Display control device, head-up display device, and display control method

Abstract

To suppress attitude variations of a vehicle from deteriorating a feeling of virtual reality of an image (a virtual object).SOLUTION: An HUD device sets a first position adjustment amount for suppressing a relative positional shift between a virtual image V20 and a road surface 6 caused by attitude variations of a vehicle; executes first image adjustment processing for adjusting a position of the virtual image on the basis of the first position adjustment amount, when an attitude of the vehicle varies in a first direction of a forward inclination or a backward inclination from a reference attitude; and executes second image adjustment processing for suppressing an adjustment of the position of the virtual image with respect to the attitude variations of the vehicle more than the first image adjustment processing, when the attitude of the vehicle varies in a second direction which is opposite to the first direction of the forward inclination or the backward inclination from the reference attitude.SELECTED DRAWING: Figure 7A

Description

【Technical Field】 【0001】 The present disclosure relates to a display control device, a head-up display device, a display control method, etc. that are used in a moving body such as a vehicle and superimpose an image on the foreground of the moving body (the actual scene in the forward direction of the moving body as seen by the vehicle occupant) for visual recognition. 【0002】 A head-up display (HUD) device superimposes an image (virtual object) on the scenery in front of the vehicle to represent augmented reality (AR) in which information or the like is added to and emphasized on the actual scene or an actual object existing in the actual scene, and can contribute to safe and comfortable vehicle operation by accurately providing desired information while minimizing the movement of the user's line of sight when driving the vehicle. 【0003】 The head-up display device described in Patent Document 1 displays an image (virtual object) at a display reference position and shifts the image outside the display reference position in accordance with the posture fluctuation of the vehicle so as to suppress the relative positional deviation between the image (virtual object) and the actual scene due to the posture fluctuation of the vehicle. Thereby, even when the posture of the vehicle fluctuates, the relative positional relationship between the image and the actual scene is maintained (the positional deviation between the image and the actual scene is suppressed), so that the image can be further harmonized with the actual scene. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 International Publication No. 2018 / 088362 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 Before the vehicle's attitude changes, the area of ​​the real-world scene that was originally superimposed and visible is defined as the superimposed real-world scene area. In a head-up display device, if a large change in the vehicle's attitude causes the virtual image display area to shift so much that it no longer overlaps the superimposed real-world scene area, adjusting the image position to match the large change in attitude will result in part or all of the adjusted image no longer fitting within the virtual image display area (becoming undisplayable). If part or all of the image is missing due to the attitude change, the sense of virtual reality of the virtual image will be impaired, which is expected to cause discomfort to the observer. 【0006】 Furthermore, if the image position is not adjusted in accordance with changes in posture for fear of part or all of the image being lost, the relative positional relationship between the image and the real scene will change in accordance with the changes in the vehicle's posture, which is expected to impair the sense of virtual reality and cause discomfort to the observer. 【0007】 A summary of specific embodiments disclosed herein is provided below. It should be understood that these embodiments are presented solely to provide the reader with an overview of these specific embodiments and do not limit the scope of this disclosure. In fact, this disclosure may encompass combinations of the embodiments described below and various embodiments not described below. 【0008】 This disclosure outlines efforts to reduce the sense of unnaturalness in the perception of virtual images. More specifically, it also relates to suppressing the decline in the sense of virtual reality of images (virtual objects) caused by changes in the vehicle's posture. 【0009】 Therefore, the display control device, head-up display device, and display control method described herein employ the following means to solve the aforementioned problems. The gist of this embodiment is that when the vehicle's posture changes in a first direction of tilting forward or backward from a reference posture, a first position adjustment process is performed to adjust the position of the virtual image based on a first position adjustment amount, and when the vehicle's posture changes in a second direction opposite to the first direction of tilting forward or backward from a reference posture, a second position adjustment process is performed that suppresses the adjustment of the position of the virtual image in response to the change in the vehicle's posture more than the first position adjustment process. 