Display control device

Abstract

This disclosure aims to suppress the shift in the display position in the vehicle's pitch direction that may occur due to changes in road gradient when a guidance display indicating the direction of travel of a vehicle at an intersection is superimposed on the foreground of the vehicle. [Solution] The display control device comprises a correction unit that derives an estimated height in the vehicle coordinate system from the vehicle traffic signal to the road surface based on a predetermined physical height of the vehicle traffic signal present at the intersection and the height coordinate of the vehicle traffic signal in the vehicle coordinate system shown in the foreground image, and derives a correction amount to correct the deviation of the display position of the guidance display in the pitch direction of the vehicle using the estimated height, and a control unit that superimposes the guidance display on the display position corrected by the correction amount.

Description

Technical Field

[0001] The present disclosure relates to a display control device.

Background Art

[0002] Patent Document 1 discloses a technique that enables suppression of the occurrence of display position deviation even when an error occurs in the estimation or calculation of the position of the host vehicle when a virtual image display element for guiding the traveling direction or the like at an intersection is superimposed and displayed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, the technique of Patent Document 1 corrects the display position of the virtual image display element on the assumption that a plane parallel to the host vehicle extends in front of the host vehicle, and does not perform correction in consideration of the height of the road surface. Therefore, in the technique of Patent Document 1, when the road gradient changes, the display position of the virtual image display element may shift in the pitch direction of the vehicle, and the virtual image display element may be displayed at a position that gives the occupant a sense of discomfort.

[0005] Therefore, an object of the present disclosure is to provide a display control device that can suppress a shift in the display position in the pitch direction of a vehicle that may occur due to a change in the road gradient when a guidance display indicating the traveling direction of a vehicle at an intersection is superimposed and displayed on the foreground of the vehicle.

Means for Solving the Problems

[0006] The display control device according to claim 1 comprises: a first acquisition unit that acquires an image of the foreground of a moving vehicle captured by an imaging device; a second acquisition unit that acquires the current location of the vehicle; a third acquisition unit that acquires a route to guide the vehicle to its destination; a generation unit that generates display information for superimposing a guidance display indicating the direction of travel of the vehicle at an intersection to be passed through, as a virtual image at the center of the intersection estimated based on the foreground image; a correction unit that derives an estimated height in the vehicle coordinate system from the vehicle signal to the road surface based on a predetermined physical height of a traffic signal at the intersection and the height coordinate of the traffic signal in the vehicle coordinate system shown in the foreground image, and derives a correction amount to correct the deviation of the display position of the guidance display in the pitch direction of the vehicle using the estimated height; and a control unit that superimposes the guidance display at the display position corrected by the correction amount.

[0007] According to the display control device of claim 1, when displaying a guidance display indicating the direction of travel of a vehicle at an intersection superimposed on the foreground of the vehicle, it is possible to suppress the shift in the display position in the pitch direction of the vehicle that may occur due to changes in the road gradient.

[0008] The display control device according to claim 2, in claim 1, wherein the correction unit increases the correction amount as the distance from the current location to the vehicle traffic signal increases, and decreases the correction amount as the distance decreases.

[0009] According to the display control device of claim 2, the amount of correction for the guidance display can be derived while taking into account the situation in which the estimated road contact position of the vehicle signal and the actual road contact position differ.

[0010] The display control device according to claim 3, in claim 1 or 2, the correction unit derives the estimated height by targeting the vehicle traffic lights among the plurality of vehicle traffic lights that are in front of the vehicle or close to the driving lane, when a plurality of vehicle traffic lights are shown in the foreground image.

[0011] According to the display control device of claim 3, when multiple traffic signals are shown in an image of the foreground of a vehicle, a correction amount can be derived using information on the traffic signals that have a high relation to the vehicle itself.

[0012] The display control device according to claim 4, in any one of claims 1 to 3, wherein the correction unit, when the vehicle signal and a specific landmark in contact with the road surface at the intersection are both located within a predetermined range from the current location, uses the difference between the height coordinate of the vehicle signal in the vehicle coordinate system and the height coordinate of the specific landmark as the estimated height, and corrects the display position of the guidance display with the difference between the height coordinate of the specific landmark and the height coordinate of a point on the extension of the vehicle's attitude at a height position corresponding to the specific landmark in the vehicle coordinate system.

