Travel state determination device and travel state determination method

Abstract

To suppress erroneous determination on wobble of a vehicle.SOLUTION: A travel state determination device 30 includes: an identification section 322 for identifying a first distance between a position of a road zone line extracted from a photographed image and a position of a vehicle; a calculation section 323 for calculating the maximum lateral displacement indicating a difference between the maximum value of the first distance and the minimum value of the first distance from the plurality of first distances identified by the identification section 322 in a period between a time before a first time from a predetermined time and the predetermined time, so as to calculate a statistic of the plurality of maximum lateral displacements in a period between a time before a second time longer than the first time from the predetermined time and the predetermined time; and a determination section 324 for determining existence of wobble of the vehicle when a division value, which is obtained by dividing the statistic calculated at the predetermined time by the statistic calculated at the time before a unit time from the predetermined time, is equal to or more than a threshold.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a driving condition determining device and a driving condition determining method. [Background technology]

[0002] The alertness estimation device of Patent Document 1 judges vehicle sway based on an evaluation value calculated from the sum of power obtained by frequency-converting the amount of vehicle widthwise movement (i.e., lateral displacement) detected at a specified time and the maximum value of power corresponding to a specified frequency at a specified time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-154345 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the past, when the detected lateral displacement was large, it was not possible to distinguish whether the vehicle was judged to be swaying due to a decrease in the wakefulness of a driver who drives with small lateral displacement when awake, or whether the vehicle was judged to be swaying due to a driver who drives with large lateral displacement even when awake. As a result, there was a problem that, depending on the driver, the vehicle was judged to be swaying even when it was not driven in a way that caused the vehicle to sway.

[0005] The present invention has been made in consideration of these points, and has an object to suppress erroneous determination of vehicle sway. [Means for solving the problem]

[0006] A driving condition determination device according to a first aspect of the present invention has an identification unit that determines a first distance between a position of a road dividing line extracted from an captured image and a position of a vehicle, a calculation unit that calculates a maximum lateral displacement indicating the difference between a maximum value of the first distances and a minimum value of the first distances from a plurality of the first distances determined by the identification unit at a predetermined time from a time that is one hour before the predetermined time, and calculates statistics of the plurality of maximum lateral displacements at the predetermined time from a time that is a second time before the predetermined time that is longer than the first time, and a determination unit that determines that the vehicle is swaying if a divided value obtained by dividing the statistics calculated at the predetermined time by the statistics calculated at a time that is a unit time before the predetermined time is equal to or greater than a threshold value.

[0007] The identification unit may identify the first distance every time the unit time elapses, and the calculation unit may calculate the maximum lateral displacement and the statistics every time the unit time elapses.

[0008] The determination unit may identify the threshold corresponding to the distance between the front and rear wheel axles of the vehicle by referring to a threshold corresponding to the distance stored in a memory unit, and the threshold may indicate a larger value when the distance between the front and rear wheel axles of the vehicle is a first axle distance than when the distance between the front and rear wheel axles of the vehicle is a second axle distance that is longer than the first axle distance.

[0009] The determination unit may identify the threshold value corresponding to the vehicle width by referring to a threshold value corresponding to the vehicle width of the vehicle stored in a memory unit, and the threshold value may indicate a larger value when the vehicle width of the vehicle is a first vehicle width than when the vehicle width of the vehicle is a second vehicle width that is wider than the first vehicle width.

[0010] The determination unit may not determine whether or not the vehicle is swaying when the vehicle speed is less than a predetermined vehicle speed.

[0011] The vehicle further includes a warning unit that warns a driver of the vehicle of the swaying of the vehicle when the judgment unit determines that the vehicle is swaying, and the warning unit may not warn the driver of the vehicle of the swaying of the vehicle when the vehicle speed is less than the predetermined vehicle speed.

[0012] The vehicle may further include a memory unit that stores the maximum lateral displacement and the statistics calculated by the calculation unit each time the unit time elapses, and the determination unit may erase the maximum lateral displacement and the statistics stored in the memory unit when the vehicle is stopped for a predetermined time.

[0013] The determination unit may determine that the vehicle is swaying when at least one of the states in which the maximum lateral displacement calculated each time the unit time elapses is greater than or equal to a predetermined maximum lateral displacement, or the state in which the statistical quantity calculated each time the unit time elapses is greater than or equal to a predetermined statistical quantity, occurs for a predetermined percentage or more from a time three hours before the predetermined time to the predetermined time.

[0014] The determination unit may identify a predetermined ratio corresponding to the distance between the front and rear wheel axles of the vehicle by referring to a predetermined ratio stored in a memory unit, and the predetermined ratio may indicate a larger value when the distance between the front and rear wheel axles of the vehicle is a first axle distance than when the distance between the front and rear wheel axles of the vehicle is a second axle distance that is longer than the first axle distance.

[0015] The determination unit may identify a predetermined percentage corresponding to the vehicle width of the vehicle by referring to a predetermined percentage stored in a memory unit, and the predetermined percentage may indicate a larger value when the vehicle width of the vehicle is a first vehicle width than when the vehicle width of the vehicle is a second vehicle width that is wider than the first vehicle width.

[0016] The identification unit may determine the first distance by subtracting a third distance between the position of the imaging device and a side position of the vehicle or a center position of the vehicle in the vehicle width direction of the imaging device from a second distance between the position of the imaging device and a road dividing line provided in the vehicle width direction, which is identified from the image captured by the imaging device equipped on the vehicle.

