JP2014071001A - System, method and program for guiding recommended lane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that can guide a position of a recommended lane so as to follow a change in an image of the recommended lane in a front landscape, even when a vehicle moves in a width direction of the lane.SOLUTION: A recommended lane guidance system includes: recommended lane acquiring means for acquiring a recommended lane on which a vehicle should drive; reference line setting means for identifying an image of the recommended lane in a display image in which landscape in front of the vehicle is captured, and for setting a reference line so as to follow the image of the identified recommended lane; and display controlling means for displaying on a display unit the front landscape on which a guidance image is overlapped, the guidance image including the recommended lane portion of which the reference line is set as a center line. When the vehicle starts to move in the width direction, the display controlling means acquires a line formed by moving the reference line set at a start time at which the vehicle starts to move in a width direction the lane, to the opposite to the moving direction of the vehicle in the width direction of the lane, and allows the display unit to overlap the guidance image including the recommended lane portion of which the acquired line is set as the center line on the front landscape and display a resulting image on the display unit.

Description

  The present invention relates to a recommended lane guidance system, method, and program for guiding recommended lanes that a vehicle should travel.

  2. Description of the Related Art Conventionally, a technique is known in which an arrow is superimposed and displayed on a road image obtained by photographing the front of a vehicle with a camera provided in the vehicle (see Patent Document 1). In Patent Document 1, an arrow that generates a line representing the center of a guided traveling lane that is a lane that can exit in a guided branching direction at a branching point, and guides the position of the guided traveling lane by giving the generated line a width. Is generated.

Japanese Patent Laid-Open No. 10-281795

In Patent Document 1, the center line of the guide lane is set based on the position of the node recorded in the map information. Therefore, if the position of the node is inaccurate, the arrow guides the position deviated from the guide lane. Resulting in. On the other hand, if an arrow is superimposed on the image of the guide travel lane in the road image based on the position of the image of the guide travel lane recognized by the image recognition of the road image, the position shifted from the guide travel lane. Can be prevented from being guided by the arrow.
However, when the vehicle moves in the width direction of the lane, the shape, position, and direction of the image of the guided travel lane in the road image change, so that the recognition accuracy of the image of the guided travel lane deteriorates or the image of the guided travel lane There was a case that recognition of was delayed. In such a case, the arrow guides the position deviating from the guidance travel lane.
The present invention has been made in view of the above problems, and provides a technique capable of guiding the position of a recommended lane so as to follow the change in the image of the recommended lane in the forward scenery even when the vehicle moves in the width direction of the lane. With the goal.

  In order to achieve the above object, in the present invention, the recommended lane acquisition means acquires a recommended lane that the vehicle should travel. The reference line setting unit recognizes an image of a recommended lane in an image obtained by capturing a front landscape of the vehicle, and sets a reference line so as to follow the recognized image of the recommended lane. The display control means causes the display unit to display a guide image including a recommended lane portion having the reference line as the center line, superimposed on the front scenery. Further, when the vehicle starts moving in the width direction of the lane, the display control means displays a reference line (hereinafter referred to as a start reference line) set at the start time when the vehicle starts moving in the width direction of the lane. A line moved in the direction opposite to the moving direction of the vehicle in the width direction (hereinafter referred to as a movement reference line) is acquired, and a guide image including a recommended lane portion with the movement reference line as a central line is superimposed on the front landscape. Display on the display.

  When the vehicle moves in the width direction of the lane, the image of the recommended lane moves in the direction opposite to the moving direction of the vehicle in the width direction of the lane in the front landscape. For example, if the vehicle moves to the right, the recommended lane image moves to the left in the forward scenery. Therefore, the recommended lane image after the start time when the vehicle starts moving in the lane width direction moves in the opposite direction to the vehicle movement direction in the lane width direction than the recommended lane image at the start time. It will exist at the position. Therefore, the movement in which the start reference line set based on the recommended lane image recognized at the start time when the vehicle starts moving in the width direction of the lane is moved in the direction opposite to the moving direction of the vehicle in the width direction of the lane. The reference line is a line at a position following the movement of the recommended lane image after the start time. Therefore, when the vehicle moves in the width direction of the lane, the recommended lane portion is displayed so as to follow the movement of the image of the recommended lane in the forward scenery by setting the movement reference line as the center line of the recommended lane portion. be able to. If the position of the start reference line is recorded, the movement reference line can be set regardless of the recognition result of the recommended lane image after the start time when the vehicle starts moving in the width direction of the lane. Therefore, after the vehicle starts moving in the width direction of the lane, even if the recognition accuracy of the recommended lane image has deteriorated or the recognition of the recommended lane image is delayed, The recommended lane portion can be displayed so as to follow the movement of the image. Further, even when the recommended lane image cannot be recognized or when the recommended lane image is not recognized, the recommended lane portion can be displayed so as to follow the movement of the recommended lane image in the forward scenery.

  Here, the recommended lane is a lane in which traveling is recommended among lanes constituting a traveling road that is a road on which the vehicle is traveling. For example, the recommended lane may be a lane that can exit to a road on the planned travel route among roads connected to an intersection on the planned travel route. The reference line setting means may recognize the image of the left and right lane markings of the recommended lane by a known line recognition method, and may recognize the region sandwiched between the recognized lane marking images as the recommended lane image. The reference line setting means may set the reference line along the recommended lane image, and may set the reference line in the length direction of the recommended lane image within the recommended lane image. For example, the reference line setting unit may set a reference line whose parallelism with respect to a line in the length direction of the recommended lane image is equal to or greater than a threshold value. The length direction of the recommended lane image in the front landscape represents the lane direction of the recommended lane. The lane direction is the direction in which the vehicle travels on the lane along the lane, and is the direction of the lane markings. On the other hand, the width direction of the lane is the vehicle width direction of the vehicle traveling on the lane, and is a direction orthogonal to the direction of the lane markings.

  The display control means may be such that the reference line constitutes the center line of the recommended lane portion, and the recommended lane portion may be geometrically divided into two by the reference line. The display control means may superimpose a guidance image including a recommended lane portion on the front landscape, and the guidance image may include a portion other than the recommended lane portion, or may be configured by only the recommended lane portion.

  The display control means determines whether or not the vehicle has started moving in the width direction of the lane, but whether or not the vehicle has started moving in the width direction of the lane based on the image recognition of the image obtained by capturing the front landscape. May be determined. Further, the display control means may determine whether or not the vehicle has started moving in the width direction of the lane based on an output signal of a sensor that detects the state of the vehicle (movement state, operation state, etc.). The moving direction of the vehicle in the width direction of the lane may be a direction approaching the recommended lane or a direction away from the recommended lane.

  The display control means may superimpose the guide image on an image representing the front scenery (hereinafter referred to as a front image). That is, the display control unit may superimpose the guide image on the front image and display the front image on which the guide image is superimposed on the display unit. The front image may be an image obtained by photographing a front landscape by an image sensor, or may be an image obtained by drawing the front landscape based on map information. Furthermore, the display unit may be configured as a head-up display that displays the guidance image so as to be superimposed on an actual front view visually recognized by the driver through the windshield of the vehicle.

