Determination device, road surface recognition method, and estimation device

Abstract

To provide a technology with which it is possible to detect recesses on road surfaces.SOLUTION: A determination device 100 comprises: one or more sensor units 10 that have an emission unit 11 that emits an emission wave and a reception unit 12 that receives a reflected wave that is generated from the emitted wave by being reflected on a target, and that measures using the reflected wave the distance to an object existing in a predetermined detection range in the front-back direction of the emission unit; and a determination unit 20 that determines using the received strength of the reflected wave whether or not recesses exist on a road surface. The determination unit determines that a recess exists when, in a second graph that is the envelope of a first graph composed of received strength on a vertical axis and the distance from the sensor unit or a time until the reflected wave is received after an emission wave is emitted on a horizontal axis, a non-reflection section exists between a first reflection section and a second reflection section, and a plurality of maximum values are located at a regular interval, the maximum values representing the received strength in the second reflection section that is greater than or equal to a predetermined threshold of received strength.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a determination device, a road surface recognition method, and an estimation device. [Background technology]

[0002] Known determination devices include those that emit transmitted waves such as ultrasonic waves or lasers, receive reflected waves reflected by the road surface, and detect the road surface based on the received waves. Patent Document 1 discloses a technique for determining the presence of a depression in the road surface by comparing the shape of the received wave with the shapes of previously received waves to detect missing parts. Patent Document 2 discloses a technique for determining the presence of a depression in the road surface by detecting parts where the distance or altitude from the measurement point of the received wave changes significantly. Patent Document 3 discloses a technique for determining the presence of a depression in the road surface by rearranging road surface height data and detecting points of change. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-132511 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-15601 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-220227 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional technology cannot distinguish between a downward step, which is a step that exists between the road surface in front and the road surface in the rear in the extension direction of the road surface and that descends from the road surface in front, and a depression. Therefore, technology that can detect depressions in the road surface has been desired. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, there is provided a determination device (100). The determination device includes one or more sensor units (10) having an emitter (11) that emits an emitted wave, a receiver (12) that receives a reflected wave generated when the emitted wave is reflected by a target, and capable of measuring a distance to an object present within a predetermined detection range in the forward and backward directions of the emitter (11), using the reflected wave; and a determination unit (20) that determines whether or not a depression exists on the road surface using the reception intensity of the reflected wave. The determination unit detects a non-reflection interval that exists between a first reflection interval of the reflected wave from the first road surface and a second reflection interval of the reflected wave from a position farther from the determination device in the longitudinal direction than the first reflection interval in a second graph that is an envelope of a first graph with the reception intensity as the vertical axis and the distance from the sensor unit or the time from the emission of the emitted wave to the reception of the reflected wave as the horizontal axis, and if the non-reflection interval exists, 3 or more and the reception intensity in each of the second reflection sections is equal to or greater than a predetermined threshold value. 3 or more If the maximum values ​​of are located at regular intervals, it is determined that the recess exists. The apparatus further includes a groove width calculation unit (31) that calculates a groove width, which is the width of the recessed portion in the extension direction of the road surface, based on the intervals between the three or more maximum values ​​on the horizontal axis using the distances measured by the sensor unit. do. According to another aspect of the present disclosure, there is provided a determination device, the determination device including one or more sensor units having an emitter that emits an emitted wave and a receiver that receives a reflected wave generated when the emitted wave is reflected by a target, and capable of measuring a distance to an object present within a predetermined detection range in a forward and backward direction of the emitter using the reflected wave, and a determination unit that determines whether a depression exists on the road surface using the received intensity of the reflected wave. The determination unit detects a non-reflection interval existing between a first reflection interval of the reflected wave from a first road surface and a second reflection interval of the reflected wave from a position farther from the determination device in the longitudinal direction than the first reflection interval in a second graph that is an envelope of a first graph with the reception intensity as the vertical axis and the distance from the sensor unit or the time from emitting the emitted wave to receiving the reflected wave as the horizontal axis, and determines that the recess exists when the non-reflection interval exists and three or more maximum values, each of which has the reception intensity in the second reflection interval equal to or greater than a predetermined threshold, are positioned at regular intervals.The determination unit further includes a groove height calculation unit (32) that calculates a groove height, which is the height of the recess, based on the length of the non-reflection interval using the distance measured by the sensor unit. According to another aspect of the present disclosure, there is provided a determination device, the determination device including one or more sensor units having an emitter that emits an emitted wave and a receiver that receives a reflected wave generated when the emitted wave is reflected by a target, and capable of measuring a distance to an object present within a predetermined detection range in a forward and backward direction of the emitter using the reflected wave, and a determination unit that determines whether a depression exists on the road surface using the received intensity of the reflected wave. The determination unit detects a non-reflection interval existing between a first reflection interval of the reflected wave from a first road surface and a second reflection interval of the reflected wave from a position farther from the determination device in the longitudinal direction than the first reflection interval in a second graph that is an envelope of a first graph with the reception intensity on the vertical axis and the distance from the sensor unit or the time from emitting the emitted wave to receiving the reflected wave on the horizontal axis, and determines that the recess exists when the non-reflection interval exists and three or more maximum values, each of which has a reception intensity equal to or greater than a predetermined threshold, are positioned at regular intervals.The determination unit further includes a groove height calculation unit that calculates a groove height, which is the height of the recess, based on the reception intensity of the first maximum value that is closest to the sensor unit in the second reflection interval of the second graph and the attenuation of the reception intensity of the three or more maximum values.