[0013] According to the display control device of claim 4, when a vehicle approaches the vicinity of an intersection, the estimated height value used to derive the correction amount can be switched to the difference in height coordinates of two landmarks at the intersection that are located at different positions in the vehicle height direction. Furthermore, according to the display control device, a guidance display can be superimposed on a display position that takes into account the height relationship between a specific landmark at the intersection and a point extended from the vehicle's orientation.

[0014] The display control device according to claim 5, in any one of claims 2 to 4, derives the correction amount using the distance from the current location to the vehicle traffic signal measured by the positioning satellite, when the positional accuracy of the positioning satellite is good.

[0015] According to the display control device of claim 5, when the positioning satellite position accuracy is good, an appropriate correction amount can be derived using the distance from the vehicle's current location to the vehicle traffic signal, which has been measured with good accuracy. [Effects of the Invention]

[0016] As explained above, the display control device according to this disclosure can suppress the shift in the display position in the vehicle's pitch direction that may occur due to changes in the road gradient when displaying guidance indicating the direction of travel of a vehicle at an intersection superimposed on the vehicle's foreground.

Brief Description of the Drawings

[0017] [Figure 1] It is a block diagram showing the hardware configuration of a vehicle. [Figure 2] It is a flowchart showing the flow of a specific process. [Figure 3] It shows a first display example of a guidance display superimposed on the foreground of the vehicle. [Figure 4] It shows a second display example of a guidance display superimposed on the foreground of the vehicle. [Figure 5] It shows a third display example of a guidance display superimposed on the foreground of the vehicle. [Figure 6] It shows a fourth display example of a guidance display superimposed on the foreground of the vehicle.

Modes for Carrying Out the Invention

[0018] Hereinafter, the vehicle 10 according to the present embodiment will be described. FIG. 1 is a block diagram showing the hardware configuration of the vehicle 10. As shown in FIG. 1, the vehicle 10 includes a display control device 15, a camera 30, a sensor group 40, a navigation device 50, and a HUD (Head-Up Display) 60.

[0019] The display control device 15 controls the display operation in the HUD 60 that forms a virtual image using AR (Augmented Reality) technology. The display control device 15 is an example of the "display control device" of the present disclosure.

[0020] The camera 30 is a so-called front camera that captures an image of the foreground including the front and the front side of the vehicle 10 during traveling. Specifically, the camera 30 is a digital camera device and includes an image sensor such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor). The camera 30 is an example of the "imaging device" of the present disclosure.

[0021] The sensor group 40 detects the driving state and driving environment of the vehicle 10. The "driving state" includes, for example, the accelerator opening, braking amount, shift position, steering angle, vehicle speed, angular velocity, longitudinal acceleration, and lateral acceleration. The "driving environment" includes the outside air temperature, rainfall amount, illuminance, and the presence state of targets within a predetermined detection range around the vehicle 10. The "targets" include pedestrians, cyclists, animals, other vehicles, road debris, guardrails, curbs, road signs, road studs, stop lines, crosswalks, and structures such as signal lights and buildings. That is, the sensor group 40 is a general term for various sensors such as an accelerator opening sensor, a steering angle sensor, a wheel speed sensor, an angular velocity sensor, an acceleration sensor, an outside air temperature sensor, a raindrop sensor, an illuminance sensor, a radar sensor, and an ultrasonic sensor.

[0022] The navigation device 50 is configured to calculate the current location (hereinafter, "vehicle position") and the travel route of the vehicle 10 based on map information and positioning information by positioning satellites. The "travel route" is a planned travel route that guides the vehicle 10 from the vehicle position to the destination.

[0023] The HUD 60 is a display device that superimposes and displays a virtual image on the foreground (e.g., the road surface, etc.) of the vehicle 10 that can be visually recognized through the front windshield 14 (see FIG. 3, etc.).

[0024] In addition, the display control device 15 includes a predetermined ECU (Electronic Control Unit) 20. The ECU 20 is configured as a so-called in-vehicle computer including a processor and a memory programmed to execute one or more functions embodied by a computer program. The ECU 20 includes an acquisition unit 21, a generation unit 22, an estimation unit 23, a derivation unit 24, a correction unit 25, and a control unit 26 as a functional configuration realized on a microcomputer.

[0025] The acquisition unit 21 acquires an image of the foreground of the moving vehicle 10 captured by the camera 30 (hereinafter referred to as the "foreground image"), and the vehicle position and route from the navigation device 50. The acquisition unit 21 is an example of the "first acquisition unit," "second acquisition unit," and "third acquisition unit" of this disclosure.