【0010】 Accordingly, the display control device in the first embodiment described herein is a display control device that is mounted on a vehicle and has a display unit that displays an image on a display surface, and controls a head-up display device that directs the light of the image to a projection unit so that a virtual image is superimposed and made visible within a virtual image display area that overlaps with the road surface in front of the vehicle, One or more processors, Memory and The system comprises one or more computer programs stored in the memory and configured to be executed by the one or more processors, The aforementioned processor, Information on the amount of attitude change indicating the attitude change of the vehicle is acquired. In order to suppress the relative positional shift between the virtual image and the road surface due to the attitude fluctuations of the vehicle, a first position adjustment amount is set that changes dynamically in accordance with the attitude fluctuation amount information. 1) When the vehicle's posture changes from its reference posture in a first direction of tilting forward or backward, a first image adjustment process is performed to adjust the position of the virtual image based on the first position adjustment amount. 2) When the vehicle's posture changes from the reference posture in a second direction opposite to the first direction, such as tilting forward or backward, a second image adjustment process is performed that suppresses the adjustment of the virtual image's position in response to the change in the vehicle's posture more than the first image adjustment process. In this embodiment, the advantage is that the image's positional shift is strongly reduced in response to changes in the vehicle's posture in the first direction (for example, tilting forward from the reference posture) (first image adjustment process), while the image's positional adjustment is suppressed in response to changes in the vehicle's posture in the second direction (for example, tilting backward from the reference posture) (second image adjustment process), thereby preventing part or all of the image from being cut off (not fitting within the virtual image display area) due to the image's positional adjustment. 【0011】 Furthermore, in the display control device in the second embodiment which is dependent on the first embodiment, the processor is 1) In the first image adjustment process, if the vehicle's attitude is less than a first attitude change amount in the first direction, the position of the virtual image is adjusted based on the first position adjustment amount; if the vehicle's attitude is greater than the first attitude change amount in the first direction, the position of the virtual image is adjusted based on a constant second position adjustment amount that is less than the first position adjustment amount. 2) In the second image adjustment process, if the vehicle's attitude is less than the second attitude change amount in the second direction, the position of the virtual image is adjusted based on the first position adjustment amount; if the vehicle's attitude is greater than the second attitude change amount in the second direction, the position of the virtual image is adjusted based on a constant third position adjustment amount which is smaller than the first position adjustment amount for the change in the vehicle's attitude. The second attitude change amount is set to be smaller than the first attitude change amount. In this embodiment, if the vehicle's attitude change is small, the position of the virtual image is adjusted based on a first position adjustment amount that changes dynamically in accordance with the vehicle's attitude change, in both the first and second directions, thereby strongly reducing the positional misalignment between the virtual image and the real scene due to the vehicle's attitude change (first image adjustment process). Furthermore, if the vehicle's attitude change is large, the virtual image is fixed and displayed at a predetermined position in the virtual image display area by a constant second position adjustment amount (third position adjustment amount) that is smaller than the first position adjustment amount that changes dynamically in accordance with the attitude change, in both the first and second directions. Therefore, even if the attitude change is large, the position adjustment amount is fixed, so it is possible to prevent the virtual image from being adjusted to a position outside the virtual image display area (second image adjustment process). For attitude changes in the first direction, the first attitude change amount is used as a threshold, and the first image adjustment process (when it is smaller than the threshold) and the second image adjustment process (when it is larger than the threshold) are switched. For attitude changes in the second direction, the second attitude change amount is used as a threshold to switch between the first image adjustment process (when it is less than the threshold) and the second image adjustment process (when it is greater than the threshold). Here, since the second attitude change amount is set to be smaller than the first attitude change amount, in the second direction, even with relatively small attitude changes compared to the first direction, it is easier to switch to the second image adjustment process, which has a smaller amount of position adjustment (position adjustment is suppressed), and the amount of position adjustment is kept small. Therefore, according to this embodiment, it is expected that the positional displacement of the virtual image can be strongly reduced even with relatively large attitude changes in the first direction, and position adjustment can be suppressed even with relatively small attitude changes in the second direction to prevent the virtual image from being cut off. 