  When the vehicle starts moving in the width direction of the lane, the display control means sets the start reference line in the width direction of the lane as the elapsed time from the start time when the vehicle started moving in the width direction of the lane becomes longer. A movement reference line that is largely moved in the opposite direction of the movement direction may be acquired, and a guide image including a recommended lane portion having the movement reference line as a center line may be superimposed on the front landscape and displayed on the display unit. . When the vehicle starts a lane change, the cumulative distance that the vehicle has moved in the lane width direction becomes longer as the elapsed period from the start time at which the vehicle started moving in the lane width direction becomes longer. Therefore, the longer the elapsed time from the start time when the vehicle starts moving in the width direction of the lane, the longer the start reference line is moved, the moving reference line is used, so that an image of the recommended lane from the start time is obtained. The recommended lane portion can be moved by a distance corresponding to the accumulated distance moved in the left-right direction.

  The display control means may increase the movement amount of the movement reference line with respect to the start reference line as the elapsed period from the start time when the vehicle starts moving in the width direction of the lane increases. It may be increased linearly or in a non-linear manner. The amount by which the image of the recommended lane moves left and right in the forward landscape after the start time when the vehicle starts moving in the width direction of the lane depends on the vehicle speed and the steering angle (the inclination of the traveling direction with respect to the lane direction). The display control means may increase the amount of movement of the movement reference line with respect to the start reference line as the vehicle speed or the steering angle increases.

  Further, the display control means, when the vehicle starts moving in the width direction of the lane, the recommended lane maintained at the same width as the width of the recommended lane portion at the start time when the vehicle starts moving in the width direction of the lane. A guidance image including a part may be superimposed on the front scenery and displayed on the display unit. In this way, the same recommended lane is continuously guided even after the start time when the vehicle starts moving in the width direction of the lane by moving the guide image whose width is maintained constant. Can give an impression.

  In addition, when the vehicle starts moving in the width direction of the lane, the display control means displays the recommended lane portion with a narrower width as the elapsed time from the start time when the vehicle started moving in the width direction of the lane becomes longer. The guidance image that is included may be superimposed on the front scenery and displayed on the display unit. By narrowing the width of the recommended lane portion, the possibility that the recommended lane portion protrudes from the image of the recommended lane can be reduced. Therefore, it can be prevented that the recommended lane portion protrudes from the image of the recommended lane to give the impression that the recommended lane portion guides a lane other than the recommended lane.

In addition, when the vehicle starts moving in the direction of approaching the recommended lane in the width direction of the lane, the display control means rotates the start reference line so that the parallelism with the vertical line of the front landscape increases. It is also possible to acquire the movement reference line and display a guidance image including a recommended lane portion with the movement reference line as the center line on the display portion so as to be superimposed on the front landscape. If the direction of the recommended lane is parallel to the direction of travel of the vehicle, the closer the recommended lane is to the vehicle in the width direction of the lane, the closer the image of the recommended lane is to parallel to the vertical line of the front landscape. Rotate. When the vehicle finally travels on the recommended lane, the image of the recommended lane is a vertical image of the front landscape. Therefore, when the vehicle starts to move in the direction of approaching the recommended lane in the width direction of the lane, the movement reference line that is rotated so that the parallelism with respect to the vertical line of the front landscape is increased. By using the center line of the recommended lane portion, the recommended lane portion can be displayed so as to follow the rotation of the image of the recommended lane.
On the other hand, when the vehicle starts to move away from the recommended lane in the width direction of the lane, the movement reference line that is rotated so that the parallelism with the horizontal line of the front landscape is increased is used. The guide image including the recommended lane portion that is acquired and has the movement reference line as the center line may be superimposed on the front scenery and displayed on the display unit. If the direction of the recommended lane is parallel to the direction of travel of the vehicle, the distance of the recommended lane from the vehicle in the width direction of the lane is such that the image of the recommended lane approaches parallel to the horizontal line of the front landscape. This is because it rotates.

Further, immediately after the vehicle starts moving in the width direction of the lane, the traveling direction of the vehicle is inclined with respect to the lane direction, and the viewing direction of the front scenery viewed from the vehicle is also inclined with respect to the lane direction. . When the vehicle starts to move to the left in the width direction of the lane, that is, when the viewing direction of the front landscape rotates counterclockwise in plan view, the image of the recommended lane rotates clockwise in the front landscape. Therefore, the display control means includes a recommended lane portion including a recommended lane portion whose center line is a line obtained by rotating the start reference line clockwise in a predetermined period immediately after the vehicle starts moving leftward in the lane width direction. The image may be displayed on the display unit so as to be superimposed on the front landscape. Thereby, even immediately after the vehicle starts moving in the left direction in the width direction of the lane, the recommended lane portion can be displayed so as to follow the rotation of the image of the recommended lane in the forward scenery.
Conversely, the display control means acquires a line obtained by rotating the start reference line counterclockwise in a predetermined period immediately after the vehicle starts moving rightward in the width direction of the lane, and the acquired line is centered. A guide image including a recommended lane portion that is a line of sq. Thereby, even immediately after the vehicle starts moving in the right direction in the width direction of the lane, the recommended lane portion can be displayed so as to follow the rotation of the image of the recommended lane in the forward scenery.

  Further, the display control means may determine whether or not the vehicle has started moving in the width direction of the lane based on the positional relationship between the lane markings of the traveling lane in which the vehicle is traveling and the vehicle. For example, the display control unit may determine that the vehicle has started moving in the width direction of the lane when the vehicle approaches the lane marking of the travel lane within a predetermined distance. Further, the display control means may determine that the vehicle has started moving in the width direction of the lane when moving in the width direction by a predetermined distance or more from the center line in the width direction of the traveling lane.

  The display control means may determine that the vehicle has started moving in the width direction of the lane when the inclination of the traveling direction of the vehicle with respect to the lane marking of the traveling lane in which the vehicle is traveling is equal to or greater than a threshold value. That is, the display control means may determine that the vehicle has started moving in the width direction of the lane when the traveling direction of the vehicle is greatly inclined with respect to the lane direction. When the traveling direction of the vehicle is greatly inclined with respect to the lane direction, the direction of the recommended lane image in the forward scenery changes, and it is difficult to recognize the recommended lane image. Therefore, in a situation where the recognition of the recommended lane image is difficult, it is possible to switch to a state in which the recommended lane portion is generated regardless of the recognition of the recommended lane image. The threshold value may be the inclination of the traveling direction of the vehicle with respect to the lane marking when the recommended lane image is difficult to recognize. For example, the recognition accuracy and the recognition reliability of the recommended lane image deteriorate to a predetermined value. The inclination of the traveling direction of the vehicle with respect to the lane marking of the traveling lane may be used. Furthermore, the threshold value may be an upper limit value of the inclination of the traveling direction of the vehicle with respect to the lane marking of the traveling lane when the vehicle travels as it is on the traveling lane without changing the lane (simply when the vehicle fluctuates). . If the lane is not changed, it is predicted that the inclination of the traveling direction of the vehicle with respect to the lane marking of the traveling lane will temporarily increase again, and the recognition accuracy and recognition reliability of the recommended lane image are improved. This is because it is predicted.

  Furthermore, as in the present invention, the method of guiding recommended lanes using guide images can also be applied as a program or method. In addition, the recommended lane guidance system, program, and method described above may be realized as a single device or may be realized using parts shared with each part provided in the vehicle. Including embodiments. That is, each means constituting the recommended lane guidance system may be distributed and provided in a plurality of substantial devices. When each means is distributed and provided in a plurality of substantive devices, a communication means for transmitting and receiving data necessary to make each means function may be provided. Furthermore, it is possible to provide a navigation device, method, and program that include at least a part of the recommended lane guidance system as described above. Further, some changes may be made as appropriate, such as a part of software and a part of hardware. Furthermore, the present invention can be realized as a recording medium for a program for controlling the recommended lane guidance system. 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.

