JP2008080959A - Parking assistant device and parking assistant method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a proper parking guide. <P>SOLUTION: An image around one's own vehicle is obtained, forecasted track lines of a left end and a right end of one's own vehicle are derived based on action of one's own vehicle, and it is determined whether or not two tangents parallel to two longitudinal sides of a target parking frame, i.e., the tangent of the forecasted track lines exist at inner side of the two longitudinal sides of the target parking frame. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a parking assistance device and method for assisting a parking operation performed in a host vehicle.

2. Description of the Related Art Conventionally, a technique for assisting parking by photographing the direction of a parking frame with a camera mounted on the host vehicle and displaying the image is known. In Patent Literature 1, a parking frame included in an image captured by a camera mounted on the host vehicle is detected, and an expected trajectory of the host vehicle is derived from a relative positional relationship between the host vehicle and the parking frame. Further, there is disclosed a technique for determining whether or not parking is possible from the predicted trajectory of the host vehicle and the steering state of the host vehicle and notifying the driver using a display or a speaker.
JP 11-339194 A

However, in the conventional technology, there are cases where accurate parking guidance cannot be performed. In Patent Document 1, in order to determine that parking is possible, it is a necessary condition that the predicted trajectory inside the host vehicle does not interfere with the corner of the parking frame when the host vehicle enters the parking frame while turning. . However, for example, if the other vehicle is not parked in the parking frame adjacent to the parking frame that the host vehicle is to park, even if the inside of the host vehicle slightly interferes with the corner of the parking frame, the target parking is performed once in reverse operation. If the frame can be parked, there is no particular problem even if it is determined that parking is possible and the driver is informed. Rather, in such a case, it is unfriendly to determine that parking is impossible and to prompt the driver to switch back.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for providing accurate parking support for parking the host vehicle in a parking frame.

  In order to achieve the above object, in a configuration in which parking assistance is performed by acquiring an image of the surroundings of the host vehicle, predicted trajectory lines at the left end and the right end of the host vehicle are derived based on the operation of the host vehicle, and the predicted It is determined whether two tangents that are tangent to the trajectory line and parallel to the two long sides of the target parking frame are present inside the two long sides of the target parking frame. Expected trajectory lines at the left end and the right end of the host vehicle are derived based on the operation of the host vehicle. The presence of a tangent line between the two expected trajectory lines and parallel to the long side of the target parking frame is present inside the long side of the target parking frame. This is equivalent to being able to place the vehicle in a posture parallel to the two straight lines inside the two straight lines that are extended lines of the long sides of the frame. In the configuration of the present invention, the vehicle is placed in the parking frame by determining the position of the tangent derived from the expected trajectory line specified by the information indicating the operation of the vehicle and the position and inclination of the longitudinal side of the parking frame. It is possible to realize whether or not the vehicle can be in a posture parallel to the two straight lines inside the two straight lines that are the extended lines of the long sides, that is, whether or not the target parking frame can be parked without being turned back.

  In the configuration in which the tangents of the predicted trajectory lines at the left end and the right end of the host vehicle are both inside the target parking frame, the inner predicted trajectory line when the host vehicle turns is the target parking frame. The case where it interferes with the long side of is allowed.

  The operation of the host vehicle is an expected course, a traveling direction, a position, a speed, and the like of the host vehicle, and the host vehicle operation information acquisition unit acquires information indicating the operation of the host vehicle. The operation of the host vehicle can be acquired by various methods. For example, detection information by a speed sensor, a rudder angle sensor, a gyro sensor, a geomagnetic sensor, or the like provided in the host vehicle can be used. Further, the expected trajectory line deriving unit only needs to be able to derive the expected trajectory line based on information indicating the operation of the host vehicle, and various configurations for that purpose can be employed. For example, when information indicating the expected trajectory at the time of reverse travel according to each steering angle is specified in advance from information such as the wheel base of the host vehicle, information indicating the steering angle output from the steering angle sensor of the host vehicle is provided. Based on this, an expected trajectory line corresponding to the rudder angle can be derived.

  Note that the image acquisition unit only needs to be able to acquire an image that can include a parking frame when the host vehicle is parked, and various configurations such as a configuration of photographing the surroundings of the host vehicle with a camera mounted on the host vehicle. Can be adopted. Of course, the image acquired in the present invention may be an image taken by a camera itself, or may be an image obtained by bird's-eye conversion of an image obtained by photographing the road surface of the host vehicle from an oblique direction. An image after overhead conversion is preferable because the relationship between the host vehicle and the parking frame can be clearly communicated to the driver.

  The target parking frame setting means only needs to be able to set the detected empty parking frame as the target parking frame. For the detection of the parking frame, for example, a configuration in which the characteristics of the parking frame (color, shape, difference from the road surface other than the frame, etc.) are extracted from the image can be adopted. An empty parking frame can be detected using, for example, a uniform image (road surface image) between the frame lines of the parking frame.

