Vehicle circumference monitoring apparatus

A vehicle circumference monitoring apparatus includes: an acquisition section that acquires a steering angle of front wheels of a vehicle; a trajectory calculation section that calculates a rear wheel width trajectory indicating a moving predicted path of a rear wheel of an inside of turning during turning of the vehicle by steering of the front wheels; and a display control section that superimpose-displays the rear wheel width trajectory in captured side image data output from an imaging section that captures side images of the vehicle when the steering angle of the vehicle is equal to or greater than a predetermined value.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application 2014-241652, filed on Nov. 28, 2014, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to a vehicle circumference monitoring apparatus.

BACKGROUND DISCUSSION

In the related art, as a technique for supporting driving operation of a vehicle, a technique for supporting driving operation of a driver by imaging a circumferential environment of the vehicle by an imaging device such as a camera mounted on the vehicle and displaying captured image data as an imaging result has been proposed. As one type of driving support, there is a driving support in which a passage predicted line of wheels is superimpose-displayed on the captured image data. For example, turning radii of a front inner wheel and a rear inner wheel are different from each other due to an inner wheel difference occurring during turning of the vehicle. Thus, a circumference monitoring apparatus, in which the passage predicted line of the rear wheel that is hardly recognized by the driver or a passage predicted line when operating a steering wheel at the maximum angle is superimpose-displayed, has been proposed.

Japanese Patent No. 3607994 is an example of the related art.

However, since the passage predicted line of the rear wheel is displayed whenever performing the operation of the steering wheel, the display is performed even during a slight operation of the steering wheel. As a result, a user would feel inconvenience. In addition, whether or not the rear wheel comes into contact with an object such as a curbstone is easily determined by referring to a display of the passage predicted line, but there is a case where the determination of which object (for example, stone) the rear wheel runs over cannot be performed smoothly, for example, during driving off-road.

SUMMARY

A vehicle circumference monitoring apparatus according to an aspect of this disclosure includes, for example, an acquisition section that acquires a steering angle of front wheels of a vehicle; a trajectory calculation section that calculates a rear wheel width trajectory indicating a moving predicted path of a rear wheel of an inside of turning during turning of the vehicle by steering of the front wheels; and a display control section that superimpose-displays the rear wheel width trajectory in captured side image data output from an imaging section that captures side images of the vehicle when the steering angle of the vehicle is equal to or greater a predetermined value.

DETAILED DESCRIPTION

Hereinafter, an example, in which a vehicle circumference monitoring apparatus of an embodiment is mounted on a vehicle1, will be described. In the embodiment, the vehicle1may be, for example, an automobile (internal combustion engine automobile) in which an internal combustion engine (engine (not illustrated)) is a driving source or an automobile (electric automobile, a fuel cell automobile, and the like) in which an electric motor (motor (not illustrated)) is a driving source. In addition, the vehicle1may be an automobile (hybrid electric vehicle) in which both are the driving source. In addition, the vehicle1is able to mount various transmissions and is able to mount various devices (systems, parts, and the like) necessary for driving the internal combustion engine or the electric motor. In addition, a type, the number, a layout, and the like of a device for driving wheels3in the vehicle1can be variously set.

As illustrated inFIG. 1, a vehicle body2according to the embodiment is configured of a vehicle interior2awhere an occupant (not illustrated) rides. A steering section4, an acceleration operation section5, a braking operation section6, a speed change operation section7, and the like are provided within the vehicle interior2ain a state of facing a seat2bof a driver as the occupant. In the embodiment, for example, the steering section4is a steering wheel protruding from a dashboard (instrument panel) and the acceleration operation section5is an accelerator pedal positioned below the feet of the driver. In addition, the braking operation section6is a brake pedal positioned below the feet of the driver and the speed change operation section7is a shift lever protruding from a center console. However, these are not limited to the embodiment.

In addition, a display device8(display output section) and a sound output device9(sound output section) are provided within the vehicle interior2a. The display device8is, for example, a liquid crystal display (LCD), an organic electroluminescent display (GELD), and the like. The sound output device9is, for example, a speaker. In addition, in the embodiment, for example, the display device8is covered by a transparent operation input section10(for example, a touch panel and the like). The occupant and the like can visually recognize a video (image) displayed on a display screen of the display device S via the operation input section10. In addition, the occupant and the like can execute an operation input (instruction input) by operating the operation input section10by touching, pressing, or moving the operation input section10with the finger or the like in a position corresponding to the video (image) displayed on the display screen of the display device8. In addition, in the embodiment for example, the display device8, the sound output device9, the operation input section10, and the like are provided in a monitor device11positioned at a center portion of the dashboard in a vehicle width direction (right and left direction). The monitor device11can have an operation input section (not illustrated) such as switches, dials, joysticks, and push buttons. In addition, a sound output device (not illustrated) can be provided in a position within the vehicle interior2adifferent from the position of the monitor device11and sound can be output from the sound output device9of the monitor device11and another sound output device. In addition, in the embodiment, for example, the monitor device11is also used as a navigation system and an audio system, but the monitor device for the vehicle circumference monitoring apparatus may be provided separately from these systems.

