Wall shape measuring device

Abstract

The wall shape measuring device (11, 12) includes a wall distance acquisition unit (S40), a wall shape calculation unit (S10, S20, S50, S70), a sudden change judgment unit (S280, S290) and an extrapolation unit (S320). The wall distance acquisition unit repeatedly judges whether a wall-like object set along a road is detected, and when it is judged that a wall-like object is detected, a wall distance value indicating the distance to the wall-like object is acquired. The wall shape calculation unit calculates a plurality of wall shape values ​​using a vehicle's driving trajectory and a plurality of past wall distance values. The sudden change judgment unit judges whether the wall distance value changes suddenly based on a preset sudden change judgment condition. When it is judged that the wall distance value changes suddenly, the extrapolation unit extrapolates the wall shape value after the wall distance value is judged to change suddenly.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This international application claims priority based on Japanese Patent Application No. 2019-163205 filed in the Japan Patent Office on September 6, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a wall shape measuring device for measuring the shape of a wall provided along a road. Background Art

[0004] Patent Document 1 describes that wall distance information indicating the result of detecting the distance to a wall existing on the side of the vehicle is acquired from a radar device mounted on the vehicle, and the wall shape is calculated based on the wall distance information and the vehicle's travel trajectory.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-85567

[0006] However, as a result of detailed research by the inventors, the following problem was discovered in the technology described in Patent Document 1: If there is a situation where there is another vehicle between a vehicle equipped with a radar device (hereinafter referred to as the vehicle itself) and a wall, then when the side of the other vehicle is mistakenly identified as a wall, the shape of the wall is calculated to be closer to the vehicle itself than the actual position of the wall, resulting in incorrect calculation of the wall shape. Summary of the invention

[0007] The present disclosure suppresses the wall shape from being calculated to be closer to the host vehicle than the actual position of the wall.

[0008] One aspect of the present disclosure provides a wall shape measurement device mounted on a vehicle, including a wall distance acquisition unit, a wall shape calculation unit, a sudden change determination unit, and an extrapolation unit.

[0009] The wall distance acquisition unit is configured to repeatedly determine whether a wall-like object set along the road on which the vehicle is traveling is detected, using a received signal obtained by receiving radar waves transmitted and reflected in a predetermined detection range around the vehicle, and, when it is determined that a wall-like object is detected, obtain a wall distance value indicating the distance to the wall-like object using the received signal.

[0010] The wall shape calculation unit is configured to calculate a plurality of wall shape values ​​indicating positions of a plurality of locations on the surface of the wall-like object using the travel trajectory of the vehicle and a plurality of past wall distance values ​​repeatedly acquired by the wall distance acquisition unit.

[0011] The sudden change determination unit is configured to determine whether the wall distance value acquired by the wall distance acquisition unit has suddenly changed based on a preset sudden change determination condition.

[0012] The extrapolation unit is configured to, when the sudden change determination unit determines that the wall distance value has suddenly changed, extrapolate the wall shape value after the sudden change determination unit determines that the wall distance value has suddenly changed.

[0013] The wall shape measuring device of the present disclosure thus constructed performs extrapolation of the wall shape value after the wall distance value changes suddenly when the wall distance value changes suddenly. Therefore, in the wall shape measuring device of the present disclosure, for example, when the situation changes from a situation where there is no other vehicle between the vehicle and the wall to a situation where there is another vehicle between the vehicle and the wall, the wall distance value changes suddenly when the side of the other vehicle is mistakenly recognized as a wall, and the wall shape value after the wall distance value changes suddenly is calculated based on the wall shape value before the wall distance value changes suddenly. Thus, the wall shape measuring device of the present disclosure can prevent the wall shape from being calculated to be closer to the vehicle than the actual position of the wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a block diagram showing the structure of the vehicle-mounted system.

[0015] Figure 2 This is a block diagram showing the structure of a radar device.

[0016] Figure 3 is a flowchart showing the wall calculation process.

[0017] Figure 4 : is a flowchart showing the filter value calculation process.

[0018] Figure 5 is a flowchart showing the extrapolation process.

[0019] Figure 6 : is a flowchart showing the interpolation process according to the first embodiment.

[0020] Figure 7 is a graph showing the interpolation method.

[0021] Figure 8 It is a diagram showing a method of calculating a wall shape.

[0022] Fig. 9 It is a figure which shows the difference of the wall shape due to the presence or absence of the extrapolation process.

[0023] Fig.10 It is a figure which shows the difference of the wall shape due to presence or absence of the interpolation process.

[0024] Fig.11 : is a flowchart showing the interpolation process according to the second embodiment.

[0025] Fig.12 : is a flowchart showing the interpolation process according to the third embodiment. DETAILED DESCRIPTION

[0026] [First embodiment]

[0027] The following, with the attached Figure 1 The first embodiment of the present disclosure will now be described.

[0028] like Figure 1 As shown, the vehicle-mounted system 1 of this embodiment includes a driving assistance ECU 2, a radar system 3, and an alarm device 4. ECU is an abbreviation of Electronic Control Unit. In this embodiment, the vehicle-mounted system 1 is mounted on a vehicle that is a four-wheeled vehicle. Hereinafter, the vehicle equipped with the vehicle-mounted system 1 is also referred to as the vehicle itself.

[0029] The radar system 3 includes a plurality of radar devices 11, 12, 13, 14, ... In the present embodiment, the radar device 11 is disposed on the rear right side of the vehicle, the radar device 12 is disposed on the rear left side of the vehicle, the radar device 13 is disposed on the front right side of the vehicle, and the radar device 14 is disposed on the front left side of the vehicle.

[0030] The radar devices 11 and 12 are configured to include the rear direction along the vehicle's forward direction and the lateral direction orthogonal to the forward direction in their detection ranges. The radar device 11 acquires information about objects on the right side and right rear side of the vehicle. The radar device 12 acquires information about objects on the left side and left rear side of the vehicle.

[0031] The radar devices 13 and 14 are configured to include the front direction along the vehicle's forward direction and the lateral direction orthogonal to the forward direction in their detection range. The radar device 13 obtains information about objects on the right side and right front side of the vehicle. The radar device 14 obtains information about objects on the left side and left front side of the vehicle.

[0032] In addition, various detection methods are known as target detection methods used in radar devices, such as FMCW method and dual-frequency CW method. The radar devices 11, 12, 13, 14, ... of this embodiment are configured as so-called "millimeter wave radars" of the FMCW method.

