Information display method and information display device for vehicle

Abstract

Coordinates of an intersection (21) at which a vehicle is to turn right or left according to the route guidance of the vehicle are acquired, and via an AR-HUD (1) of the vehicle, an arrow-shaped virtual image (11) is displayed as superimposed on the intersection (21) visible through a windshield (2). In accordance with a look-down angle (θ1) with respect to the intersection (21), the virtual image (11) is displayed on the position of the intersection (21) in a long-distance area where the position of the intersection (21) is within a display area (1A) of the AR-HUD (1). In a short-range area where the position of the intersection (21) is below the display area (1A), the position of the virtual image (11) is limited to a position at the lower portion of the display area (1A), and a switch is made to an animation display in which a reciprocating motion in the vehicle width direction is performed.

Description

Vehicle information display method and device

[0001] The present invention relates to an information display for a vehicle that uses an AR-HUD (Augmented Reality Head-Up Display) to display a virtual image above a node where a vehicle should turn right or left, such as an intersection.

[0002] In recent years, HUDs (head-up displays), which project and display various information necessary while driving a vehicle onto the windshield in front of the driver's seat, have become increasingly popular. Furthermore, AR-HUDs (augmented reality head-up displays) are known as a more advanced version of HUD technology. AR-HUDs can superimpose virtual information made up of virtual images onto real information visible through the windshield, reducing the need for the driver to move their viewpoint or focus as much as conventional HUDs, which display information on the glass surface of the windshield.

[0003] Patent Document 1 discloses a technology for displaying guidance information from a car navigation system via an AR-HUD. For example, it describes displaying multiple arrows arranged in a roughly L-shape superimposed on the actual view of an intersection where a driver should turn right or left.

[0004] When a virtual object, i.e., a virtual image, is displayed by the AR-HUD, the driver perceives the distance to the object based on the downward angle, which is the angle downward relative to the horizontal plane. Meanwhile, with regard to a real intersection, the driver sitting in the driver's seat looks down at the intersection, and the driver's downward angle relative to the real intersection increases as the vehicle approaches the intersection.

[0005] Therefore, the appropriate display position of the virtual image indicating an intersection where a right or left turn should be made becomes lower as the vehicle approaches the intersection. However, the display area of ​​the AR-HUD is limited compared to the width of the field of view through the windshield, and depending on the size of the display area, the appropriate display position may be lower than the display area of ​​the AR-HUD. Therefore, if an attempt is made to continue displaying a virtual image, such as an arrow indicating an intersection, within the display area of ​​the AR-HUD, the virtual image must be displayed above the actual intersection position (i.e., relatively farther back in 3D space). As a result, the display of the virtual image is shifted from the actual intersection where a right or left turn should be made, which is likely to cause misidentification, for example, when there are multiple roads where right or left turns can be made.

[0006] Patent No. 7088151

[0007] This invention is an information display method for a vehicle, which acquires the coordinates of a node where a right or left turn should be made using route guidance for the vehicle, and displays a virtual image representing the position of the node where a right or left turn should be made via the vehicle's AR-HUD, superimposed on the view ahead as seen through the windshield; the method acquires the distance between the vehicle and the node; and in a long-distance area where the position of the node as seen through the windshield is within the display area of ​​the AR-HUD, the virtual image is displayed above the position of the node; and in a close-distance area where the position of the node as seen through the windshield is below the display area of ​​the AR-HUD, the virtual image is displayed below the display area of ​​the AR-HUD, and this virtual image is displayed as an animation that moves in the width direction of the vehicle.

[0008] In this way, when the vehicle approaches a node where it should turn right or left, the display of the virtual image changes from a normal display to an animated display, thereby alerting the driver that the display position of the virtual image is shifting from the correct node position.

[0009] An explanatory diagram of the configuration of an information display device according to one embodiment. An explanatory diagram of the scene seen through the windshield when an intersection is far away. An explanatory diagram of the scene seen through the windshield when an intersection is close by. An explanatory diagram showing the relationship between the distance to the intersection and the downward angle. A flowchart showing the processing flow according to one embodiment. An explanatory diagram of (a) normal display of a virtual image and (b) animation display of the virtual image.