[0026] The generation unit 22 generates display information for superimposing a virtual image of a guidance display 80 (see Figures 3-6) indicating the direction of travel of the vehicle 10 at an intersection where the vehicle 10 is scheduled to pass, as the center position of the intersection estimated based on the foreground image.

[0027] The estimation unit 23 estimates the intersection center, which is the central position of the intersection, based on the foreground image. The method for estimating the intersection center is not particularly limited, and any method disclosed in Japanese Patent Application Publication No. 2023-015597 may be used as appropriate.

[0028] The derivation unit 24 derives an initial value for the distance from the vehicle's position to the traffic signal at the intersection using various methods. In this embodiment, this distance is considered to be the distance from the current location to the intersection and is referred to as the "intersection distance".

[0029] The derivation unit 24 derives the intersection distance based on the image recognition results of the vehicle traffic signals. For example, the derivation unit 24 estimates the distance to the vehicle traffic signals using known techniques such as Structure from Motion (SfM) and derives this distance as the initial value of the intersection distance.

[0030] Furthermore, the derivation unit 24 derives an initial value for the intersection distance based on the predetermined physical width of the vehicle traffic signal and the image width in the direction corresponding to the width of the vehicle traffic signal shown in the foreground image. In this case, the derivation unit 24 uses the following formula (1).

[0031] (1) D = w / (tan(image width of vehicle traffic signal [pix] * (camera horizontal field of view [deg] / camera horizontal resolution [pix]) / 2.0)) / 2

[0032] In equation (1), D represents the "intersection distance [m]" and w represents the "physical width of the traffic signal [m]". w is a predetermined value (e.g., 1.25) used in the country where vehicle 10 operates. The image width [pix] of the traffic signal in equation (1) is obtained from the image recognition results of the traffic signal captured by camera 30. The camera horizontal field of view [deg] and camera horizontal resolution [pix] in equation (1) are obtained from camera 30.

[0033] Next, the derivation unit 24 derives the initial value of the intersection distance using the method described above, and then derives the change in the intersection distance over time using the following formula (2). (2) Intersection distance = Camera measured distance × α + (Previous distance - Vehicle speed × Time) × (1 - α)

[0034] In equation (2), the camera measurement distance is the intersection distance derived using the image recognition results of the traffic signal for vehicles (e.g., SfM). α is a coefficient set between 0.01 and 1.0, which increases as the previous distance is farther and decreases as it is closer. The previous distance is the intersection distance derived in the previous (immediate) measurement. By using equation (2), the farther the distance from the vehicle position to the traffic signal for vehicles, the larger the proportion of the camera measurement distance in the intersection distance. Conversely, the closer the distance from the vehicle position to the traffic signal for vehicles, the smaller the proportion of the camera measurement distance in the intersection distance and the larger the proportion of the distance calculated by the time integral of the vehicle speed. As a result, according to the display control device 15, as the vehicle 10 approaches the intersection, the proportion of the camera measurement distance, which is prone to reduced distance accuracy due to disturbances around the traffic signal for vehicles, in the intersection distance can be reduced, thereby suppressing the situation in which the estimated height derived in the vicinity of the intersection, as described later, varies.

[0035] The correction unit 25 derives an estimated height in the vehicle coordinate system from the vehicle signal to the road surface based on the predetermined physical height of the vehicle signal and the height coordinate of the vehicle signal in the vehicle coordinate system shown in the foreground image. Then, the correction unit 25 uses this estimated height to derive a correction amount to correct the misalignment of the display position of the guidance display 80 in the pitch direction of the vehicle 10. The vehicle coordinate system is a relative coordinate system fixed to the vehicle 10 and changing with the movement and orientation of the vehicle 10. For example, the vehicle coordinate system is a three-dimensional coordinate system with an x-axis parallel to the vehicle width direction, a y-axis parallel to the vehicle height direction, and a z-axis parallel to the vehicle longitudinal direction. Hereinafter, the height coordinate may also be referred to as the "y-coordinate".

[0036] Here, the correction unit 25 derives the estimated height using the following formulas (3) and (4). (3) θ[deg] (= atan physical height of the traffic signal [m] / distance to the intersection [m]) (4) θ[pix] = θ[deg] × (Camera horizontal resolution [pix] / Camera horizontal field of view [deg])

[0037] In equation (3), the physical height [m] of the vehicle traffic signal is set to a value (e.g., 5.0) that is predetermined by law (e.g., road structure regulations) in the country where the vehicle 10 travels. In equation (4), θ [pix] represents the "estimated height".