[0006] According to the determination device of this aspect, for example, in the case of a downward step, since the multiple maximum values ​​are not positioned at regular intervals, it is possible to distinguish between a recess and a downward step and detect the recess. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram showing an outline of the configuration of a determination device. [Figure 2] FIG. 4 is an explanatory diagram showing an example of a recess; [Figure 3] 10 is a flowchart illustrating an example of a recess detection process. [Figure 4] 1 is a first graph showing the relationship between distance and reception strength. [Figure 5]2 is a second graph showing the envelope of the first graph. [Figure 6] FIG. 10 is an explanatory view showing an example of a recess in the third embodiment. [Figure 7] 10 is a second graph in the third embodiment. [Figure 8] FIG. 10 is an explanatory view showing another example of a recess in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: As shown in Fig. 1, the determination device 100 includes a sensor unit 10, a determination unit 20, a calculation unit 30, and an output unit 40. The determination device 100 detects the distance to a surrounding object. The determination device 100 is, for example, a sonar mounted on a vehicle. The determination device 100 may employ millimeter-wave radar, LiDAR (Light Detection and Ranging), or a TOF camera (TOF: Time Of Flight) that can measure three-dimensional positions using the time of flight of light.

[0009] The sensor unit 10 has an emitter 11 that emits an emitted wave and a receiver 12 that receives various reflected waves generated when the emitted wave is reflected by a target. The sensor unit 10 can measure the distance to an object present in a predetermined detection range in the forward and backward directions of the emitter 11 using the reflected waves received by the receiver 12. The forward and backward directions of the emitter 11 are directions determined based on the determination device 100. In this embodiment, the emitter 11 emits sound waves as the emitted waves. The emitter 11 may also emit radio waves or light waves.

[0010] The determination unit 20 determines whether or not a depression exists on the road surface using the reception intensity of the reflected wave received by the sensor unit 10. As shown in Fig. 2, a "depression" is a groove 303 that exists between a first road surface 301 and a second road surface 302 that is farther from the determination device 100 than the first road surface 301 in the extension direction of the road surface. In the present disclosure, a depression that exists between the first road surface 301 and the second road surface 302 is also included in the depression.

[0011] The calculation unit 30 (see FIG. 1) calculates the length of each portion of the recessed portion using the reception intensity of the reflected wave received by the sensor unit 10. The calculation unit 30 has a groove width calculation unit 31 and a groove height calculation unit 32. The groove width calculation unit 31 calculates the groove width Lw, which is the width of the recessed portion in the extension direction of the road surface, using the distance measured by the sensor unit 10. The groove height calculation unit 32 calculates the groove height Lh, which is the height of the recessed portion, using the distance measured by the sensor unit 10. Below, a method by which the calculation unit 30 calculates the groove width Lw and groove height Lh will be described using the road surface shape shown in FIG. 2 as an example. Details of how the calculation unit 30 calculates the groove width Lw and groove height Lh will be described later.

[0012] The output unit 40 outputs the groove width Lw and groove height Lh calculated by the calculation unit 30. The output unit 40 outputs the groove width Lw and groove height Lh to, for example, a vehicle equipped with the determination device 100. The determination unit 20, the calculation unit 30, and the output unit 40 are collectively referred to as an estimation device 200.

[0013] 3 is a process in which the determination unit 20 determines whether or not a depression exists on the road surface. In step S100, the determination unit 20 acquires the reception intensity of reflected waves. More specifically, the determination unit 20 acquires the reception intensity of each reflected wave generated by reflection from the road surface or the wall surface of a depression and acquired by the sensor unit 10 via the receiving unit 12 at a certain point in time.

[0014] In step S110, the determination unit 20 detects a non-reflection interval from the reception intensity acquired in step S100. More specifically, the non-reflection interval is detected from the envelope of a graph showing the relationship between the reception intensity and the distance from the sensor unit 10. In this embodiment, a "non-reflection interval" is a continuous interval where the reception intensity is lower than a predetermined value, existing between a first reflection interval caused by a wave reflected from the first road surface 301 and a second reflection interval caused by a wave reflected from the wall surface of the groove 303 connected to the second road surface 302 or the second road surface 302. If a non-reflection interval is not detected, the determination unit 20 may determine that a recess has not been detected and terminate the recess detection process.

[0015] The vertical axis of the first graph shown in FIG. 4 represents the reception strength of the reflected wave acquired by the receiving unit 12. The horizontal axis represents the distance from the sensor unit 10. The vertical axis of the second graph shown by the thick line in FIG. 5 represents the reception strength of the reflected wave acquired by the receiving unit 12. The horizontal axis represents the distance from the sensor unit 10. The second graph represents the envelope of the first graph. More specifically, the second graph is the envelope of the graph groups G1, G2, G3, and G4 in the first graph. The graph groups G1 to G4 are a set of graphs in which the maximum value of the reception strength is equal to or greater than a predetermined value, and the set of graphs is a set of graphs in which the reception strength is equal to or greater than 0. The envelope is an approximate curve that is tangent to the maximum value of the reception strength.