【0012】 In the display control device of the third embodiment, which is dependent on the second embodiment, the processor fixes the position of the virtual image with respect to the change in the vehicle's attitude when the vehicle's attitude changes from the reference attitude in the second direction faster than a predetermined speed. In the second embodiment, for attitude changes in the second direction, the first image adjustment process (when it is less than the threshold) and the second image adjustment process (when it is greater than the threshold) are switched using the second attitude change amount as a threshold. If the attitude change in the second direction is fast, the second attitude change amount (threshold) is crossed at high speed, that is, the first image adjustment process and the second image adjustment process are switched at high speed. In this embodiment, it is also assumed that if the attitude change in the second direction is fast, the position of the virtual image is fixed, which has the advantage of preventing the first image adjustment process and the second image adjustment process from switching at high speed. 【0013】 In the display control device in the fourth embodiment dependent on the third embodiment, the processor is: If the vehicle's posture changes from the reference posture in the second direction faster than a predetermined speed, the position of the virtual image relative to the change in the vehicle's posture is fixed until it is determined that the vehicle's posture is in a predetermined stable state. In this embodiment, by fixing the position of the virtual image relative to the change in the vehicle's posture until it is determined that the vehicle's posture is in a predetermined stable state, it is also assumed that it is possible to more reliably prevent the first image adjustment process and the second image adjustment process from switching rapidly until the posture fluctuation stabilizes. 【0014】 In a fifth embodiment of the display control device which may be dependent on the second to fourth embodiments, the second direction is the direction in which the posture of the vehicle is tilted backward from the reference posture. The virtual image includes a first virtual image and a second virtual image displayed closer to the lower edge of the virtual image display area than the first virtual image. The processor can set the second attitude change amount and the third position adjustment amount for each virtual image. The second pose change amount of the second virtual image is set to be smaller than the second pose change amount of the first virtual image, and the third position adjustment amount of the second virtual image is set to be smaller than the third position adjustment amount of the first virtual image. According to this embodiment, it is possible to prevent cropping of virtual images near the edges of the virtual image display area, and to strongly reduce image positional displacement even with relatively large pose changes in virtual images far from the edges of the virtual image display area. 【0015】 In a sixth embodiment of the display control device, which may be dependent on the second to fifth embodiments, the processor reduces the visibility of the virtual image while adjusting the position of the virtual image based on the third position adjustment amount. According to this embodiment, an advantage is also anticipated that when a positional misalignment occurs between the virtual image and the real scene, reducing the visibility of the virtual image makes it more difficult to recognize the misalignment. 【0016】 In a seventh embodiment of the display control device which may be dependent on the first to sixth embodiments, The aforementioned depression angle adjustment amount includes at least a first depression angle adjustment amount and a second depression angle adjustment amount which provides a larger adjustment amount for changes in the vehicle's attitude compared to the first depression angle adjustment amount. The aforementioned processor, In the first image adjustment process, the display position of the virtual image is adjusted based on the first position adjustment amount, and the depression angle of the virtual image is further adjusted based on the first depression angle adjustment amount. In the second image adjustment process, the display position of the virtual image is adjusted based on the second position adjustment amount, and the depression angle of the virtual image is adjusted based on the second depression angle adjustment amount. In the present embodiment, since the