[0033] The plurality of radar devices 11 , 12 , 13 , 14 , . . . constituting the radar system 3 all have substantially the same structure and function.

[0034] like Figure 2As shown, the radar devices 11, 12, 13, 14...repeatedly transmit radar waves and receive reflected waves each time a processing cycle is passed, and based on the received signal Sr, the distance D to the target object that reflected the radar wave, the relative speed Vr of the target object, and the azimuth θ of the target object are detected.

[0035] The radar devices 11 , 12 , 13 , 14 . . . generate driving assistance information for assisting the driver in driving the vehicle based on the detected observation values ​​(D, Vr, θ), and output the driving assistance information to the driving assistance ECU 2 .

[0036] The driving assistance ECU 2 performs various processes for assisting the driver in driving the vehicle based on the driving assistance information input from the radar devices 11, 12, 13, 14, etc. The processes related to driving assistance may include, for example, a process of issuing an alert to the driver that there is an approaching object, a process of avoiding a collision with an approaching object by controlling the braking system and the steering system, or a process of performing vehicle control for automatically changing lanes.

[0037] The radar devices 11 , 12 , 13 , 14 , . . . include a transmission circuit 20 , a distributor 30 , a transmission antenna 40 , a reception antenna 50 , a reception circuit 60 , a processing unit 70 , an output unit 80 , and a network interface (hereinafter referred to as a network I / F) 90 .

[0038] The transmission circuit 20 is a circuit for supplying a transmission signal Ss to the transmission antenna 40. The transmission circuit 20 outputs a high-frequency signal in the millimeter wave band to the distributor 30 located upstream of the transmission antenna 40. Specifically, the transmission circuit 20 alternately repeats the uplink modulation interval and the downlink modulation interval with a modulation period Tm, and outputs the high-frequency signal generated in each modulation interval to the distributor 30. In addition, the transmission circuit 20 generates a high-frequency signal that is frequency modulated to increase the frequency in the uplink modulation interval, and generates a high-frequency signal that is frequency modulated to decrease the frequency in the downlink modulation interval.

[0039] The distributor 30 distributes the high frequency signal power input from the transmission circuit 20 into a transmission signal Ss and a local signal L.

[0040] The transmission antenna 40 radiates a radar wave having a frequency corresponding to the transmission signal Ss based on the transmission signal Ss supplied from the distributor 30 .

[0041] The receiving antenna 50 is an antenna for receiving radar waves reflected by a target object, that is, reflected waves. The receiving antenna 50 is configured as a linear array antenna having a plurality of antenna elements 51 arranged in a row. A reception signal Sr of the reflected waves from each antenna element 51 is input to the receiving circuit 60 .

[0042] The receiving circuit 60 processes the receiving signal Sr input from each antenna element 51 constituting the receiving antenna 50, and generates and outputs a beat signal BT for each antenna element 51. Specifically, the receiving circuit 60 uses the mixer 61 to mix the receiving signal Sr input from the antenna element 51 and the local signal L input from the distributor 30 for each antenna element 51, thereby generating and outputting a beat signal BT for each antenna element 51.

[0043] Hereinafter, the beat signal BT generated by mixing the received signal Sr and the transmitted signal during the period of transmitting the radar wave in the uplink modulation interval is referred to as the uplink beat signal. In addition, the beat signal BT generated by mixing the received signal Sr and the transmitted signal during the period of transmitting the radar wave in the downlink modulation interval is referred to as the downlink beat signal.

[0044] However, the process until the beat signal BT is output includes a process of amplifying the received signal Sr, a process of removing unnecessary signal components from the beat signal BT, and a process of converting the beat signal BT into digital data. In this way, the receiving circuit 60 converts the generated beat signal BT for each antenna element 51 into digital data and outputs it. The output beat signal BT for each antenna element 51 is input to the processing unit 70.

[0045] The processing unit 70 is an electronic control device centered around a microcomputer having a CPU 71, a ROM 72, and a RAM 73. The various functions of the microcomputer are realized by the CPU 71 executing a program stored in a non-migrating physical recording medium. In this example, the ROM 72 corresponds to a non-migrating physical recording medium storing the program. In addition, by executing the program, a method corresponding to the program is executed. In addition, a part or all of the functions executed by the CPU 71 may be constituted in hardware by one or more ICs. In addition, the number of microcomputers constituting the processing unit 70 may be one or more.

[0046] In addition, the processing unit 70 may include a coprocessor that performs a fast Fourier transform (hereinafter referred to as FFT) process, etc. FFT is an abbreviation of Fast Fourier Transform.

[0047] The network I / F 90 is a communication interface for the processing unit 70 to perform data communication with other control systems 5 via the network 6. In the present embodiment, the network 6 is a CAN known as an in-vehicle network. CAN is an abbreviation of Controller Area Network. CAN is a registered trademark.

[0048] The other control system 5 includes a plurality of vehicle-mounted devices (for example, ECUs and sensors) other than the driving support ECU 2 .

[0049] Various odometry information is periodically sent from other control systems 5 to the network 6. The processing unit 70 acquires the odometry information via the network 6. The acquired odometry information includes the speed of the vehicle (hereinafter referred to as the vehicle speed) Vs, the yaw rate ω of the vehicle, the steering angle α of the vehicle, the turning radius Rs of the vehicle, and the like.

[0050] The other control system 5 calculates the vehicle speed Vs, the yaw rate ω, and the steering angle α based on the detection signals from the vehicle speed sensor, the yaw rate sensor, and the steering angle sensor (not shown), and further calculates the turning radius Rs based on the steering angle α using a predetermined calculation method. In addition, instead of the processing unit 70 acquiring the turning radius Rs via the network 6, the processing unit 70 may calculate the turning radius Rs inside the radar devices 11, 12, 13, 14, ... based on the steering angle α acquired via the network 6.

[0051] In the vehicle-mounted system 1 configured in this manner, the CPU 71 of the radar devices 11 and 12 executes the wall calculation process.

[0052] First, the procedure of the wall calculation process executed by the CPU 71 of the radar device 11 will be described. The wall calculation process is a process that is repeatedly executed every time the above-mentioned processing cycle passes during the operation of the processing unit 70.