It is a block diagram of a navigation apparatus. (2A)-(2C) is a figure which shows the visual field of a camera, (2D) is a figure which shows a front image. (3A) to (3C) are diagrams showing a front image, and (3D) is a graph of the movement amount of the movement reference line. It is a flowchart of a recommended lane guidance process. (5A)-(5C) is a figure which shows a front image, (5D) is a figure which shows a guidance image.

Here, embodiments of the present invention will be described in the following order.
(1) Configuration of navigation device:
(2) Recommended lane guidance processing:
(3) Other embodiments:

(1) Configuration of navigation device:
FIG. 1 is a block diagram showing a configuration of a navigation device 10 as a recommended lane guidance system according to an embodiment of the present invention. The navigation device 10 is provided in a vehicle. The navigation device 10 includes a control unit 20 and a recording medium 30. The control unit 20 includes a CPU, a RAM, a ROM, and the like, and executes a program stored in the recording medium 30 or the ROM. The recording medium 30 records map information 30a. The map information 30a includes node data indicating the position of the node set corresponding to the end point (intersection) of the road, link data indicating information regarding the road between the nodes, and the center position in the width direction of the road between the nodes. Shape interpolation point data and the like for specifying are included. The link data includes the number of lanes included in the road, the lane number of each lane counted from one lane in the width direction of the road (left side in this embodiment), and the intersection when the lane is traveled to the intersection. Lane information indicating roads that can exit the road.

  The vehicle also includes a GPS receiver 41, a vehicle speed sensor 42, a gyro sensor 43, a camera 44, and a display 45. The GPS receiver 41 receives radio waves from GPS satellites and outputs a signal for calculating the current position of the vehicle to the controller 20 via an interface (not shown). The vehicle speed sensor 42 outputs a signal corresponding to the rotational speed of the wheels included in the vehicle to the control unit 20. The gyro sensor 43 outputs a signal corresponding to the angular acceleration acting on the vehicle to the control unit 20. The control unit 20 specifies the current position of the vehicle based on output signals from the GPS receiving unit 41, the vehicle speed sensor 42, the gyro sensor 43, and the like, and the map information 30a. The control unit 20 identifies the road on which the vehicle is traveling based on the link data of the map information 30a as the traveling road, and determines the current position of the vehicle in the width direction of the traveling road based on the shape interpolation point data of the map information 30a. Correct to the center position. Further, the control unit 20 specifies the traveling direction of the vehicle based on the output signal from the gyro sensor 43 and the like.

  The camera 44 is an image sensor that captures a front landscape in front of the vehicle and generates a front image representing the front landscape. 2A to 2C are plan views showing how the camera 44 captures a front image. As shown in FIGS. 2A to 2C, the camera 44 has a field of view V with the front side of the vehicle in the direction of the optical axis, and generates a front image representing a front scene in the field of view V. The camera 44 captures a front landscape every predetermined time period or mileage period, and outputs a front image to the control unit 20 via an interface (not shown). In the present embodiment, the camera 44 is provided at the center position in the width direction of the vehicle. The traveling direction F of the vehicle is a direction from the center position in the width direction of the vehicle toward the front front, and coincides with the direction of the optical axis of the camera 44 in the horizontal direction. The display 45 displays various images including a front image and a guide image based on the video signal output from the control unit 20.

  FIG. 2D is a diagram illustrating a front image. The horizontal direction in the front image (the horizontal direction of the image) corresponds to the width direction of the road and lane, and the image of the object located farther from the vehicle on the road surface is higher in the vertical direction of the front image (vertical direction of the image). Located in. The midpoint of the lower side of the front image corresponds to the current position P of the vehicle (the position of the camera 44), and the position on the horizontal bisector of the front image corresponds to the position on the straight line F in the projection space K. To do.

  The recommended lane guidance program 21 includes a recommended lane acquisition unit 21a, a reference line setting unit 21b, and a display control unit 21c. The recommended lane acquisition unit 21a is a module that causes the control unit 20 to execute a function of acquiring a recommended lane that the vehicle should travel. With the function of the recommended lane acquisition unit 21a, the control unit 20 searches for a planned travel route that can reach the destination point based on the map information 30a by a known route search method, and acquires a recommended lane based on the planned travel route. . Note that the control unit 20 only needs to be able to acquire the planned travel route, and may acquire the planned travel route searched by an external computer via communication or the like, or may be read from the removable memory and acquired.

  With the function of the recommended lane acquisition unit 21a, the control unit 20 specifies the intersection that forms the end point of the traveling road as the nearest intersection when the traveling road on which the vehicle is currently traveling is a road on the planned traveling route. Further, the control unit 20 specifies an exit road that is a road on the planned travel route to exit from the nearest intersection among the connection roads connected to the nearest intersection. Then, the control unit 20 acquires, as recommended lanes, lanes that can exit to the exit road on the planned travel route at the nearest intersection among the lanes included in the travel road. As shown in FIGS. 2A to 2C, in the present embodiment, the rightmost lane of the traveling road is a recommended lane.

  The reference line setting unit 21b recognizes a recommended lane image in a front image obtained by photographing a front landscape of the vehicle, and causes the control unit 20 to execute a function of setting a reference line along the recognized recommended lane image. It is. With the function of the reference line setting unit 21b, the control unit 20 recognizes the image of the lane markings of each lane in the front image by performing a known Hough transform or the like. Then, the control unit 20 recognizes an area between the lane markings in the front image as a lane image, and the order counted from the left side of the front image among the recognized lane images is the recommended lane. The lane image that matches the lane number is recognized as the recommended lane image.

  With the function of the reference line setting unit 21b, the control unit 20 acquires the horizontal center line RC of the recommended lane image, and sets the reference line along the center line. In the present embodiment, the control unit 20 sets the reference line Z on the horizontal center line RC of the recommended lane image in the front image. The center line in the horizontal direction of the image of the recommended lane corresponds to the line where the center position in the width direction of the recommended lane exists in the real space, and is a line representing the direction of the recommended lane. The recommended lane direction is the direction of the lane marking of the recommended lane.

Here, a procedure for specifying the horizontal center line of the recommended lane image will be described. As shown in FIG. 2D, the control unit 20 uses the function of the reference line setting unit 21b to display a center line RC (dashed line) that passes through the midpoint of the image BL of the left and right partition lines of the recommended lane in the horizontal direction of the front image. Identify. In the front image, the control unit 20 controls the horizontal midpoint b (white triangle) between the intersection points a (white circles) between the horizontal auxiliary straight line O (two-dot chain line) and the left and right partition line images BL of the recommended lane. ).
Then, the control unit 20 specifies the horizontal midpoint b of the image BL of the left and right partition lines of the recommended lane for each of two or more auxiliary straight lines O having different vertical positions, and the midpoints b Is identified as the center line RC indicating the center position in the width direction in the recommended lane. If the recommended lane is not a straight lane, the horizontal midpoint b of the image BL of the left and right partition lines of the recommended lane is specified for three or more auxiliary straight lines O, and the midpoints b are connected to each other. A curve or a broken line may be specified as the center line RC.