  Furthermore, in this invention, you may provide the obstruction determination means which determines whether an obstruction exists in the area | region adjacent to the outer side of the longitudinal side of a target parking frame. When it is determined that there is an obstacle, even if it is determined that parking is possible when the contact point between the tangent line and the expected trajectory line is present on the own vehicle side from the end point on the own vehicle side of the long side of the target parking frame, Good. By adopting this configuration, it is possible to avoid the own vehicle coming into contact with the obstacle. That is, the fact that the contact does not exist on the own vehicle side from the end point on the own vehicle side of the longitudinal side of the target parking frame means that the turning operation is terminated before the target parking frame (the own vehicle is placed on the long side of the target parking frame). Meaning that they cannot be parallel). In such a case, in a situation where an obstacle exists in an area adjacent to the outside of the longitudinal side of the target parking frame, there is a possibility of contacting the obstacle. The determination of the obstacle may be performed on both of the two long sides, or may be performed on the long side on the inner ring side of the own vehicle when the own vehicle turns to enter the target parking frame. good. The determination of the position of the contact may be performed for one contact or both contacts.

  Further, in this configuration, when there is no obstacle in the area adjacent to the outside of the long side of the target parking frame, it is not determined that parking is impossible even if the contact point is not on the own vehicle side from the end point of the long side. . For this reason, for example, when the space adjacent to the target parking frame is sufficiently large, the allowable range for determining that parking is possible is widened, the degree of freedom of the driver's operation can be increased, and whether or not parking is accurately determined. be able to.

  The obstacle may be, for example, another vehicle parked in a parking frame adjacent to the target parking frame, or a fence, a fence, a cliff, a hole, or the like. Further, the position of the contact point that should be determined to be able to park may be varied according to the position of the obstacle with respect to the longitudinal side of the target parking frame. That is, it is possible to adopt a configuration in which the position of the contact for determining whether or not parking is possible is set farther from the own vehicle as the distance from the end point on the own vehicle side to the obstacle on the longer side of the target parking frame becomes longer. For example, when an obstacle existing in a region adjacent to the outside of the long side is located farther from the center of the long side of the target parking frame when viewed from the host vehicle, the distance between the end point and the center position It is possible to adopt a configuration that determines that parking is possible when there is a contact at a predetermined position.

  Furthermore, in this invention, you may provide the image display means to display the said image. In this configuration, when it is determined that the host vehicle can be parked, the predicted trajectory line may be highlighted. The image display means only needs to be able to display the image, and can be constituted by various displays. By highlighting the expected trajectory line, the driver can clearly recognize that the target parking frame can be parked by maintaining the current operation of the host vehicle. Since it is only necessary for the driver to be able to recognize that parking is possible, in addition to highlighting the expected trajectory line, any means for guiding information indicating the determination result by the parking determination means may be employed. The driver may be notified by voice. Further, for example, the predicted trajectory line may not be displayed when it is not determined that parking is possible, and the expected trajectory line may be displayed only when it is determined that parking is possible. The predicted trajectory line is not limited to being displayed as two lines, but may be displayed as a band-like region including the predicted trajectory line as an outline.

  Further, as in the present invention, whether the host vehicle can be parked in the target parking frame based on the positional relationship between the tangent line of the predicted trajectory line derived based on the operation of the host vehicle and the frame line of the target parking frame. The determination method can also be applied as a program or method. In addition, the above parking assistance device, program, and method may be realized as a single parking assistance device, or may be realized by using parts shared with each part provided in the vehicle. The embodiment is included. For example, it is possible to provide a navigation device, a method, and a program including the parking assist device as described above. Further, some changes may be made as appropriate, such as a part of software and a part of hardware. Furthermore, the invention is also established as a recording medium for a program for controlling the parking assistance device. Of course, the software recording medium may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium to be developed in the future.

Here, embodiments of the present invention will be described in the following order.
(1) Configuration of navigation device:
(2) Parking support processing:
(2-1) Camera image display processing:
(2-2) Parking frame detection process:
(2-3) Expected locus line display processing:
(3) Other embodiments:

(1) Configuration of navigation device:
FIG. 1 is a block diagram showing a configuration of a navigation device 10 including a parking assistance device according to the present invention. The navigation device 10 includes a control unit 20 including a CPU, RAM, ROM, and the like and a storage medium 30, and the control unit 20 can execute a program stored in the storage medium 30 or the ROM. In the present embodiment, the navigation program 21 can be implemented as one of the programs, and the navigation program 21 has a function of assisting when the host vehicle is parked as one of the functions.

  In order to realize a parking assist function in the navigation program 21, the GPS receiver 40, the shift device 41, the camera 42, the vehicle speed sensor 43, the steering angle sensor 44, and the display are displayed on the own vehicle (the vehicle on which the navigation device 10 is mounted). A unit 45 is provided, and transmission / reception of signals between these units and the control unit 20 is realized by an interface (not shown).

  The GPS receiver 40 receives radio waves from GPS satellites and outputs information for calculating the current position of the host vehicle via an interface (not shown). The control unit 20 acquires this signal and acquires the current position of the host vehicle. Moreover, the control part 20 can acquire the information which shows a shift position from the shift apparatus 41 of the own vehicle via the interface which is not shown in figure.