[0017] A driving condition determination method according to a second aspect of the present invention includes an identification step executed by a computer to identify a first distance between the position of a road dividing line extracted from a captured image and the position of a vehicle; a calculation step to calculate a maximum lateral displacement indicating the difference between the maximum value of the first distances and the minimum value of the first distances from the multiple first distances identified in the identification step from a time that is one hour before a predetermined time to the predetermined time, and to calculate statistics of the multiple maximum lateral displacements at the predetermined time from a time that is a second time before the predetermined time that is longer than the first time; and a determination step to determine that the vehicle is swaying if a divided value obtained by dividing the statistics calculated at the predetermined time by the statistics calculated at a time that is a unit time before the predetermined time is equal to or greater than a threshold value. Effect of the Invention

[0018] According to the present invention, it is possible to suppress erroneous determination of vehicle sway. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a diagram for explaining an overview of a vehicle S according to the present embodiment. [Diagram 2] 1 is a diagram for explaining the position of an imaging device 11 and the positions of road dividing lines. [Diagram 3] 10 is a diagram for explaining an operation for determining swaying of a vehicle S. FIG. [Figure 4] 4 is a diagram showing an example of a processing sequence in the traveling condition determination device 30. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] <Overview of Vehicle S> Fig. 1 is a diagram for explaining an overview of a vehicle S according to this embodiment. The vehicle S shown in Fig. 1 includes a speed sensor 10, an imaging device 11, a display unit 20, a sound output unit 21, and a driving state determination device 30. The vehicle S has a function of determining whether the vehicle S is running while swaying based on the distance between the position of a road dividing line (e.g., a white line) of a road on which the vehicle S runs and the position of the vehicle S. The swaying of the vehicle S determined by the vehicle S in this embodiment is, for example, swaying caused by a driver with a reduced state of wakefulness (as an example, swaying of the vehicle S due to drowsy driving).

[0021] The speed sensor 10 is a sensor for detecting the speed of the vehicle S. The imaging device 11 is a camera such as a monocular camera, and is provided, for example, on the upper front part of the vehicle S. Every time a unit time (for example, 0.1 second) elapses, the imaging device 11 identifies the distance between the position of the imaging device 11 and the position of the road dividing line on the road on which the vehicle S is traveling, based on a captured image of the road dividing line.

[0022] The display unit 20 is a display that displays information such as speed, remaining fuel, time, or temperature, and displays a warning image or warning lamp if it is determined that the vehicle S is running erratically. The display unit 20 is provided on the instrument panel of the vehicle S, but may be provided on an information terminal used by the driver. The sound output unit 21 is a speaker that outputs a warning sound if it is determined that the vehicle S is running erratically. The sound output unit 21 is provided, for example, around the instrument panel of the vehicle S.

[0023] When the driving condition determination device 30 determines that the vehicle S is traveling unsteadily based on the distance between the position of the imaging device 11 and the position of the vehicle S, which is specified by the imaging device 11, it executes a process of displaying a warning image or warning lamp on the display unit 20 and emitting a warning sound from the sound output unit 21. The driving condition determination device 30 may have a housing including electronic components, or may be a printed circuit board on which electronic components are mounted.

[0024] Incidentally, the swaying of the vehicle S can be determined based on the amount of change in the distance between the position of the imaging device 11 and the position of the road dividing line, which is specified by the imaging device 11 every time a unit time has passed. The amount of change is, for example, the difference between the distance between the position of the imaging device 11 and the position of the road dividing line, which is specified by the imaging device 11 at a predetermined time, and the distance between the position of the imaging device 11 and the position of the road dividing line, which is specified by the imaging device 11 at a time unit time before the predetermined time, and is so-called lateral displacement. As an example, the predetermined time is the current time or the time immediately before the current time. That is, every time a unit time has passed, it is determined whether the amount of change is greater than a predetermined value, and if the amount of change is greater than the predetermined value, it can be determined that the vehicle S is running swaying. However, in this case, it is not possible to distinguish whether the lateral displacement is greater due to a decrease in the awake state of a driver who drives with small lateral displacement in an awake state, or whether the lateral displacement is greater due to driving by a driver who drives with large lateral displacement even in an awake state.

[0025] Therefore, the traveling condition determination device 30 calculates, each time a unit time has elapsed, a difference between the maximum and minimum values ​​of the distance between the position of the road dividing line and the position of the vehicle S, which is determined from a time from the predetermined time to a first time (e.g., 10 seconds) before the predetermined time (hereinafter referred to as "maximum lateral displacement"). Then, each time a unit time has elapsed, the traveling condition determination device 30 calculates a statistical amount (e.g., average value) of the multiple maximum lateral displacements calculated from the predetermined time to a second time (e.g., 120 seconds) before the predetermined time. Furthermore, each time a unit time has elapsed, the traveling condition determination device 30 calculates a divided value (hereinafter sometimes referred to as "increase rate") by dividing the statistical amount calculated at the predetermined time by the statistical amount calculated at the time unit time before the predetermined time. If the increase rate is equal to or greater than a threshold value, the traveling condition determination device 30 determines that the vehicle S is swaying.