[0010] An embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0011] FIG. 1 is an explanatory diagram showing the configuration of an information display device for a vehicle according to one embodiment. The vehicle according to this embodiment is a typical automobile equipped with an AR-HUD (Augmented Reality Head-Up Display) 1 in front of the driver's seat. The AR-HUD 1 displays virtual information superimposed on real information visible through a windshield 2. In the present invention, the display may take any form; for example, a projector may be provided below the windshield 2, and light reflected by the surface of the windshield 2 and reaching the driver's eyes generates a virtual image of the virtual information on a virtual focal plane located an appropriate distance (e.g., several meters) in front of the driver. The virtual information may include a virtual image indicating a right or left turn for route guidance to be displayed superimposed on an intersection, as described below, or other appropriate information such as a speed limit or actual vehicle speed.

[0012] The AR-HUD 1 is controlled by a controller 3. That is, the controller 3 generates a virtual image and controls its display position. A car navigation system 4 using a GPS, which provides route guidance for the vehicle, is connected to the controller 3. The car navigation system 4 includes map information, which includes coordinate data for nodes such as intersections. The car navigation system 4 also identifies the vehicle's position. The illustrated system also includes information acquisition devices such as a radar 5 and a camera 6 for detecting the positions of preceding vehicles and pedestrians. Note that a node is a component that, together with links, constitutes a road network on a digitized road map, and indicates a point such as an intersection or other nodal point on a road network representation. Each node and link has a unique number, and nodes are connected by links to constitute the road network. Hereinafter, a node where a right or left turn should be made is also referred to as an intersection.

[0013] An information display device using the AR-HUD 1 according to one embodiment includes a viewpoint detection camera 7 that detects the driver's viewpoint position in order to optimize the position of the virtual image of the AR-HUD 1. The viewpoint detection camera 7 constitutes, for example, part of a driver monitoring system (DMS) that monitors the driver's condition. The viewpoint detection camera 7 is disposed, for example, near the upper edge of the windshield, facing the driver's head. The controller 3 processes images acquired by the viewpoint detection camera 7 to detect the driver's viewpoint position (i.e., the position of the driver's eyes). Note that the driver's viewpoint position may be detected without using a camera, and may be detected indirectly, for example, from the driver's seating position, driver height, or the like. The controller 3 corrects the position at which the virtual image, i.e., the object, is generated by the AR-HUD 1 according to the viewpoint position thus detected, so that the actual scene seen by the driver through the windshield 2 and the object of the AR-HUD 1 are properly superimposed.

[0014] The controller 3 is configured as a part of the functions of an in-vehicle computer system that performs various controls, and in a mode in which route guidance is provided by the car navigation system 4, it displays virtual images indicating right and left turns required for route guidance, virtual images indicating the destination, etc. via the AR-HUD 1. The controller 3 performs functions such as obtaining the coordinates of nodes (intersections) via the car navigation system 4, creating display data for the virtual images, calculating the distance between the vehicle and the intersection, and changing the display mode of the virtual images according to this distance.

[0015] FIG. 2 is a simplified explanatory diagram showing the view seen through the windshield 2 when a vehicle approaches an intersection where a right turn is to be made, for example. A rectangular display area 1A of the AR-HUD 1 is present in a portion of the view through the windshield 2. The display area 1A is essentially positioned directly in front of the driver. Note that the frame around the periphery of the display area 1A is not actually displayed; it is shown in the figure for illustrative purposes. As described above, this display area 1A displays various virtual information required during driving via the AR-HUD 1. For example, a virtual image 11 (a so-called icon) in the shape of a right-pointing arrow indicating a right turn is displayed superimposed on the real view at the intersection node. The virtual image 11 in the illustrated example has three arrowhead-shaped segments 11a, 11b, and 11c spaced apart, as shown in FIG. 6( a). In this example of the virtual image 11, the central segment 11b corresponds to the node position. The road Rt in real space located on the right side of this virtual image 11 is the road on which the vehicle should turn right. If the vehicle should turn left, the virtual image will show an arrow pointing left.

[0016] The arrow-shaped virtual image 11 is displayed with an appropriate color and brightness. The size of the virtual image 11 is calculated so that it has a constant size (for example, a constant width) at the intersection in 3D space, so that in the display area 1A, the longer the distance to the intersection, the smaller the image will appear, and the shorter the distance, the larger the image will appear.