[0053] If wall calculation is performed, then Figure 3 As shown, the CPU 71 first obtains the distance measurement information from other control systems 5 via the network 6 in S10. The distance measurement information obtained in S10 includes at least the vehicle speed Vs, the yaw rate ω, the steering angle α, and the turning radius Rs. The CPU 71 stores the distance measurement information from N cycles before the above-mentioned processing cycle to the present in the RAM 73. N is an integer greater than 2. In addition, N is determined by considering the distance detected in the vehicle (for example, 100m behind) and the vehicle speed of the vehicle.

[0054] Then, in S20, CPU71 calculates the driving trajectory of the vehicle from N cycles before the above-mentioned processing cycle to the present. Specifically, CPU71 uses the ranging information obtained in S10 (i.e., the acquired values ​​in each processing cycle until N cycles before) to calculate the estimated value of the position of the vehicle in each processing cycle from 1 cycle before to N cycles before based on the current position (hereinafter, the estimated position of the vehicle). Moreover, CPU71 uses the line connecting the current position and the calculated estimated position of the vehicle in each cycle as the driving trajectory of the vehicle. In addition, the technology for calculating the driving trajectory of the vehicle based on the ranging information is well known, so the description of the details is omitted.

[0055] In addition, the distance measurement information obtained in S10 contains errors due to various factors such as detection errors and noise of the vehicle speed sensor and the yaw rate sensor. Therefore, in S20, the CPU 71 calculates the estimated existence range of the vehicle's estimated position taking into account the error of the distance measurement information for each vehicle's estimated position in the past processing cycle until N cycles ago. The estimated existence range can be expressed as an error variance based on the vehicle's estimated position. And, by projecting the error variance to the lane width direction (i.e., the direction perpendicular to the direction of travel), the existence probability of the vehicle's estimated position in the lane width direction can be expressed as a predetermined probability distribution centered on the vehicle's estimated position.

[0056] In this embodiment, the error variance of the estimated position of the vehicle caused by the error factor of the ranging information is modeled as a normal distribution. That is, the existence probability of the estimated position of the vehicle calculated using the ranging information is the peak value with the highest probability in the normal distribution, and the farther away from the estimated position of the vehicle in the lane width direction, the less the existence probability according to the normal distribution.

[0057] Then, in S30, the CPU 71 calculates the adjacent lane probability map. Specifically, the CPU 71 specifies the position of the adjacent lane (specifically, the positions of both ends in the lane width direction) for each estimated position of the vehicle up to N cycles ago. Then, the error variance at the estimated position of the vehicle is projected to the position of the specified adjacent lane to calculate the probability distribution of the adjacent lane.

[0058] Specifically, the CPU 71 specifies the positions of two lane dividing lines (i.e., lane dividing lines on both sides of the adjacent lanes) that divide the adjacent lanes, i.e., the estimated value of the position of the lane dividing line on the side close to the host vehicle (hereinafter, the inner dividing line) (hereinafter, the inner dividing position), i.e., the inner estimated dividing position, and the estimated value of the position of the lane dividing line on the side away from the host vehicle (hereinafter, the outer dividing line) (hereinafter, the outer dividing position), i.e., the outer estimated dividing position. Then, the CPU 71 sets the probability distribution of the lane width direction of each dividing position by directly projecting the error variance of the host vehicle estimated position onto each estimated dividing position.

[0059] That is, for the inner dividing position, the inner inferred dividing position is the peak value of the normal distribution, and as it moves away from the inner inferred dividing position, the probability of the inner dividing position decreasing according to the normal distribution. For the outer dividing position, the outer inferred dividing position is the peak value of the normal distribution, and as it moves away from the outer inferred dividing position, the probability of the outer dividing position decreasing according to the normal distribution.

[0060] Then, the CPU 71 calculates the adjacent lane probability map by connecting the points with equal probability of existence of the inner dividing position (for example, points with prescribed probabilities P1, P2, and P3) in each processing cycle until N cycles ago, and connecting the points with equal probability of existence of the outer dividing position (for example, points with prescribed probabilities P1, P2, and P3 the same as the inner side). The adjacent lane probability map is a map indicating an area with a probability of P1, P2, and P3 of the existence of an adjacent lane. In other words, it can also be said to be a map indicating that when an object exists in the area represented by the adjacent lane probability map, the probability of the object existing in the adjacent lane is P1, P2, and P3.

[0061] In addition, in the present embodiment, the probabilities P1, P2, and P3 are 100%, 70%, and 30%. Furthermore, the map representing the region of probability P1 is formed by a line connecting the points of 1σ (i.e., 68.3%). The map representing the region of probability P2 is formed by a line connecting the points of 2σ (i.e., 95.5%). The map representing the region of probability P3 is formed by a line connecting the points of 3σ (i.e., 99.7%).

[0062] Next, CPU71 obtains the instantaneous value of the wall distance in S40. Specifically, first, CPU71 extracts multiple peaks (in this embodiment, three peaks in order of power from high to low) within the peak extraction frequency range for the power spectra of the uplink beat signal and the downlink beat signal, and performs azimuth expansion processing (for example, MUSIC, DBF, CAPON, etc.).

[0063] The power spectrum is calculated by performing frequency analysis processing (e.g., FFT processing) on ​​the uplink beat signal and the downlink beat signal respectively. In the power spectrum, the power of the beat signal is represented for each frequency bin. The frequency bin is a frequency range that becomes a unit scale of the power spectrum. A power spectrum is obtained for each antenna element in the plurality of antenna elements 51. The power spectrum that is the object of peak extraction in S40 is an average power spectrum obtained by averaging the power spectra obtained from each antenna element 51.

[0064] Furthermore, the CPU 71 further extracts the azimuth peak from the azimuth expansion spectrum, and performs matching in consideration of the characteristics of the wall among the multiple azimuth peaks in the uplink and downlink directions. Then, the CPU 71 determines that the wall is detected when the matching is successful, and determines that the wall cannot be detected when the matching is not successful.

[0065] Furthermore, the CPU 71 determines that pair matching is established when all of the following first pair matching determination conditions, second pair matching determination conditions, and third pair matching determination conditions are established.

[0066] The first pair of matching judgment conditions is that the frequencies of the upward and downward directions are substantially the same. The first pair of matching judgment conditions is set based on the fact that the wall on the front side has no relative speed with respect to the vehicle.