[0026] By operating the driving condition determination device 30 as described above, when the driver is awake but driving with a large lateral displacement, the maximum lateral displacement continues to be large, and the statistical amount also continues to be large, so the increase rate becomes less than the threshold value, and it can be determined that the vehicle S is not swaying. As a result, when it is determined that the vehicle S is swaying, the probability that the swaying of the vehicle S is caused by the driver being driven by a driver with a reduced level of wakefulness increases, so it is possible to suppress erroneous determination of the swaying of the vehicle S. The configuration and operation of the traveling condition determination device 30 will be described in detail below.

[0027] <Configuration of the driving condition determination device 30> The traveling condition determination device 30 includes a storage unit 31 and a control unit 32. The control unit 32 includes an acquisition unit 321, an identification unit 322, a calculation unit 323, a determination unit 324, and a warning unit 325.

[0028] The storage unit 31 includes a storage medium such as a read only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), or a solid state drive (SSD). The storage unit 31 stores a program executed by the control unit 32. The storage unit 31 stores various types of information for the control unit 32 to determine the swaying of the vehicle S.

[0029] The control unit 32 is, for example, a processor such as a CPU (Central Processing Unit) or an ECU (Electronic Control Unit). The control unit 32 executes a program stored in the storage unit 31 to function as an acquisition unit 321, an identification unit 322, a calculation unit 323, a determination unit 324, and a warning unit 325. The control unit 32 may be configured with one processor, or may be configured with multiple processors or a combination of one or more processors and an electronic circuit. The configuration of each unit realized by the control unit 32 will be described below.

[0030] The acquisition unit 321 acquires the vehicle speed of the vehicle S detected by the speed sensor 10. The acquisition unit 321 acquires the vehicle speed of the vehicle S, for example, every time a unit time elapses. The acquisition unit 321 stores the vehicle speed detected by the speed sensor 10 in the storage unit 31 in association with the time acquired from the speed sensor 10. The acquisition unit 321 acquires the distance between the position of the imaging device 11 and the position of the road dividing line on the road on which the vehicle S is traveling, which is specified by the imaging device 11, every time a unit time elapses. The unit time is, for example, 0.1 seconds. The acquisition unit 321 stores the distance acquired from the imaging device 11 in association with the time acquired from the imaging device 11 in the storage unit 31.

[0031] FIG. 2 is a diagram for explaining the position of the imaging device 11 and the position of the road dividing line. In FIG. 2, the imaging device 11, the vehicle S, the road dividing line WL provided on the left side of the traveling direction of the vehicle S, and the road dividing line WR provided on the right side of the traveling direction of the vehicle S are shown. In FIG. 2, the imaging device 11 is installed in the center of the vehicle S in the vehicle width direction, but may be installed in a different position. In this embodiment, an operation in which the imaging device 11 specifies the position of the road dividing line WL will be described. In FIG. 2, the acquisition unit 321 acquires a distance L2 between the position of the road dividing line WL provided in the vehicle width direction of the vehicle S and the position of the imaging device 11. The acquisition unit 321 may acquire flag information indicating that the distance L2 is a distance corresponding to the road dividing line WL of the road dividing line WL or the road dividing line WR, together with the distance L2.

[0032] The identification unit 322 identifies a distance L1 between the position of the road dividing line WL extracted from the captured image by the imaging device 11 and the position of the vehicle S. The position of the vehicle S is, for example, the position of the side of the vehicle S. The identification unit 322 identifies the distance L1, for example, every time a unit time elapses. The identification unit 322 acquires, for example, from the acquisition unit 321, a distance L2 between the position of the road dividing line WL provided in the vehicle width direction of the vehicle S identified from the captured image captured by the imaging device 11 and the position of the imaging device 11. Then, the identification unit 322 identifies the distance L1 by subtracting a distance L3 between the position of the imaging device 11 and the position of the left side of the vehicle S in the vehicle width direction of the imaging device 11 with respect to the traveling direction from the distance L2. The distance L3 is stored in the storage unit 31. In addition, the distance L3 is not limited to the distance between the position of the imaging device 11 and the position of the left side of the vehicle S. The distance L3 may be, for example, the distance between the position of the imaging device 11 and the center position of the vehicle S.

[0033] The calculation unit 323 calculates a maximum lateral displacement indicating a difference between the maximum value of the distance L1 and the minimum value of the distance L1 from a plurality of distances L1 identified by the identification unit 322 from a time that is one hour before the predetermined time to a predetermined time. The first time is a time during which the maximum lateral displacement can be calculated at a period corresponding to a frequency in the vicinity of 0.1 Hz, and is, for example, 10 seconds. The calculation unit 323 calculates the maximum lateral displacement, for example, every time a unit time elapses.

[0034] FIG. 3 is a diagram for explaining the operation of determining the sway of the vehicle S. FIG. 3(a) shows the distance L1 for each time. FIG. 3(b) shows the maximum lateral displacement for each time. FIG. 3(c) shows the statistics for each time. FIG. 3(d) shows the increase rate for each time. The horizontal axes of FIG. 3(a), FIG. 3(b), FIG. 3(c) and FIG. 3(d) show time. The vertical axis of FIG. 3(a) shows the distance L1, the vertical axis of FIG. 3(b) shows the maximum lateral displacement, the vertical axis of FIG. 3(c) shows the statistics, and the vertical axis of FIG. 3(d) shows the increase rate. In FIG. 3(d), the threshold value DT is shown. The statistics shown in FIG. 3(c) and the increase rate and threshold value DT shown in FIG. 3(d) will be described later.