In addition, as illustrated inFIGS. 1 and 2, in the embodiment, for example, the vehicle1is a four-wheel vehicle (four-wheeled automobile) and has two right and left front wheels3F and two right and left rear wheels3R. Then, for example, a tire angle of the front wheel3F is changed (steered) in compliance with an operation of the steering section4(steering wheel). A steering system12(seeFIG. 3) is, for example, an electric power steering system, a steer by wire (SBW) system, and the like. As illustrated inFIG. 3, the steering system12compensates a steering force by adding torque (assist torque) to the steering section4by an actuator12aand steers the front wheels3F.

In addition, in the embodiment, for example, as illustrated inFIG. 2, a plurality (for example, four in the embodiment) of imaging sections16(16ato16d) are provided in the vehicle1(vehicle body2). The imaging section16is a digital camera in which an imaging device such as a charge coupled device (CCD) and a CMOS image sensor (CIS) is built. The imaging section16can output captured image data (moving image data and frame data) at a predetermined frame rate. The imaging sections16respectively have a wide-angle lens and can image (capture an image) an image, for example, at a range (viewing angle) of 140° to 220° in the horizontal direction. In addition, an optical axis of the imaging section16is set downward (for example, a vertical direction or an obliquely downward direction). Thus, the imaging section16can image an environment of an outside of the circumference of the vehicle body2including a road surface on which the vehicle1is able to move and a region above the road surface.

In the embodiment, for example, the imaging section16afunctioning as a first imaging section is positioned in an end portion2c(end portion in a plan view) of a front side (front side in a longitudinal direction of the vehicle) of the vehicle body2and is provided on a front grille and the like. The imaging section16bfunctioning as a second imaging section is positioned in an end portion2dof a left side (left side in the vehicle width direction) of the vehicle body2and is provided on a door mirror2g(protrusion portion) of the left side. In addition, the imaging section16cfunctioning as the first imaging section is positioned in an end portion2eon a rear side (rear side in the longitudinal direction of the vehicle) of the vehicle body2and is provided on a wall portion below a door2hof a rear trunk. The imaging section16dfunctioning as the second imaging section is positioned in an end portion2fof a right side (right side in the vehicle width direction) of the vehicle body2and is provided on the door mirror2g(protrusion portion) of the right side. In addition, in the embodiment, a mounting method of the camera is not limited and may be provided so as to acquire captured image data in a front direction, captured image data in a right-left side direction, and captured image data in a rear direction with respect to the vehicle1.

An electronic control unit (ECU; seeFIG. 3)14executes a calculating process and an imaging process based on the captured image data acquired by the plurality of the imaging sections16and displays the captured image data in which the imaging process is performed on the display device8.

In addition, in the embodiment, for example, as illustrated inFIG. 3, in a circumference monitoring system (vehicle circumference monitoring apparatus)100, a brake system18, a steering angle sensor19(angle sensor), an accelerator sensor20, a shift sensor21, a wheel speed sensor22, an acceleration sensor26, and the like are electrically connected via an in-vehicle network23(electric communication line) in addition to the ECU14, the monitor device11, and the like. The in-vehicle network23is configured as, for example, a controller area network (CAN). The ECU14can control the brake system18and the like by transmitting a control signal through the in-vehicle network23. Furthermore, the ECU14can receive detection results of a torque sensor12b, a brake sensor18b, the steering angle sensor19, the accelerator sensor20, the shift sensor21, the wheel speed sensor22, the acceleration sensor26, and the like via the in-vehicle network23. In addition, the ECU14can receive instruction signals (a control signal, an operation signal, an input signal, and data) of the operation input section10and the like.

In the embodiment, two acceleration sensors26(26aand26b) are provided in the vehicle1. Moreover, in the embodiment, the vehicle1is a vehicle on which an electronic stability control (ESC) is mounted. Then, the acceleration sensors26(26aand26b) of the related art mounted on the vehicle on which the ESC is mounted are used. Moreover, in the embodiment, the acceleration sensor is not limited and a sensor that is able to detect the acceleration of the vehicle1in the right and left direction may be used.