[0016] 5, the section from distance d1 to distance d2 is the first reflection section A1, and the section from distance d3 to distance d7 is the second reflection section A2. The section between the first reflection section A1 and the second reflection section A2 is the non-reflection section A3. Note that in this embodiment, the reception intensity in the non-reflection section A3 is 0, but this is not limiting, and the reception intensity in the non-reflection section A3 may be greater than 0.

[0017] In step S120 (see FIG. 3), the determination unit 20 determines that a concave portion exists when, in the second graph shown in FIG. 5, a plurality of maximum values ​​P1 to P3, in which the reception intensity in the second reflection section A2 is within a predetermined range, are located at regular intervals. The maximum values ​​in which the reception intensity in the second reflection section A2 is within a predetermined range are maximum values ​​in the second reflection section A2 in which the reception intensity is equal to or greater than a first threshold reception intensity Th1 and equal to or less than a second threshold reception intensity Th2. More specifically, the determination unit 20 determines that a concave portion exists when the difference D1 between the value of the distance d4, which is the position on the horizontal axis of the first maximum value P1, and the value of the distance d5, which is the position on the horizontal axis of the second maximum value P2, and the difference D2 between the value of the distance d5, which is the position on the horizontal axis of the second maximum value P2, and the value of the distance d6, which is the position on the horizontal axis of the third maximum value P3, are within a predetermined range. In this embodiment, the first threshold reception intensity Th1 and the second threshold reception intensity Th2 are constant values. Note that the first threshold reception intensity Th1 and the second threshold reception intensity Th2 may be values ​​that take into account air attenuation according to the distance d1 from the determination device 100, and may be values ​​that decrease as the distance d1 increases.

[0018] If the recess detection process determines that a recess exists, the calculation unit 30 calculates the groove width Lw and groove height Lh. In this embodiment, the groove width calculation unit 31 calculates the groove width Lw based on the differences D1 and D2 on the horizontal axis between multiple maximum values ​​P1 to P3. Since the emitted wave emitted from the emission unit 11 is multiple-reflected by the inner wall of the recess, the interval between the maximum values ​​increases as the groove width Lw increases. For example, the groove width calculation unit 31 calculates the average value of the differences D1 and D2 as the groove width Lw. The average value may be an arithmetic average or a weighted average.

[0019] In this embodiment, the groove height calculation unit 32 calculates the groove height Lh based on the length of the non-reflection section A3. When the groove height Lh is small, the number of times the incident wave is multiple-reflected within the recess is smaller than when the groove height Lh is large, and therefore the non-reflection section A3 is shorter. For example, the groove height calculation unit 32 calculates the groove height Lh using the following equation (1):

[0020] Lh = Ln × sinθ…(1) Here, Ln is the length of the non-reflection section A3, and θ is the incident angle of the emitted wave emitted from the emission portion 11.

[0021] According to the determination device 100 of this embodiment described above, the determination unit 20 detects the non-reflection section A3 from the reception intensity, and determines that a concave portion exists when the reception intensity in the second reflection section A2 is within a predetermined range and multiple maximum values ​​P1 to P3 are located at regular intervals. For example, unlike a concave portion, a downward step does not cause multiple reflections, and therefore multiple maximum values ​​are not located at regular intervals. Therefore, it is possible to distinguish between a concave portion and a downward step and detect the concave portion.

[0022] In this embodiment, the groove width calculation unit 31 calculates the average value of the differences D1 and D2 on the horizontal axis between the multiple maximum values ​​P1 to P3 as the groove width Lw. Therefore, the groove width calculation unit 31 can calculate the groove width Lw without using any other sensors.

[0023] In this embodiment, the groove height calculation unit 32 calculates the groove height Lh using equation (1) based on the length of the non-reflection section A3. Therefore, the groove height calculation unit 32 can calculate the groove height Lh without using any other sensors.

[0024] B. Second embodiment: In the second embodiment, a method for the groove height calculation unit 32 to calculate the groove height Lh will be described using the road surface shape shown in FIG. 2 as an example. The second embodiment differs from the first embodiment in that the groove height calculation unit 32 calculates the groove height Lh based on the reception intensity of the first maximum value P1 located closest to the sensor unit 10 in the second reflection section A2 of the second graph and the attenuation of the reception intensity of the multiple maximum values ​​P1 to P3 (hereinafter simply referred to as "reception intensity attenuation"). Details of the reception intensity attenuation will be described later. The configuration of the determination device 100 of the second embodiment is the same as that of the determination device 100 of the first embodiment, so a description of the configuration of the determination device 100 will be omitted.