[0035] For example, at time T2 shown in Fig. 3(a), the calculation unit 323 calculates the maximum lateral displacement H0 shown in Fig. 3(b) from a plurality of distances L1 identified by the determination unit 322 from time T0, which is one hour before time T2, to time T2. Next, at time T3, which is a unit time after time T2 shown in Fig. 3(a), the calculation unit 323 calculates the maximum lateral displacement H1 shown in Fig. 3(b) from a plurality of distances L1 identified by the determination unit 322 from time T1, which is one hour before time T3, to time T3. The calculation unit 323 repeats the above operation every time a unit time elapses. The calculation unit 323 stores the calculated maximum lateral displacement in the storage unit 31.

[0036] It is known that the period during which the lateral displacement of the vehicle S (i.e., the amount of change between the distance L1 at a predetermined time and the distance L1 at the time unit time before the predetermined time) increases due to driving by a driver with a decreased state of alertness is approximately 10 seconds. Therefore, by the calculation unit 323 calculating the maximum lateral displacement in a first time (e.g., 10 seconds) every time a unit time elapses as described above, the determination unit 324 can easily determine the swaying of the vehicle S caused by the decreased state of alertness of the driver.

[0037] The calculation unit 323 calculates statistics of a plurality of maximum lateral displacements from a time a second time before the predetermined time, which is longer than the first time, to the predetermined time. The calculation unit 323 calculates the statistics, for example, every time a unit time elapses. The second time is a time determined by an experiment or a simulation, for example, 120 seconds. The statistics is any one of an average value, a median value, a maximum value, or a value indicating a frequency characteristic calculated using FFT (Fast Fourier Transform).

[0038] For example, at time T2 shown in FIG. 3(b), the calculation unit 323 calculates a statistic A0 shown in FIG. 3(c) from a plurality of maximum lateral displacements calculated by the calculation unit 323 from time T4, which is the second hour before time T2, to time T2. Next, at time T3, which is a unit time after time T2 shown in FIG. 3(b), the calculation unit 323 calculates a statistic A1 shown in FIG. 3(c) from a plurality of maximum lateral displacements calculated by the calculation unit 323 from time T5, which is the second hour before time T3, to time T3. The calculation unit 323 repeats the above operation every time a unit time elapses. The calculation unit 323 stores the calculated statistic in the storage unit 31.

[0039] Even though the driver is awake, the driver may temporarily erroneously perform an operation to increase the steering angle, and immediately after that, reduce the steering angle. When such an erroneous operation occurs, the maximum lateral displacement calculated in the first time period including the time when the erroneous operation occurred becomes large. Therefore, the calculation unit 323 calculates a statistic (e.g., an average value or a median value) of the maximum lateral displacement in the second time period as described above, so that the determination unit 324 can determine the sway of the vehicle S using a value that is less influenced by the momentarily large maximum lateral displacement. As a result, the determination unit 324 can easily exclude the sway of the vehicle S caused by an erroneous operation by the driver who is awake.

[0040] The determination unit 324 determines that the vehicle S is swaying when the increase rate, which is a divided value obtained by dividing a statistical amount calculated at a predetermined time by a statistical amount calculated at a time unit time before the predetermined time, is equal to or greater than a threshold value DT. The threshold value DT is a value determined by an experiment or simulation in order to reduce the probability of issuing a false alarm, and is, for example, 1.5. As an example, the determination unit 324 determines whether or not the vehicle S is swaying each time a unit time elapses.

[0041] For example, at time T2 shown in FIG. 3(c), the determination unit 324 calculates the increase rate D0 shown in FIG. 3(d) by dividing the statistic A0 calculated by the calculation unit 323 at time T2 by the statistic A2 calculated by the calculation unit 323 at time T6, which is a unit time before time T2. The determination unit 324 determines that the vehicle S is not swaying because the increase rate D0 is less than the threshold value DT. Next, at time T3 shown in FIG. 3(c), the determination unit 324 calculates the increase rate D1 shown in FIG. 3(d) by dividing the statistic A1 calculated by the calculation unit 323 at time T3 by the statistic A0 calculated by the calculation unit 323 at time T2, which is a unit time before time T3. The determination unit 324 determines that the vehicle S is swaying because the increase rate D1 is equal to or greater than the threshold value DT.

[0042] By operating the determination unit 324 in this manner, when a driver who is prone to causing the vehicle S to sway even when in an awake state is driving, the maximum lateral displacement statistics will continue to be large, so the rate of increase will be less than the threshold value DT, and it can be determined that the vehicle S is not swaying. As a result, it becomes easier to determine swaying of the vehicle S caused by a decrease in the driver's state of wakefulness, and erroneous determination of swaying of the vehicle S can be suppressed.

[0043] Incidentally, the distance between the front and rear wheel axles (so-called wheelbase) and the vehicle width of the vehicle S differ depending on the type of the vehicle S. And since the stability of the vehicle S during driving differs depending on the length of the wheelbase or the vehicle width, even if the driver performs the same operation on the same lane, the maximum lateral displacement, statistics, and rate of increase differ depending on the type of the vehicle S. Therefore, the determination unit 324 may specify the value of the threshold value DT shown in FIG. 3(d) based on at least one of the wheelbase and the vehicle width.