[0017] FIG. 3 is an explanatory diagram illustrating a state in which the vehicle approaches the intersection from the state illustrated in FIG. 2 . As described above, as the vehicle approaches the intersection, the driver's viewpoint becomes larger as the vehicle approaches the intersection. Therefore, the display position of the virtual image 11, calculated based on the vehicle's positional relationship with the intersection, gradually moves downward and reaches the lower edge of the display area 1A, as illustrated in FIG. 3 . FIG. 6B is an explanatory diagram of the display area 1A at this time. The display position of the virtual image 11 is limited by the lower limit shown in FIGS. 3 and 6B . In other words, the lower limit is when the entire virtual image 11, including the three segments 11a to 11c, is displayed at the bottom of the display area 1A, and no part of the image is missing. When the virtual image 11 reaches the lower limit of the display area 1A, or more specifically, just before that, the display switches to an animation display in which the virtual image 11 moves in the vehicle width direction.

[0018] As shown in Figure 6(b), in one example of animation display, the display position of the virtual image 11 is changed back and forth in the vehicle width direction as indicated by the arrow 13. For example, it is displayed as if it is moving back and forth at a frequency of about several Hz. The amount of change in the display position is determined by the angle in the vehicle width direction. This ensures that the form of the change in the movement remains similar even if the distance to the intersection changes.

[0019] In another example of animation display, three segments 11a, 11b, and 11c that make up the virtual image 11 and are aligned in the vehicle width direction are sequentially lit up, making it possible to display the arrow-shaped virtual image 11 as if it were flowing in the direction of its direction.

[0020] As shown in FIG. 3 , when the virtual image 11 is limited to the lower limit of the display area 1A, the display position of the virtual image 11 is positioned relatively higher than the ideal display position corresponding to the road Rt where the vehicle is to turn right. Therefore, from the driver's perspective, the virtual image 11 appears to be located further back in the real 3D space than the road Rt where the vehicle is to turn right. When this positional relationship occurs, in the above embodiment, the arrow-shaped virtual image 11 is switched to an animation display in which the image moves back and forth from side to side, thereby attracting the driver's attention. For example, in the example of FIG. 3 , there is another road Rm behind the road Rt where the vehicle is to turn right. Misidentification is likely to occur when the two roads are relatively close to each other. By drawing attention with the animation display, the driver can be informed that the position of the arrow-shaped virtual image 11 may be misaligned with the road Rt, thereby reducing misidentification.

[0021] In a more preferred embodiment, the period of the animation display changes stepwise or continuously so that the shorter the distance from the vehicle to the intersection, the shorter the period of the animation display.

[0022] In this way, the periodic change in the animation display allows the driver to intuitively know that he or she is approaching the desired intersection, and misidentifying the road on which to turn right is more reliably prevented.

[0023] FIG. 4 is an explanatory diagram of the above-mentioned look-down angle. The driver looks down at a real intersection 21 from his / her viewpoint 15, and the look-down angle θ1 at that time is geometrically determined by the height Hd of the viewpoint 15 from the road surface and the distance x from the vehicle to the intersection 21. This look-down angle θ1 relative to the intersection 21 is referred to as the "first look-down angle." The plane labeled 16 in the figure indicates a virtual focal plane on which a virtual image is generated by the AR-HUD 1. This focal plane 16 is located outside the windshield 2, i.e., in front of the vehicle. The outline of this focal plane 16 forms the display area 1A of the AR-HUD 1. The triangle labeled 17 indicates the visual angle at which the driver views the display area 1A of the AR-HUD 1. The look-down angle θ2 is determined by the driver's line of sight relative to the lower edge of the display area 1A. This look-down angle θ2 relative to the lower edge of the display area 1A is referred to as the "second look-down angle."

[0024] 4(a), the first look-down angle θ1 is smaller than the second look-down angle θ2, and the intersection 21 appears within the display area 1A of the AR-HUD 1. Therefore, the display position of the virtual image 11 calculated based on the position coordinates of the intersection 21 is within the display area 1A of the AR-HUD 1.

[0025] When the distance x becomes shorter, the first look-down angle θ1 becomes equal to the second look-down angle θ2, as shown in FIG. 4B. The distance x at this time is set to the lower limit distance xm. In this state, the virtual image 11 is displayed on the lower edge of the display area 1A of the AR-HUD 1 (ignoring the size of the virtual image 11). Then, as shown in FIG. 4C, in an area where the distance x is shorter than the lower limit distance xm, the virtual image 11 can no longer be displayed at the correct position corresponding to the position coordinates of the intersection 21.