[0025] In this embodiment, the groove height calculation unit 32 uses, as the amount of attenuation of the reception intensity, for example, the slope of the tangent at the first maximum value P1 of the approximation formula of the third graph, which is an envelope of the multiple maximum values ​​P1 to P3. The groove height calculation unit 32 calculates the groove height Lh using a function or table that has been previously obtained through experiments or simulations to determine the relationship between the first maximum value P1, the amount of attenuation of the reception intensity, and the groove height Lh. When the groove height Lh is small, the emitted wave that enters the groove 303 exits the groove 303 more quickly than when the groove height Lh is large, and therefore the reception intensity is significantly attenuated each time the wave is reflected by the inner wall of the groove 303. When the groove height Lh is large, the emitted wave that enters the groove 303 exits the groove 303 more slowly than when the groove height Lh is small, and therefore the reception intensity is not significantly attenuated even when the wave is reflected by the inner wall of the groove 303. Therefore, the groove height calculation unit 32 calculates the groove height Lh by assuming that the groove height Lh when the reception strength of the first maximum value P1 is high and the attenuation of the reception strength is large is smaller than the groove height Lh when the reception strength of the first maximum value P1 is low and the attenuation of the reception strength is small.

[0026] According to the determination device 100 of the second embodiment described above, the groove height calculation unit 32 calculates the groove height Lh based on the reception intensity of the first maximum value P1 and the attenuation of the reception intensity of the multiple maximum values ​​P1 to P3. Therefore, the groove height calculation unit 32 can calculate the groove height Lh based on the attenuation of the reception intensity of the reflected wave.

[0027] C. Third embodiment: The third embodiment differs from the first embodiment in that the determination unit 20 determines whether or not a recess exists using the reception intensity of a reflected wave whose incident angle is within a predetermined threshold range. The configuration of the determination device 100 of the third embodiment is the same as the configuration of the determination device 100 of the first embodiment, and therefore a description of the configuration of the determination device 100 will be omitted.

[0028] In the third embodiment, a method in which the determination unit 20 determines whether or not a recessed portion exists will be described using the road surface shape shown in Fig. 6 as an example. As shown in Fig. 6, in the extension direction of the road surface, between a first road surface 301 and a second road surface 302 that is farther from the determination device 100 than the first road surface 301, there is a groove 303 descending from the first road surface 301, and there is an obstacle 305 on the second road surface 302. In other words, the road surface shape shown in Fig. 6 differs from the road surface shape shown in Fig. 2 in that there is an obstacle 305.

[0029] 7, the solid line represents the second graph of the received intensity of the reflected wave when the incident angle to the receiving unit 12 is within a first range, and the dashed line represents the second graph of the received intensity of the reflected wave when the incident angle is within a second range. The first range is a range of incident angles larger than the second range. The first range is a range of incident angles within a threshold range, and the second range is a range of incident angles outside the threshold range.

[0030] In this embodiment, in step S120 (see FIG. 3), the determination unit 20 determines that a concave portion exists if multiple maximum values ​​in the second reflection section A2c are located at regular intervals using the reception intensity of reflected waves whose incidence angles are within a predetermined threshold range. As shown in FIG. 7, the multiple maximum values ​​P1-P3 and P6 in the second reflection section A2c in the second graph are not located at regular intervals, but the multiple maximum values ​​P1-P3 in the second reflection section A2c in the graph showing the reception intensity of reflected waves whose incidence angles are within the first range are located at regular intervals. Therefore, the determination unit 20 determines that a concave portion exists. When an obstacle 305 is located deep inside a groove 303 in the extension direction of the road surface, the incidence angle of the reflected wave from the groove 303 differs from the incidence angle of the reflected wave from the obstacle 305. Therefore, the determination unit 20 can determine whether a concave portion exists based on the reception intensity of reflected waves whose incidence angles are within a predetermined threshold range. Furthermore, multiple maximum values ​​do not occur in the second reflection section A2c of the second graph due to the reflected wave from one obstacle 305. Therefore, there is only one maximum value in the graph showing the reception intensity of the reflected wave whose incident angle is within the second range in the second reflection section A2c of the second graph shown in FIG. 7, and therefore it can be determined that the reflected wave is not a wave reflected from groove 303 but a wave reflected from obstacle 305.

[0031] Furthermore, as shown in Figure 8, in the direction of extension of the road surface, there is a groove 303 descending from the first road surface 301 between the first road surface 301 and the second road surface 302 that is farther from the determination device 100 than the first road surface 301, and multiple obstacles 304 are continuous on the second road surface 302 along the direction of travel of the road surface, and similarly, it is possible to distinguish between the reflected wave from the groove 303 and the reflected wave from the obstacle 305.

[0032] According to the determination device 100 of the third embodiment described above, the determination unit 20 determines whether or not a recess exists using the reception intensity of a reflected wave whose incident angle is within a threshold range. Therefore, even if, for example, an obstacle 305 is present deep inside the groove 303, the recess can be detected with high accuracy.

[0033] Furthermore, the determination unit 20 can distinguish between the second graph caused by the groove 303 and the second graph caused by the obstacle 305. Therefore, the calculation unit 30 can more accurately calculate the intervals on the horizontal axis between the multiple maximum values ​​and the length of the non-reflection section A3, and can therefore more accurately calculate the groove width Lw and groove height Lh.