By the function of the reference line setting unit 21b, the control unit 20 sets the front end point FE and the rear end point BE on the center line RC, and sets a straight line connecting the front end point FE and the rear end point BE to the reference line Z. Set as. Control unit 20, on the center line RC, and sets the front end point FE in the position of a predetermined height H ₁ in the vertical direction of the front image. Similarly, the control unit 20 sets the rear end point BE at the position of the height H ₂ (<H ₁ ) lower than the front end point FE in the longitudinal direction of the front image on the center line RC. The heights H ₁ and H ₂ in the vertical direction of the front image where the front end point FE and the rear end point BE are set are maintained constant, and as a result, the length of the reference line Z in the vertical direction of the front image is also constant. Maintained. Since the center line RC is a line in the recommended lane image, the reference line Z is also a line in the recommended lane image.

  In the present embodiment, the reference line Z is a straight line on the center line RC. However, the control part 20 should just set the reference line Z so that the center line RC may be followed, and does not necessarily need to set the reference line Z on the center line RC. For example, the control unit 20 may set the reference line Z such that the center line RC and the reference line Z are within a predetermined distance and the angle formed by the center line RC and the reference line Z is within a predetermined angle. . Furthermore, when the center line RC is a broken line or a curve, the control unit 20 may set an approximate curve of the center line RC as the reference line Z.

  The display control unit 21c is a module that causes the control unit 20 to execute a function of superimposing a guide image including a recommended lane portion with the reference line Z as a center line on the front image on the front image and displaying it on the display 45. That is, the control unit 20 sets the reference line Z set based on the recommended lane image recognized in the front image as the center line of the recommended lane portion. Specifically, the control unit 20 generates a recommended lane portion that is line-symmetric with respect to the reference line Z, thereby setting the reference line Z as a central line in the width direction of the recommended lane portion. The width direction of the recommended lane portion is a direction orthogonal to the reference line Z.

  FIG. 3A is a diagram illustrating a front image on which a guide image including a recommended lane portion RL is superimposed. The guide image of this embodiment consists of only the recommended lane portion RL having an arrow shape. The head of the arrow indicated by the recommended lane portion RL has a triangular shape, and the vertex corresponding to the tip of the head of the arrow is the front end point FE. The control unit 20 sets the width of the recommended lane portion RL so that the entire recommended lane portion RL falls within the recommended lane image in the front image. Specifically, the control unit 20 sets the width of the recommended lane portion RL based on the width of the lower end of the head of the arrow having the widest width (the base of the triangle of the head) among the recommended lane portions RL. And

  That is, the control unit 20 controls the reference BL and the left and right division line images BL of the recommended lane on the straight line HL (broken line orthogonal to the reference line Z) where the lower end of the head of the arrow of the recommended lane portion RL is set. The distance to the line Z is specified, and the width of the lower end of the head of the arrow of the recommended lane portion RL is set so that it is not more than twice the smaller one of the specified distances. The distance from the front end point FE (the height of the head of the arrow) at the intersection of the reference line Z and the straight line HL is recorded on the recording medium 30. In this embodiment, the ratio of the width of the recommended lane portion RL to the width of the lower end of the head of the arrow is recorded on the recording medium 30 for each distance from the front end point FE on the reference line Z. To do. Then, the control unit 20 multiplies the width corresponding to the distance from the front end point FE on the reference line Z by the width of the lower end of the head of the arrow, so that the recommended lane portion RL of each position on the reference line Z is obtained. A width is specified, and a recommended lane portion RL having the specified width is generated. When the recommended lane portion RL is generated, the control unit 20 causes the display 45 to display the recommended lane portion RL superimposed on the front image by the function of the display control unit 21c.

  As described above, by the function of the display control unit 21c, the control unit 20 sets the reference line Z set based on the image of the recommended lane recognized in the front image as the center line of the recommended lane portion RL. Each time the latest front image is acquired, the image of the recommended lane is recognized, and the reference line Z of the recommended lane portion RL is set based on the recognized recommended lane image. The recommended lane portion RL can be made to follow the change. That is, even if the position or shape of the recommended lane image in the front image changes, the recommended lane portion RL can be superimposed on the front image so as to be within the recommended lane image. However, when the vehicle is moving in the width direction of the lane, the control unit 20 is different from the above method because the reference line Z cannot be accurately set based on the recommended lane image recognized in the front image. A recommended lane portion RL is generated by a technique.

By the function of the display control unit 21c, the control unit 20 causes the reference line Z (start reference line) set at the start time when the vehicle starts moving in the width direction of the lane when the vehicle starts moving in the width direction of the lane. Z ₀ ) is acquired in a direction (movement reference line Z _T ) obtained by moving Z ₀ ) in the direction opposite to the moving direction of the vehicle in the width direction of the lane, and the recommended lane portion RL having the movement reference line Z _T as the center line is obtained. The included guide image is superimposed on the front image and displayed on the display 45. That is, when the vehicle starts moving in the width direction of the lane, it is not the reference line Z based on the recommended lane image recognized in the latest front image, but the start time when the vehicle starts moving in the width direction of the lane The recommended lane portion RL is generated with the movement reference line Z _T obtained by moving the start reference line Z ₀ at the center as the center line.

  Based on the function of the display control unit 21c, the control unit 20 determines whether or not the vehicle has started moving in the width direction of the lane based on the positional relationship between the lane markings of the traveling lane in which the vehicle is traveling and the vehicle. . Specifically, by the function of the display control unit 21c, the control unit 20 causes the vehicle to move in the width direction of the lane when the inclination of the traveling direction of the vehicle with respect to the lane marking of the traveling lane in which the vehicle is traveling is equal to or greater than a threshold. It is determined that the movement has started. FIG. 2A shows a state in which the inclination angle A of the traveling direction F of the vehicle with respect to the lane marking of the traveling lane is 0 °, and it is not determined that the vehicle has started moving in the width direction of the lane. In the case of FIG. 2A, assuming that the image of the recommended lane can be recognized without any problem in the front image, the recommended lane portion RL having the reference line Z based on the image of the recommended lane as the center line as shown in FIG. 2B and 2C show a state in which it is determined that the inclination angle A of the traveling direction F of the vehicle with respect to the lane marking of the traveling lane is equal to or greater than a threshold value and the vehicle has started moving in the width direction of the lane. In FIG. 2B, the vehicle moves rightward so as to approach the recommended lane on the right end, and in FIG. 2C, the vehicle moves leftward so as to move away from the recommended lane on the right end.

The controller 20 travels based on the position and direction of the lane marking line BL recognized in the front image and the optical specifications of the camera 44 (optical axis direction, viewing angle, imaging magnification, etc.). The inclination angle A of the traveling direction F of the vehicle with respect to the lane marking is specified. The lane marking image BL closest to the midpoint CC on the left side of the midpoint CC on the lower side of the front image indicating the position of the vehicle (the position of the camera 44) is the lane marking image BL on the left side of the travel lane. The lane marking image BL closest to the midpoint CC on the right side of the midpoint CC is the lane marking image BL on the right side of the travel lane. In the present embodiment, the control unit 20 has a higher reliability (recognition degree, edge amount, etc. with the previously recognized lane marking image) among the left and right lane marking images BL of the traveling lane. The inclination angle A is specified based on the image line lane marking BL. Furthermore, the control unit 20 determines that the vehicle has started moving in the width direction of the lane when the period in which the inclination angle A is equal to or greater than the threshold value continues longer than the predetermined reference period. That is, the time when the period in which the inclination angle A is equal to or greater than the threshold is equal to the reference period means the start time t ₀ when the vehicle starts moving in the width direction of the lane.

