] Next, in S20, a determination is made as to whether the number of peaks detected in S10 is greater than a set threshold. Multiple relative speeds are observed from the stationary rotating object. Therefore, if the number of peaks detected in S20 is less than the threshold, the detected peak is determined not to be at the observation point of the stationary rotating object, and this process ends. On the other hand, if the number of peaks detected in S20 is greater than the threshold, the process proceeds to S30.

[0058] In S30 , the relative velocity Vn and position Pn of the observation point detected as peak n are calculated. n is a natural number from 1 to N. N is the number of peaks detected in S10 . Position Pn is calculated based on the distance and orientation of the observation point and is represented by X and Y coordinate values.

[0059] Next, in S40 , each of the N observation points is used as a reference, and the position difference with other observation points is calculated cyclically.

[0060] Then, in S50, as Figure 11 As shown, the N observation points are grouped according to their closest locations. Specifically, multiple reference points are set from the N observation points. Then, for each reference point, a group is created, consisting of combinations of observation points whose position differences calculated in S40 are below a set position threshold. The position threshold is set based on the maximum size that can be assumed for a fixed rotating object such as the outdoor unit 70.

[0061] Next, in S60 , the group with the largest number of members among the groups created in S50 is selected as group A.

[0062] Next, in S70 , the relative speed Vf and position Pf are calculated. The relative speed Vf corresponds to the fastest relative speed among the relative speeds of the observation points of group A, and the position Pf corresponds to the position of the observation point having the relative speed Vf. Figure 11 as well as Figure 12 An example is shown in which the relative speed of peak 7 in group A is the fastest.

[0063] Then, in S80, if Figure 12As shown in FIG. 1 , the relative speed Vf calculated in S70 is used to calculate the relative speed Vc = -1×Vf. The relative speed Vc is equivalent to the speed after the sign of the relative speed Vf is reversed. Figure 13 As shown, the position Pc of the peak corresponding to the relative velocity Vc is calculated. If there is no peak at a position corresponding to the relative velocity Vc, the position closest to the peak at the position corresponding to the relative velocity Vc, which is closer to 0 km / m than the position corresponding to the relative velocity Vc, is calculated as the position Pc. This prevents positions outside the observation point from being calculated as the position Pc, thereby preventing erroneous determinations.

[0064] Next, in S90, it is determined whether the position difference between position Pf and position Pc is less than a position threshold. In other words, it is determined whether the relative speed in the direction approaching vehicle 50 and the relative speed in the direction away from vehicle 50 are observed within a predetermined range where the position difference is less than the position threshold.

[0065] In addition, if Figure 8 As shown, when the absolute value of the relative velocity Vv observed from the other vehicle 80 is small, the difference between the position where the relative velocity Vv is observed and the position where the relative velocity -Vv is observed is relatively small. On the other hand, when the absolute value of the relative velocity Vv is large, the difference between the position where the relative velocity Vv is observed and the position where the relative velocity -Vv is observed is relatively large. Therefore, in the determination at S90, the observation point with the fastest relative velocity within group A is used to avoid erroneously determining that the intended alarm target is a fixed rotating object.

[0066] And, as Figure 14 as well as Figure 15 As shown, when another vehicle 80 passes behind vehicle 50, the entire length of the other vehicle 80 is detected, resulting in a relatively large positional difference between the location where the relative velocity Vv is observed and the location where the relative velocity -Vv is observed. On the other hand, fixed rotating objects such as the outdoor unit 70 are shorter than the length of the other vehicle 80. Therefore, the detection range of fixed rotating objects is narrower than that of other vehicles 80. Consequently, for fixed rotating objects, the positional difference between the location where the relative velocity Vv is observed and the location where the relative velocity -Vv is observed is relatively small. Therefore, in the determination at S90, the observation point with the fastest relative velocity within group A, where the expected positional difference is significant, is used to avoid mistakenly determining that the intended alarm target is a fixed rotating object.

[0067] If it is determined in S90 that the position difference is less than the position threshold, the process proceeds to S100 . If it is determined that the position difference is greater than the position threshold, the process ends.