[0034] D. Other Embodiments: (D1) In the above-described embodiment, the determination device 100 includes the sensor unit 10, the determination unit 20, the calculation unit 30, and the output unit 40. Alternatively, the determination device 100 may include only the sensor unit 10 and the determination unit 20.

[0035] (D2) In the above-described embodiment, the calculation unit 30 includes the groove width calculation unit 31 and the groove height calculation unit 32. Alternatively, the calculation unit 30 may include only one of the groove width calculation unit 31 and the groove height calculation unit 32.

[0036] (D3) In the above-described embodiment, the sensor unit 10 may be a directional sensor. Compared to a non-directional sensor, this sensor can suppress reflected waves from the road surface that are present in an equidistant circle, allowing for more accurate detection of non-reflective sections. The sensor unit 10 may also be a phased array in which multiple MEMS (Micro Electro Mechanical System) devices are arranged. The sensor unit 10 may have, for example, a PMUT (Piezoelectric Micromachined Ultrasonic Transducer) in which the emitter 11 and receiver 12 are integrated, or may have a microphone array as the receiver 12.

[0037] (D4) In the above-described embodiment, the sensor unit 10 may emit emitted waves of multiple frequencies. In this case, the determination unit 20 determines whether or not a recess exists in the reflected wave for each frequency, and determines that a recess exists if the number of determination results indicating the presence of a recess is equal to or greater than a predetermined threshold. The threshold is a value equal to or less than the number of types of frequencies of reflected waves that the sensor unit 10 can receive.

[0038] (D5) In the above-described embodiment, the determination device 100 may include a plurality of sensor units 10. In this case, the determination unit 20 determines whether or not a recess exists for each sensor unit 10, and determines that a recess exists when the number of determination results indicating the presence of a recess is equal to or greater than a predetermined threshold. The threshold is a value equal to or less than the number of sensor units 10 included in the determination device 100.

[0039] (D6) In the above-described embodiment, the determination unit 20 determines whether or not a concave portion exists using a plurality of maximum values ​​P1 in the second reflection section A2 of the second graph, where the reception intensity is within a predetermined range. However, the determination unit 20 may determine whether or not a concave portion exists using a plurality of maximum values ​​P1 in the second reflection section A2 of the second graph, where the reception intensity is equal to or greater than a predetermined first threshold reception intensity Th1.

[0040] (D7) In the above-described embodiment, the groove width calculation unit 31 calculates the average value of the difference D1 and the difference D2 as the groove width Lw. This is not limiting, and the groove width calculation unit 31 may calculate the distance between a certain maximum value and another maximum value adjacent to the certain maximum value as the groove width Lw. For example, the groove width calculation unit 31 may calculate the difference D1 as the groove width Lw, or may calculate the difference D2 as the groove width Lw.

[0041] (D8) In the above-described embodiment, the calculation unit 30 may correct the distance measured by the sensor unit 10 using the measured values ​​of at least one of the temperature and humidity. More specifically, the calculation unit 30 may correct for attenuation of sound waves due to absorption by air. The higher the temperature, the greater the attenuation associated with sound wave propagation. Furthermore, the higher the humidity, the greater the attenuation associated with sound wave propagation. In other words, as the temperature and humidity increase, the reception intensity decreases. Furthermore, because the propagation speed of sound waves increases, the intervals between the maximum values ​​in the second graph become narrower.

[0042] According to this embodiment, for example, the groove width calculation unit 31 can accurately estimate the interval between multiple maximum values ​​in the graph, and therefore can accurately calculate the groove width Lw. The groove width calculation unit 31 corrects the reception strength, for example, based on the fact that the reception strength is proportional to the following equation (2). T∝exp(-αx)…(2) Here, T is the sound pressure, α is the sound absorption coefficient, and x is the distance measured by the sensor unit 10. α is determined by the temperature and humidity. Note that the groove width calculation unit 31 preferably performs correction when the emission unit 11 emits sound waves or radio waves. Furthermore, the determination unit 20 may determine the first threshold reception intensity Th1 and the second threshold reception intensity Th2 using a measured value of at least one of the temperature and humidity.

[0043] (D9) In the above-described embodiment, the groove height calculation unit 32 may calculate the groove height Lh, for example, by the following equation (3).

[0044] Lh=α×Ln+β×Lw+γ×tanθ…(3) Here, α, β, and γ are regression coefficients. The regression coefficients can be obtained in advance, for example, by experiment or simulation. The incident angle is determined, for example, based on the vertical distance hs (see FIG. 2) from the first road surface 301 to the sensor unit 10, which is measured in advance, and the linear distance Lu (see FIG. 2) to the end point Pt (see FIG. 2) of the first road surface 301, which is measured by the sensor unit 10. Note that the variables in the above formula (3) are not limited to these, and for example, the vertical distance hs or the linear distance Lu may be used instead of tan θ. Furthermore, the groove height calculation unit 32 may calculate the groove height Lh using a nonlinear formula.