  The camera 42 is attached to the host vehicle so as to include the surroundings of the host vehicle (in the present embodiment, the rear of the host vehicle) in the field of view, and sequentially outputs image data indicating captured images. The control unit 20 acquires this image data via an interface (not shown) and uses it for parking assistance and various types of guidance.

  The vehicle speed sensor 43 outputs a signal corresponding to the rotational speed of the wheels provided in the host vehicle. The control unit 20 acquires this signal via an interface (not shown), and acquires the speed of the host vehicle. The steering angle sensor 44 outputs a signal corresponding to the rotation angle of the steering of the host vehicle. The control unit 20 acquires this signal via an interface (not shown), and acquires information indicating the steering rotation angle. In the present embodiment, the speed of the host vehicle and the rotation angle of the steering are referred to when deriving an expected trajectory line, synthesizing an image, and specifying an extension line.

  By executing the navigation program 21, the control unit 20 outputs information indicating a route to the destination and information for parking assistance based on various information acquired as described above. That is, the control unit 20 outputs a control signal for performing various types of guidance based on the image to the display unit 45 and displays the image on the display unit 45. Of course, you may give various guidance using a speaker.

  In this embodiment, it has the function to display the image for parking assistance as a part of function of the above navigation program 21, The navigation apparatus 10 functions as a parking assistance apparatus concerning this invention by this process. . In order to perform this processing, the navigation program 21 includes an image acquisition unit 21a, an image display unit 21b, a target parking frame setting unit 21c, a host vehicle motion information acquisition unit 21d, an expected trajectory line deriving unit 21e, an obstacle determination unit 21f, and a parking. And a determination unit 21g.

  The storage medium 30 stores map information 30a for performing guidance by the navigation program 21, and stores overhead view conversion data 30b for converting an image taken by the camera 42 into an overhead view image. The map information 30a includes node data indicating nodes set on the road, link data indicating connection between nodes, data indicating targets, and the like, and is used for specifying the position of the host vehicle and guiding to the destination. The

  The overhead conversion data 30b is data for converting an image acquired by the camera 42 into an overhead image, and the coordinates of each pixel in the image acquired by the camera 42 and the coordinates of each pixel in the image after the overhead conversion. Is table data in which The overhead view conversion data 30b only needs to associate the coordinates of the image before and after the conversion, may define a correspondence relationship for all the coordinate values necessary for the image, and may correspond to a representative coordinate value. Between the representative coordinate values may be calculated by interpolation processing.

  The image acquisition unit 21a is a module that acquires image data from the camera 42 and performs overhead conversion based on the overhead conversion data 30b. The acquired data includes the image display unit 21b, the target parking frame setting unit 21c, and an obstacle determination. It is transferred to the part 21f. The image display unit 21 b outputs a signal for displaying the image indicated by the image data to the display unit 45. In the present embodiment, the image display unit 21b can display two or more images in a superimposed manner, and the expected trajectory line deriving unit 21e described later with respect to the overhead image displayed by the image acquisition unit 21a. It is possible to superimpose an expected trajectory line of the vehicle and display it on the display unit 45. Moreover, based on the determination result of the parking determination part 21g mentioned later, it highlights by changing the color and thickness of an estimated locus line, or blinking. It is also possible to display an extension line of the parking frame on the display unit 45 in a superimposed manner.

  The target parking frame setting unit 21c is a module that detects an empty parking frame from the image obtained by overhead conversion by the image acquisition unit 21a and sets it as a target parking frame. In this embodiment, when two frame lines parallel to the longitudinal direction of the parking frame are detected and it is detected that no vehicle is present inside the two frame lines, end points are extracted for each of the frame lines. , Get its coordinates. The coordinates of the end points are used for determination performed by an obstacle determination unit 21f and a parking determination unit 21g described later. In addition, when the target parking frame set by the target parking frame setting unit 21c is outside the display range of the display unit 45, an extension line of the parking frame is specified based on the coordinates of the end points, and the extension line It is used when generating an image showing The image display unit 21b generates an image indicating the extension line and causes the display unit 45 to display an image superimposed on the overhead image.

  The obstacle determination unit 21f is arranged in a region adjacent to the long side of the target parking frame based on the image obtained by overhead conversion by the image acquisition unit 21a and the position of the target parking frame set by the target parking frame setting unit 21c. It is determined whether there is an obstacle. The determination of the obstacle may be performed on both sides of the target parking frame, or on an area adjacent to the longitudinal side on the inner ring side of the own vehicle when the own vehicle turns and enters the target parking frame. It may be done. The obstacle is not limited to other vehicles, and may be a fence, a fence, a cliff, a hole, or the like.

  The own vehicle operation information acquisition unit 21 d is a module that acquires information output from the vehicle speed sensor 43 and the steering angle sensor 44. Output information from a gyro sensor, a geomagnetic sensor, or the like (not shown) may be used. The predicted trajectory line deriving unit 21e is a module for deriving an expected trajectory line based on information indicating the motion of the host vehicle acquired by the host vehicle motion information acquiring unit 21d.