[0044] The determination unit 324, for example, identifies the threshold value DT corresponding to the wheelbase of the vehicle S by referring to the threshold value DT corresponding to the wheelbase stored in the storage unit 31. Since the shorter the wheelbase of the vehicle S, the lower the stability. The threshold value DT stored in the storage unit 31 indicates a larger value as the wheelbase becomes shorter. For example, when the wheelbase of the vehicle S has a first axle distance, the threshold value DT indicates a larger value than when the wheelbase has a second axle distance longer than the first axle distance. When the wheelbase is divided into a plurality of ranges, the threshold value DT may be a value corresponding to each range. For example, the threshold value DT indicates a larger value as the range indicates a shorter value.

[0045] As an example, the determination unit 324 identifies the wheelbase of the vehicle S by referring to the vehicle information stored in the storage unit 31, and identifies a threshold value DT corresponding to the wheelbase from among the multiple threshold values ​​DT stored in the storage unit 31. Then, the determination unit 324 determines whether the calculated increase rate is equal to or greater than the identified threshold value DT, thereby determining the sway of the vehicle S. By the determination unit 324 operating in this manner, it is possible to eliminate the need to store the threshold value DT corresponding to the wheelbase for each vehicle S in the storage unit 31. Furthermore, the determination unit 324 can determine the sway of the vehicle S in consideration of the stability of the vehicle S based on the wheelbase, thereby improving the accuracy of the determination.

[0046] Furthermore, the determination unit 324 identifies the threshold value DT corresponding to the vehicle width of the vehicle S, for example, by referring to the threshold value DT corresponding to the vehicle width of the vehicle S stored in the storage unit 31. Since the vehicle S is less stable as the vehicle width is narrower, the threshold value DT stored in the storage unit 31 indicates a larger value as the vehicle width is narrower. For example, the threshold value DT indicates a larger value when the vehicle width of the vehicle S is a first vehicle width than when the vehicle width of the vehicle S is a second vehicle width that is wider than the first vehicle width. When the vehicle width is divided into a plurality of ranges, the threshold value DT may be a value corresponding to each range. For example, the threshold value DT indicates a larger value as the range indicates a narrower value.

[0047] As an example, the determination unit 324 identifies the vehicle width of the vehicle S by referring to the vehicle information stored in the storage unit 31, and identifies a threshold value DT corresponding to the vehicle width from among the multiple threshold values ​​DT stored in the storage unit 31. Then, the determination unit 324 determines whether the calculated increase rate is equal to or greater than the identified threshold value DT, thereby determining the swaying of the vehicle S. By the determination unit 324 operating in this manner, it is possible to eliminate the need to store the threshold value DT corresponding to the vehicle width for each vehicle S in the storage unit 31. Furthermore, the determination unit 324 can determine the swaying of the vehicle S in consideration of the stability of the vehicle S based on the vehicle width, thereby improving the accuracy of the determination.

[0048] The driver's wakefulness is more likely to decrease on a lane with few branching points and high speed driving, such as an expressway or a trunk road, than on a lane with many branching points and low speed driving, such as an ordinary road. Therefore, the determination unit 324 may determine the swaying of the vehicle S when the vehicle speed of the vehicle S is equal to or higher than a predetermined vehicle speed. The predetermined vehicle speed is, for example, 60 kilometers per hour. For example, when the vehicle speed of the vehicle S acquired by the acquisition unit 321 from the speed sensor 10 is equal to or higher than the predetermined vehicle speed, the determination unit 324 determines whether or not the vehicle S is swaying, and does not determine whether or not the vehicle S is swaying, when the vehicle speed of the vehicle S is lower than the predetermined vehicle speed. By operating in this manner, the determination unit 324 can determine the swaying of the vehicle S only when there is a high need to determine the swaying of the vehicle S, thereby reducing the processing load.

[0049] For example, when vehicle S is stopped due to a traffic light or traffic congestion, calculation unit 323 calculates the maximum lateral displacement and the statistics based on distance L1 identified by identification unit 322 every time a unit time elapses, and stores them in storage unit 31. Then, when vehicle S starts to move due to a change in the traffic light or the end of traffic congestion, the maximum lateral displacement and the statistics immediately after starting to move include values ​​when vehicle S stopped, which reduces the accuracy of determining the sway of vehicle S. Therefore, determination unit 324 may erase the maximum lateral displacement and the statistics stored in storage unit 31 when vehicle S stops.

[0050] For example, when the determination unit 324 determines that the vehicle speed acquired by the acquisition unit 321 from the speed sensor 10 is 0, the determination unit 324 determines the time when the acquisition unit 321 acquired the vehicle speed indicating 0. When the vehicle speed acquired by the acquisition unit 321 is 0 for a predetermined time from the specified time, the determination unit 324 determines that the vehicle S has been stopped for a predetermined time. The predetermined time is, for example, a time corresponding to the first time (10 seconds). When the vehicle S has been stopped for a predetermined time, the determination unit 324 erases the maximum lateral displacement and the statistics calculated by the calculation unit 323 every time a unit time elapses, which are stored in the storage unit 31. By operating in this manner, the determination unit 324 can determine the sway of the vehicle S by excluding the maximum lateral displacement and the statistics based on the distance L1 when the vehicle S is stopped, and therefore the likelihood of erroneously determining the sway of the vehicle S can be reduced.