[0067] The second pair of matching judgment conditions is that the directions of the upper and lower lines are roughly the same. The second pair of matching judgment conditions is set based on the detection of the wall in the positive side direction by both the upper and lower lines.

[0068] The third pair of matching judgment conditions is that the uplink and downlink powers are substantially consistent. The third pair of matching judgment conditions is set based on the fact that the powers of the received signals Sr reflected from the same target object are substantially consistent.

[0069] Here, when it is determined that a wall is detected, the CPU 71 acquires the distance D calculated from the peak pair for which matching is established as the instantaneous value of the wall distance.

[0070] Then, the CPU 71 executes a filter value calculation process in S50 .

[0071] Next, the procedure of the filter value calculation process will be described.

[0072] If the filter value calculation process is performed, then Figure 4 As shown, the CPU 71 first determines in S210 whether the right wall has been detected in the past. The past in S210 refers to the period from the last startup of the processing unit 70 to the present time.

[0073] Here, if the wall on the right side was not detected in the past, CPU71 determines in S220 whether the wall on the right side is detected in this cycle. Here, if the wall on the right side is detected in this processing cycle, CPU71 updates the wall filter values ​​FV(N), FV(N-1), FV(N-2), ..., FV(1), and FV(0) provided in RAM73 in S230. Specifically, first, CPU71 stores the values ​​of the wall filter values ​​FV(N), FV(N-1), ..., and FV(1) as wall filter values ​​FV(N-1), FV(N-2), ..., and FV(0), respectively. Next, CPU71 stores the instantaneous value of the wall distance obtained in S40 (hereinafter referred to as this value) as the wall filter value FV(N).

[0074] Then, in S240 , the CPU 71 initializes (that is, sets to 0) the extrapolation counter CT1 provided in the RAM 73 , and ends the filter value calculation process.

[0075] In addition, when the wall on the right side is not detected in this processing cycle in S220, CPU71 updates the wall filter values ​​FV(N), FV(N-1), FV(N-2), ..., FV(1), and FV(0) in S250. Specifically, first, CPU71 stores the values ​​of the wall filter values ​​FV(N), FV(N-1), ..., and FV(1) as wall filter values ​​FV(N-1), FV(N-2), ..., and FV(0), respectively. Then, CPU71 stores the pre-set initial value as the wall filter value FV(N). In the present embodiment, the initial value is set to a value equivalent to 15m.

[0076] Then, the CPU 71 initializes the extrapolation counter CT1 in S260 , and ends the filter value calculation process.

[0077] In addition, in the case where the wall on the right side was detected in the past in S210, the CPU 71 determines in S270 whether the wall on the right side is detected in this processing cycle. Here, in the case where the wall on the right side is not detected in this processing cycle, the CPU 71 moves to S320. On the other hand, in the case where the wall on the right side is detected in this processing cycle, the CPU 71 calculates the difference DT1 in S280. Specifically, in the case where the extrapolation processing described later is not performed in the previous processing cycle, the CPU 71 stores the value representing the difference between the value stored as the wall filter value FV(N) (i.e., the wall filter value in the previous cycle) and the current value as the difference DT1 provided in the RAM 73. On the other hand, in the case where the extrapolation processing was performed in the previous cycle, the CPU 71 stores the value representing the difference between the wall filter value immediately before the start of the extrapolation processing and the current value as the difference DT1.

[0078] Then, the CPU 71 determines in S290 whether the value stored as the difference DT1 is smaller than a preset first threshold value Vth1.

[0079] Here, when the value stored as the difference DT1 is less than the first threshold value Vth1, CPU71 updates the wall filter values ​​FV(N), FV(N-1), FV(N-2), ..., FV(1), and FV(0) in S300. Specifically, first, CPU71 stores the values ​​of the wall filter values ​​FV(N), FV(N-1), ..., and FV(1) as wall filter values ​​FV(N-1), FV(N-2), ..., and FV(0), respectively. Then, CPU71 stores the value calculated by the right side of formula (1) as the wall filter value FV(N). In addition, TV1 in formula (1) is the current value.

[0080] FV(N)=TV1×0.3+FV(N-1)×0.7…(1)

[0081] Then, the CPU 71 initializes the extrapolation counter CT1 in S310 , and ends the filter value calculation process.

[0082] If the value stored as the difference DT1 in S290 is equal to or greater than the first threshold value Vth1, the CPU 71 proceeds to S320.

[0083] Then, when the process moves to S320 , the CPU 71 executes the extrapolation process and ends the filter value calculation process.

[0084] Next, the procedure of the extrapolation process will be described.

[0085] If extrapolation is performed, Figure 5 As shown, the CPU 71 first determines whether the value of the extrapolation counter CT1 is less than a preset second threshold value Vth2 in S410. In this embodiment, the second threshold value Vth2 is set to 10.

[0086] Here, when the value of the extrapolation counter CT1 is less than the second threshold value Vth2, the CPU 71 updates the wall filter values ​​FV(N), FV(N-1), FV(N-2), ..., FV(1), and FV(0) in S420. Specifically, first, the CPU 71 stores the values ​​of the wall filter values ​​FV(N), FV(N-1), ..., and FV(1) as wall filter values ​​FV(N-1), FV(N-2), ..., and FV(0), respectively. Then, the CPU 71 stores the value of the wall filter value FV(N-1) as the wall filter value FV(N).

[0087] Then, the CPU 71 increments the extrapolation counter CT1 by 1 (ie, adds 1) in S430 , thereby terminating the extrapolation process.

[0088] If the value of the extrapolation counter CT1 is greater than the second threshold value Vth2 in S410, the CPU 71 determines in S440 whether the value of the extrapolation counter CT1 is less than a preset third threshold value Vth3. In this embodiment, the third threshold value Vth3 is set to 30.

[0089] Here, when the value of the extrapolation counter CT1 is less than the third threshold value Vth3, CPU71 updates the wall filter values ​​FV(N), FV(N-1), FV(N-2), ..., FV(1), and FV(0) in S450. Specifically, first, CPU71 stores the values ​​of the wall filter values ​​FV(N), FV(N-1), ..., and FV(1) as wall filter values ​​FV(N-1), FV(N-2), ..., and FV(0), respectively. Then, CPU71 stores the value calculated by the right side of formula (2) as the wall filter value FV(N). In addition, MD in formula (2) is a pre-set maximum distance. In the present embodiment, the maximum distance MD is set to a value equivalent to 15m. That is, CPU71 calculates the wall filter value FV(N) using the maximum distance MD as the current value TV1 in formula (1).