The ECU14has, for example, a central processing unit (CPU)14a, a read only memory (ROM)14b, a random access memory (RAM)14c, a display control section14d, a sound control section14e, a solid state drive (SSD, flash memory)14f, and the like. The CPU14aexecutes various calculating processes such as the imaging process associated with an image displayed on the display device8, calculation of a moving path of the vehicle1, and determination of the presence or absence of interference with an object. The CPU14areads a program stored (installed) in a non-volatile storage device such as the ROM14band executes the calculating process in compliance with the related program.

The RAM14ctemporarily stores various data that are used in the calculation in the CPU14a. In addition, the display control section14dmainly executes the imaging process using the captured image data obtained by the imaging section16, the imaging process (for example, synthesizing and the like) of the captured image data displayed on the display device8, and the like in the calculating process in the ECU14. In addition, the sound control section14emainly executes a process for sound data output from the sound output device9in the calculation process in the ECU14. In addition, the SSD14fis a rewritable non-volatile storage section and can store data even if a power supply of the ECU14is turned off. Moreover, the CPU14a, the ROM14b, the RAM14c, and the like can be integrated within the same package. In addition, the ECU14may be a configuration in which other logical calculation processors such as a digital signal process (DSP), a logical circuit, and the like are used instead of the CPU14a. In addition, a hard disk drive (HDD) may be provided instead of the SSD14fand the SSD14for the HOD may be provided separately from the ECU14.

As illustrated inFIG. 4, the CPU14aincludes various modules that read programs installed and stored in a storage device such as the ROM14b, and are realized by executing the programs. The CPU14aincludes, for example, a steering angle acquisition section28, a trajectory calculation section30, an index acquisition section32, a braking state acquisition section34, and the like as modules associated with display control of the side image in the embodiment.

The steering angle acquisition section28acquires a detection result of the steering angle sensor19supplied via the in-vehicle network23and calculates the steering angle of the front wheels3F. The acquired steering angle is supplied to the trajectory calculation section30, the index acquisition section32, the display control section14d, and the like. The trajectory calculation section30calculates the rear wheel width trajectory indicating the moving predicted path of the rear wheel3R on the inside of turning during turning of the vehicle1by steering of the front wheels3F on the basis of the steering angle supplied from the steering angle acquisition section28. In addition, the trajectory calculation section30calculates the front wheel width trajectory indicating the moving predicted path of the front wheels3F of the vehicle1on the basis of the steering angle supplied from the steering angle acquisition section28. The calculated rear wheel width trajectory or the front wheel width trajectory is supplied to the display control section14dand is superimpose-displayed on a circumference image of the vehicle1that is captured by the imaging section16.

The index acquisition section32reads an index indicating the exterior information of the vehicle1stored in a storage device such as the SSD14fbased on the steering angle supplied from the steering angle acquisition section28and supplies the index to the display control section14d. As the index indicating the exterior information of the vehicle1, for example, information indicating a vehicle width of the vehicle1, information indicating the grounding position of the wheel3, information indicating a distance of the front of the vehicle, and the like are included. A detailed index will be described later.

The braking state acquisition section34acquires the information indicating the braking control state from the brake system18via the in-vehicle network23and supplies the information to the display control section14d. A braking device (for example, a disc brake device) mounted on each wheel3of the vehicle1is able to perform braking control for each wheel3. For example, it is possible to perform anti-lock brake control for lowering or eliminating a braking force of the wheel3that is temporarily locked if the wheel3is locked. It is possible to reduce the turning radius by generating the braking force to the rear wheel on the inside of turning by using the function. That is, it is possible to move the rear wheels3R based on a moving trajectory (trajectory of which the turning radius is small) different from a rear wheel width trajectory36calculated based on the steering angle. If such the braking control is performed, the display control section14dcan alert the user by changing the display mode of the rear wheel width trajectory36. Specific examples of the change of the display mode of the rear wheel width trajectory36will be described later.

The display control section14ddetermines an additional image superimposed on the circumference image of the vehicle1supplied from the imaging section16based on the rear wheel width trajectory or the front wheel width trajectory supplied from the trajectory calculation section30, the index supplied from the index acquisition section32, braking control information supplied from the braking state acquisition section34, and the like. Then, the additional image and the circumference image are output and displayed on the display device8by merging the additional image and the circumference image. Moreover, modules realized within the CPU14amay be individually configured for each function as described above, or may be one module in which a plurality of functions are collected. In contrast, the module may be realized by further subdividing the functions.