  The parking determination unit 21g includes the direction of the frame line of the target parking frame set by the target parking frame setting unit 21c and the position of the end point thereof, information indicating the predicted trajectory line by the predicted trajectory line deriving unit 21e, and the obstacle determination unit 21f. This is a module for determining whether the host vehicle can be parked in the target parking frame based on the determination result.

(2) Parking support processing:
Next, guidance processing performed by the navigation device 10 in the above configuration will be described. 2-6 is a flowchart which shows the process of the navigation program 21 in this embodiment, and has shown the process regarding parking assistance. In the present embodiment, the navigation program 21 is started together with various devices such as the camera 42 by turning on the ignition switch of the host vehicle (step S100).

  The navigation program 21 determines whether or not the start trigger of the parking assistance process has been detected while executing the guidance process of the host vehicle (step S200). The start trigger in this embodiment is a signal indicating that the shift position of the shift device has been switched to reverse, and the navigation program 21 detects a signal from the shift device 41 in order to detect this start trigger, Based on this signal, it detects that it switched to reverse.

  When the start trigger is detected in step S200, the image acquisition unit 21a acquires the image from the camera 42 and performs overhead conversion, and the image display unit 21b displays the overhead image on the display unit 45 (step S300: camera image). Display processing). In the present embodiment, the target parking frame setting unit 21c detects the target parking frame in order to superimpose the extension line depending on the relationship between the display range of the overhead image and the parking frame. When the target parking frame is outside the display range on the display unit 45, a process for superimposing the extension line on the image is performed (step S400: parking frame detection / drawing process).

  Further, in the present embodiment, the image display unit 21b has a function of superimposing an expected trajectory line indicating an expected course of the host vehicle in order to reliably support entry into the target parking frame, and subsequent to step S400. A process of displaying the predicted locus line is performed (step S500). In the present embodiment, parking assistance is performed by performing the above steps S300 to S500 for one frame of images continuously acquired by the camera 42. That is, after carrying out the above processing, it is determined whether or not a parking assistance end trigger (in this embodiment, a signal indicating that the shift position is parked in the shift device 41) has been detected (step S1). S600) If the end trigger is not detected, the process target frame is set as the next frame, and steps S300 to S500 are repeated.

(2-1) Camera image display processing:
Next, the process in step S300 will be described in detail. In this process, the image acquisition unit 21a acquires an image from the camera 42 (step S310), and acquires an overhead image of the image acquired by the camera 42 with reference to the overhead conversion data 30b (step S320). In other words, in the present embodiment, the image provided to the driver for parking assistance is an image obtained by viewing the host vehicle from above, and provides an intuitively easy-to-understand image for the driver. The image data after the overhead conversion is recorded in a memory (not shown).

  7 and 8 show examples of overhead images displayed on the display unit 45. In each of FIGS. 7A, 7B, 8A, and 8B, examples of screens of the display unit 45 are rectangular (45a). Is shown. Further, in FIG. 7A, another vehicle C is parked in the parking frames on both sides of the empty parking frame F (a frame in which no vehicle is present inside the parking frame), and the own vehicle M moves backward and the empty parking frame F The example of the bird's-eye view image of the state which is trying to park is shown.

  In this embodiment, the camera 42 is attached to the rear part of the host vehicle M, and the range below the broken line E in FIG. In this example, the overhead view conversion data 30b is obtained by associating the coordinates in the image when the road surface is photographed obliquely with the camera 42 with the coordinates below the broken line E in FIG. The coordinates of the image are converted based on this correspondence, and the image data is recorded in the memory (not shown) to obtain an overhead image such as the lower part of the broken line E shown in FIG. 7A. In the present embodiment, a part of the image after the overhead conversion is displayed on the display unit 45, and an image having a predetermined coordinate is extracted from the image after the overhead conversion and recorded in the memory. It has become.

  On the other hand, in the present embodiment, a configuration is adopted in which an image of the host vehicle M itself and an image of the side of the host vehicle M are displayed above the broken line E (portion corresponding to outside the field of view of the camera 42). The display unit 21b performs a process of combining these images with the image after the overhead conversion (step S330). That is, the image data of the own vehicle M is prepared in advance, and the image data is recorded in the memory (not shown) to display the own vehicle M at a predetermined position.

  Furthermore, the side image of the host vehicle M is generated based on the image of the previous frame. That is, when the host vehicle M moves backward, the field of view of the camera 42 in the frame before the present includes an area outside the field of view of the camera 42 in the current frame (an image on the side of the host vehicle M). Yes. Therefore, if the information output from the vehicle speed sensor 43 and the steering angle sensor 44 is acquired and the operation of the host vehicle M is detected, the side image of the host vehicle M in the current frame is associated with the image in the previous frame. The image of the side of the host vehicle M in the current frame can be extracted from the frame before the current time.

  Therefore, in the present embodiment, an image of the side of the host vehicle M in the current frame is extracted from the image of the previous frame, and appropriately moved based on the operation of the host vehicle M so as to be displayed at an appropriate position. , Rotate and record in the memory (not shown). When the image data to be displayed on the display unit 45 is recorded in the memory as described above, the image display unit 21b outputs the data to the display unit 45 (step S340), and an image for parking assistance is displayed on the display unit 45. indicate. By performing the camera image display process as described above in the loop of steps S300 to S600 shown in FIG. 2, an image as shown in FIG. 7A or 7B is displayed on the display unit 45 in accordance with the operation of the host vehicle M. Is displayed.