[0090] FV(N)=MD×0.3+FV(N-1)×0.7…(2)

[0091] Then, in S460, the CPU 71 increments the extrapolation counter CT1 by 1, thereby terminating the extrapolation process.

[0092] In addition, when the value of the extrapolation counter CT1 in S440 is greater than the third threshold value Vth3, CPU71 updates the wall filter values ​​FV(N), FV(N-1), FV(N-2), ..., FV(1), and FV(0) in S470. Specifically, first, CPU71 stores the values ​​of the wall filter values ​​FV(N), FV(N-1), ..., and FV(1) as wall filter values ​​FV(N-1), FV(N-2), ..., and FV(0), respectively. Then, CPU71 stores the pre-set invalid value as the wall filter value FV(N). In the present embodiment, the invalid value is set to a value equivalent to 100m.

[0093] Then, in S480, the CPU 71 increments the extrapolation counter CT1 by 1, thereby terminating the extrapolation process.

[0094] Then, if the filter value calculation process is completed, Figure 3 As shown, the CPU 71 performs interpolation processing in S60.

[0095] Next, the procedure of the interpolation process will be described.

[0096] If interpolation is performed, Figure 6 As shown, the CPU 71 first determines in S610 whether the right wall has been detected in the past.

[0097] Here, if the right wall was not detected in the past, the CPU 71 ends the interpolation process. On the other hand, if the right wall was detected in the past, the CPU 71 determines in S620 whether the right wall was detected in this processing cycle.

[0098] Here, if the right wall is not detected in this processing cycle, the CPU 71 ends the interpolation process. On the other hand, if the right wall is detected in this processing cycle, the CPU 71 determines in S630 whether the extrapolation process was executed in the previous processing cycle.

[0099] Here, if the extrapolation process was not performed in the previous processing cycle, the CPU 71 ends the interpolation process. On the other hand, if the extrapolation process was performed in the previous processing cycle, the CPU 71 determines in S640 whether the value of the extrapolation counter CT1 is less than a fourth threshold value Vth4 set in advance. In addition, in this embodiment, the fourth threshold value Vth4 is set to 40.

[0100] Here, when the value of the extrapolation counter CT1 is greater than the fourth threshold value Vth4, the CPU 71 ends the interpolation process. On the other hand, when the value of the extrapolation counter CT1 is less than the fourth threshold value Vth4, the CPU 71 calculates the difference DT3 in S650. Specifically, the CPU 71 stores the value indicating the difference between the wall filter value immediately before the start of the extrapolation process and the current value as the difference DT3 provided in the RAM 73.

[0101] Then, the CPU 71 determines in S660 whether the value stored as the difference DT3 is smaller than a fifth threshold value Vth5 set in advance. In the present embodiment, the fifth threshold value Vth5 is set to a value corresponding to 1 m.

[0102] Here, when the value stored as the difference DT3 is greater than the fifth threshold value Vth5, the CPU 71 ends the interpolation process. On the other hand, when the value stored as the difference DT3 is less than the fifth threshold value Vth5, the CPU 71 interpolates the wall filter value during the extrapolation period in S670 and ends the interpolation process. Specifically, the CPU 71 performs linear interpolation using, for example, the wall filter value immediately before the start of the extrapolation process and the wall filter value FV(N), thereby calculating the wall filter value during the extrapolation period.

[0103] For example, Figure 7As shown, period PT1 is a period of wall detection, and the wall filter value varies between 5m and 6m. Period PT2 is a period of extrapolation, and in the first 10 cycles, the wall filter value maintains the previous value. Moreover, if more than 10 cycles, the wall filter value gradually approaches the maximum distance (i.e., 15m). And, if more than 30 cycles, the wall filter value becomes an invalid value. Period PT3 is a period of wall detection, and the wall filter value varies around 6m.

[0104] The interpolation process calculates the wall filter value during the extrapolation period by connecting the wall filter value PF1 immediately before the extrapolation process and the wall filter value PF2 immediately after the extrapolation process is completed with a straight line as indicated by the interpolation straight line CL.

[0105] Then, if the interpolation process is completed, Figure 3 As shown, CPU 71 calculates the wall shape value in S70. Specifically, Figure 8 As shown, CPU 71 uses each position of the estimated position CP(N), CP(N-1), CP(N-2) ..., CP(1), CP(0) of the vehicle constituting the driving trajectory TR of the vehicle from the current time to N cycles ago as a starting point, and sets the position separated to the right by the wall filter values ​​FV(N), FV(N-1), FV(N-2), ..., FV(1), FV(0) along the lateral direction orthogonal to the forward direction as the wall position WP(N), WP(N-1), WP1(N-2), ..., WP(1), WP(0). The wall positions WP(N) to WP1(0) are wall shape values.

[0106] Then, if the processing of S70 is completed, Figure 3 As shown, CPU71 calculates the existence probability of the target in the adjacent lane in S80. Specifically, CPU71 adds the wall shape value calculated in S70 to the adjacent lane probability map calculated in S30 to calculate the existence probability distribution of the target. That is, CPU71 basically calculates the existence probability of the target based on the adjacent lane probability map. However, in the case of the existence of a wall, CPU71 uniformly sets the existence probability of the adjacent lane to 0 for the area outside the wall in the adjacent lane probability map, and the existence probability of the target in this area is 0. Alternatively, CPU71 can also delete the object mark detected outside the wall.

[0107] Then, the CPU 71 determines the existence of the target in the adjacent lane in S90. Specifically, the CPU 71 determines whether the target exists in the adjacent lane based on the target existence probability calculated in S80 and the position information of the detected target. The target adjacent lane existence probability is not calculated only by the value of the current cycle, but by multiplying the past adjacent lane existence probability by the filter value of the forgetting coefficient to calculate the final adjacent lane existence probability.

[0108] For example, when the filtered value of the object existence probability is 70% or more, the CPU 71 determines that the object exists in the adjacent lane. On the contrary, when the filtered value of the object existence probability is less than 70%, the CPU 71 determines that the object does not exist in the adjacent lane.