The threshold value and the reference period are recorded on the recording medium 30. In the present embodiment, the threshold value is an upper limit value of the inclination angle A when the vehicle travels on a single lane without changing the lane, and is set based on experiments. The reference period is an average period from when the inclination angle A becomes equal to the threshold value until the vehicle crosses the lane marking of the travel lane, and is set based on experiments. Note that the greater the lane width, the greater the inclination angle A when the vehicle travels on a single lane without changing the lane. Therefore, the inclination angle A may be set larger as the lane width is larger. In addition, the longer the lane width, the longer the period until it crosses the lane marking of the traveling lane. Therefore, the reference period may be set longer as the lane width is larger. In addition, the longer the vehicle speed, the shorter the period until the lane line of the travel lane is crossed. Therefore, the reference period may be set shorter as the vehicle speed increases. Further, the control unit 20 does not necessarily specify the inclination angle A based on the lane marking line BL of the travel lane. Among the travel road lane images recognized in the front image, the reliability in the line recognition is high. The tilt angle A may be specified based on the image BL of the largest marking line. The control unit 20 may specify the tilt angle A based on the output signal from the gyro sensor 43 or the output signal from the steering sensor that detects the steering angle of the vehicle. Further, the control unit 20 sets the reference line Z at the start time t ₀ when the vehicle starts moving in the width direction of the lane, and records the set reference line Z on the recording medium 30 as the start reference line Z ₀ . Further, the shape (width) of the recommended lane portion RL superimposed on the front image is recorded on the recording medium 30 at the start time t ₀ when the vehicle starts moving in the width direction of the lane.

Control unit 20 of the function of the display control unit 21c, when the vehicle starts to move in the width direction of the lane, moving the reference moving the start reference line Z ₀ in the direction opposite to the direction of the movement of the vehicle in the width direction of the lane The line Z _T is acquired, and the guide image including the recommended lane portion RL having the movement reference line Z _T as the center line is superimposed on the front image and displayed on the display 45. When the traveling direction F of the vehicle is tilted to the right with respect to the direction of the lane marking image BL of the traveling lane (FIG. 2B), the controller 20 moves the vehicle in the lane width direction to the right. To be identified. Similarly, when the traveling direction F of the vehicle is tilted to the left with respect to the direction of the lane marking image BL of the travel lane (FIG. 2C), the control unit 20 moves the vehicle in the lane width direction. Is the left direction.

The control unit 20 acquires the elapsed period t from the start time t ₀ when the vehicle starts moving in the width direction of the lane, and acquires the movement amount X (t) that increases as the elapsed period t increases. Then, the control unit 20 translates the movement reference line Z _T obtained by translating the start reference line Z ₀ by the movement amount X (t) in the direction opposite to the vehicle movement direction in the width direction of the lane (lateral direction of the front image). get. 3B and 3C are diagrams showing the movement reference line Z _T acquired in the case of FIGS. 2B and 2C. When the vehicle moves to the right as shown in FIG. 2B, a movement reference line Z _T (solid line) moved to the left with respect to the start reference line Z ₀ (broken line) is acquired (FIG. 3B), and the vehicle as shown in FIG. 2C. Is moved in the left direction, a movement reference line Z _T moved in the right direction with respect to the start reference line Z ₀ (broken line) is acquired (FIG. 3C).

  FIG. 3D is a graph showing the relationship between the elapsed period t and the movement amount X (t). As indicated by a solid line in FIG. 3D, the movement amount X (t) increases linearly as the elapsed period t increases. For example, the moving amount X (t) is set by investigating the moving amount in the horizontal direction of the image of the recommended lane in the forward image taken every elapsed period t. The movement amount X (t) is recorded on the recording medium 30 for each elapsed period t.

Control unit 20 of the function of the display control unit 21c, the movement reference line Z _T moving the moving amount X (t) only start reference line Z ₀ in the direction opposite to the direction of the movement of the vehicle in the width direction of the lane center line The recommended lane portion RL is generated. Control unit 20, by generating a recommended lane portion RL which is line symmetrical with respect to the moving reference line Z _T, to produce a recommended lane portion RL to the moving reference line Z _T a middle line in the width direction.

Specifically, the control unit 20 of the function of the display control unit 21c, when the vehicle starts to move in the width direction of the lane, the recommended lane portion RL at start time t ₀ when the vehicle starts to move in the width direction of the lane A guide image including the recommended lane portion RL maintained at the same width as the width of the image is superimposed on the front image and displayed on the display 45. The control unit 20 obtains the shape (width) of the recommended lane portion RL superimposed on the front image from the recording medium 30 at the start time t ₀ when the vehicle starts moving in the width direction of the lane, and recommends it at the start time t ₀ . A recommended lane portion RL having the same shape (width) as the lane portion RL is generated. That is, the control unit 20 determines the recommended lane portion RL at the start time t ₀ so that the bisector (center line) that bisects the recommended lane portion RL in the width direction matches the movement reference line Z _T. The translation is performed in the horizontal direction of the front image by the movement amount X (t). When the recommended lane portion RL is generated, the control unit 20 causes the display 45 to display the recommended lane portion RL superimposed on the front image by the function of the display control unit 21c. As shown in FIGS. 3B and 3C, a recommended lane portion having a movement reference line Z _T (solid line) translated in the horizontal direction by a movement amount X (t) with respect to the start reference line Z ₀ (dashed line) as a center line. RL is superimposed on the front image.

When the vehicle moves in the width direction of the lane, the recommended lane image in the front image moves in the direction opposite to the moving direction of the vehicle in the width direction of the lane. Accordingly, the movement reference line Z _T obtained by moving the start reference line Z ₀ at the start time t ₀ when the vehicle starts moving in the width direction of the lane in the direction opposite to the movement direction of the vehicle in the width direction of the lane is defined as the center line. The recommended lane portion RL can be displayed so as to follow the movement of the recommended lane image in the front image by superimposing the recommended lane portion RL to be performed on the front image. In addition, the movement reference line Z _T can be set regardless of the recognition result of the recommended lane image after the start time t ₀ when the vehicle starts moving in the width direction of the lane. Therefore, after the vehicle starts moving in the width direction of the lane, even if the recognition accuracy of the image of the recommended lane deteriorates or the recognition of the image of the recommended lane is delayed, the recommended lane in the front image The recommended lane portion RL can be displayed so as to follow the movement of the image. For example, a recommended lane portion RL having a reference line Z set based on an image of a recommended lane with poor recognition accuracy as a central line is superimposed on the image of another lane, and the driver may misidentify the recommended lane. Can be prevented. Further, even when the recommended lane image cannot be recognized, the recommended lane portion RL can be displayed so as to follow the movement of the recommended lane image in the front image.

Here, the longer the elapsed period t from the start time t ₀ when the vehicle starts to change lanes, the longer the cumulative distance that the vehicle has moved in the direction of movement in the width direction of the lane. Therefore, the longer the elapsed time t from the start time t ₀ when the vehicle starts moving in the width direction of the lane, the longer the start reference line Z ₀ is moved, and the start reference line Z _T is set as the movement reference line Z _T. The recommended lane portion RL can be moved by a distance corresponding to the cumulative distance that the recommended lane image has moved in the left-right direction from time t ₀ .

Further, the control unit 20 recommends the recommended lane portion maintained at the same width as the width of the recommended lane portion RL at the start time t ₀ after the start time t ₀ at which the vehicle starts moving in the lane width direction. Generate RL. Thereby, the impression that the same recommended lane is continuously guided can be given.