[0051] When the determination unit 324 determines that the vehicle S is swaying, the warning unit 325 executes at least one of displaying a warning image or a warning lamp, and emitting a warning sound, thereby warning the driver of the swaying of the vehicle S. For example, when the determination unit 324 determines that the vehicle S is swaying, the warning unit 325 causes the display unit 20 to display a warning image or a warning lamp. When the determination unit 324 determines that the vehicle S is swaying, the warning unit 325 causes the sound output unit 21 to emit a warning sound.

[0052] For example, when the speed of the vehicle S is equal to or higher than a predetermined speed, the determination unit 324 determines that the vehicle S is swaying, and the warning unit 325 issues a warning to the driver. On the other hand, when the speed of the vehicle S is lower than the predetermined speed, the warning unit 325 does not warn the driver of the swaying of the vehicle S even if the determination unit 324 determines that the vehicle S is swaying. By operating the warning unit 325 in this manner, it is possible to suppress the issuance of a warning on lanes where the wakefulness state is unlikely to decrease, such as general roads with many branching points and where the driver is traveling at a low speed. As a result, the warning unit 325 can issue a warning to the driver on an appropriate lane and at an appropriate time.

[0053] <Processing sequence in the driving condition determination device 30> Fig. 4 is a diagram showing an example of a processing sequence in the driving condition determination device 30. The processing sequence shown in Fig. 4 shows an operation of the driving condition determination device 30 to determine swaying of the vehicle S while driving. The driving condition determination device 30 executes the processing sequence shown in Fig. 4 every time a unit time elapses.

[0054] The acquisition unit 321 acquires a distance L2 between the position of the road dividing line WL provided in the vehicle width direction of the vehicle S, which is identified from the captured image captured by the imaging device 11, and the position of the imaging device 11 (S11). The identification unit 322 identifies a distance L1 between the position of the road dividing line WL and the position of the vehicle S by subtracting a distance L3 between the position of the imaging device 11 and the position of the left side of the vehicle S in the vehicle width direction of the imaging device 11 with respect to the traveling direction from the distance L2 acquired by the acquisition unit 321 (S12). The identification unit 322 stores the identified distance L1 and the time when the distance L1 was identified in the storage unit 31.

[0055] The calculation unit 323 calculates a maximum lateral displacement indicating a difference between the maximum value of the distance L1 and the minimum value of the distance L1 from the multiple distances L1 identified by the identification unit 322 from a time that is one hour before the predetermined time to the predetermined time (S13). The calculation unit 323 stores the calculated maximum lateral displacement and the time at which the maximum lateral displacement was calculated in the storage unit 31. The calculation unit 323 calculates statistics of the multiple maximum lateral displacements from a time that is second hours before the predetermined time to the predetermined time (S14).

[0056] The determination unit 324 calculates an increase rate by dividing the statistical amount calculated by the calculation unit 323 at a predetermined time by the statistical amount calculated by the calculation unit 323 a unit time before the predetermined time (S15). The determination unit 324 stores the calculated increase rate in the storage unit 31. If the calculated increase rate is equal to or greater than the threshold value DT (YES in S16), the determination unit 324 determines that the vehicle S is swaying (S17). On the other hand, if the calculated increase rate is less than the threshold value DT (NO in S16), the determination unit 324 determines that the vehicle S is not swaying (S18).

[0057] <First Modification> In the above description, the determination unit 324 has exemplified an operation of determining sway of the vehicle S by determining whether or not the increase rate calculated at a predetermined time is equal to or greater than the threshold value DT, but the present invention is not limited to this. The determination unit 324 may determine sway of the vehicle S when at least one of a state in which the maximum lateral displacement calculated every time a unit time elapses is equal to or greater than a predetermined maximum lateral displacement or a state in which the statistical amount calculated every time a unit time elapses is equal to or greater than a predetermined statistical amount is equal to or greater than a predetermined rate in a predetermined time. The predetermined maximum lateral displacement and the predetermined statistical amount are values ​​determined by experiments or simulations and are stored in the storage unit 31. The predetermined rate is a value determined by experiments or simulations stored in the storage unit 31, and is, for example, 0.33 (i.e., 33%) when the maximum value is 1.

[0058] The determination unit 324 determines whether the calculated maximum lateral displacement is equal to or greater than the predetermined maximum lateral displacement stored in the storage unit 31, for example, every time a unit time elapses. The determination unit 324 determines whether the calculated statistical amount is equal to or greater than the predetermined statistical amount stored in the storage unit 31, every time a unit time elapses. The determination unit 324 then identifies a first ratio of a state in which the maximum lateral displacement is equal to or greater than the predetermined maximum lateral displacement and a second ratio of a state in which the statistical amount is equal to or greater than the predetermined statistical amount, from a time that is three hours before a predetermined time (for example, the current time) to a predetermined time. The third time is a time determined by an experiment or a simulation, and is, for example, a time that is equal to or greater than the first time and equal to or less than the second time. The determination unit 324 determines that the vehicle S is swaying when at least one of the identified first ratio and second ratio is equal to or greater than the predetermined ratio stored in the storage unit 31. By operating in this manner, the judgment unit 324 can determine that the vehicle S is not swaying even if a state in which the maximum lateral displacement and statistics are equal to or greater than a predetermined value temporarily occurs due to the driver making a temporary incorrect operation, thereby improving the accuracy of judging the swaying of the vehicle S.