[0109] Next, CPU71 extracts the alarm object in S100. Specifically, when CPU71 determines in S90 that the target exists in the adjacent lane, it confirms the positional relationship between the target and the vehicle. Moreover, when the positional relationship between the two satisfies the prescribed conditions, CPU71 extracts the target as the alarm object. The prescribed conditions are, for example, at least one of the following first extraction conditions and second extraction conditions. The first extraction condition is that the distance between the vehicle and the target (hereinafter, relative distance) is less than a prescribed distance. The second extraction condition is that the arrival time to the vehicle, inferred from the relative speed detected by the radar device, is less than a prescribed time.

[0110] Then, the CPU 71 executes the alarm output process in S110 and ends the wall calculation process. Specifically, when the CPU 71 extracts the alarm object in S100, it outputs an alarm instruction to the driving assistance ECU 2, and the alarm instruction indicates the output of the alarm indicating the existence of the alarm object. If the driving assistance ECU 2 obtains the alarm instruction, it causes the alarm device 4 to output the alarm of the content indicated by the alarm instruction.

[0111] The wall calculation process executed by the CPU 71 of the radar device 12 is the same as the wall calculation process executed by the CPU 71 of the radar device 11 except that the left wall is used as a target. Therefore, the description of the procedure of the wall calculation process executed by the CPU 71 of the radar device 12 is omitted.

[0112] Fig. 9 The line WF1 of the graph GR1 shown in the figure shows the wall shape when the extrapolation process is not performed when the erroneous detection of the wall occurs. In the portion surrounded by the ellipse EL1, the wall shape is calculated to be close to the vehicle.

[0113] on the other hand, Fig. 9 Line WF2 of graph GR2 shown in the figure shows the wall shape when extrapolation processing is performed when the same wall error detection as in graph GR1 occurs. The wall shape is improved in the portion surrounded by ellipse EL2 arranged at the same position as ellipse EL1.

[0114] Fig. 9 Line WF3 of the graph GR3 shown shows the wall shape when no extrapolation processing is performed when a wall error detection different from the graph GR1 occurs. In the portion surrounded by the ellipse EL3, the wall shape is calculated to be close to the vehicle.

[0115] on the other hand, Fig. 9 The line WF4 of the graph GR4 shown shows the wall shape when the extrapolation process is performed when the same wall error detection as in the graph GR3 occurs. In the portion surrounded by the ellipse EL4 arranged at the same position as the ellipse EL3, the wall shape is not calculated to be close to the vehicle, and the wall shape is improved. However, the wall shape is calculated to be closer to the outside of the actual wall.

[0116] Fig.10 The diagram GR5 shown is Fig. 9 The same as shown in the graph GR4. That is, Fig.10 Line WF5 of graph GR5 shows the wall shape when extrapolation is performed instead of interpolation when the same wall error detection as in graph GR3 occurs. In the portion surrounded by ellipse EL5, the wall shape is calculated to be outside the actual wall.

[0117] on the other hand, Fig.10 The line WF6 of the graph GR6 shown shows the wall shape when the interpolation process is performed when the same wall error detection as in the graph GR5 occurs. The dotted line WF7 of the graph GR6 is the same as the line WF5 of the graph GR5. In the portion surrounded by the ellipse EL6 arranged at the same position as the ellipse EL5, the wall shape is not calculated to be close to the vehicle and is not calculated to be closer to the outside of the actual wall. That is, the wall shape is calculated to be near the position of the actual wall, and the wall shape is improved.

[0118] The radar devices 11 and 12 configured in this way repeatedly determine whether a wall set along the road on which the vehicle is traveling is detected, using a received signal Sr obtained by receiving radar waves transmitted to and reflected in a predetermined detection range around the vehicle. When the radar devices 11 and 12 determine that a wall is detected, they use the received signal Sr to obtain an instantaneous value of the wall distance indicating the distance to the wall.

[0119] The radar devices 11 and 12 calculate a plurality of wall shape values ​​indicating the positions of a plurality of locations on the surface of the wall, using the vehicle's travel trajectory and a plurality of past instantaneous values ​​of wall distances that have been repeatedly acquired.

[0120] The radar devices 11 and 12 determine whether the acquired instantaneous value of the wall distance changes suddenly based on a preset sudden change determination condition. The sudden change determination condition is that the difference DT1 is smaller than the first threshold value Vth1 and the difference DT2 is smaller than the first threshold value Vth1.

[0121] When determining that the instantaneous value of the wall distance has changed suddenly, the radar devices 11 and 12 extrapolate the wall shape value after the instantaneous value of the wall distance has changed suddenly.

[0122] In this way, when the instantaneous value of the wall distance changes suddenly, the radar devices 11 and 12 extrapolate the wall shape value after the instantaneous value of the wall distance changes suddenly. Therefore, in the radar devices 11 and 12, for example, if the situation changes from a situation where there is no other vehicle between the vehicle and the wall to a situation where there is another vehicle between the vehicle and the wall, the instantaneous value of the wall distance changes suddenly, and the wall shape value after the wall distance value changes suddenly is calculated based on the wall shape value before the instantaneous value of the wall distance changes suddenly. In this way, the radar devices 11 and 12 can prevent the wall shape from being calculated to be closer to the vehicle than the actual position of the wall.

[0123] The radar devices 11 and 12 calculate the wall filter value after filtering the instantaneous value of the wall distance, and calculate the multiple wall shape values ​​using the driving trajectory and the multiple wall filter values. Moreover, when the number of extrapolation times (i.e., the value of the extrapolation counter CT1) is less than the preset second threshold value Vth2, the driving assistance ECU2 extrapolates the wall shape value by keeping the current wall filter value as the previous wall filter value. Thus, the radar devices 11 and 12 can prevent the wall shape from being calculated to be closer to the vehicle than the actual wall position.

[0124] When the number of extrapolation is less than the third threshold value Vth3 set larger than the second threshold value Vth2, the radar devices 11 and 12 extrapolate the wall shape value by making the wall filter value close to the preset maximum distance MD. In this way, the radar devices 11 and 12 can prevent the wall shape from being calculated to be closer to the vehicle than the actual wall position.

[0125] When the number of extrapolation times is greater than the third threshold value Vth3, the radar devices 11 and 12 set the wall filter value to an invalid value larger than the maximum distance MD to extrapolate the wall shape value. Thus, the radar devices 11 and 12 can indicate that the calculation result of the wall shape is invalid by the wall shape value.