An example of a calculation procedure of the rear wheel width trajectory36will be described with reference toFIG. 5. If the steering angle of the front wheels3F is changed by operating the steering section4(steering wheel), a turning center G1of the vehicle1exists at an intersection point of a direction orthogonal to an orientation3Fa of the front wheel3F and an extension direction of a rear wheel axle38supporting the rear wheels3R. That is, when the vehicle1turns according to the steering angle of the front wheels3F, a center point38aof the rear wheel axle38also moves along a circular arc of which a center is the turning center G1. In addition, the rear wheels3R also move along the circular arc of which the center is the turning center G1. As described above, if the turning is performed in a normal driving such as a case where the braking force is applied to the rear wheels3R or slip does not occur, the rear wheel width trajectory36of the rear wheels3R is uniquely determined based on the steering angle of the front wheels3F. In this case, since the orientation indicated by the rear wheel width trajectory36is changed every moment depending on the change of the steering angle, if a display length of the rear wheel width trajectory36is too long, a shake amount of the rear wheel width trajectory36on a leading end side is increased, the moving predicted path is unlikely to be understood, and the user may feel uncomfortable and inconvenience. In contrast, if the display length of the rear wheel width trajectory36is too short, the moving direction of the rear wheels3R superimposed on a portion of a vehicle side of the vehicle1is unlikely to be grasped. Then, the trajectory calculation section30of the embodiment displays the rear wheel width trajectory36of a length corresponding to a moving amount of the center point38athat is moved by a predetermined distance during turning. For example, the rear wheel width trajectory36is displayed in a case where the center point38amoves by a predetermined distance38bof 2.0 m on the circular arc of a radius R1around the turning center G1during turning. In this case, when a turning angle of the vehicle1is θ1, the display length of the rear wheel width trajectory36can be calculated.

Moreover, a situation where an attention is to be focused on conditions of the road surface where the rear wheels3R pass through, is for example, considered as a case when driving on a rough road such as an off-road at low speed. Thus, even if the steering angle is changed, it is preferable that the display length of the rear wheel width trajectory36, in which a shake width of the rear wheel width trajectory36that is displayed every time is reduced and a traveling direction of the rear wheels3R can be sufficiently predicted, is determined. As a result of repeated experiments in view of theses points, for example, a result was obtained in which it is preferable that the moving distance of the center point38aof the rear wheel axle38described above is 2.0 m. However, the display length of the rear wheel width trajectory36is not limited to the example described above and may be appropriately changed. The display length of the rear wheel axle38may be initially set and fixed or may be set by using the operation input section10and the like by the user.

In the embodiment, the rear wheel width trajectory36is displayed so as to correspond to an actual width of the rear wheel3R and is superimposed on the side image that is captured by the imaging section16b(imaging section16d). Thus, the user can easily understand which uneven portion of the road surface the rear wheels3R pass through, the degree of the influence to be received when the rear wheels3R run over the unevenness of the road surface, and the like. Thus, the trajectory calculation section30can acquire information of the wheel width of the rear wheel3R and the like and if the rear wheel3R is exchanged, a display width of the rear wheel width trajectory36may be also changed in compliance with an actual width of the rear wheel3R. The change may be reflected on the trajectory calculation section30by automatically acquiring the information of the wheel3or may be input via the operation input section10and the like by the user.

The trajectory calculation section30may also calculate the front wheel width trajectory indicating the moving predicted path of the front wheels3F of the vehicle1. In addition, the display control section14dmay superimpose-display the front wheel width trajectory on captured front image data output from the imaging section16athat captures the front image of the vehicle1. The front wheel width trajectory can be displayed as an index indicating a direction facing the front wheel3F based on the steering angle supplied from the steering angle acquisition section28. The front wheel width trajectory may be displayed at all times or may be displayed if the steering section4(steering wheel) is operated at a predetermined angle or more. In addition, the display length of the front wheel width trajectory may also be a predetermined value such as a length corresponding to, for example, 5 m or may be appropriately set by using the operation input section10by the user on a front image on which the front wheel width trajectory is superimposed.

Meanwhile, since the orientation of the rear wheels3R is always the longitudinal direction of the vehicle, if the vehicle1is turned by steering the front wheels3F, when the steering angle of the front wheels3F is small, a protrusion amount of the rear wheel width trajectory36on the inside of turning is reduced, is substantially superimposed on the side portion of the vehicle1, and is in a state of being unlikely to be recognized. In addition, troublesome is given to the user that the rear wheel width trajectory36that slightly protrudes from the side portion of the vehicle1is difficult to be distinguished from a side portion contour line of the vehicle1thereby. Thus, if the steering angle of the vehicle1supplied from the rear wheel axle38is equal to or greater than the predetermined value, the display control section14dsuperimpose-displays the rear wheel width trajectory36on the captured side image data supplied from the imaging section16b(imaging section16d) of the vehicle1. That is, if the steering angle of the front wheels3F is increased to a certain extent and a necessity of the display of the moving predicted path of the rear wheels3R is increased, the rear wheel width trajectory36is displayed. As the predetermined value of the steering angle to start the display of the rear wheel width trajectory36, for example, it is possible to make the steering angle to be 270°. In this case, since the rear wheel width trajectory36is displayed by sufficiently being separated from the side portion contour line of the vehicle1, the moving predicted path of the rear wheels3R is easily grasped. In addition, it is possible to suppress that troublesome is given to the user that the rear wheel width trajectory36is difficult to be distinguished from the side portion contour line of the vehicle1.