(2-2) Parking frame detection process:
Next, the process in step S400 will be described in detail. The target parking frame setting unit 21c performs processing for detecting an empty parking frame based on the image after overhead conversion acquired by the image acquisition unit 21a and processing for displaying an extended line of the parking frame. Therefore, the target parking frame setting unit 21c determines whether or not the target parking frame has not been detected (step S410). That is, it is determined whether or not a flag indicating that the target parking frame has been detected has been set in a loop before this determination timing.

  When it is determined in step S410 that the target parking frame has not been detected, a process of detecting a white line from the overhead image is performed (step S420). That is, a pixel having a predetermined gradation range (gradation range corresponding to white) and a portion where the edges are arranged in a straight line is detected. The detection of the straight line can be performed by a known method such as Hough transform.

  When the white line detection process is performed, the target parking frame setting unit 21c further detects a pair of white lines (step S430). That is, a plurality of white lines are detected, and it is determined whether or not there is a set that is substantially parallel and substantially equal in length among these white lines, so that the detected white lines are the white lines of the parking frame. It is determined whether or not there is. When the white line pair is not detected in step S430, the flow shown in FIG. 4 is exited and the process returns to the loop shown in FIG.

  When a pair of white lines is detected in step S430, it is determined based on the pattern, color, etc. between the white lines whether a vehicle is present between these white lines (step S440). That is, if the image between the white lines is a uniform image corresponding to the image of the road surface, the vehicle does not exist, and if the image between the white lines reflects an image more complicated than the road surface or an image of the vehicle, the vehicle It is determined whether or not the parking frame is an empty parking frame. If the determination in step S440 is false, the process exits the flow shown in FIG. 4 and returns to the loop shown in FIG.

When it is determined in step S440 that no vehicle exists between the white lines (that is, an empty parking frame is detected), a flag indicating the detection is set, and the empty parking frame is set as the target parking frame. The coordinates indicating the end points of these white line pairs are acquired (step S450). For example, the end points P _{1 to} P ₄ of the parking frame F shown in FIG. 7A are specified, and the coordinates on the overhead image are specified.

On the other hand, when it is not determined in step S410 that the target parking frame has not been detected, an extension line drawing process is performed in a process after step S460 for the case where the parking frame F is outside the display range of the display unit 45. . Therefore, the information output from the vehicle speed sensor 43 and the rudder angle sensor 44 is acquired to detect the displacement amount of the host vehicle M (step S460), and the end points of the parking frame in the overhead image of the current frame based on this displacement amount. coordinates of P ₁ to P ₄ is corrected (step S470). That is, the coordinates of the end points P _{1 to} P ₄ stored in the memory before starting step S460 are the coordinates on the overhead image in the previous frame, but the endpoint P ₁ in the overhead image in the current frame. coordinates to P ₄ varies depending on the variation of the vehicle M. Therefore, the coordinates are corrected based on the vehicle speed sensor 43 and the rudder angle sensor 44 as in step S330.

Next, it is determined whether or not the parking frame F is outside the display range of the display unit 45 based on the coordinates of the end points P _{1 to} P ₄ (step S480). That is, as described above, the display unit 45 is configured to display a range of coordinates set in advance in the coordinate system in the image after the overhead conversion, so that the end points P _{1 to} P ₄ of the parking frame F are displayed. It is determined whether or not the parking frame F is outside the display range of the display unit 45 based on the coordinates. If it is not determined in step S480 that the parking frame F is outside the display range of the display unit 45, the relationship between the host vehicle M and the parking frame F is clear from the display on the display unit 45, and thus is illustrated in FIG. Returning to the loop shown in FIG. 2 through the flow.

  On the other hand, when it is determined in step S480 that the parking frame F is outside the display range of the display unit 45, the parking frame F is prevented in order to prevent the relationship between the host vehicle M and the parking frame F from becoming unclear. A process for drawing an extension line is performed (step S490). That is, an extended line image is generated that extends a straight line connecting the end points of the parking frame F to a predetermined position on the own vehicle M side. In the present embodiment, an extension line is drawn when a straight line is extended from the end point of the parking frame F to the rear end of the host vehicle M, and the intersection of the extension line of the parking frame F and the rear end of the host vehicle M is drawn. Is specified, and broken line image data connecting the intersection and the end point of the parking frame F is generated and transferred to the image display unit 21b. As a result, the image display unit 21b acquires the image data, records it in the memory (not shown), and displays an image in which the extension line is superimposed on the display unit 45.

  7A, 7B, and 8A are examples corresponding to the flow of images when the vehicle M attempts to park by turning back. That is, FIG. 7A is an example of a bird's-eye view when trying to park by approaching the parking frame F (target parking frame) while moving backward on the host vehicle M, and FIG. Is an example of a bird's-eye view image when the vehicle cannot be moved backward as it is due to the relationship with the other vehicle C around.