[0126] The sudden change judgment condition when extrapolation is not performed is that the difference between the instantaneous value of the wall distance this time and the wall filter value last time is greater than the first threshold value Vth1. In addition, the sudden change judgment condition when extrapolation is performed is that the difference between the instantaneous value of the wall distance this time and the wall filter value immediately before the extrapolation is performed is greater than the first threshold value Vth1.

[0127] The radar devices 11 and 12 determine whether a wall is detected. In addition, when the difference between the instantaneous value of the wall distance and the wall filter value immediately before the extrapolation is performed is less than the preset fifth threshold value Vth5, the radar devices 11 and 12 determine that a wall is detected. Moreover, when it is determined that a wall is detected and the extrapolation period during which the extrapolation is performed (i.e., the value of the extrapolation counter CT1) is less than the preset fourth threshold value Vth4, the driving assistance ECU2 interpolates a plurality of wall shape values ​​during the extrapolation period. Thus, the radar devices 11 and 12 can suppress the wall shape from being significantly different from the actual wall position.

[0128] In the above-described embodiment, the radar devices 11 and 12 correspond to the wall shape measuring device, S40 corresponds to the process as the wall distance acquiring unit, and S10 , S20 , S50 , and S70 correspond to the process as the wall shape calculating unit.

[0129] In addition, S280 and S290 correspond to the processing as a sudden change determination unit, and S320 corresponds to the processing as an extrapolation unit.

[0130] In addition, the right wall and the left wall correspond to the wall-like object, the wall distance instantaneous value corresponds to the wall distance value, and the wall filter value FV corresponds to the wall distance filter value.

[0131] The value of the extrapolation counter CT1 corresponds to the number of extrapolation times, the second threshold Vth2 corresponds to the hold determination value, the third threshold Vth3 corresponds to the maximum determination value, the maximum distance MD corresponds to the maximum value, and the first threshold Vth1 corresponds to the sudden change determination value.

[0132] In addition, S650 and S660 are equivalent to the processing as a wall detection judgment unit, S640 and S670 are equivalent to the processing as a period interpolation unit, the value of the extrapolation counter CT1 is equivalent to the extrapolation period, the fourth threshold Vth4 is equivalent to the interpolation judgment time, and the fifth threshold Vth5 is equivalent to the wall detection judgment value.

[0133] [Second embodiment]

[0134] The following, with the attached Figure 1 The second embodiment of the present disclosure will be described together. In the second embodiment, the parts different from the first embodiment will be described. The same reference numerals are given to the common structures.

[0135] The in-vehicle system 1 of the second embodiment is different from the first embodiment in that the interpolation process is changed.

[0136] like Fig.11 As shown, the interpolation process of the second embodiment is different from that of the first embodiment in that S640 is omitted and S632 and S634 are added.

[0137] That is, when the extrapolation process was executed in the last processing cycle in S630, the CPU 71 calculates the travel distance ML during the extrapolation period in S632. Specifically, the CPU 71 confirms the extrapolation start timing for starting the extrapolation process based on the value of the extrapolation counter CT1. In addition, the CPU 71 tracks the travel trajectory TR from the estimated position of the vehicle at the extrapolation start timing to the estimated position of the vehicle at the current time CP (N), and calculates the tracked distance. Then, the CPU 71 stores the value representing the calculated distance as the travel distance ML provided in the RAM 73.

[0138] Next, the CPU 71 determines in S634 whether the value stored as the driving distance ML is less than the sixth threshold value Vth6 set in advance. Here, if the value stored as the driving distance ML is greater than the sixth threshold value Vth6, the CPU 71 ends the extrapolation process. On the other hand, if the value stored as the driving distance ML is less than the sixth threshold value Vth6, the CPU 71 moves to S650.

[0139] The radar devices 11 and 12 configured in this way determine whether a wall is detected. Furthermore, when it is determined that a wall is detected and the travel distance ML of the vehicle during the extrapolation period is less than a preset sixth threshold value Vth6, the radar devices 11 and 12 interpolate a plurality of wall shape values ​​during the extrapolation period. Thus, the radar devices 11 and 12 can suppress a large difference between the wall shape and the actual wall position.

[0140] In the above-described embodiment, S632 , S634 , and S670 correspond to the processing as the distance interpolation unit, and the sixth threshold value Vth6 corresponds to the interpolation determination distance.

[0141] [Third Embodiment]

[0142] The following, with the attached Figure 1 The third embodiment of the present disclosure will be described together. In the third embodiment, the parts different from the second embodiment will be described. The same reference numerals are given to the common structures.

[0143] The in-vehicle system 1 of the third embodiment is different from the second embodiment in that the interpolation process is changed.

[0144] like Fig.12 As shown, the interpolation process of the third embodiment is different from that of the second embodiment in that S640 is added.

[0145] That is, when the value stored as the travel distance ML in S634 is smaller than the sixth threshold value Vth6, the CPU 71 proceeds to S640.

[0146] If the process moves to S640, the CPU 71 determines whether the value of the extrapolation counter CT1 is less than the fourth threshold value Vth4. Here, if the value of the extrapolation counter CT1 is greater than the fourth threshold value Vth4, the CPU 71 ends the interpolation process. On the other hand, if the value of the extrapolation counter CT1 is less than the fourth threshold value Vth4, the CPU 71 moves to S650.

[0147] The radar devices 11 and 12 configured in this way determine whether a wall is detected. Furthermore, when it is determined that a wall is detected, and the extrapolation period is less than a preset fourth threshold value Vth4, and the travel distance ML of the vehicle during the extrapolation period is less than a preset sixth threshold value Vth6, the radar devices 11 and 12 interpolate a plurality of wall shape values ​​during the extrapolation period. Thus, the radar devices 11 and 12 can suppress a large difference between the wall shape and the actual wall position.

[0148] In the above-described embodiment, S632 , S634 , S640 , and S670 correspond to the processing as the period distance interpolation unit.

[0149] As mentioned above, although one embodiment of the present disclosure has been described, the present disclosure is not limited to the above embodiment, and can be implemented with various modifications.

[0150] [Modification 1]

[0151] For example, in the above embodiment, the object target is detected by using the FMCW method, but the detection method is not limited thereto. For example, the object target may also be detected by using a dual-frequency CW method or an FCM method.