[0038] Next, the correction unit 25 derives the correction amount using the following formula (5). (5) Correction amount = β × {(y coordinate of display position before correction - y coordinate of vehicle signal) - estimated height}

[0039] In equation (5), β is a coefficient set between 0.01 and 1.0. The pre-correction display position y coordinate indicates the y coordinate of the display position of the guidance display 80 in the vehicle coordinate system before correcting for deviations in the pitch direction. The vehicle signal y coordinate indicates the y coordinate of the vehicle signal in the vehicle coordinate system.

[0040] The control unit 26 superimposes the guidance display 80 onto the display position corrected by the above correction amount. This display position is considered to be the position on the road surface that is below the y coordinate of the vehicle signal by the physical height (θ [pix] of the vehicle signal) of the vehicle signal in the vehicle coordinate system.

[0041] Figure 2 is a flowchart showing the flow of a specific process performed by the display control device 15. The specific process is carried out by the display control device 15 functioning as each of the above-mentioned parts.

[0042] In step S10 shown in Figure 2, the display control device 15 derives the current intersection distance. Then, the identification process proceeds to step S11.

[0043] In step S11, the display control device 15 derives the pre-correction display position of the guidance display 80. For example, the display control device 15 estimates the intersection center in a plane extended from the vehicle's orientation in the three-dimensional space of the vehicle coordinate system, using the method disclosed in Japanese Patent Application Publication No. 2023-015597 as appropriate, and sets the position of the intersection center as the pre-correction display position. In other words, the display position determined using the above-mentioned prior art becomes the pre-correction display position in this embodiment. The identification process then proceeds to step S12.

[0044] In step S12, the display control device 15 derives the estimated height described above. Then, the identification process proceeds to step S13.

[0045] In step S13, the display control device 15 uses the estimated height to derive a correction amount to correct for the misalignment of the display position of the guide display 80 in the pitch direction. Then, the specific processing proceeds to step S14.

[0046] In step S14, the display control device 15 superimposes the guidance display 80 onto the display position corrected by the correction amount. Then, the specific processing is completed.

[0047] Figure 3 shows a first example of the guidance display 80 superimposed on the foreground of the vehicle 10. In this embodiment, the vehicle 10 is a right-hand drive vehicle and travels on the left side of the road. The same applies to the other examples from Figure 4 onwards.

[0048] As shown in Figure 3, the passenger compartment 12, which is the interior space where the occupants sit in the vehicle 10, is covered at the front in the vehicle's longitudinal direction by a front windshield 14. The front windshield 14 is formed in a plate shape from translucent glass or synthetic resin. The front windshield 14 is inclined so that, when viewed from the side with a line of sight parallel to the vehicle's width direction, the upper end is located further rearward in the vehicle's longitudinal direction than the lower end in the vehicle's height direction.

[0049] A dashboard 16 is located below the front windshield 14 inside the passenger compartment 12. A HUD 60 (see Figure 1) is housed within the dashboard 16.

[0050] In Figure 3, the foreground of vehicle 10 shows intersection 70A. Intersection 70A is the intersection that vehicle 10 is scheduled to pass through, located ahead of vehicle 10 on the road it is currently traveling on. Intersection 70A is the same intersection that the navigation device 50 is guiding the vehicle through. The road the vehicle is traveling on is the road that vehicle 10 is currently traveling on and may also be called a "straight road." A "straight road" is a road that can be traveled "straight" without requiring right or left turns, and is not limited to straight sections, but may also have curves and bends. Figure 3 shows vehicle 10 descending a slope and approaching intersection 70A on a flat road, and is scheduled to turn left at intersection 70A. In the example in Figure 3, it is assumed that there are no other intersections between vehicle 10 and intersection 70A. That is, intersection 70A is assumed to be the first intersection that the vehicle is about to pass from its current position.

[0051] Here, intersection 70A is a four-way intersection, and the traffic signal 72 for vehicles is located directly in front of vehicle 10, in other words, on the extension of the driving lane. The traffic signal 72 for vehicles is located in front of intersection 70A in the vehicle's front-to-back direction on the road being traveled, that is, on the far side.