In such a situation, the driver of the host vehicle M performs a turnover that moves forward once and then reverses again. FIG. 8A is a display example on the display unit 45 when the host vehicle M is once moved forward. In this example, the parking frame F has reached the outside of the display range of the screen 45a. In this case, the relationship between the parking frame F and the host vehicle M cannot be grasped only from the display image of the display unit 45, but in the present embodiment, each of the end points P ₁ and P ₂ of the parking frame F as described above. The extension line L is displayed on the side of the host vehicle M up to the rear end of the host vehicle M (the position of the broken line B shown in FIG. 8A). Therefore, the driver of the host vehicle M can grasp the relationship between the host vehicle M and the parking frame F very easily by the extension line L of the screen 45a. Of course, it is only necessary to show that the extension line L is an extension line of the parking frame F, and various lines such as a broken line and a solid line can be adopted, and various aspects can be adopted as a display aspect such as blinking the line. Is possible.

(2-3) Expected trajectory line display processing:
Next, the process in step S500 will be described in detail. In order to appropriately guide the host vehicle M to the parking frame F, the image display unit 21b displays the predicted trajectory of the host vehicle M on the display unit 45, and when the predicted trajectory matches the parking frame F. Highlight. Therefore, the host vehicle operation information acquisition unit 21d acquires information output from the steering angle sensor 44 to acquire the steering angle in the host vehicle M (step S510), and the predicted trajectory line deriving unit 21e is based on the steering angle. The coordinates for drawing the expected trajectory line of the host vehicle M are specified (step S520).

  That is, in the present embodiment, a plurality of positions (from which the left rear end and the right rear end of the host vehicle are predicted to pass when traveling backward at each rudder angle from information such as the wheel base of the host vehicle M in advance) Coordinates on the bird's-eye view image) are specified. Therefore, in step S520, the predicted trajectory line deriving unit 21e performs calculation to generate a line connecting the plurality of positions to be an expected trajectory line, and records image data indicating the line in the memory (not shown). In the present embodiment, the predicted trajectory line is a line indicating the course of the left and right rear ends of the host vehicle. For example, the line O illustrated in FIGS. 7A and 8A is the predicted trajectory line of the host vehicle M in each state. . As described above, when the course of the left and right rear ends of the host vehicle is shown as an expected trajectory line, when the host vehicle is parked in the parking frame F, the relationship with the parked other vehicle C or the like is clearly grasped. It is possible to easily determine whether or not switching is necessary.

  Furthermore, in the present embodiment, in order to make the parking operation of the host vehicle M easier, when the predicted trajectory is such that the host vehicle M can be parked in the parking frame F without interfering with other vehicles, the prediction The locus is highlighted. For this reason, the parking determination unit 21g determines whether or not the expected trajectory line matches the frame line of the parking frame F (step S530). Here, it is called that the state in which the host vehicle can be parked in the parking frame F when the vehicle travels backward on the expected trajectory line is met. When it is determined in step S530 that the predicted trajectory line matches the frame line of the parking frame F, the predicted trajectory line deriving unit 21e performs setting for enhancing the expected trajectory line (step S540). When the frame line of the parking frame F does not match, the step S540 is skipped.

  That is, when emphasizing the expected trajectory line, the image data recorded in the memory (not shown) in step S520 is corrected, and the line is thickened, changed to a conspicuous color, or the line type is changed. Data is recorded in the memory. Then, the image display unit 21b performs display based on the image data recorded in the memory in the display unit 45 (step S550), so that the expected trajectory line is emphasized when the course is appropriate, and the course is changed. When it is inappropriate, parking assistance can be performed in a state where the expected trajectory line is not emphasized. Therefore, the driver can park very easily. FIG. 8B shows an example in which the predicted trajectory line O is emphasized by a thick line.

  Next, the process in step S530 will be described in detail. FIG. 6 is a flowchart showing the match determination processing in step S530, and FIG. 9 is an explanatory view illustrating the relationship between the host vehicle M and the parking frame F at the time of match determination. The parking determination unit 21g calculates a tangent and a contact point of the predicted trajectory line in order to determine whether or not the predicted trajectory line matches the frame line of the parking frame F (step S531). Here, the tangent of the predicted trajectory line is a tangent parallel to the parking frame F, and the parking determination unit 21g acquires the coordinates for drawing the predicted trajectory line acquired in step S520, and the predicted trajectory line Get the tangent and contact in the drawn state.

  When the tangent line and the contact point of the predicted trajectory line are obtained, the parking determination unit 21g determines whether or not the tangent line of the predicted trajectory line exists inside the white line pair of the parking frame F (step S532). That is, when the tangent line of the predicted trajectory line exists between the white line pair of the parking frame F, the host vehicle M is moved backward and the longitudinal direction of the own vehicle is directed parallel to the white line pair between the white line pair of the parking frame F. Means you can. Therefore, in the present embodiment, first, it is determined whether or not the tangent line of the predicted trajectory line exists inside the white line pair. If it is not determined that the tangent line exists inside the white line pair, the processing of FIG. 6 is skipped. The process returns to the process shown in FIG.