  The control unit 20 determines that the vehicle has started moving in the width direction of the lane when the inclination A in the traveling direction of the vehicle with respect to the lane marking of the traveling lane in which the vehicle is traveling is equal to or greater than a threshold value. When the traveling direction of the vehicle is greatly inclined with respect to the lane direction, the direction of the recommended lane image in the front image varies, and it is difficult to recognize the recommended lane image. Therefore, in a situation where it is difficult to recognize the recommended lane image, it is possible to switch to a state in which the recommended lane portion RL is generated regardless of the recognition of the recommended lane image.

(2) Recommended lane guidance processing:
FIG. 4 is a flowchart of recommended lane guidance processing. The recommended lane guidance process is a loop process that is executed each time the control unit 20 acquires a front image at a predetermined time period or a travel distance period. With the function of the recommended lane acquisition unit 21a, the control unit 20 acquires, as recommended lanes, lanes that can exit to the exit road on the planned travel route at the nearest intersection among the lanes included in the travel road.

First, the control unit 20 acquires a front image captured by the camera 44 (step S100). Next, the control unit 20 determines whether or not the vehicle is moving in the width direction of the lane by the function of the display control unit 21c (step S105). That is, the control unit 20 determines whether it is difficult to recognize the recommended lane image in the front image. Specifically, when the period when the inclination angle A of the traveling direction F of the vehicle with respect to the lane marking of the travel lane in which the vehicle is traveling is equal to or greater than a threshold value continues longer than a predetermined reference period, It is determined that the vehicle is moving in the width direction of the lane (FIGS. 2A to 2C). Note that the vehicle moving in the width direction of the lane means that the vehicle has started moving in the width direction of the lane and before the vehicle has finished moving in the width direction of the lane. The control unit 20 specifies the time when the period in which the inclination angle A is equal to or greater than the threshold becomes equal to the reference period as the start time t ₀ when the vehicle starts moving in the width direction of the lane. Further, the control unit 20 does not determine that the vehicle is moving in the width direction of the lane at the start time t ₀ when the vehicle starts moving in the width direction of the lane.

  When it is not determined that the vehicle is moving in the width direction of the lane (step S105: N), the control unit 20 recognizes the image of the recommended lane in the front image by the function of the reference line setting unit 21b (step S110). ). That is, when it is not difficult to recognize the recommended lane image in the front image, the recommended lane image is recognized in the front image. Specifically, the control unit 20 selects a lane image whose order counted from the left side of the front image matches the lane number of the recommended lane among the lane images sandwiched between the lane markings BL. Recognize as an image.

Next, the control unit 20 sets the reference line Z along the recommended lane image by the function of the reference line setting unit 21b (step S115). That is, the control unit 20 sets a reference line Z corresponding to a line indicating the center position in the width direction of the recommended lane in the real space in the image of the recommended lane. Specifically, the control unit 20 sets the front end point FE and the rear end point BE at positions of heights H ₁ and H ₂ (<H ₁ ) in the vertical direction of the front image on the center line RC, respectively. Then, a straight line on the center line RC connecting the front end point FE and the rear end point BE is set as the reference line Z (FIG. 2D).

  And the control part 20 produces | generates the recommendation lane part RL which makes the reference line Z the center line by the function of the display control part 21c (step S120). In other words, the control unit 20 performs setting so that the recommended lane portion RL is generated based on the reference line Z based on the recognized recommended lane image when it is not difficult to recognize the recommended lane image in the front image. . Specifically, the control unit 20 generates a recommended lane portion RL that is line-symmetric with respect to the reference line Z.

In the present embodiment, the control unit 20 generates a recommended lane portion RL that falls within the recommended lane image by the function of the display control unit 21c. That is, when the recognition of the recommended lane image in the front image is not difficult, the width of the recommended lane portion RL is set so as to fit in the recognized recommended lane image. Specifically, on the straight line HL (FIG. 3A) on which the lower end of the head of the arrow is set in the recommended lane portion RL, the control unit 20 and the reference line Z And the width of the lower end of the head of the arrow of the recommended lane portion RL is set so as to be equal to or less than twice the smaller one of the specified distances. Then, the control unit 20 generates a recommended lane portion RL having the width set as described above and being line symmetric with respect to the reference line Z. The control unit 20 of the function of the display control unit 21c, when the vehicle if a starting time t ₀ which starts moving in the width direction of the lane (period inclination angle A is equal to or greater than the threshold value was equal to the reference period the), and records on the recording medium 30 to the reference line Z is set as the start reference line Z ₀ at step S115, the recording and the shape of the recommended lane portion RL generated in step S120 (width) on the recording medium 30 Keep it.

  Next, by the function of the display control unit 21c, the control unit 20 causes the recommended lane portion RL to be superimposed on the front image and displayed on the display 45 (step S160). With the above processing (steps S110 to S120, S160), when the vehicle travels along the travel lane as shown in FIG. 2A, the recommended lane portion RL is superimposed on the front image so as to fit within the recommended lane image. (FIG. 3A). Since it is not difficult to recognize the recommended lane image in the front image, the recommended lane portion RL can be superimposed on the front image so as to fit in the recommended lane image based on the recognized recommended lane image.

On the other hand, when it is determined that the vehicle is moving in the width direction of the lane (step S105: Y), the control unit 20 starts the movement of the vehicle in the width direction of the lane by the function of the reference line setting unit 21b. The movement amount X (t) is acquired based on the elapsed period t from time t ₀ (step S130). That is, the control unit 20 acquires the elapsed period t from the start time t ₀ when the vehicle starts moving in the width direction of the lane, and acquires the movement amount X (t) that increases as the elapsed period t increases ( FIG. 3D). Next, by the function of the display control unit 21c, the control unit 20 determines whether the moving direction of the vehicle in the width direction of the lane is the left direction or the right direction (step S135). Specifically, the control unit 20 specifies the direction in which the traveling direction F of the vehicle is inclined with respect to the lane marking of the traveling lane as the moving direction of the vehicle in the width direction of the lane, and the specified moving direction is the left direction. It is determined whether the direction is the right direction.

If the moving direction of the vehicle in the width direction of the lane is determined to be the left direction (step S135: left), the control unit 20 by the function of the reference line setting unit 21b moves the start reference line Z ₀ to the right The movement reference line Z _T is set (step S140). Specifically, the control unit 20 acquires a line obtained by moving the start reference line Z ₀ recorded on the recording medium 30 to the right by the movement amount X (t) corresponding to the elapsed period t, and acquires the line. Set the stroke line as the movement reference line Z _T

On the other hand, when the moving direction of the vehicle in the width direction of the lane is determined to be the right direction (step S135: right), the control unit 20 by the function of the reference line setting unit 21b, a start reference line Z ₀ to the left The moved movement reference line Z _T is set (step S145). Specifically, the control unit 20 acquires a line obtained by moving the start reference line Z ₀ recorded on the recording medium 30 leftward by the movement amount X (t) corresponding to the elapsed period t, and acquires the line. Set the stroke line as the movement reference line Z _T

Next, the control unit 20 of the function of the display control unit 21c generates the recommended lane part RL of the moving reference line Z _T and the center line (step S150). That is, the control unit 20 generates a recommended lane portion RL that is line symmetric with respect to the movement reference line Z _T. Specifically, the control unit 20 of the function of the display control unit 21c, starting the recommended lane portion RL shape at time t ₀ (width) obtained from the recording medium 30, the recommended lane portion RL having the same shape at the start time t ₀ A (lane) recommended lane portion RL is generated. That is, the control unit 20 determines the recommended lane portion RL at the start time t ₀ so that the bisector (center line) that bisects the recommended lane portion RL in the width direction matches the movement reference line Z _T. The translation is performed in the horizontal direction of the front image by the movement amount X (t). Then, by the function of the display control unit 21c, the control unit 20 causes the display 45 to display a guide image including the recommended lane portion RL superimposed on the front image (step S160). With the above processing (steps S130 to S160), as shown in FIGS. 3B and 3C, the recommended lane portion RL is superimposed on the front image so as to follow the image of the recommended lane moving in the horizontal direction in the front image. be able to. When the lane change progresses to some extent, the inclination angle A of the traveling direction F of the vehicle with respect to the lane marking is again equal to or less than the threshold value. In this case, in step S105, it is determined that the vehicle is not moving in the width direction of the lane, and the state returns to the state in which the recommended lane portion RL is generated based on the reference line Z based on the recommended lane image recognized in step S110.