[0052] In Figure 3, the black circle B indicates the true intersection center at intersection 70A, and the dashed line L1 indicates the pre-correction display position of the guidance display 80. As shown in Figure 3, the pre-correction display position based on the intersection center estimated by the display control device 15 during downhill driving is shifted downward in the pitch direction from the true intersection center indicated by the black circle B. The guidance display 80B, which is superimposed on the pre-correction display position, is shown by a dashed line in the figure and is shifted downward in the pitch direction from the true intersection center.

[0053] In Figure 3, the virtual line L2 indicates the upper end position of the vehicle traffic signal 72, and the virtual line L3 indicates the corrected display position of the guidance display 80. The display control device 15 uses known techniques to obtain the y-coordinate of the vehicle traffic signal 72 in the vehicle coordinate system corresponding to the position indicated by the virtual line L2 from the foreground image. Next, the display control device 15 uses equations (3) and (4) to derive the estimated height from the vehicle traffic signal 72 to the road surface of the intersection 70A from the y-coordinate and the physical height of the vehicle traffic signal. Then, the display control device 15 uses the estimated height in equation (5) to derive a correction amount, and corrects the display position from the pre-correction display position to the corrected display position indicated by the virtual line L3 based on this correction amount. As a result, the guidance display 80A superimposed on the corrected display position is located closer to the true center of the intersection, indicated by the black circle B, than the guidance display 80B.

[0054] As described above, the display control device 15 derives an estimated height based on the physical height of the vehicle signal and the y-coordinate of the vehicle signal 72 shown in the foreground image in the vehicle coordinate system, and uses this estimated height to derive a correction amount to correct for the deviation of the display position in the pitch direction. The display control device 15 then superimposes the guidance display 80A onto the display position corrected by this correction amount. As a result, the display control device 15 can suppress deviations in the display position in the pitch direction that may occur due to changes in the road gradient when the guidance display 80 is superimposed on the foreground of the vehicle 10.

[0055] Figure 4 shows a second example of the guidance display 80 superimposed on the foreground of the vehicle 10. In the explanations from Figure 4 onward, the parts that overlap with Figure 3 will be omitted or simplified.

[0056] In the foreground of vehicle 10 shown in Figure 4, intersection 70B is depicted. Intersection 70B has a traffic signal 72 installed on the side of the vehicle 10's lane and a traffic signal 74 installed on the opposite lane side of vehicle 10.

[0057] Here, as a function of the correction unit 25, the display control device 15 derives an estimated height for the vehicle traffic signal closest to the front of the vehicle 10 or the driving lane when multiple vehicle traffic signals are shown in the foreground image. In the case shown in Figure 4, the display control device 15 derives an estimated height for the vehicle traffic signal 72 installed on the driving lane side of the vehicle 10. Thus, according to the display control device 15, when multiple vehicle traffic signals are shown in the foreground image, the correction amount can be derived using the information of the vehicle traffic signal that is most relevant to the vehicle itself.

[0058] Figure 5 shows a third example of the guidance display 80 superimposed on the foreground of the vehicle 10. As an example, Figure 5 shows the case where the vehicle 10 is closer to intersection 70A than in Figure 3.

[0059] In Figure 5, the virtual line L4 shows the road-facing position of pole 72A of the vehicle traffic signal 72 based on the estimated height, and the virtual line L5 shows the actual road-facing position of pole 72A. As shown in Figure 5, the estimated road-facing position of pole 72A shown by the virtual line L4 may be shifted upward in the pitch direction from the actual road-facing position of pole 72A shown by the virtual line L5. Here, as a vehicle 10 approaches the vicinity of intersection 70A, the difference in height between the estimated road-facing position of pole 72A and the actual road-facing position of pole 72A becomes more noticeable.

[0060] Therefore, the display control device 15, as a function of the correction unit 25, increases the correction amount as the distance from the vehicle position to the vehicle traffic signal 72 increases, and decreases the correction amount as the distance decreases. Specifically, the display control device 15 increases the value of β in equation (5) as the distance increases, and decreases it as the distance decreases. For example, if the vehicle 10 is located near the intersection 70A, even if the guidance display 80 is superimposed on the pre-correction display position, that is, on a plane extended from the vehicle's posture, the effect of changes in the road gradient is small, and problems are unlikely to occur even with a small correction amount. With the above configuration, the display control device 15 can derive the correction amount for the guidance display 80 while taking into account the situation in which the estimated road contact position of the pole 72A and the actual road contact position differ.