[0045] (D10) In the above-described embodiment, the groove width calculation unit 31 may estimate the groove width Lw using a model that has learned the relationship between the reception intensity and the non-reflection section A3 by supervised machine learning. More specifically, the groove width calculation unit 31 uses the model that has learned by supervised machine learning to The groove width calculation unit 31 can output whether or not a recess exists and the groove width Lw. Alternatively, the groove width calculation unit 31 may calculate the groove width Lw based on whether or not a position at each distance from the determination device 100 is included in the first reflection section A1 or the second reflection section A2, and the interval between multiple maximum values ​​of the second graph in the second reflection section A2, which are determined using a model trained by supervised machine learning. For example, a support vector machine (SVM) or a deep neural network (DNN) can be used as the supervised machine learning.

[0046] (D11) In the above-described embodiment, the groove height calculation unit 32 may estimate the groove height Lh using a model that has learned the relationship between the reception intensity and the non-reflection section A3 by supervised machine learning. More specifically, the groove height calculation unit 32 uses the model that has learned by supervised machine learning to The presence or absence of a recess and the groove height Lh can be output. The groove height calculation unit 32 may also calculate the groove height Lh based on the length of the non-reflective section A3 obtained using a model trained by supervised machine learning. For example, SVM, DNN, or random forest can be used as the supervised machine learning.

[0047] (D12) In the second embodiment described above, the groove height calculation unit 32 uses, for example, the approximation of the third graph, which is the envelope of the multiple maximum values ​​P1 to P3, as the amount of attenuation of the reception intensity. However, this is not limiting. The groove height calculation unit 32 may also use, as the amount of attenuation of the reception intensity, the difference in reception intensity between any two of the multiple maximum values ​​P1 to P3. For example, the groove height calculation unit 32 may use, as the amount of attenuation of the reception intensity, the difference between the reception intensity of the first maximum value P1, which is located closest to the sensor unit 10 in the second reflection section A2 of the second graph, and the reception intensity of the third maximum value P3, which is located farthest from the sensor unit 10 in the second reflection section A2 of the second graph. Furthermore, the groove height calculation unit 32 may also use, as the amount of attenuation of the reception intensity, a value calculated based on the difference in reception intensity between any two of the multiple maximum values ​​P1 to P3 and the reception intensity of the first maximum value P1.

[0048] (D13) In the fourth embodiment described above, the determination unit 20 determines whether a recess exists using the reception intensity of reflected waves whose incidence angles are within a predetermined threshold range. This is not limiting, and the determination unit 20 does not need to set a threshold range for the incidence angle of reflected waves used to determine whether a recess exists. The determination unit 20 determines whether a recess exists using multiple maximum values ​​P1 to P3 in a graph showing the reception intensity of reflected waves with the same incidence angle. The incidence angle of the reflected wave from the groove 303 is different from the incidence angle of the reflected wave from the obstacle 305. Furthermore, a reflected wave from one obstacle 305 does not produce multiple maximum values ​​in the second reflection section A2c of the second graph. Therefore, multiple maximum values ​​in the graph showing the reception intensity of reflected waves with the same incidence angle in the second reflection section A2c of the second graph shown in FIG. 7 can be determined to be reflected waves from the groove 303.

[0049] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0050] 10...sensor unit, 11...emission unit, 12...receiving unit, 20...determination unit, 30...calculation unit, 31...groove width calculation unit, 32...groove height calculation unit, 40...output unit, 100...determination device, 200...estimation device, 301...first road surface, 302...second road surface, 303...groove, 304, 305...obstacle

Claims

1. A determination device (100), one or more sensor units (10) having an emission unit (11) that emits an emission wave and a receiving unit (12) that receives a reflected wave generated when the emission wave is reflected by a target, and capable of measuring the distance to an object present within a predetermined detection range in the forward and backward directions of the emission unit using the reflected wave; a determination unit (20) that determines whether or not a depression exists on the road surface using the reception intensity of the reflected wave, The determination unit In a second graph which is an envelope of the first graph, the vertical axis represents the received wave intensity and the horizontal axis represents the distance from the sensor unit or the time from the emission of the emitted wave to the reception of the reflected wave, Detecting a non-reflection section that exists between a first reflection section due to the reflected wave from a first road surface and a second reflection section due to the reflected wave from a position farther from the determination device in the longitudinal direction than the first reflection section, When the non-reflective section exists and three or more maximum values, each of which has a reception intensity in the second reflective section equal to or greater than a predetermined threshold, are located at regular intervals, it is determined that the recess exists; The determination device further includes a groove width calculation unit (31) that calculates a groove width, which is the width of the recess in the extension direction of the road surface, based on the spacing on the horizontal axis between the three or more maximum values ​​using the distance measured by the sensor unit.

2. The determination device according to claim 1, The groove width calculation unit corrects the distance measured by the sensor unit using a measured value of at least one of air temperature and humidity.

3. 3. The determination device according to claim 1 or 2, The groove width calculation unit estimates the groove width using a model that learns the relationship between the reception intensity and the non-reflection section through supervised machine learning.