(3) Other embodiments:
The control unit 20 may set the movement amount X (t) corresponding to the distance that the vehicle has moved in the width direction of the lane from the start time t _{0 at} which the vehicle has started moving in the width direction of the lane. The relationship between the elapsed period t from ₀ and the movement amount X (t) is not limited to the relationship indicated by the solid line in FIG. 3D. The greater the inclination angle A in the traveling direction of the vehicle and the vehicle speed with respect to the lane marking of the travel lane, the greater the distance that the vehicle moves in the width direction of the lane. The increasing slope may be increased. When the lane is changed, the inclination angle A gradually increases from the start time t ₀ when the vehicle starts moving in the width direction of the lane, takes a maximum value at a certain time t _C and then gradually decreases. I will do it. Therefore, as indicated by a broken line in FIG. 3D, the movement amount X (t) may be represented by a nonlinear function having an inflection point at which the inclination turns to decrease at the time t _C when the inclination angle A reaches a maximum value. The time t _{C at} which the inclination angle A reaches the maximum value can be obtained by investigating the driver's steering operation. Further, since an object image closer to the camera 44 is formed larger in the front image, the inclination of the movement amount X (t) may be increased as the recommended lane is closer to the camera 44.

When the vehicle starts moving in the direction of approaching the recommended lane in the width direction of the lane, the control unit 20 rotates the start reference line Z _{0 so} that the parallelism with respect to the vertical line of the front image increases. The movement reference line Z _T may be acquired, and a recommended lane portion RL having the movement reference line Z _T as a central line may be generated. When the direction of the recommended lane is parallel to the traveling direction F of the vehicle, the closer the recommended lane is to the vehicle in the width direction of the lane, the closer the image of the recommended lane approaches to the vertical line of the front landscape. Rotate to. When the vehicle finally travels on the recommended lane, the image of the recommended lane is a vertical image of the front landscape. 2A and 2D show a state in which the vehicle travels on the second traveling lane with the lane number counted from the leftmost lane, but the third closer to the vehicle in the width direction than the image of the fourth (rightmost) lane. The lane image is closer to being parallel to the vertical line of the front image. Similarly, the image of the second traveling lane is closer to the vertical line of the front image than the image of the third lane. Therefore, when the vehicle starts moving in the direction of approaching the recommended lane in the width direction of the lane, the movement reference is obtained by rotating the start reference line Z _{0 so} that the parallelism with the vertical line of the front image is increased. By setting the line Z _T as the center line of the recommended lane portion RL, the recommended lane portion RL can be displayed so as to follow the rotation of the image of the recommended lane.
On the other hand, when the vehicle starts to move away from the recommended lane in the width direction of the lane, the movement reference is obtained by rotating the start reference line Z _{0 so} that the parallelism with respect to the horizontal line of the front image is increased. The line Z _T may be acquired, and the recommended lane portion RL having the movement reference line Z _T as the center line may be generated. When the recommended lane is parallel to the traveling direction F of the vehicle, the image of the recommended lane rotates so as to approach parallel to the horizontal line of the front image as the recommended lane moves away from the vehicle in the width direction of the lane. Because it does.

Further, the control unit 20 acquires a movement reference line Z _T obtained by rotating the start reference line Z ₀ clockwise in a predetermined period immediately after the vehicle starts moving in the right direction in the width direction of the lane, and moves the movement. A recommended lane portion RL having the reference line Z _T as the center line may be generated. Immediately after the vehicle starts moving to the right in the width direction of the lane, that is, immediately after the viewing direction of the front image rotates clockwise in plan view (FIG. 2A → FIG. 2B), the image of the recommended lane in the front image is It rotates counterclockwise (FIG. 3A → FIG. 3B). Therefore, when the vehicle starts moving in the right direction in the width direction of the lane, as shown in FIG. 5A, the movement reference line Z _T obtained by rotating the start reference line Z ₀ counterclockwise by the angle G is set to the center. The recommended lane portion RL as a line may be superimposed on the front image. Thereby, the recommended lane portion RL can be displayed so as to follow the rotation of the image of the recommended lane in the front image. Of course, the movement reference line Z _T may be translated in the left direction while rotating clockwise.
Conversely, the control unit 20 moves the start reference line Z ₀ clockwise in a predetermined period immediately after the vehicle starts moving leftward in the width direction of the lane (FIG. 2A → FIG. 2C). Z _T is acquired, and the recommended lane portion RL having the movement reference line Z _T as the center line may be superimposed on the front image. As a result, the recommended lane portion RL is displayed so as to follow the rotation of the recommended lane image in the front image as shown in FIG. 5B even immediately after the vehicle starts moving in the left direction in the width direction of the lane. Can do. Of course, it may be moved parallel to the right while rotating the moving reference line Z _T counterclockwise. The predetermined period immediately after the vehicle starts moving leftward or rightward in the width direction of the lane is the maximum inclination angle A from the start time t ₀ when the vehicle starts moving in the width direction of the lane. It may be a period until the time t _C (FIG. 3D) or a period until the inclination angle A becomes equal to or less than the threshold after the time t _C. Further, when the predetermined period ends, that is, when the traveling direction F of the vehicle becomes close to the direction of the recommended lane, the control unit 20 determines whether the vehicle approaches the recommended lane in the width direction of the lane. Correspondingly, it may set a direction of rotating the moving reference line Z _T.

  The control unit 20 may superimpose a guide image including the recommended lane portion RL on the front image, and the guide image may include a portion other than the recommended lane portion RL. For example, as shown in FIG. 5C, the guide image includes a portion CL that connects the rear end point BE of the recommended lane portion RL and the midpoint CC of the lower side of the front image indicating the position of the vehicle (the position of the camera 44). But you can. Furthermore, the control unit 20 may determine whether or not the vehicle has started moving in the width direction of the lane based on a driving operation on the vehicle. For example, when a turn indicator is operated to change the lane, it may be determined that the vehicle has started moving in the width direction of the lane.

In addition, the control unit 20 superimposes a guide image including the recommended lane portion RL with a narrower width on the front image as the elapsed time t from the start time t ₀ when the vehicle starts moving in the width direction of the lane becomes longer. It may be displayed on the display 45. For example, as shown in FIG. 5D, the recommended lane portion RL is made narrower than the recommended lane portion RL (dashed line) at the start time t ₀ when the vehicle starts moving in the width direction of the lane. However, the possibility of protruding from the recommended lane image can be reduced. Therefore, it can be prevented that the recommended lane portion RL protrudes from the image of the recommended lane to give the impression that the recommended lane portion RL is guiding a lane other than the recommended lane. Note that, by reducing the width of the recommended lane portion RL in the direction opposite to the vehicle movement direction in the lane width direction, the start reference line Z ₀ is moved in the direction opposite to the vehicle movement direction in the lane width direction. The recommended lane portion RL having the movement reference line Z _T as the center line can be generated. In the case of FIG. 5D, the width of the recommended lane portion RL becomes narrower in the left direction as the movement reference line Z _T moves in the left direction.