[0026] Therefore, in one embodiment, the display of the virtual image 11 is switched from the normal display to the animation display before (preferably just before) the first look-down angle θ1 becomes equal to or greater than the second look-down angle θ2.

[0027] In other words, as the vehicle approaches the intersection 21, the virtual image 11 approaches the lower edge of the display area 1A of the AR-HUD 1, and it is desirable that the animation display begin at a distance x at which the entire virtual image 11 can be displayed within the display area 1A.

[0028] 5 is a flowchart showing the flow of the intersection display process that is repeatedly executed when the car navigation system 4 determines a node (intersection) where a right or left turn should be made and commands the information display device to display it. First, in step 1, the distance x from the vehicle to the intersection 21 is detected, and in step 2, it is determined whether this distance x is equal to or less than a predetermined threshold value xs at which display should begin.

[0029] When the vehicle approaches the target intersection 21 and the distance x becomes equal to or less than the threshold value xs, the process proceeds from step 2 to step 3, where a first look-down angle θ1 is calculated based on the distance x. Then, in step 4, it is determined whether the first look-down angle θ1 is equal to or greater than a predetermined threshold value θn. The threshold value θn is set by subtracting an appropriate, relatively small margin from the second look-down angle θ2 shown in FIG. 4. As described above, this margin is set so that the animation display starts near the limit at which the entire virtual image 11 can be displayed within the display area 1A.

[0030] If the first look-down angle θ1 is less than the threshold value θn, the process proceeds from step 4 to step 5, where a normal display without animation is performed. Then, in step 10, the AR-HUD 1 performs a superimposed display of the virtual image 11. As described above, the display position of the virtual image 11 is calculated according to the positional relationship between the coordinates of the vehicle and the coordinates of the intersection 21, and always corresponds to the position of the actual intersection 21 (in other words, the road Rt where the vehicle should turn right or left).

[0031] If it is determined in step 4 that the first look-down angle θ1 is equal to or greater than a predetermined threshold θn, the process proceeds from step 4 to step 6, where an animation display is performed. In this animation display, the display position of the virtual image 11 is limited to the lower limit position of the display area 1A. Next, the process proceeds to step 7, where it is determined whether the distance x is equal to or less than a predetermined threshold xt that changes the cycle of the animation display. If it is determined that the distance x is greater than the threshold xt, the process proceeds to step 8, where a slow cycle is selected as the cycle of the animation display. If the distance x is equal to or less than the threshold xt, the process proceeds to step 9, where a fast cycle is selected as the cycle of the animation display. For example, a cycle of about 2 Hz is set up to a distance of about 20 to 30 m, and a cycle of about 4 Hz is set at a distance closer than this. In step 10, the animation display of the virtual image 11 is performed via the AR-HUD 1 according to the cycle selected in this manner.

[0032] In this example, the animation display cycle is changed in two stages, but it may be controlled in more stages. Also, the cycle may be changed continuously according to the distance x.

[0033] When the animation display cycle is changed in stages, the number of stages of the cycle change may be varied depending on the conditions of the road on which the vehicle is traveling. For example, if the distance between adjacent intersections is long, the number of stages may be reduced (for example, two stages of 2 Hz and 4 Hz), and if the distance between adjacent intersections is short, the number of stages may be increased (for example, three stages of 2 Hz, 4 Hz, and 8 Hz). The shorter the distance between intersections, the more likely it is that the display position of the virtual image 11 will shift, causing a driver to mistakenly identify the road on which to turn. Therefore, by increasing the number of stages, the driver's attention can be drawn to avoid taking the wrong road.

[0034] Similarly, the number of steps of the frequency change may be varied based on the vehicle speed. For example, when the vehicle speed is high, the number of steps is reduced (for example, two steps of 2 Hz and 4 Hz), and when the vehicle speed is low, the number of steps is increased (for example, three steps of 2 Hz, 4 Hz, and 8 Hz). This is based on the fact that speeds are generally low in urban areas where intersecting roads appear at short intervals, and generally high in suburban areas where intersecting roads are widely spaced.

[0035] Instead of changing the cycle of the animation display, the brightness of the animation display may be changed. In one example, the brightness of the animation display is changed in a stepwise or continuous manner so that it becomes darker as the distance x becomes shorter. This gradual darkening allows the driver to know that they are approaching a target intersection where they should turn right or left.