4. A determination device, one or more sensor units each having an emission unit that emits an emission wave and a receiving unit that receives a reflected wave generated when the emission wave is reflected by a target, and capable of measuring a distance to an object present within a predetermined detection range in the forward and backward directions of the emission unit using the reflected wave; a determination unit that determines whether or not a depression exists on the road surface using the reception intensity of the reflected wave, The determination unit In a second graph which is an envelope of the first graph, the vertical axis represents the received wave intensity and the horizontal axis represents the distance from the sensor unit or the time from the emission of the emitted wave to the reception of the reflected wave, Detecting a non-reflection section that exists between a first reflection section due to the reflected wave from a first road surface and a second reflection section due to the reflected wave from a position farther from the determination device in the longitudinal direction than the first reflection section, When the non-reflective section exists and three or more maximum values, each of which has a reception intensity in the second reflective section equal to or greater than a predetermined threshold, are located at regular intervals, it is determined that the recess exists; The determination device further comprises a groove height calculation unit (32) that calculates a groove height, which is the height of the recess, based on the length of the non-reflective section using the distance measured by the sensor unit.

5. A determination device, one or more sensor units each having an emission unit that emits an emission wave and a receiving unit that receives a reflected wave generated when the emission wave is reflected by a target, and capable of measuring a distance to an object present within a predetermined detection range in the forward and backward directions of the emission unit using the reflected wave; a determination unit that determines whether or not a depression exists on the road surface using the reception intensity of the reflected wave, The determination unit In a second graph which is an envelope of the first graph, the vertical axis represents the received wave intensity and the horizontal axis represents the distance from the sensor unit or the time from the emission of the emitted wave to the reception of the reflected wave, Detecting a non-reflection section that exists between a first reflection section due to the reflected wave from a first road surface and a second reflection section due to the reflected wave from a position farther from the determination device in the longitudinal direction than the first reflection section, When the non-reflective section exists and three or more maximum values, each of which has a reception intensity in the second reflective section equal to or greater than a predetermined threshold, are located at regular intervals, it is determined that the recess exists; The determination device further includes a groove height calculation unit that calculates a groove height, which is the height of the recess, based on the reception strength of the first maximum value that is located closest to the sensor unit in the second reflection section of the second graph and the attenuation of the reception strength of the three or more maximum values.

6. The determination device according to claim 4, The groove height calculation unit estimates the groove height using a model that learns the relationship between the reception intensity and the non-reflection section through supervised machine learning.

7. The determination device according to claim 1, The sensor unit can detect an incident angle of the reflected wave, The determination unit determines whether or not a depression exists on the road surface using the reception intensity of the reflected wave when the incident angle is within a predetermined range.

8. The determination device according to claim 1, the sensor unit emits the emitted waves of a plurality of frequencies, The determination unit determines whether or not the recess exists for each frequency, and determines that the recess exists when the number of determination results indicating the presence of the recess is equal to or greater than a predetermined threshold.

9. The determination device according to claim 1, A plurality of the sensor units are provided, The determination unit determines whether or not the recess exists for each sensor unit, and determines that the recess exists if the number of determination results indicating the presence of the recess is equal to or greater than a predetermined threshold.

10. The determination device according to claim 1, The sensor unit is a directional sensor.

11. The determination device according to claim 10, The determination device, wherein the sensor unit is a phased array.

12. The determination device according to claim 1, The emitting unit emits a sound wave or an electric wave as the emitted wave.

13. A road surface recognition method for determining whether or not a depression exists on a road surface, comprising: a step of acquiring a distance measured by one or more sensors having an emission unit that emits an emission wave and a receiving unit that receives a reflected wave generated when the emission wave is reflected by a target, the one or more sensors being capable of measuring a distance to an object present within a predetermined detection range in the forward and backward directions of the emission unit, and a reception intensity of the reflected wave; a step of detecting a non-reflection section that exists between a first reflection section of the reflected wave from a first road surface and a second reflection section of the reflected wave from a position farther from the sensor in the longitudinal direction than the first reflection section in a second graph that is an envelope of a first graph with the vertical axis representing the reception intensity and the horizontal axis representing the distance from the sensor or the time from the emission of the emitted wave to the reception of the reflected wave, and determining that the recess exists when the non-reflection section exists and three or more maximum values ​​of the reception intensity in the second reflection section that are equal to or greater than a predetermined threshold are located at regular intervals; and calculating a groove width, which is the width of the recess in the extension direction of the road surface, based on the spacing between the three or more maximum values ​​on the horizontal axis using the distance measured by the sensor.

14. A road surface recognition method for determining whether or not a depression exists on a road surface, comprising: a step of acquiring a distance measured by one or more sensors having an emission unit that emits an emission wave and a receiving unit that receives a reflected wave generated when the emission wave is reflected by a target, the one or more sensors being capable of measuring a distance to an object present within a predetermined detection range in the forward and backward directions of the emission unit, and a reception intensity of the reflected wave; a step of detecting a non-reflection section that exists between a first reflection section of the reflected wave from a first road surface and a second reflection section of the reflected wave from a position farther from the sensor in the longitudinal direction than the first reflection section in a second graph that is an envelope of a first graph with the vertical axis representing the reception intensity and the horizontal axis representing the distance from the sensor or the time from the emission of the emitted wave to the reception of the reflected wave, and determining that the recess exists when the non-reflection section exists and three or more maximum values ​​of the reception intensity in the second reflection section that are equal to or greater than a predetermined threshold are located at regular intervals; and calculating a groove height, which is the height of the recess, based on the length of the non-reflective section using the distance measured by the sensor.