[0061] Furthermore, as a function of the correction unit 25, the display control device 15 estimates the height by using the difference in the y coordinates between the vehicle signal 72 and a specific landmark in the vehicle coordinate system when both the vehicle signal 72 and a specific landmark in the intersection 70A are located within a predetermined range from the vehicle's position. The specific landmark is a landmark that is in contact with the road surface, and includes, for example, a stop line, a pedestrian crossing, and a preceding vehicle. In the intersection 70A, there is a stop line 76 and a pedestrian crossing 78 as such specific landmarks. If there are multiple specific landmarks in the intersection 70A, the display control device 15 derives the estimated height using the specific landmark closest to the vehicle signal 72 from among the multiple specific landmarks. In the case shown in Figure 5, since the pedestrian crossing 78 is closer to the vehicle signal 72 than the stop line 76, the display control device 15 derives the estimated height using the y coordinate of the pedestrian crossing 78.

[0062] In Figure 5, the virtual line L6 indicates the location of the pedestrian crossing 78. The display control device 15 estimates the height by calculating the difference between the y-coordinate of the vehicle traffic signal 72 in the vehicle coordinate system corresponding to the location indicated by the virtual line L2 and the y-coordinate of the pedestrian crossing 78 in the vehicle coordinate system corresponding to the location indicated by the virtual line L6. The display control device 15 then uses this estimated height in formula (5) to derive a correction amount. The guidance display 80 in Figure 5 shows the case where it is superimposed on the display position corrected by the correction amount derived using formula (5) with the estimated height.

[0063] With the above configuration, when the vehicle 10 approaches the vicinity of intersection 70A, the display control device 15 can switch the estimated height value used to derive the correction amount to the difference in y coordinates of two targets located at intersection 70A that are at different positions in the vehicle height direction.

[0064] Figure 6 shows a fourth example of the guidance display 80 superimposed on the foreground of the vehicle 10. At intersection 70A shown in Figure 6, there is a preceding vehicle 18 traveling in front of vehicle 10, which serves as the specific landmark mentioned above.

[0065] In Figure 6, the virtual line L7 indicates the lower end position of the preceding vehicle 18, and the virtual line L8 is an explanatory line for describing point P on the extension of the vehicle attitude at a height position corresponding to the preceding vehicle 18 in the vehicle coordinate system. In this embodiment, point P is the intersection point with the perpendicular line from the coordinate position of the preceding vehicle 18 in the vehicle coordinate system. The display control device 15 corrects the display position of the guidance display 80 by using the difference between the y coordinate of the preceding vehicle 18 in the vehicle coordinate system corresponding to the position indicated by the virtual line L7 and the y coordinate of point P in the vehicle coordinate system corresponding to the position indicated by the virtual line L8 as an additional correction amount. In Figure 6, the guidance display 80 is shown superimposed on the display position that has been corrected by the correction amount derived using formula (5) and then further corrected by the additional correction amount.

[0066] With the above configuration, the display control device 15 can superimpose the guidance display 80 at a display position that takes into account the height relationship between a specific landmark present at intersection 70A and a plane extended from the vehicle's orientation.

[0067] Furthermore, as a function of the correction unit 25, the display control device 15 derives a correction amount using the distance from the vehicle position measured by the positioning satellite to the traffic signal 72 when the positioning satellite position accuracy is good. If the positioning satellite position accuracy is poor, the display control device 15 derives a correction amount using the intersection distance derived using formula (2). For example, the display control device 15 considers the positioning satellite position accuracy to be good if the number of satellites that can be detected is greater than or equal to a predetermined number, and poor if it is less than the predetermined number. With the above configuration, the display control device 15 can derive an appropriate correction amount using the distance from the vehicle position measured accurately to the traffic signal 72 when the positioning satellite position accuracy is good.

[0068] (others) In the above embodiment, the display control device 15 may, as a function of the correction unit 25, change the value of "physical height of the vehicle signal [m]" used in formula (3) based on region determination based on the vehicle position. The display control device 15 may obtain the region value corresponding to the determination result from the memory of the ECU 20, and for example, use "5.0" as the value for region A, and use "6.0" as the value for region B. Furthermore, if the display control device 15 detects, based on region determination based on the vehicle position, that the vehicle is located in a region that is not subject to correction for deviation in the pitch direction, it may superimpose the guidance display 80 on the pre-correction display position without performing any correction.