depression angle adjustment of the virtual image in accordance with the posture variation is commonly performed in the first image adjustment process and the second image adjustment process, it is assumed that there is an advantage that it is difficult for an observer to feel the loss (decrease) of the augmented reality due to the switching to the second image adjustment process with a small position adjustment amount. Further, in the second image adjustment process, since the position adjustment amount is small, the image shift becomes larger due to the posture variation as compared with the first image adjustment process. However, by increasing the second depression angle adjustment amount, it is also assumed that there is an advantage that the discomfort of the depression angle shift can be strongly suppressed, the depression angle of the image and the depression angle of the road surface are harmonized, and the loss (decrease) of the augmented reality can be suppressed. 【0017】 In a display control device according to an eighth embodiment that may depend on the first to seventh embodiments, the processor avoids changing the form of the virtual image during the second image adjustment process, and changes the form of the virtual image after the second image adjustment process. In the present embodiment, it is also assumed that there is an advantage that the change in the form of the virtual image can be avoided during the second image adjustment process in which the position adjustment of the virtual image with respect to the posture variation of the vehicle is suppressed and the relative position between the virtual image and the actual scene is shifted relatively largely, thereby suppressing the discomfort given to the observer. 【0018】 A head-up display device according to a ninth embodiment that may depend on the first to eighth embodiments includes a display unit mounted on a vehicle and displaying an image on a display surface, a relay optical system that directs display light from the display unit to a projection unit, one or more processors, a memory, and one or more computer programs stored in the memory and configured to be executed by the one or more processors. A head-up display device that overlays and visually recognizes a virtual image within a virtual image display area overlapping a road surface in front of the vehicle, where the processor Obtain posture variation amount information indicating the posture variation of the vehicle, To suppress the relative positional deviation between the virtual image and the road surface due to the posture variation of the vehicle, set a first position adjustment amount that dynamically changes according to the posture variation amount information, 1) When the posture of the vehicle changes in a first direction of pitching forward or backward from a reference posture, execute a first image adjustment process for adjusting the position of the virtual image based on the first position adjustment amount, 2) When the posture of the vehicle changes in a second direction opposite to the first direction of pitching forward or backward from the reference posture, execute a second image adjustment process for suppressing the adjustment of the position of the virtual image with respect to the posture change of the vehicle more than the first image adjustment process. 【0019】 In a display control method according to a tenth embodiment that can be subordinate to the first to eighth embodiments, a display control method for controlling a head-up display device mounted on a vehicle and having a display unit that displays an image on a display surface, and overlapping and visually recognizing a virtual image in a virtual image display area overlapping with the road surface in front of the vehicle by directing the light of the image toward a projection target portion, Obtaining posture variation amount information indicating the posture variation of the vehicle, To suppress the relative positional deviation between the virtual image and the road surface due to the posture variation of the vehicle, setting a first position adjustment amount that dynamically changes according to the posture variation amount information, 1) When the posture of the vehicle changes in a first direction of pitching forward or backward from a reference posture, a first image adjustment process for adjusting the position of the virtual image based on the first position adjustment amount, 2) When the posture of the vehicle changes in a second direction opposite to the first direction of pitching forward or backward from the reference posture, a second image adjustment process for suppressing the adjustment of the position of the virtual image with respect to the posture change of the vehicle more than the first image adjustment process, are included. 【Brief Description of Drawings】 【0020】 [Figure 1] FIG. 1 is a diagram showing an example in which the vehicle display system of the present embodiment is applied to a vehicle. [Figure 2]Figure 2 shows the configuration of a head-up display device. [Figure 3] Figure 3 is a block diagram of several embodiments of a vehicle display system. [Figure 4] Figure 4 illustrates a model space in which content and virtual viewpoints are arranged according to several embodiments. [Figure 5] Figure 5 shows an example of the foreground seen by an observer while a vehicle is in motion, and an image superimposed on the foreground (a virtual image). [Figure 6] Figure 6 shows the virtual image before position adjustment processing. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen when the observer is facing forward. [Figure 7A] Figure 7A shows the virtual image after the first image adjustment process. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen by the observer when facing forward. [Figure 7B] Figure 7B shows the virtual image after the second image adjustment process. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen by the observer when facing forward. [Figure 8A] Figure 8A shows the virtual image after the first image adjustment process. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen when the observer is facing forward. [Figure 8B] Figure 8B shows the virtual image after the second image adjustment process. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen when the observer is facing forward. [Figure 9] Figure 9 illustrates image adjustment processing for attitude changes, showing an example where the first and second image adjustment processes are switched depending on the magnitude of the attitude change (or position adjustment amount). [Figure 10] Figure 10 illustrates the image adjustment process for attitude changes, showing another example where the first and second image adjustment processes are switched depending on the magnitude of the attitude change (or position adjustment amount). [Figure 11]Figure 11 shows the virtual image before posture change; the left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen when the observer is facing forward. [Figure 12A] Figure 12A shows the virtual image after size adjustment processing when the virtual image display area is shifted downward relative to the real scene due to forward tilting. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen when the observer is facing forward. [Figure 12B] Figure 12B shows the virtual image after size adjustment processing when the virtual image display area is shifted upward relative to the real scene due to backward tilting. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen when the observer is facing forward. [Figure 13] Figure 13 illustrates a first image adjustment process in which position adjustment is performed without size adjustment when vehicle 1 is tilted backward. The left figure shows the virtual image and foreground before the attitude change and before the first image adjustment process, and the right figure shows the virtual image and foreground after the attitude change and after the first image adjustment process. [Figure 14] Figure 14 illustrates a second image adjustment process in which size adjustment is performed without position adjustment when vehicle 1 tilts backward. The left figure shows the virtual image and foreground before attitude change and size correction, and the right figure shows the virtual image and foreground after attitude change and size correction. [Figure 15] Figure 15 illustrates a second image adjustment process that performs position and size adjustment when vehicle 1 tilts backward. The left figure shows the virtual image and foreground before the attitude change and before the second image adjustment process, while the right figure shows the virtual image and foreground after the attitude change and after the second image adjustment process. [Figure 16] Figure 16 shows the flow of display control in several embodiments. [Figure 17] Figure 17 is a diagram illustrating the limits of the position adjustment amount. [Figure 18] Figure 18 is a diagram illustrating the limits of the position adjustment amount. [Modes for carrying out the invention] 【0021】 Figures 1 to 18 below provide an explanation of the configuration and operation of an exemplary vehicle display system. However, the present invention is not limited to the following embodiments (including those shown in the drawings). Modifications (including the deletion of components) can be made to the embodiments described below. Furthermore, in order to facilitate understanding of the present invention, explanations of known technical matters will be omitted as appropriate. 【0022】 Refer to Figure 1. Figure 1 shows an example of the configuration of a virtual image display system for vehicles. In Figure 1, the left-right direction of the vehicle (an example of a moving object) 1 (in other words, the width direction of vehicle 1) is defined as the X-axis (the positive direction of the X-axis is to the left when vehicle 1 is facing forward), the up-down direction (in other words, the height direction of vehicle 1) along a line segment perpendicular to the left-right direction and perpendicular to the ground or a surface equivalent to the ground (in this case, the road surface 6) is defined as the Y-axis (the positive direction of the Y-axis is upward), and the front-rear direction along a line segment perpendicular to each of the left-right and up-rear directions is defined as the Z-axis (the positive direction of the Z-axis is the straight-ahead direction of vehicle 1). This is the same in other drawings as well. 