[0068] In S100, members of group A are determined to be observation points of a fixed rotating object and are excluded from the alarm target. This concludes the present process. In this embodiment, the processes of S10 to S90 correspond to the processes performed by the speed calculation unit and the position determination unit, while the process of S100 corresponds to the process performed by the exclusion unit.

[0069] <4. Effect>

[0070] According to the first embodiment described above, the following effects are obtained.

[0071] (1) Determine whether the radar device 10 observes multiple relative velocities. If multiple relative velocities are observed, determine whether the multiple observation points corresponding to the multiple relative velocities fall within a specified range. This allows the presence of a fixed rotating object to be determined within the specified range, and excludes the observation point group observed from the fixed rotating object from the alarm target. This, in turn, prevents unnecessary alarms.

[0072] (2) Determine whether both the speed in the direction of approaching the vehicle and the speed in the direction of moving away from the vehicle are observed within a predetermined range. This allows for accurate determination of the observation point group observed from the fixed rotating body.

[0073] (3) Using the positional differences between observation points, observation point groups falling within a predetermined range are grouped. This allows multiple observation points observed from a fixed rotating object to be collectively excluded from the alarm targets.

[0074] (Second embodiment)

[0075] <1. Differences from the First Embodiment>

[0076] Since the basic structure of the second embodiment is the same as that of the first embodiment, the description of the common structure will be omitted and the description will focus on the differences. In addition, the same reference numerals as those in the first embodiment represent the same structure, and reference is made to the previous description.

[0077] In the first embodiment described above, the observation points are grouped based on their positional differences. In contrast, the second embodiment differs from the first embodiment in that the observation points are grouped based on at least one of their distance differences and their azimuth differences. Furthermore, the mobile object warning device 30 of the second embodiment functions as a velocity calculation unit, a position determination unit, and an exclusion unit, as well as a azimuth threshold setting unit and a distance threshold setting unit.

[0078] <2. Exclusion Process>

[0079] Next, refer to Figure 16The elimination process executed by the mobile object alarm device 30 of the second embodiment will be described with reference to the flowchart of FIG. The mobile object alarm device 30 repeatedly executes this process in a predetermined cycle.

[0080] First, in S100 and S110, execute Figure 9 The processes shown in S10 and S20 are the same.

[0081] Next, in S120 , the relative velocity Vn, distance Rn, and orientation θn of the observation point detected as peak n are calculated. n is a natural number from 1 to N. N is the number of peaks detected in S100 .

[0082] Next, in S130 , each of the N observation points is used as a reference, and the difference in distance and direction from other observation points is calculated cyclically.

[0083] Next, in S140, the N observation points are grouped according to the distance and bearing proximity. Specifically, multiple reference points are set from the N observation points. For each reference point, a group is created by including combinations of observation points whose distance difference calculated in S130 is below the distance threshold and whose bearing difference calculated in S130 is below the bearing threshold as members.

[0084] Here, the orientation threshold value may also be a variable value. Specifically, the orientation threshold value setting unit may also set the orientation threshold value based on the distance of at least one observation point in the observation point group within the group, for example, the distance of the reference point. Figure 17 FIG shows a state in which the outdoor unit 70 is installed opposite to the radar device 10, that is, a state in which the radiation direction of the radar device 10 is substantially perpendicular to the rotation plane of the fan 75. Figure 18 as well as Figure 19 As shown, when the distance between the vehicle 50 and the outdoor unit 70 is close, the directions of the plurality of observation points observed from the fan 75 have a greater spread than when the distance between the vehicle 50 and the outdoor unit 70 is far. Figure 20 The theoretical spread of the direction of the observation point observed from fan 75 is shown. The theoretical spread of the direction is calculated using the formula: Azimuth spread = arctan (fan radius / observation distance) × 2. The fan radius is the radial length of each of the plurality of blades of fan 75.

[0085] Specifically, the azimuth threshold setting unit uses the maximum value of the fan radius assumed in commercially available outdoor units and sets the azimuth spread calculated according to the above equation as the azimuth threshold.