[0152] The processing unit 70 and the method thereof described in the present disclosure may also be implemented by a special-purpose computer, which is provided by constituting a processor and a memory programmed to perform one or more functions embodied by a computer program. Alternatively, the processing unit 70 and the method thereof described in the present disclosure may also be implemented by a special-purpose computer, which is provided by constituting a processor composed of one or more special-purpose hardware logic circuits. Alternatively, the processing unit 70 and the method thereof described in the present disclosure may also be implemented by one or more special-purpose computers, which are constituted by a combination of a processor and a memory programmed to perform one or more functions and a processor composed of one or more hardware logic circuits. In addition, a computer program may also be stored as an instruction executed by a computer in a non-migratable tangible recording medium that can be read by a computer. In the method for implementing the functions of each part included in the processing unit 70, it is not necessarily necessary to include software, and all of its functions may also be implemented using one or more hardware.

[0153] It is also possible to realize multiple functions of one constituent element of the above-mentioned embodiment by multiple constituent elements, or realize one function of one constituent element by multiple constituent elements. In addition, it is also possible to realize multiple functions of multiple constituent elements by one constituent element, or realize one function realized by multiple constituent elements by one constituent element. In addition, it is also possible to omit a part of the structure of the above-mentioned embodiment. In addition, it is also possible to add or replace at least a part of the structure of the above-mentioned embodiment relative to the structure of other above-mentioned embodiments.

[0154] In addition to the above-mentioned radar devices 11 and 12, the present disclosure can also be implemented in various ways such as a system with the radar devices 11 and 12 as components, a program for causing a computer to function as the radar devices 11 and 12, a non-migrating physical recording medium such as a semiconductor memory recording the program, a wall shape measurement method, etc.

Claims

1. A wall shape measuring device, which is a wall shape measuring device mounted on a vehicle, wherein: have: a wall distance acquisition unit configured to: repeatedly determine whether a wall-like object provided along a road on which the vehicle is traveling is detected, using a received signal obtained by receiving a radar wave transmitted to and reflected from a predetermined detection range around the vehicle, and, if it is determined that the wall-like object is detected, to acquire a wall distance value indicating a distance to the wall-like object, using the received signal; a wall shape calculation unit configured to calculate a plurality of wall shape values ​​indicating positions of a plurality of locations on a surface of the wall-like object using a travel trajectory of the vehicle and a plurality of past wall distance values ​​repeatedly acquired by the wall distance acquisition unit; a sudden change determination unit configured to determine whether the wall distance value acquired by the wall distance acquisition unit changes suddenly based on a preset sudden change determination condition; as well as an extrapolation unit configured to, when the sudden change determination unit determines that the wall distance value has changed suddenly, extrapolate the wall shape value after the sudden change determination unit determines that the wall distance value has changed suddenly, The wall shape calculation unit calculates a wall distance filter value obtained by filtering the wall distance value acquired by the wall distance acquisition unit, and calculates a plurality of the wall shape values ​​using the travel trajectory and the plurality of the wall distance filter values. When the number of times the extrapolation unit continuously extrapolates the wall shape value is less than a preset retention judgment value, the extrapolation unit extrapolates the wall shape value by maintaining the current wall distance filter value as the previous wall distance filter value, When the number of extrapolation times is smaller than a maximum determination value set larger than the hold determination value, the extrapolation unit extrapolates the wall shape value by bringing the wall distance filter value closer to a preset maximum value.

2. The wall shape measuring device according to claim 1, wherein: When the number of extrapolation times is equal to or greater than the maximum determination value, the extrapolation unit extrapolates the wall shape value by setting the wall distance filter value to an invalid value set to be larger than the maximum value.

3. The wall shape measuring device according to claim 1 or 2, wherein: The wall shape calculation unit calculates a wall distance filter value obtained by filtering the wall distance value acquired by the wall distance acquisition unit, and calculates a plurality of the wall shape values ​​using the travel trajectory and the plurality of the wall distance filter values. The sudden change determination condition when the extrapolation unit does not perform extrapolation is that a difference between the current wall distance value and the previous wall distance filter value is equal to or greater than a preset sudden change determination value.

4. The wall shape measuring device according to claim 1 or 2, wherein: The wall shape calculation unit calculates a wall distance filter value obtained by filtering the wall distance value acquired by the wall distance acquisition unit, and calculates a plurality of the wall shape values ​​using the travel trajectory and the plurality of the wall distance filter values. The sudden change determination condition when the extrapolation unit performs extrapolation is that a difference between the current wall distance value and the wall distance filter value immediately before the extrapolation by the extrapolation unit is equal to or greater than a preset sudden change determination value.

5. The wall shape measuring device according to claim 1 or 2, wherein: The wall shape measuring device comprises: a wall detection determination unit configured to determine whether the wall-like object is detected; and The period interpolation unit is configured to interpolate a plurality of the wall shape values ​​in the extrapolation period when the wall detection judgment unit judges that the wall-shaped object is detected and the extrapolation period during which the extrapolation is performed by the extrapolation unit is shorter than a preset interpolation judgment time.

6. The wall shape measuring device according to claim 1 or 2, wherein: The wall shape measuring device comprises: a wall detection determination unit configured to determine whether the wall-like object is detected; and A distance interpolation unit is configured to interpolate multiple wall shape values ​​during the extrapolation period when the wall detection judgment unit determines that the wall-shaped object is detected and the driving distance of the vehicle during the extrapolation period of the extrapolation performed by the extrapolation unit is less than a preset interpolation judgment distance.

7. The wall shape measuring device according to claim 1 or 2, wherein: The wall shape measuring device comprises: a wall detection determination unit configured to determine whether the wall-like object is detected; and A period distance interpolation unit is configured to interpolate multiple wall shape values ​​during the extrapolation period when the wall detection judgment unit determines that the wall-shaped object is detected, the extrapolation period of the extrapolation unit is less than a preset interpolation judgment time, and the travel distance of the vehicle during the extrapolation period is less than a preset interpolation judgment distance.

8. The wall shape measuring device according to claim 5, wherein: The wall shape calculation unit calculates a wall distance filter value obtained by filtering the wall distance value acquired by the wall distance acquisition unit, and calculates a plurality of the wall shape values ​​using the travel trajectory and the plurality of the wall distance filter values. The wall detection determination unit determines that the wall-like object is detected when the difference between the current wall distance value and the wall distance filter value immediately before the extrapolation by the extrapolation unit is performed is smaller than a preset wall detection determination value.

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