15. A road surface recognition method for determining whether or not a depression exists on a road surface, comprising: a step of acquiring a distance measured by one or more sensors having an emission unit that emits an emission wave and a receiving unit that receives a reflected wave generated when the emission wave is reflected by a target, the one or more sensors being capable of measuring a distance to an object present within a predetermined detection range in the forward and backward directions of the emission unit, and a reception intensity of the reflected wave; a step of detecting a non-reflection section that exists between a first reflection section of the reflected wave from a first road surface and a second reflection section of the reflected wave from a position farther from the sensor in the longitudinal direction than the first reflection section in a second graph that is an envelope of a first graph with the vertical axis representing the reception intensity and the horizontal axis representing the distance from the sensor or the time from the emission of the emitted wave to the reception of the reflected wave, and determining that the recess exists when the non-reflection section exists and three or more maximum values ​​of the reception intensity in the second reflection section that are equal to or greater than a predetermined threshold are located at regular intervals; and calculating a groove height, which is the height of the recess, based on the reception strength of a first maximum value that is located closest to the sensor in a second reflection section of the second graph and the attenuation of the reception strength of the three or more maximum values.

16. An estimation device (200) for determining whether or not a depression exists on a road surface, comprising: a determination unit that has an emission unit that emits an emission wave and a receiving unit that receives a reflected wave generated when the emission wave is reflected by a target, and that determines whether or not the recess exists using a distance measured by one or more sensors that can measure a distance to an object present in a predetermined detection range in the forward and backward directions of the emission unit using the reflected wave; an output unit (40) that outputs a determination result as to whether or not the recessed portion exists; The determination unit In a second graph, which is an envelope of the first graph, the vertical axis represents the received intensity of the reflected wave, and the horizontal axis represents the distance from the sensor or the time from the emission of the emitted wave until the reception of the reflected wave. Detecting a non-reflection section that exists between a first reflection section of the reflected wave from a first road surface and a second reflection section of the reflected wave from a position farther from the estimation device in the longitudinal direction than the first reflection section; When the non-reflective section exists and three or more maximum values ​​of the reception intensity in the second reflective section, which are reception intensities equal to or greater than a predetermined threshold, are located at regular intervals, it is determined that the recess exists; The estimation device further includes a groove width calculation unit that calculates a groove width, which is the width of the recess in the extension direction of the road surface, based on the spacing on the horizontal axis between the three or more maximum values ​​using the distance measured by the sensor.

17. An estimation device (200) for determining whether or not a depression exists on a road surface, comprising: a determination unit that has an emission unit that emits an emission wave and a receiving unit that receives a reflected wave generated when the emission wave is reflected by a target, and that determines whether or not the recess exists using a distance measured by one or more sensors that can measure a distance to an object present in a predetermined detection range in the forward and backward directions of the emission unit using the reflected wave; an output unit (40) that outputs a determination result as to whether or not the recessed portion exists; The determination unit In a second graph, which is an envelope of the first graph, the vertical axis represents the received intensity of the reflected wave, and the horizontal axis represents the distance from the sensor or the time from the emission of the emitted wave until the reception of the reflected wave. Detecting a non-reflection section that exists between a first reflection section of the reflected wave from a first road surface and a second reflection section of the reflected wave from a position farther from the estimation device in the longitudinal direction than the first reflection section; When the non-reflective section exists and three or more maximum values ​​of the reception intensity in the second reflective section, which are reception intensities equal to or greater than a predetermined threshold, are located at regular intervals, it is determined that the recess exists; The estimation device further includes a groove height calculation unit that calculates a groove height, which is the height of the recess, based on the length of the non-reflective section using the distance measured by the sensor.

18. An estimation device (200) for determining whether or not a depression exists on a road surface, comprising: a determination unit that has an emission unit that emits an emission wave and a receiving unit that receives a reflected wave generated when the emission wave is reflected by a target, and that determines whether or not the recess exists using a distance measured by one or more sensors that can measure a distance to an object present in a predetermined detection range in the forward and backward directions of the emission unit using the reflected wave; an output unit (40) that outputs a determination result as to whether or not the recessed portion exists; The determination unit In a second graph, which is an envelope of the first graph, the vertical axis represents the received intensity of the reflected wave, and the horizontal axis represents the distance from the sensor or the time from the emission of the emitted wave until the reception of the reflected wave. Detecting a non-reflection section that exists between a first reflection section of the reflected wave from a first road surface and a second reflection section of the reflected wave from a position farther from the estimation device in the longitudinal direction than the first reflection section; When the non-reflective section exists and three or more maximum values ​​of the reception intensity in the second reflective section, which are reception intensities equal to or greater than a predetermined threshold, are located at regular intervals, it is determined that the recess exists; The estimation device further includes a groove height calculation unit that calculates a groove height, which is the height of the recess, based on the reception intensity of the first maximum value that is located closest to the sensor in the second reflection section of the second graph and the attenuation of the reception intensity of the three or more maximum values.

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