[0059] Furthermore, the determination unit 324 may specify a predetermined ratio for determining the sway of the vehicle S according to at least one of the wheelbase or the vehicle width related to the stability of the vehicle S during driving. The determination unit 324 specifies the predetermined ratio corresponding to the wheelbase by, for example, referring to a predetermined ratio corresponding to the wheelbase stored in the storage unit 31. The shorter the wheelbase of the vehicle S, the lower the stability, which makes it easier for the driver to make an error in operation. Therefore, the predetermined ratio stored in the storage unit 31 indicates a larger value as the wheelbase of the vehicle S becomes shorter. For example, when the wheelbase of the vehicle S has a first axle distance, the predetermined ratio indicates a larger value than when the wheelbase has a second axle distance longer than the first axle distance. When the wheelbase is divided into a plurality of ranges, the predetermined ratio may be a value corresponding to each range. For example, the predetermined ratio indicates a larger value as the range indicates a shorter value.

[0060] Further, the determination unit 324, for example, identifies the predetermined ratio corresponding to the vehicle width of the vehicle S by referring to the predetermined ratio corresponding to the vehicle width of the vehicle S stored in the storage unit 31. The narrower the vehicle width of the vehicle S, the lower the stability, which makes it easier for the driver to make an error in operation. Therefore, the predetermined ratio stored in the storage unit 31 indicates a larger value as the vehicle width of the vehicle S becomes narrower. For example, when the vehicle width of the vehicle S is a first vehicle width, the predetermined ratio indicates a larger value than when the vehicle width of the vehicle S is a second vehicle width that is wider than the first vehicle width. When the vehicle width is divided into a plurality of ranges, the predetermined ratio may be a value corresponding to each range. For example, the predetermined ratio indicates a larger value as the range indicates a narrower value. As described above, the determination unit 324 identifies the predetermined ratio according to at least one of the wheelbase or vehicle width of the vehicle S, so that the sway of the vehicle S can be determined taking into account the stability of the vehicle S, thereby improving the accuracy of the determination.

[0061] <Second Modification> In the above description, the identification unit 322 has specified the distance L1 between the position of the road dividing line WL on the left side of the vehicle S in the traveling direction and the position of the left side of the vehicle S in the traveling direction, but the present invention is not limited to this. As shown in Fig. 2, the identification unit 322 may specify the distance R1 between the position of the road dividing line WR on the right side of the vehicle S in the traveling direction and the position of the right side of the vehicle S in the traveling direction.

[0062] 2, the acquisition unit 321 acquires a distance R2 between the position of the road dividing line WR on the right side in the traveling direction of the vehicle S identified by the imaging device 11 and the position of the imaging device 11. The identification unit 322 identifies the distance R1 by subtracting a distance R3 between the position of the imaging device 11 and the right side of the vehicle S or the center of the vehicle S in the vehicle width direction of the imaging device 11 in the traveling direction of the vehicle S from the distance R2 acquired by the acquisition unit 321.

[0063] The identification unit 322 may determine whether to identify the distance L1 or the distance R1 based on flag information acquired together with the distance L2 or the distance R2 acquired by the acquisition unit 321. For example, the identification unit 322 identifies whether the distance acquired by the acquisition unit 321 corresponds to the road dividing line WL or the road dividing line WR by referring to flag information corresponding to the distance L2 or the distance R2 acquired by the acquisition unit 321. When the acquisition unit 321 acquires the distance L2 corresponding to the road dividing line WL, the identification unit 322 identifies the distance L1, and when the acquisition unit 321 acquires the distance R2 corresponding to the road dividing line WR, the identification unit 322 identifies the distance R1. By operating in this manner, even if the imaging device 11 cannot identify one of the road dividing lines on the left and right sides of the vehicle S, the identification unit 322 can identify the distance between the position of the vehicle S and the position of the road dividing line based on the other road dividing line.

[0064] <Effects of the driving condition determination device 30> As described above, the driving condition determination device 30 has an identification unit 322 that identifies a first distance between the position of a road dividing line extracted from a captured image and the position of the vehicle S every time a unit time has elapsed, a calculation unit 323 that calculates a maximum lateral displacement indicating the difference between the maximum value of the first distance and the minimum value of the first distance from the multiple first distances identified by the identification unit 322 at a predetermined time from a time one hour before the predetermined time every time a unit time has elapsed, and calculates statistics of the multiple maximum lateral displacements at the predetermined time from a time a second time before the predetermined time that is longer than the first time, and a determination unit 324 that determines that the vehicle S is swaying if a divided value (increase rate) obtained by dividing the statistics calculated at the predetermined time by the statistics calculated at a time unit time before the predetermined time is equal to or greater than a threshold value DT.

[0065] With the driving condition determination device 30 configured in this manner, if the vehicle S sways due to driving by a driver who is prone to swaying even in an awake state, the increase rate becomes less than the threshold value DT, and it can be determined that the vehicle is not swaying. As a result, if it is determined that the vehicle S is swaying, the probability that the vehicle S has been determined to be swaying due to a decrease in the wakefulness state of a driver who is prone to swaying in an awake state increases, and the accuracy of determining that the vehicle S is swaying due to a decrease in the wakefulness state can be improved.