【0023】 As shown in the figure, the vehicle display system 10 installed in the vehicle (mobile body) 1 includes an eye position detection unit (gaze detection unit) 409 for pupil (or face) detection that detects the position and gaze direction of the left eye 700L and right eye 700R of the observer (typically a driver seated in the driver's seat of the vehicle 1), an external sensor 411 consisting of a camera (e.g., a stereo camera) that captures images of the area in front of the vehicle 1 (broadly speaking, the surroundings), an attitude detection unit 415 that detects the attitude of the vehicle 1, a head-up display device (hereinafter also referred to as a HUD device) 20, and a display control device 30 that controls the HUD device 20. Note that the eye position detection unit (gaze detection unit) 409 and the external sensor 411 may be omitted. 【0024】 Figure 2 shows one configuration of a head-up display device 20. The HUD device 20 is installed, for example, in the dashboard (reference numeral 5 in Figure 1). The HUD device 20 comprises an image display device (display unit) 40, a relay optical system 80, and a housing 22 that houses the image display device 40 and the relay optical system 80 and has a light emission window 21 that allows display light K from the image display device 40 to be emitted from the inside to the outside. 【0025】 The image display device (display unit) 40 is, in this case, a parallax-type 3D display device. This stereoscopic display device (parallax-type 3D display device) 40 consists of a display unit 50, which is a glasses-free stereoscopic display device that uses a multi-view image display method capable of controlling depth representation by allowing the viewer to see a left-view image and a right-view image, and a light source unit 60 that functions as a backlight. Note that the image display device (display unit) 40 is not limited to a stereoscopic image display device that displays 3D images, but may also display 2D images. 【0026】 The display unit 50 includes a display surface 50a that generates an image M on the display surface 50a by optical modulation of illumination light from a light source unit 60, and an optical layer (an example of a light ray separation unit) 52 that separates the light emitted from the display surface 50a into left-eye display light (reference numeral K10 in Figure 1), such as left-eye rays K11, K12, and K13, and right-eye display light (reference numeral K20 in Figure 1), such as right-eye rays K21, K22, and K23. The optical layer 52 includes optical filters such as lenticular lenses, parallax barriers, lens arrays, and microlens arrays. In this embodiment, the optical layer 52 is not limited to the optical filters described above, but includes all forms of optical layers arranged on the front or rear surface of the display surface 50a. However, this is just an example and not limited to it. 【0027】 Furthermore, the image display device 40 may emit left-eye display light (reference numeral K10 in Figure 1), such as rays K11, K12, and K13, and right-eye display light (reference numeral K20 in Figure 1), such as rays K21, K22, and K23, instead of or in addition to the optical layer (example of a ray separator) 52. Specifically, for example, the display control device 30, described later, displays a left-viewpoint image on the display surface 50a when the directional backlight unit emits illumination light directed towards the left eye 700L, thereby directing the left-eye display lights K10, such as the left-eye rays K11, K12, and K13, towards the observer's left eye 700L. When the directional backlight unit emits illumination light directed towards the right eye 700R, it displays a right-viewpoint image on the display surface 50a, thereby directing the right-eye display lights K20, such as the right-eye rays K21, K22, and K23, towards the observer's left eye 700L. However, this is just one example and is not limited to this. 【0028】 The display control device 30, described later, can control the appearance of the content FU displayed by the HUD device 20 (perceived by the observer) by performing, for example, image rendering processing (graphics processing) and display drive processing, directing the left-eye display light K10, which is the basis for the left-viewpoint image V11, to the observer's left eye 700L, and the right-eye display light K20, which is the basis for the right-viewpoint image V12, to the right eye 700R, and adjusting the left-viewpoint image V11 and the right-viewpoint image V12. The display control device 30, described later, may also control the display (display 50) to reproduce a light field that reproduces (approximately) the light rays emitted in various directions from a point in a certain space. 【0029】 The relay optical system 80 has curved mirrors (concave mirrors, etc.) 81 and 82 that reflect light from the image display device 40 and project the image display light K10 and K20 onto the windshield (projection area) 2. However, it may further include other optical elements (refractive optical elements such as lenses, diffractive optical elements such as holograms, reflective optical elements, or combinations thereof). 