[0069] In the above embodiment, the case where the vehicle 10 is approaching intersections 70A and 70B on a flat road while descending a slope was described as an example, but the embodiment is not limited to this. The configuration of the above embodiment can also be applied when the vehicle 10 is approaching intersections 70A and 70B on a flat road while ascending a slope.

[0070] In the above embodiment, the display control device 15 increased the correction amount as the distance from the vehicle position to the vehicle signal 72 increased, and decreased the correction amount as the distance decreased, but it is not necessarily limited to this. For example, depending on the positional relationship between the vehicle 10 and the vehicle signal 72, the display control device 15 may decrease the correction amount as the distance from the vehicle position to the vehicle signal 72 increases, and increase the correction amount as the distance decreases.

[0071] In the above embodiment, intersections 70A and 70B are described as crossroads, but the embodiment is not limited to this, and the configuration of the above embodiment can also be applied to T-junctions.

[0072] In the above embodiment, the content of the specific processing shown in Figure 2 is not limited to that described above, and for example, steps to perform other processing may be added as appropriate.

[0073] In the above embodiment, the specific processing performed by the display control device 15 after reading the software (program) may be performed by various processors. Examples of such processors include PLDs (Programmable Logic Devices) such as FPGAs (Field-Programmable Gate Arrays) whose circuit configuration can be changed after manufacturing, and dedicated electrical circuits that are processors with circuit configurations specifically designed to perform specific processing, such as ASICs (Application Specific Integrated Circuits). Furthermore, the specific processing may be performed by one of these various processors, or by a combination of two or more processors of the same or different types (for example, multiple FPGAs, and a combination of a CPU and an FPGA). More specifically, the hardware structure of these various processors is an electrical circuit that combines circuit elements such as semiconductor elements.

[0074] Furthermore, in the above embodiment, the software (program) may be pre-stored (installed) in the memory of the ECU20, or it may be provided in the form of being recorded on a recording medium such as a CD-ROM (Compact Disk Read Only Memory), DVD-ROM (Digital Versatile Disk Read Only Memory), or USB (Universal Serial Bus) memory. Alternatively, the software (program) may be downloaded from an external device via a network. The technology disclosed herein is also applicable to programs and program products. [Explanation of Symbols]

[0075] 10 vehicles 15 Display control device 21 Acquisition Department (1st Acquisition Department, 2nd Acquisition Department, 3rd Acquisition Department) 22 Generation part 25 Correction section 26 Control Unit 30. Camera (imaging device) Intersection of 70A and 70B 80 Directional signs

Claims

1. A first acquisition unit acquires an image of the foreground of a moving vehicle captured by an imaging device, A second acquisition unit for acquiring the current location of the aforementioned vehicle, A third acquisition unit acquires a route to guide the vehicle to its destination, A generation unit generates display information for superimposing a guidance display indicating the direction of travel of the vehicle at an intersection located ahead of the vehicle's intended path, as a virtual image at the center of the intersection estimated based on the foreground image. A correction unit that derives an estimated height in the vehicle coordinate system from the vehicle signal to the road surface based on a predetermined physical height of the vehicle signal present at the intersection and the height coordinate of the vehicle signal in the vehicle coordinate system shown in the foreground image, and uses the estimated height to derive a correction amount to correct the deviation of the display position of the guidance display in the pitch direction of the vehicle, A control unit that superimposes the guidance display onto the display position corrected by the correction amount, A display control device equipped with the following features.

2. The correction unit increases the correction amount as the distance from the current location to the vehicle traffic signal increases, and decreases the correction amount as the distance decreases. The display control device according to claim 1.

3. When the foreground image shows multiple traffic signals, the correction unit derives the estimated height by targeting the traffic signals closest to the front of the vehicle or to the driving lane among the multiple traffic signals. The display control device according to claim 1.

4. The correction unit, If the aforementioned vehicle traffic signal and a specific marker grounded on the road surface at the intersection are both located within a predetermined range from the current location, the difference between the height coordinate of the vehicle traffic signal and the height coordinate of the specific marker in the vehicle coordinate system shall be defined as the estimated height. The display position of the guidance display is corrected by the difference between the height coordinates of a specific target and the height coordinates of a point on the extension of the vehicle's orientation at a height corresponding to the specific target in the vehicle coordinate system. The display control device according to claim 1.

5. The correction unit, when the positioning satellite's position accuracy is good, derives the correction amount using the distance from the current location to the vehicle traffic light measured by the positioning satellite. The display control device according to claim 2.

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