Moreover, if the steering angle is less than 270°, it is considered that the rear wheel3R substantially passes through the same path as the front wheel3F. As described above, the display control section14dcan superimpose-display the front wheel width trajectory of the front wheel3F on the front image. Thus, even if the steering angle is less than the predetermined value and the rear wheel width trajectory36is not displayed, the user can estimate the moving predicted path of the rear wheel3R by confirming the front wheel width trajectory. Moreover, if the steering angle is less than the predetermined value, the trajectory calculation section30may not perform the calculation of the rear wheel width trajectory36or even if the steering angle is less than the predetermined value, may perform the calculation thereof. If the steering angle is less than the predetermined value, when the calculation of the rear wheel width trajectory36is not performed, it is possible to reduce a processing load of the CPU14a. In contrast, if the steering angle is calculated at all times, when the steering angle is equal to or greater than the predetermined value, it is possible to quickly execute the superimpose-display. In addition, even if the steering angle is less than the predetermined value, when the user wants to perform the superimpose-display of the rear wheel width trajectory36, it is possible to quickly perform the superimpose-display. Moreover, the steering angle (for example, 270°) in which the display of the rear wheel width trajectory36is started is an example and the user may appropriately set and change the steering angle via the operation input section10and the like.

Moreover, if the steering angle is less than the predetermined value and the rear wheel width trajectory36is not displayed, the display control section14dmay superimpose-display the index indicating the exterior information of the vehicle1on the captured side image data that is captured by the imaging section16b(imaging section16d). As described above, the index indicating the exterior information of the vehicle1is, for example, information indicating the vehicle width of the vehicle1, information indicating the grounding position of the wheel3, information indicating the distance of the vehicle front, and the like. The information indicating the vehicle width of the vehicle1is a vehicle width line40aindicating the vehicle width, a vehicle width offset line40bthat is offset from the vehicle width line40ain an outside direction of the vehicle width by, for example, 0.35 m, and the like. A relationship between the vehicle1and the circumference, for example, presence or absence of contact and appropriateness of an interval can be easily grasped by the user by displaying the vehicle width line40a, the vehicle width offset line40b, and the like. In addition, a grounding line42(seeFIG. 6) indicating the grounding position of the wheel3is displayed on, for example, the vehicle width offset line40band is displayed so as to easily grasp a correspondence between the vehicle width of the vehicle1and the grounding position of the wheel3. In addition, a plurality of interval lines44indicating the distance of the vehicle front are displayed, for example, at predetermined intervals relative to the end portion2cof the front of the vehicle1and front distance feeling of the vehicle1is easily understood. In addition, a part of the interval lines44may also be displayed on the side screen. Since the indexes are fixed lines with respect to the vehicle1, even if the indexes are displayed at all times, inconvenience and discomfort are not given to the user.

If the rear wheel width trajectory36is not displayed, that is, if the steering angle is less than the predetermined value, the indexes of the vehicle width line40a, the vehicle width offset line40b, the grounding line42, the interval line44, and the like may be displayed instead of the rear wheel width trajectory36. In addition, in another embodiment, even after the steering angle is equal to or greater than the predetermined value and the rear wheel width trajectory36is displayed, the indexes may be displayed together with the rear wheel axle38. If one of the index and the rear wheel width trajectory36is selectively displayed, it is possible to highlight each display and it is possible to be easily recognized by the user. On the other hand, when displaying the index even after the rear wheel width trajectory36is displayed, there is an effect that the relationship between the moving predicted path of the rear wheel3R and the exterior of the vehicle1is easily understood.

If the steering angle is equal to or greater than the predetermined value based on the steering angle supplied from the steering angle acquisition section28, that is, if the superimpose-display of the rear wheel width trajectory36is performed, the index acquisition section32may acquire a maximum moving trajectory46from the SSD14f. The maximum moving trajectory46is the moving predicted path of the rear wheel3R on the inside of turning if the steering angle is a maximum angle and is temporarily determined based on the maximum steering angle. Similar to the rear wheel width trajectory36, the maximum moving trajectory46can be superimpose-displayed on the captured side image data. It is preferable that the maximum moving trajectory46is displayed in a display mode different from the rear wheel width trajectory36so as to easily identify the maximum moving trajectory46from the rear wheel width trajectory36. The maximum moving trajectory46is mainly used for grasping whether or not the rear wheels3R come into contact with an object, for example, a curbstone and the like on the side of the vehicle1. Thus, the maximum moving trajectory46may be displayed as the outermost line of the rear wheel3R. In addition, the maximum moving trajectory46and the rear wheel width trajectory36may be displayed with different display colors or, for example, the maximum moving trajectory46is blink-displayed and then may be highlighted.