[0086] In addition, the distance threshold value may also be a variable value. Specifically, the distance threshold value setting unit may also set the distance threshold value based on the reflection intensity of at least one observation point in the observation point group within the group, for example, the reflection intensity of the reference point. Figure 21 As shown, when the radial direction of the fan 75 is toward the radar device 10 , the distances of the plurality of observation points observed from the fan 75 have the largest spread.

[0087] In addition, if Figure 22 As shown, particularly in the 2FCW method, the lower the signal-to-noise ratio (SN ratio) of the reflected wave, that is, the lower the reflection intensity, the greater the error in the observed distance. If the distance threshold is fixed to a relatively high value based on the lowest SN ratio value, observation points other than fixed rotating objects may be identified as fixed rotating objects. On the other hand, if the distance threshold is fixed to a relatively low value based on the highest SN ratio value, observation points on fixed rotating objects may not be identified as fixed rotating objects, and observation points on fixed rotating objects may not be excluded from the alarm targets.

[0088] Therefore, the distance threshold setting unit sets the distance threshold to a larger value as the reflection intensity decreases. Specifically, the distance threshold setting unit sets the distance threshold using the distance error equation corresponding to distance threshold=fan diameter+SN ratio.

[0089] Next, in S150 , the group with the largest number of members among the groups created in S140 is selected as group A.

[0090] Next, in S160 , the relative speed Vf, distance Rf, and azimuth θf are calculated. The relative speed Vf corresponds to the fastest relative speed among the relative speeds at the observation points of group A, and the distance Rf and azimuth θf correspond to the distance and azimuth of the observation point having the relative speed Vf.

[0091] Next, in S170 , the relative speed Vf calculated in S160 is used to calculate a relative speed Vc = −1×Vf. The relative speed Vc corresponds to the speed obtained by reversing the sign of the relative speed Vf. Furthermore, the distance Rc and the direction θc corresponding to the relative speed Vc are calculated.

[0092] Next, in S180, a determination is made as to whether the difference between distance Rf and distance Rc is less than a distance threshold, and whether the difference between heading θf and heading θc is less than a heading threshold. Specifically, a determination is made as to whether the relative velocity in the direction approaching vehicle 50 and the relative velocity in the direction moving away from vehicle 50 are observed within a predetermined range where the difference in distance is less than the distance threshold and the difference in heading is less than the heading threshold.

[0093] If an affirmative determination is made in S180 , the process proceeds to S190 , and if a negative determination is made, the present process is terminated.

[0094] In S190, the members of group A are determined to be observation points of a fixed rotating body and are excluded from the alarm targets. This concludes the present process. Furthermore, in S120, both the distance and the azimuth of each peak are calculated, but it is also possible to calculate only one of the distance and azimuth. Furthermore, when the distance is calculated in S120, the distance or the difference in distance is also calculated in S130, S140, S160, S170, and S180, and only the difference in distance is used to determine whether the multiple observation points are within the specified range. Furthermore, when the azimuth is calculated in S120, the azimuth or the difference in azimuth is also calculated in S130, S140, S160, S170, and S180, and only the difference in azimuth is used to determine whether the multiple observation points are within the specified range. In this embodiment, the processes of S100 to S180 correspond to the processes performed by the velocity calculation unit and the position determination unit, and the process of S190 corresponds to the processes performed by the exclusion unit.

[0095] <3. Effect>

[0096] According to the second embodiment described above, in addition to the effects (1) to (3) of the first embodiment described above, the following effects are obtained.

[0097] (4) Determining whether a plurality of observation points fall within a predetermined range based on at least one of a difference in orientation or a difference in distance between the observation points. A group of observation points observed from a fixed rotating body can be determined using at least one of the orientation or distance of the observation points instead of their positions.

[0098] (5) By setting the orientation threshold according to the distance of the observation point, the observation point group observed from the fixed rotating body can be determined with high accuracy.

[0099] (6) By setting the distance threshold according to the reflection intensity of the observation point, the observation point group observed from the fixed rotating body can be determined with high accuracy.