In step S532, when it is determined that the tangent line of the predicted trajectory line exists inside the white line pair of the parking frame F, in the present embodiment, the predicted trajectory is further considered in consideration of the presence of other vehicles in the adjacent parking frame. It is determined whether or not the line and the parking frame F match. Figure 9A, in 9B, shows the predicted locus line O and the tangent L _T and the contact P _c of the vehicle M in overhead view of the vehicle M and the parking frame F.

In any of these examples, the expected trajectory line O exists inside the pair of white lines of the parking frame F. However, in FIG. 9A, the contact point P _c exists on the own vehicle side from the parking frame F. However, the other vehicle C and the host vehicle M do not interfere with each other. On the other hand, in the example shown in FIG. 9B, since the contact point P _c exists between the parking frames F, there is a possibility that the other vehicle C and the own vehicle M interfere with each other when the own vehicle M travels as it is.

Therefore, the obstacle determination unit 21f determines whether or not both sides of the white line pair where the tangent to the predicted trajectory line is an empty parking frame (step S533), and the parking determination unit 21g determines that the both sides are empty parking frames. If there is, it is determined as coincidence (step S535). That is, the setting is made so that step S530 is true in FIG. When it is not determined in step S533 that the adjacent white line pair where the tangent to the expected trajectory line exists is an empty parking frame, the parking determination unit 21g determines that the contact point _Pc is in front of the parking frame (end points P ₁ and P ₂ and the host vehicle). It is determined whether or not it exists (step S534). If it is determined in step S534 that the contact point _Pc is present in front of the parking frame, a match determination is made (step S535). If it is not determined that the contact point _Pc is present in front of the parking frame, step S535 is skipped. To do.

  As described above, when another vehicle is parked on both sides of the target parking frame, the contact point between the tangent line and the expected trajectory line should be on the own vehicle side from the end point on the own vehicle side of the long side of the target parking frame. Can be avoided as a condition for determining whether or not parking is possible, thereby avoiding the possibility of contacting other vehicles parked on both sides. In addition, when no other vehicle is parked on both sides of the target parking frame, it is not determined that parking is impossible even if the contact point is not on the own vehicle side from the end of the long side, so there is a space adjacent to the target parking frame. When it is sufficiently wide, the allowable range for determining that parking is possible widens, and the degree of freedom of operation by the driver can be increased.

(3) Other embodiments:
The above embodiment is an example for carrying out the present invention, and the host vehicle is the target based on the positional relationship between the tangent line of the expected trajectory line derived based on the operation of the host vehicle and the frame line of the target parking frame. As long as it can be determined whether parking is possible within the parking frame, various other embodiments can be employed.

  In the above-described embodiment, after the parking frame F is once displayed on the display unit 45, an extension line of the parking frame is displayed when the parking frame F is outside the display range. If the parking frame F can be detected even before it is displayed, the extension line can be displayed. More specifically, the image captured by the camera 42 includes a parking frame. However, when the image is overhead-converted and a part thereof is displayed on the display unit 45, the parking frame is out of the image display range. Sometimes it becomes. In this case, even if the parking frame is outside the display range, the parking frame can be detected based on the image, and an extension line of the parking frame can be displayed on the display unit 45. Therefore, it is possible to display an extended line of the parking frame in a state where the turn-over is not performed once. Of course, the detection of the parking frame may be performed on the image after the overhead view conversion, or may be performed on the image captured by the camera 42.

  Furthermore, in the above-described embodiment, the display image on the display unit 45 is an overhead image, but parking assistance may be performed using an image captured by the camera 42 instead of the overhead image. Even in this case, it is possible to clearly present the relationship between the host vehicle and the parking frame by displaying an extension line of the parking frame when the parking frame is outside the display range of the image. Furthermore, as a display mode of the image on the display unit 45, in addition to fixing the position of the host vehicle M, a configuration in which the position of the parking frame F is fixed may be employed, or fixed to other reference objects. Various configurations may be employed.

  Furthermore, the parking assistance start trigger is not limited to the output signal of the shift device, and parking assistance may be started by a driver's instruction, or when the entry to the parking lot is confirmed by the navigation device. Parking assistance may be started, and various configurations can be employed. In the above-described embodiment, the parking frame is assumed to be a white line and a parallel straight line, but of course, the characteristics of the parking frame (color, shape, difference from the road surface other than the frame, etc.) are imaged. Any configuration extracted from can be used. For example, if the color of the parking frame is not a white line but another color, the other color frame is detected. If the parking frame is a rectangular frame, the rectangular frame is detected. It becomes the structure according to the color, shape, etc. of a parking frame.

  Furthermore, in the above-described embodiment, it is determined whether or not both sides of the empty parking frame that the vehicle M intends to park are empty parking frames, but of course, it is determined whether or not one is an empty parking frame. And when one is an empty parking frame and the other is a parked parking frame, it is good also as a structure which discriminate | determines whether the other vehicle and the own vehicle M on the said parked parking frame interfere. For example, when one of the adjacent frames of the parking frame in which the host vehicle is parked is an empty parking frame and the other is a parked parking frame, the expected trajectory line of the own vehicle M exists inside the one empty parking frame. For example, it is possible to adopt a configuration in which an expected trajectory line is set to be emphasized, and if the expected trajectory line exists inside the other parked parking frame, the expected trajectory line is not set to be emphasized. Further, the determination of the position of the contact point between the predicted trajectory line and the tangent line parallel to the target parking frame may be performed with respect to the contact point of one of the predicted trajectory lines on the inner peripheral side or the outer peripheral side of the host vehicle. , May be performed for both contacts.