FIG. 6is a display example of the display device8when the steering angle is equal to or greater than the predetermined value and is a display example illustrating a state where the rear wheel width trajectory36is superimpose-displayed on a right-side image region48aand a front wheel width trajectory52is superimpose-displayed on a front image region50. In the display example ofFIG. 6, the right-side image region48ais assigned from a right upper end to a lower end of the display region of the display device8and a left-side image region48bis assigned from a left upper end to a lower end of the display region. The right-side image region48aand the left-side image region48bare vertically long display regions so as to display the front wheels3F and the rear wheels3R (part). In addition, the front image region50is assigned in a center upper portion interposed between the right-side image region48aand the left-side image region48b. Furthermore, a posture symbol display region54adisplaying a posture symbol54indicating a posture of the vehicle1is assigned in a center lower portion interposed between the right-side image region48aand the left-side image region48b.

FIG. 6illustrates a state where the steering section4(steering wheel) is steered equal to or greater than 270° in the right direction and the rear wheel width trajectory36is superimpose-displayed on the right-side image region48a. In addition,FIG. 6illustrates an example in which the vehicle width offset line40b, the grounding line42of the front wheel3F, the interval line44(interval line44that is closest to the end portion2cof the vehicle1), and the like are superimpose-displayed together with the rear wheel width trajectory36. On the other hand, the vehicle width offset line40b, the grounding line42, and the interval line44are superimpose-displayed on the left-side image region48bin an opposite direction of the steering direction. The front wheel width trajectories52, the plurality of the interval lines44, the right and left vehicle width offset lines40b, and the like are displayed on the front image region50. In addition, since the imaging section16aimaging the front image displayed on the front image region50uses the wide-angle lens, the front image and the front wheel width trajectories52, the interval lines44, the vehicle width offset line40b, and the like which are superimpose-displayed thereon are displayed in a shape that is slightly curved. A display posture of the posture symbol54is changed corresponding to a roll angle or a pitch angle of the vehicle1that can be calculated based on data of the acceleration sensors26acquired via the in-vehicle network23by the CPU14a. As a result, the user can be supported so as to objectively and easily understand the posture of the vehicle1.

As described above, if the steering angle is equal to or greater than the predetermined value (for example, 270°), the moving predicted path of the rear wheel3R is easily grasped by superimpose-displaying the rear wheel width trajectory36of a width corresponding to the wheel width of the rear wheel3R on the side image even if confirmation of an entire shape or confirmation of a position of the rear wheel3R is visually difficult on the screen of the display device8. In addition, if turning of the rear wheel3R is continued, grasping of the road surface on which the rear wheels3R will run over is easily performed and it is possible to realize the driving support so as to appropriately perform a change in the path, an adjustment of the speed, and the like.

FIG. 7is a display example when the steering angle is less than the predetermined value in which the rear wheel width trajectory36is not displayed, and the vehicle width offset lines40b, the grounding lines42, the interval lines44, and the like that are the indexes indicating the exterior information of the vehicle1are superimpose-displayed on the right-side image region48aand the left-side image region48b. In addition, the vehicle width offset lines40band the interval lines44are superimpose-displayed together with the front wheel width trajectory52on the front image region50.FIG. 7illustrates a case of driving on ruts on a road covered with snow. In this case, it is possible to easily realize safe driving and to perform favorable driving support by steering so as to match the front wheel width trajectory52and the ruts. In addition, when driving on the ruts or the off-road, the steering state of the steering section4may be swung right and left by a state of the road surface. However, since the display control section14ddoes not execute the superimpose-display of the rear wheel width trajectory36in the steering angle that is less than the predetermined value, it is possible to suppress discomfort given to the user due to excessive display.

However, as described above, if the braking force is generated in the rear wheel3R on the inside of turning when the vehicle1is turned, turning can be performed with a radius that is smaller than the turning radius determined by the steering angle. For example, as illustrated inFIG. 8, if the turning operation is performed in a state of non-braking, turning is performed in a trajectory indicated by a dotted line arrow56. On the other hand, for example, if the braking force is applied only to the left rear wheel3RL when turning to the left, the vehicle1behaves so as to rotate about the left rear wheel3RL and as indicated by a solid line arrow58, turning is performed in a trajectory that is smaller than that during non-braking. As described above, if the braking control is executed during turning, the rear wheel width trajectory36that is determined according to the steering angle and the real moving directions of the left rear wheel3RL may be different from each other. That is, reliability of the rear wheel width trajectory36calculated based on the steering angle may be lowered.