[0066] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0067] 10 Speed ​​Sensor 11 Imaging equipment 20 Display section 21 Sound output part 30. Driving condition determination device 31 Storage section 32 Control section 321 Acquisition Department 322 Specific part 323 Calculation Department 324 Judgment section 325 Warning section

Claims

1. an identification unit that identifies a first distance between a position of a road dividing line extracted from a captured image and a position of a vehicle; a calculation unit that calculates a maximum lateral displacement indicating a difference between a maximum value of the first distances and a minimum value of the first distances from a time that is a first hour before a predetermined time and at the predetermined time, from the plurality of first distances identified by the identification unit, and calculates statistics of the plurality of maximum lateral displacements at the predetermined time from a time that is a second hour before the predetermined time and that is longer than the first time; a determination unit that determines that the vehicle is swaying when a divided value obtained by dividing the statistical amount calculated at the predetermined time by the statistical amount calculated at a time unit time before the predetermined time is equal to or greater than a threshold value; A driving condition determination device having the following.

2. The determination unit determines the first distance every time the unit time elapses, The calculation unit calculates the maximum lateral displacement and the statistics every time the unit time elapses. The driving condition determination device according to claim 1 .

3. the determination unit refers to a threshold value corresponding to a distance between a front wheel axle and a rear wheel axle of the vehicle, the threshold value being stored in a storage unit, to identify the threshold value corresponding to the distance; the threshold value indicates a value larger when a distance between a front wheel axle and a rear wheel axle of the vehicle is a first axle distance than when a distance between the front wheel axle and a rear wheel axle of the vehicle is a second axle distance longer than the first axle distance. The driving condition determination device according to claim 1 or 2.

4. The determination unit refers to a threshold value corresponding to a vehicle width of the vehicle, the threshold value being stored in a storage unit, to identify the threshold value corresponding to the vehicle width; The threshold value indicates a larger value when the vehicle width of the vehicle is a first vehicle width than when the vehicle width of the vehicle is a second vehicle width that is wider than the first vehicle width. The driving condition determination device according to claim 1 or 2.

5. The determination unit does not determine whether or not the vehicle is swaying when the vehicle speed is less than a predetermined vehicle speed. The driving condition determination device according to claim 1 or 2.

6. a warning unit that warns a driver of the vehicle of swaying of the vehicle when the determination unit determines that the vehicle is swaying, The warning unit does not warn the driver of the swaying of the vehicle when the vehicle speed is less than the predetermined vehicle speed. The driving condition determination device according to claim 1 or 2.

7. The method further includes a storage unit that stores the maximum lateral displacement and the statistics calculated by the calculation unit every time the unit time elapses, the determination unit erases the maximum lateral displacement and the statistics stored in the storage unit when the vehicle has been stopped for a predetermined time. The driving condition determination device according to claim 1 or 2.

8. The determination unit determines that the vehicle is swaying when at least one of a state in which the maximum lateral displacement calculated every time the unit time elapses is equal to or greater than a predetermined maximum lateral displacement or a state in which the statistical amount calculated every time the unit time elapses is equal to or greater than a predetermined statistical amount occurs at a predetermined rate or more from a time that is three hours before the predetermined time to the predetermined time. The driving condition determination device according to claim 1 or 2.

9. the determination unit refers to a predetermined ratio corresponding to a distance between a front wheel axle and a rear wheel axle of the vehicle, the predetermined ratio being stored in a storage unit, to identify the predetermined ratio corresponding to the distance; the predetermined ratio indicates a larger value when a distance between a front wheel axle and a rear wheel axle of the vehicle is a first wheelbase distance than when a distance between the front wheel axle and a rear wheel axle of the vehicle is a second wheelbase distance that is longer than the first wheelbase distance. The driving condition determination device according to claim 8.

10. The determination unit refers to a predetermined ratio corresponding to a vehicle width of the vehicle, the predetermined ratio being stored in a storage unit, to identify the predetermined ratio corresponding to the vehicle width; The predetermined ratio indicates a larger value when the vehicle width of the vehicle is a first vehicle width than when the vehicle width of the vehicle is a second vehicle width that is wider than the first vehicle width. The driving condition determination device according to claim 8.

11. the identification unit identifies the first distance by subtracting a third distance between a position of the imaging device and a side or a center of the vehicle in the vehicle width direction of the imaging device from a second distance between a position of the imaging device and a position of a road dividing line provided in a vehicle width direction of the vehicle, the second distance being identified from the captured image captured by the imaging device. The driving condition determination device according to claim 1 or 2.

12. The computer executes a specifying step of specifying a first distance between a position of a road dividing line extracted from the captured image and a position of a vehicle; a calculation step of calculating a maximum lateral displacement indicating a difference between a maximum value of the first distances and a minimum value of the first distances from the plurality of first distances identified in the identification step, from a time a first hour before the predetermined time to the predetermined time, and calculating statistics of the plurality of maximum lateral displacements at the predetermined time from a time a second hour before the predetermined time that is longer than the first time; a determination step of determining that the vehicle is swaying when a divided value obtained by dividing the statistical amount calculated at the predetermined time by the statistical amount calculated at a time unit time before the predetermined time is equal to or greater than a threshold value; A driving condition determination method comprising the steps of:

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