  Furthermore, the control unit 20 determines that the vehicle is in the width direction of the lane when the lane marking of the traveling lane and the vehicle are within a predetermined distance as the positional relationship between the lane marking of the traveling lane in which the vehicle is traveling and the vehicle. It may be determined that the movement has started. The predetermined distance may be a distance at which it can be determined that the vehicle has straddled the lane marking of the travel lane, that is, a vehicle width equivalent value.

  The forward image may be obtained by drawing a forward landscape based on the map information 30a. When drawing a front landscape based on the map information 30a, a guide image may be drawn simultaneously with the front image. Here, superimposing the guidance image on the front landscape and displaying it on the display 45 may display the guidance image on the display 45 and consequently superimposing the guidance image on the front landscape. For example, the display 45 only needs to display at least a guide image and does not have to display a front image. In other words, the display 45 may superimpose the guidance image on the actual front scenery viewed by the driver through the windshield of the vehicle. For example, the guide image may be superimposed on the actual front landscape by making the display 45 a transflective type so that the actual front landscape can be seen through the display 45.

DESCRIPTION OF SYMBOLS 10 ... Navigation apparatus, 20 ... Control part, 21 ... Recommended lane guidance program, 21a ... Recommended lane acquisition part, 21b ... Reference line setting part, 21c ... Display control part, 30 ... Recording medium, 30a ... Map information, 41 ... GPS Receiving part 42 ... Vehicle speed sensor 43 ... Gyro sensor 44 ... Camera 45 ... Display b ... Middle point BE ... Rear end point CC ... Middle point F ... Traveling direction FE ... Front end point RC ... centerline, RL ... recommended lane section, t ... age, t ₀ ... start time, X (t) ... movement amount, Z ... reference line, Z ₀ ... start reference line, Z _T ... moving reference line, A ... slope Horn.

Claims (10)

A recommended lane acquisition means for acquiring a recommended lane for the vehicle to travel;
A reference line setting means for recognizing an image of the recommended lane in an image obtained by photographing a front landscape of the vehicle, and setting a reference line along the recognized image of the recommended lane;
A recommended lane guidance system comprising display control means for displaying a guidance image including a recommended lane portion with the reference line as a center line on a display portion so as to be superimposed on the front scenery,
When the vehicle starts moving in the width direction of the lane, the display control means displays the reference line set at the start time when the vehicle starts moving in the width direction of the lane in the width direction of the lane. Acquiring a line moved in a direction opposite to the moving direction of the vehicle, and displaying the guidance image including the recommended lane portion with the acquired line as a central line on the front landscape and displaying the same on the display unit;
Recommended lane guidance system. When the vehicle starts moving in the width direction of the lane, the display control means displays the reference line set at the start time in the width direction of the lane as the elapsed period from the start time becomes longer. A line greatly moved in the direction opposite to the moving direction of the vehicle is acquired, and the guide image including the recommended lane portion having the acquired line as a central line is superimposed on the front scenery and displayed on the display unit. ,
The recommended lane guidance system according to claim 1. When the vehicle starts to move in the width direction of the lane, the display control means displays the guide image including the recommended lane portion maintained at the same width as the width of the recommended lane portion at the start time. Superimposed on the front landscape and displayed on the display unit,
The recommended lane guidance system according to claim 1. When the vehicle starts to move in the width direction of the lane, the display control unit displays the guide image including the recommended lane portion with the width narrowed as the elapsed time from the start time becomes longer. Superimposed and displayed on the display unit,
The recommended lane guidance system according to claim 1. The display control means includes
When the vehicle starts to move in the direction of approaching the recommended lane in the width direction of the lane, the reference line set at the start time becomes parallel to the vertical line of the front landscape. A line that has been rotated and the guide image including the recommended lane portion with the acquired line as a central line is superimposed on the front landscape and displayed on the display unit,
When the vehicle starts to move away from the recommended lane in the width direction of the lane, the reference line set at the start time becomes parallel to the horizontal line of the front landscape. Acquiring a rotated line, and superimposing the guidance image including the recommended lane portion with the acquired line as a central line on the front landscape, and causing the display unit to display the guidance image.
The recommended lane guidance system according to any one of claims 1 to 4. The display control means includes
In a predetermined period immediately after the vehicle starts moving leftward in the width direction of the lane, a line obtained by rotating the reference line set at the start time in a clockwise direction is acquired, and the acquired line is The guide image including the recommended lane portion as a line of the image is superimposed on the front scenery and displayed on the display unit,
In a predetermined period immediately after the vehicle starts moving rightward in the width direction of the lane, a line obtained by rotating the reference line set at the start time counterclockwise is obtained and rotated counterclockwise. Acquiring the line, and displaying the guidance image including the recommended lane portion with the acquired line as a central line on the front landscape and displaying the superimposed image on the display unit.
The recommended lane guidance system according to any one of claims 1 to 5. The display control means determines whether or not the vehicle has started moving in the width direction of the lane, based on a positional relationship between a lane marking of a traveling lane in which the vehicle is traveling and the vehicle.
The recommended lane guidance system according to any one of claims 1 to 6. The display control means determines that the vehicle has started moving in the width direction of the lane when the inclination of the traveling direction of the vehicle with respect to the lane marking of the traveling lane in which the vehicle is traveling is equal to or greater than a threshold value. ,
The recommended lane guidance system according to any one of claims 1 to 7. A recommended lane acquisition process for acquiring a recommended lane for the vehicle to travel;
A reference line setting step for recognizing an image of the recommended lane in an image obtained by capturing a landscape in front of the vehicle, and setting a reference line along the recognized image of the recommended lane;
A display control step of displaying a guide image including a recommended lane portion with the reference line as a center line on the display portion in a superimposed manner on the front landscape, and a recommended lane guidance method comprising:
In the display control step, when the vehicle starts moving in the width direction of the lane, the reference line set at the start time when the vehicle starts moving in the width direction of the lane is changed to the reference line in the width direction of the lane. Acquiring a line moved in a direction opposite to the moving direction of the vehicle, and displaying the guidance image including the recommended lane portion with the acquired line as a central line on the front landscape and displaying the same on the display unit;
Recommended lane guidance method. A recommended lane acquisition function for acquiring a recommended lane for the vehicle to travel,
A reference line setting function for recognizing an image of the recommended lane in an image obtained by photographing a front landscape of the vehicle, and setting a reference line along the recognized image of the recommended lane;
A recommended lane guidance program for causing a computer to execute a display control function for superimposing a guidance image including a recommended lane portion with the reference line as a central line on the front landscape to be displayed on a display unit,
When the vehicle starts moving in the width direction of the lane, the display control function causes the computer to display the reference line set at the start time when the vehicle starts moving in the width direction of the lane. A line moved in the direction opposite to the moving direction of the vehicle is acquired, and the guide image including the recommended lane portion with the acquired line as a central line is superimposed on the front landscape and displayed on the display unit Let
Recommended lane guidance program.

Images