【0030】 In Figure 1, the image display device 40 of the HUD device 20 displays parallax images for each of the left and right eyes. Each parallax image is displayed as V10 projected onto the virtual image display area (virtual image plane) VS, as shown in Figure 1. The focus of each of the observer's (person's) eyes is adjusted to match the position of the virtual image display area VS. The position of the virtual image display area VS is referred to as the "adjustment position (or image formation position)," and the distance from a predetermined reference position (for example, the center 205 of the eyebox 200 of the HUD device 20, the observer's viewpoint, or a specific position on the vehicle 1) to the virtual image display area VS is referred to as the adjustment distance (image formation distance). 【0031】 Furthermore, the virtual image display area VS is a virtual (apparent) surface set in the real space in front of the occupant (viewer such as a driver), corresponding to the display surface 50a of the display unit 50. Examples of virtual image display areas VS include an elevation surface VS1 perpendicular to the road surface 6, an inclined surface VS2 tilted relative to the road surface 6, a road surface superimposed on the road surface 6 VS3, and a surface (not shown) where the side closer to the occupant (viewer) is an elevation surface (including a pseudo-elevation surface) and the side further away is an inclined surface. In displays using surfaces other than the elevation surface VS1, the display distance of the virtual image differs depending on the display position on the virtual image display area, thus enabling the representation of depth. 【0032】 Figure 3 is a block diagram of a virtual image display system for a vehicle according to several embodiments. The display control device 30 comprises one or more I / O interfaces 31, one or more processors 33, one or more image processing circuits 35, and one or more memories 37. Figure 3 is only one embodiment, and the illustrated components may be combined with fewer components, or additional components may be included. For example, the image processing circuit 35 (e.g., a graphics processing unit) may be included in one or more processors 33. 【0033】 As shown in the figure, the processor 33 and the image processing circuit 35 are operably connected to the memory 37. More specifically, the processor 33 and the image processing circuit 35 can control the vehicle display system 10 (image display device 40), for example, by executing a program stored in the memory 37, such as generating and / or transmitting image data. The processor 33 and / or the image processing circuit 35 may include at least one general-purpose microprocessor (e.g., a central processing unit (CPU)), at least one application-specific integrated circuit (ASIC), at least one field-programmable gate array (FPGA), or any combination thereof. The memory 37 includes any type of magnetic medium such as a hard disk, any type of optical medium such as CDs and DVDs, any type of semiconductor memory such as volatile memory, and non-volatile memory. The volatile memory may include DRAM and SRAM, and the non-volatile memory may include ROM and NVRAM. 【0034】 As shown in the figure, the processor 33 is operably connected to the I / O interface 31. The I / O interface 31 communicates (also referred to as CAN communication) with, for example, the vehicle ECU 401 and / or other electronic devices (reference numerals 403 to 419 described later) installed in the vehicle, in accordance with the CAN (Controller Area Network) standard. The communication standard adopted by the I / O interface 31 is not limited to CAN, and includes, for example, wired communication interfaces such as CANFD (CAN with Flexible Data Rate), LIN (Local Interconnect Network), Ethernet (registered trademark), MOST (Media Oriented Systems Transport: MOST is a registered trademark), UART, or USB, or in-vehicle communication (internal communication) interfaces, which are short-range wireless communication interfaces within tens of meters, such as personal area networks (PANs) such as Bluetooth (registered trademark) networks, and local area networks (LANs) such as 802.11x Wi-Fi (registered trademark) networks. Furthermore, the I / O interface 31 may also include an external communication interface for outside vehicles, such as a wide-area communication network (e.g., an internet communication network) using cellular communication standards such as wireless wide-area network (WWAN0, IEEE802.16-2004 (WiMAX: Worldwide Interoperability for Microwave Access)), IEEE802.16e-based (Mobile WiMAX), 4G, 4G-LTE, LTE Advanced, and 5G. 【0035】 As shown in the figure, the processor 33 is interconnected with the I / O interface 31 so as to be able to exchange information with various other electronic devices connected to the vehicle display system 10 (I / O interface 31). For example, the vehicle ECU 401, road information database 403, vehicle position detection unit 405, operation detection unit 407, eye position detection unit 409, external sensor 411, brightness detection unit 413, attitude detection unit 415, portable information terminal 417, and external communication device 419 are interconnected to the I / O interface 31 so as to be able to operate. The I / O interface 31 may also include a function to process (convert, calculate, analyze) information received from other electronic devices connected to the vehicle display system 10. 