[0036] The animation display may be terminated when it is detected that the driver has operated the turn signal, and the display may be restored to the normal display of the virtual image 11. Alternatively, when it is detected that the driver has operated the turn signal, it may be terminated to display the virtual image 11. At the stage when the driver operates the turn signal, it is considered that the driver has already recognized the road on which he or she should turn.

[0037] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications are possible. For example, the shape of the virtual image 11 is not limited to the configuration shown in Figure 6, and the present invention can be applied to virtual images of any other shape.

Claims

1. A vehicle information display method, which acquires the coordinates of the nodes to be turned right or left through vehicle route guidance, and displays a virtual image representing the positions of the nodes to be turned right or left, superimposed on the forward scene visible through the windshield via the vehicle's AR-HUD. The method includes acquiring the distance between the vehicle and the nodes, and displaying the virtual image above the position of the node in a far-distance area where the position of the node visible through the windshield is within the display area of the AR-HUD, and in a near-distance area where the position of the node visible through the windshield is below the display area of the AR-HUD, displaying the virtual image at the lower part of the display area of the AR-HUD, and making this virtual image display an animation moving in the vehicle width direction.

2. The vehicle information display method according to claim 1, wherein in the process of the virtual image approaching the lower edge of the display area as the vehicle approaches the node, the animation display is started at a distance where the entire virtual image can be displayed within the display area.

3. The vehicle information display method according to claim 2, which obtains the driver's viewpoint position, obtains a first downward viewing angle with respect to the node from this viewpoint position, obtains a second downward viewing angle with respect to the lower edge of the display area of the AR-HUD from the viewpoint position, and starts the animation display before the first downward viewing angle is greater than or equal to the second downward viewing angle.

4. The vehicle information display method according to claim 1, wherein the period of the animation display is changed stepwise or continuously so that the shorter the distance, the shorter the period.

5. The vehicle information display method according to claim 1, wherein the brightness of the animation display is changed stepwise or continuously so that the shorter the distance, the darker the brightness.

6. The vehicle information display method according to claim 1, wherein when a driver's direction indicator operation is detected, the animation display is terminated and the virtual image is returned to normal display.

7. The vehicle information display method according to claim 1, wherein when a driver's direction indicator operation is detected, the display of the virtual image is terminated.

8. The virtual image according to claim 1 has a shape with a directivity indicating the right or left direction to turn at the node.

9. The method for displaying vehicle information according to claim 1, wherein the size of the virtual image displayed in the display area changes according to the distance to the node so as to correspond to a constant size in the real space on the node.

10. The method for displaying vehicle information according to claim 1, wherein the above animation display is performed by reciprocally changing the display position of the virtual image in the vehicle width direction.

11. The method for displaying vehicle information according to claim 10, wherein the amount of change in the reciprocal change is defined by an angle in the vehicle width direction.

12. The method for displaying vehicle information according to claim 1, wherein the virtual image is composed of a plurality of segments arranged in the vehicle width direction, and the above animation display is performed by sequentially lighting up these plurality of segments.

13. The method for displaying vehicle information according to claim 1, wherein the period of the above animation display is changed step by step so that the shorter the distance, the shorter the period, and when the distance between intersections arranged one after another is short, the number of stages of the period change is increased compared to when the distance between intersections is long.

14. The method for displaying vehicle information according to claim 1, wherein the period of the above animation display is changed step by step so that the shorter the distance, the shorter the period, and when the vehicle speed is low, the number of stages of the period change is increased compared to when the vehicle speed is high.

15. A vehicle information display device comprising: a node coordinate acquisition unit that acquires the coordinates of a node to be turned right or left based on vehicle route guidance; an AR-HUD that displays a virtual object superimposed on the scenery ahead visible through the windshield; and a control unit that controls the AR-HUD to display a virtual image as the object at the position of the node to be turned right or left, wherein the control unit acquires the distance between the vehicle and the node, displays the virtual image on the position of the node in a long-distance area where the position of the node visible through the windshield is within the display area of the AR-HUD, and in a short-distance area where the position of the node visible through the windshield is below the display area of the AR-HUD, displays the virtual image at the lower part of the display area of the AR-HUD and makes this virtual image an animation display that moves in the vehicle width direction.

Images