Then, if a signal indicating execution of the braking control of the rear wheel on the inside of turning is acquired from the braking state acquisition section34during the turning operation (seeFIG. 4), as illustrated inFIG. 9, the display control section14dmay superimpose-display the rear wheel width trajectory36, for example, in a dotted line mode or superimpose-display the rear wheel width trajectory36in a semi-transparent mode. That is, a display mode of at least the rear wheel width trajectory36is changed if a turning predicted state based on the steering angle and an actual turning state of the vehicle1correspond to each other and do not correspond to each other, and thereby an effect that the display reliability of the rear wheel width trajectory36is lowered is notified to the user. Similarly, since the moving predicted path is calculated based on the steering angle, the reliability of the front wheel width trajectory52is also lowered if the turning radius is changed by the braking control. Thus, if the braking control of the rear wheel on the inside of turning is executed, also for the front wheel width trajectory52, the user may be alerted by switching the display to the display of the dotted line mode or the semi-transparent mode. In addition, a message or a mark of the alert indicating that the display reliability of the rear wheel width trajectory36or the front wheel width trajectory52is lowered may be displayed on the display device8. In addition, the rear wheel width trajectory36or the front wheel width trajectory52may be displayed in a display color different from during the non-braking and may be blink-displayed. In addition, the display color of the right-side image region48a(left-side image region48b) or the front image region50may be changed. Furthermore, the user may be alerted by outputting a sound message from the sound output device9. Moreover, if the posture or the turning direction of the vehicle1during the braking control can be calculated based on a detection result of the acceleration sensor26or a detection result of another sensor, it is possible to improve the display accuracy of the rear wheel width trajectory36or the front wheel width trajectory52based on the result. Thus, the superimpose-display may be performed similar to that during non-braking.

An example of the procedure of the imaging process of the circumference monitoring system100having such a configuration will be described with reference a flowchart ofFIG. 10. Moreover, if the front image region50that displays the front image, the right-side image region48a, or the left-side image region48bis displayed, the process illustrated in the flowchart ofFIG. 10is repeatedly executed in a predetermined cycle. In addition, each imaging section16, the steering angle sensor19, the brake sensor18h, and the like continuously supply the detection data to the ECU14in a predetermined control cycle.

If the display of the display device8including the right-side image region48a, the left-side image region48b, and the front image region50is required, the ECU14causes the display control section14dto acquire the captured image data of the circumference of the vehicle1via each imaging section16(S100). Sequentially, the steering angle acquisition section28acquires a current steering angle based on the detection data of the steering angle sensor19(S102). In addition, the index acquisition section32reads an index to be displayed to correspond to the current steering angle from the SSD14fand supplies the index to the display control section14d(S104). Then, the ECU14causes the display control section14dto respectively display the front image on the front image region50, the right side image on the right-side image region48a, and the left side image on the left-side image region48b(S106), and causes the index information to be superimpose-displayed on each display region (S108).

In addition, the trajectory calculation section30calculates the front wheel width trajectory52based on the steering angle supplied from the steering angle acquisition section28(S110) and the display control section14dsuperimpose-displays the calculated front wheel width trajectory52on the front image region50(S112).

Furthermore, if the steering angle supplied from the steering angle acquisition section28is equal to or greater than the predetermined value, for example, equal to or greater than 270° (Yes in S114), the trajectory calculation section30calculates the rear wheel width trajectory36based on the steering angle (S116). In a case where a signal indicating that the rear wheel on the inside of turning is in the braking control is not received from the braking state acquisition section34, that is, in a case where the turning correction control is not performed for reducing the turning radius (No of S118), the display control section14dsuperimpose-displays the rear wheel width trajectory36in a “bright” state (S120). That is, as illustrated inFIG. 6, the rear wheel width trajectory36is clearly displayed in the solid line state, the flow is temporarily completed, and the process is repeatedly executed from S100in the next control cycle. On the other hand, in the process of S118, in a case where the signal indicating that the rear wheel on the inside of turning is in the braking control is received, that is, in a case where the turning correction control is executed for reducing the turning radius (Yes of S118), the rear wheel width trajectory36is superimpose-displayed in a semi-transparent state (S122). That is, as illustrated inFIG. 9, the effect that the display reliability of the rear wheel width trajectory36is lowered, that is, the rear wheel width trajectory36is displayed as a reference display is indicated, the flow is temporarily completed, and the process is repeatedly executed from S100in the next control cycle.