  Furthermore, in the above-described embodiment, an extension line is displayed when all of the parking frame is outside the display range of the display unit 45, but a part of the parking frame is displayed on the display range of the display unit 45. If the relationship between the vehicle and the parking frame becomes unclear by going outside, it can be configured to display an extension line when a part of the parking frame is outside the display range. is there. In addition, when carrying out parallel parking, in addition to the configuration in which the frame line parallel to the longitudinal direction of the parking frame is extended and displayed, the configuration in which the frame line parallel to the short direction of the parking frame is extended and displayed It may be adopted.

  The means for notifying the driver that parking is possible is not limited to the image display means of the above embodiment, and any means for guiding information indicating the determination result by the parking determination means may be employed, for example, a speaker The driver may be notified by voice using. Further, for example, the predicted trajectory line may not be displayed when it is not determined that parking is possible, and the expected trajectory line may be displayed only when it is determined that parking is possible. The predicted trajectory line is not limited to being displayed as two lines, but may be displayed as a band-like region including the predicted trajectory line as an outline.

  In addition, the parking determination unit 21g may vary the threshold value of the position of the contact that determines that parking is possible, for example, according to the position of an obstacle with respect to the long side of the target parking frame. That is, it is possible to adopt a configuration in which the position of the contact for determining whether or not parking is possible is set farther from the own vehicle as the distance from the end point on the own vehicle side to the obstacle on the longer side of the target parking frame becomes longer. For example, when an obstacle existing in a region adjacent to the outside of the long side is located farther from the center of the long side of the target parking frame when viewed from the host vehicle, the distance between the end point and the center position It is possible to adopt a configuration that determines that parking is possible when there is a contact at a predetermined position. As a result, the allowable range for determining that parking is possible widens, and the degree of freedom of operation by the driver can be further increased.

It is a block diagram of the navigation apparatus containing a parking assistance apparatus. It is a flowchart which shows a parking assistance process. It is a flowchart of a camera image display process. It is a flowchart of a parking frame detection / drawing process. It is a flowchart of an expected locus line display process. It is a flowchart of a match determination process. (7A) and (7B) are diagrams showing examples of overhead images. (8A) and (8B) are diagrams showing examples of overhead images. (9A) and (9B) are explanatory views illustrating the relationship between the host vehicle M and the parking frame F at the time of match determination.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Navigation apparatus, 20 ... Control part, 21 ... Navigation program, 21a ... Image acquisition part, 21b ... Image display part, 21c ... Target parking frame setting part, 21d ... Own vehicle operation information acquisition part, 21e ... Expected locus line derivation Part, 21f ... obstacle judgment part, 21g ... parking judgment part, 30 ... storage medium, 30a ... map information, 30b ... overhead view conversion data, 40 ... GPS reception part, 41 ... shift device, 42 ... camera, 43 ... vehicle speed sensor 44 ... rudder angle sensor, 45 ... display unit

Claims (4)

Image acquisition means for acquiring an image around the host vehicle;
Target parking frame setting means for setting an empty parking frame included in the acquired image as a target parking frame;
Own vehicle operation information acquisition means for acquiring information indicating the operation of the own vehicle;
Expected trajectory line deriving means for deriving the expected trajectory lines at the left end and the right end of the host vehicle based on the operation of the host vehicle;
When two tangents that are parallel to the two long sides of the target parking frame that are tangents to the expected trajectory line at the left end and the right end of the host vehicle are present inside the two long sides, the target parking frame Parking determination means for determining that the host vehicle can be parked inside;
A parking assistance device comprising: An obstacle determination means for determining whether an obstacle exists in an area adjacent to the outside of the longitudinal side of the target parking frame;
When it is determined that the obstacle is present, the parking determination unit performs parking when the contact point between the tangent line and the expected trajectory line exists on the own vehicle side from the end point on the own vehicle side of the long side. Determine that it is possible,
The parking assistance device according to claim 1. Image display means for displaying the image;
The image display means highlights the predicted trajectory line when it is determined that the host vehicle can be parked.
The parking assistance device according to claim 1 or 2. An image acquisition step of acquiring an image around the host vehicle;
A target parking frame setting step of setting an empty parking frame included in the acquired image as a target parking frame;
A host vehicle operation information acquisition step of acquiring information indicating the operation of the host vehicle;
An expected trajectory line deriving step of deriving the expected trajectory lines at the left end and the right end of the host vehicle based on the operation of the host vehicle;
When two tangents that are parallel to the two long sides of the target parking frame that are tangents to the expected trajectory line at the left end and the right end of the host vehicle are present inside the two long sides, the target parking frame A parking determination step for determining that the host vehicle can be parked inside;
Parking assistance method including.

Images