[0100] (Other embodiments)

[0101] As mentioned above, although the form for implementing this disclosure was described, this disclosure is not limited to the above-mentioned embodiment, and can be implemented with various modifications.

[0102] (a) In the above embodiment, the fan of an outdoor unit is used as an example of a fixed rotating body. However, the fixed rotating body is not limited to the fan of an outdoor unit. For example, the solid rotating body may be a fan of an outdoor electric fan, a rotor of a generator, or the like.

[0103] (b) The mobile alarm device 30 and its method described in the present disclosure may also be implemented by a dedicated computer, which is provided by a processor and memory programmed to execute one or more functions embodied by a computer program. Alternatively, the mobile alarm device 30 and its method described in the present disclosure may also be implemented by a dedicated computer, which is provided by a processor composed of one or more dedicated hardware logic circuits. Alternatively, the mobile alarm device 30 and its method described in the present disclosure may also be implemented by one or more dedicated computers, which are composed of a processor and memory programmed to execute one or more functions and a processor composed of one or more hardware logic circuits. In addition, the computer program may be stored as instructions executed by the computer on a non-transitory tangible recording medium that is readable by the computer. In the method of implementing the functions of each component included in the mobile alarm device 30, it is not necessary to include software, and all its functions may be implemented using one or more hardware components.

[0104] (c) It is also possible to implement multiple functions of one component in the above-mentioned embodiment by multiple components, or to implement one function of one component by multiple components. In addition, it is also possible to implement multiple functions of multiple components by one component, or to implement one function implemented by multiple components by one component. In addition, it is also possible to omit part of the structure of the above-mentioned embodiment. It is also possible to add or replace at least part of the structure of the above-mentioned embodiment with the structure of other above-mentioned embodiments.

[0105] (d) In addition to the above-mentioned mobile body alarm device, the present disclosure can also be implemented in various ways, such as a driving assistance system that uses the mobile body alarm device as a component, a program for enabling a computer to function as the mobile body alarm device, a non-transitional physical recording medium such as a semiconductor memory that records the program, a mobile body detection method, etc.

Claims

1. A mobile object alarm device that detects a mobile object approaching a vehicle and outputs an alarm, comprising: a speed calculation unit configured to calculate at least one relative speed of an observation point based on detection information detected by a sensor mounted on the vehicle; a position determination unit that, when a plurality of relative speeds are calculated by the speed calculation unit, determines whether an observation point corresponding to each of the plurality of relative speeds falls within a predetermined range; as well as an excluding unit configured to exclude all observation points within the predetermined range from the alarm target when the position determining unit determines that the observation point corresponding to each of the plurality of relative speeds falls within the predetermined range; A first judgment is performed respectively on whether a plurality of relative speeds corresponding to a plurality of observation points include a relative speed in a direction approaching the above-mentioned vehicle and a relative speed in a direction away from the above-mentioned vehicle, and a second judgment is performed on whether the difference in orientation between the plurality of observation points is below a set orientation threshold. If the result of the first judgment is that the relative speed in a direction approaching the above-mentioned vehicle and the relative speed in a direction away from the above-mentioned vehicle are included, and the result of the second judgment is that the difference in orientation between the plurality of observation points is below the set orientation threshold, the plurality of observation points are judged to be observation points obtained from a fixed rotating body, and the plurality of observation points are excluded from the alarm targets.

2. The mobile object alarm device according to claim 1, wherein: The position determination unit determines that the plurality of observation points fall within the predetermined range when a difference in position between the plurality of observation points observed by the sensor is equal to or smaller than a set position threshold.

3. The mobile object alarm device according to claim 1 or 2, wherein: The position determination unit determines that the plurality of observation points fall within the predetermined range when a difference in distance between the plurality of observation points observed by the sensor is equal to or smaller than a set distance threshold.

4. The mobile object alarm device according to claim 1, wherein Also features: The azimuth threshold setting unit is configured to set the azimuth threshold based on a distance of at least one observation point among the plurality of observation points.

5. The mobile object alarm device according to claim 3, wherein: Also features: The distance threshold setting unit is configured to set the distance threshold based on a magnitude of a reflection signal at at least one of the plurality of observation points.

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