In the process of S114, if the steering angle supplied from the steering angle acquisition section28is less than the predetermined value, for example, is less than 270°, the process of S116and subsequent steps is skipped, the flow is temporarily completed, and the process is repeatedly executed from S100in the next control cycle. Moreover, in the process of S120or S122, if the rear wheel width trajectory36is superimpose-displayed, the index information that is superimpose-displayed in the process of S108may not be displayed. In addition, in another embodiment, only if the rear wheel width trajectory36is superimpose-displayed in the “bright” state in the process of S120, the index information that is superimpose-displayed in the process of S108is not displayed and if the rear wheel width trajectory36is superimpose-displayed in the “semi-transparent” state in the process of S122, the display of the index information may be maintained. As described above, the user can more appropriately confirm the situation of the circumference of the vehicle1by displaying in highlight display contents to be focused on by the user depending on the situation. Moreover, the flowchart illustrated inFIG. 10is an example and if the steering angle of the vehicle1is equal to or greater than the predetermined value, as long as it is possible to superimpose-display the rear wheel width trajectory36on the side captured image data output from the imaging section16b(imaging section16d) capturing the side image of the vehicle1, the process contents may be appropriately changed and it is possible to obtain the same effects as in the embodiment.

A vehicle circumference monitoring apparatus according to an aspect of this disclosure includes, for example, an acquisition section that acquires a steering angle of front wheels of a vehicle; a trajectory calculation section that calculates a rear wheel width trajectory indicating a moving predicted path of a rear wheel of an inside of turning during turning of the vehicle by steering of the front wheels; and a display control section that superimpose-displays the rear wheel width trajectory in captured side image data output from an imaging section that captures side images of the vehicle when the steering angle of the vehicle is equal to or greater a predetermined value. According to the configuration, for example, the rear wheel width trajectory is displayed, if the steering angle is equal to or greater than the predetermined value, for example, in a case where an operation of a steering wheel is greatly performed (for example, 270° or greater). That is, the rear wheel width trajectory is displayed in a case where turning of the vehicle is great and the inner wheel difference is great. In addition, since the rear wheel width trajectory corresponding to the rear wheel width is displayed, prediction of an object on which the rear wheel will run over is made easier and an image in the event that the rear wheel actually runs over the object is easily displayed on the side image, and it is possible to increase driving support with respect to a user.

The display control section of the vehicle circumference monitoring apparatus may, for example, superimpose-display a maximum moving trajectory of the rear wheel of the inside of turning if the steering angle is the maximum angle in the captured side image data when superimpose-displaying the rear wheel width trajectory. According to the configuration, for example, a relationship between the rear wheels and the object on a road when the steering angle is the maximum is easily understood, for example, determination of a change amount when a moving direction of the rear wheels is changed is easily performed, and it is possible to increase the driving support with respect to the user.

The display control section of the vehicle circumference monitoring apparatus may, for example, superimpose-display an index indicating exterior information of the vehicle in the captured side image data if at least the steering angle of the vehicle is less than a predetermined value. According to the configuration, for example, if the steering angle is less than the predetermined value without the necessity to heavily consider the moving direction of the rear wheels and the like, it is possible to simplify the superimpose-display of the side image, it is possible to display the exterior information of the vehicle, for example, information necessary during driving of the vehicle such as a vehicle width and a grounding position of the wheels of the vehicle, and then it is possible to increase the driving support with respect to the user.

The trajectory calculation section of the vehicle circumference monitoring apparatus may, for example, further calculate a front wheel width trajectory indicating a moving predicted path of the front wheels of the vehicle and the display control section may superimpose-display the front wheel width trajectory in captured front image data output from an imaging section that captures a front image of the vehicle. According to the configuration, for example, the display of the moving predicted path of the front wheels is displayed in addition to the moving predicted path of the rear wheels and then it is possible to realize the driving support such as enabling posture control of the vehicle in further detail.

The display control section of the vehicle circumference monitoring apparatus may, for example, change a display mode of at least the rear wheel width trajectory if a turning predicted state based on the steering angle and an actual turning state of the vehicle correspond to each other and do not correspond to each other. According to the configuration, if turning performance of the vehicle is adjusted by executing steering control and other controls such as braking control during turning of the vehicle by a combination therebetween, it is possible to easily notify the user of the occurrence of a difference in the turning predicted state based on the steering angle and the actual turning state of the vehicle by changing the display mode, and it is possible to increase the driving support with respect to the user.

The embodiment and the modification example of this disclosure are described, but the embodiment and the modification example are presented as examples, and are not intended to limit the scope of this disclosure. Theses novel embodiments are capable of being embodied in other various forms and various omissions, substitutions, and changes can be performed without departing from the scope of this disclosure. These embodiments or modifications are included in the scope or the gist of this disclosure, and are included in the invention described in the claim and equivalents thereof.