【0036】 The image display device 40 is operably connected to the processor 33 and the image processing circuit 35. Therefore, in some embodiments, the image displayed by the display surface 50a may be based on image data received from the processor 33 and / or the image processing circuit 35. The processor 33 and the image processing circuit 35 control (adjust) the image displayed by the display surface 50a based on information obtained from the I / O interface 31. 【0037】 The software components stored in memory 37 include a drawing module 510 and an image adjustment module 520 (position adjustment module 522, depression angle adjustment module 524, size adjustment module 526). 【0038】 The drawing module 510 forms an image M based on information acquired by the display control device 30 (navigation information, vehicle information, etc.) and temporarily stores the formed image M in a buffer (not shown). The image M displayed on the display 50 is seen by the observer 700 as a virtual image V20. At this time, the virtual image V20 represents the content FU. 【0039】 Figure 4 illustrates the model space in which the content FU and virtual viewpoint VP are placed. In Figure 4, the coordinate system of the virtual viewpoint VP is such that the depth direction is the Z1 axis, the left-right direction is the X1 axis (corresponding to the width direction X of vehicle 1), and the up-down direction is the Y1 axis (corresponding to the up-down direction Y of vehicle 1). The drawing module 510 calculates the vertex data of each content FU to be drawn in each drawing frame. In this case, it constructs the model space of each content FU. Then, it calculates the data of each vertex to be drawn on the "model coordinate system (local coordinate system)" for each virtual object. The drawing module 510 converts the content FU drawn in the model coordinate system into a 2D image by projecting it onto a predetermined projection plane (virtual image display area VS, described later) based on the virtual viewpoint VP, and this 2D image is designated as image M. Note that the drawing module 510 may also place each content FU placed in the "model coordinate system (local coordinate system)" into the "world coordinate system" space. In other words, the vertex data of each content FU (Functional Unit) to be rendered, calculated in the "model coordinate system," may be placed on the "world coordinate system." However, some or all of the content FUs do not need to be placed on the "world coordinate system." 【0040】 The observer 700 perceives that content FU is located at a predetermined target position MP by viewing the virtual image V20 formed (imaged) in the virtual image display area VS via the projection unit 2. For example, if content FU is an arrow guiding a path, the arrow of the virtual image V20 is displayed in the virtual image display area VS so that it appears as if content FU is located at a predetermined target position MP in the real scene when viewed from the virtual viewpoint VP. In other words, when an image (in this case, virtual image V20) is displayed that has been projected onto the virtual image display area VS with respect to the virtual viewpoint VP, the observer 700, when viewing from a position similar to the virtual viewpoint VP (for example, the center 205 of the eye box 200), can perceive that content FU is located at a predetermined target position MP as seen from the virtual viewpoint VP, as shown in Figure 13. 【0041】 Typically, the virtual plane 100 on which the target position MP, where the content FU is placed (set), is located, is set to match the height of the foreground (road surface 6) (i.e., the set height is set to 0m). However, this is just an example and not an exhaustive one. In other examples, the target position MP (virtual plane 100) may be set higher than the height of the foreground (road surface 6) (i.e., the set height may be set to 0.5m or 1m). In other examples, the target position MP (virtual plane 100) may be set lower than the height of the foreground (road surface 6) (i.e., the set height may be set to -1m or -2m). The depression angle β is the angle (downward angle) between the horizontal direction (Z1-X1 plane) and the content FU (target position MP) as seen from a given virtual viewpoint VP. 【0042】 The image adjustment module 520 (position adjustment module 522, depression angle adjustment module 524, size adjustment module 526) in Figure 3 performs the following processes in accordance with the attitude changes of the vehicle 1: adjusting the position of the virtual image V20 displayed in the virtual image display area VS (position adjustment process), adjusting the depression angle (depression angle adjustment process), and adjusting the size (size adjustment process). 【0043】 Figure 6 shows the virtual image before position adjustment processing. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen by the observer when facing forward. In Figure 6, the vehicle posture AT10 is assumed to be AT11. The content FU is positioned so that it appears to overlap the target position MP (first region 110) on the virtual plane 100 to the viewer. The content FU has a predetermined size and is positioned to overlap the first region 110 of the virtual plane 100. In Figure 6, the size of the content FU is the first length L10 in the depth direction of the first region 110. The arbitrary virtual plane 100 is a virtual plane on which the content FU is placed, and for example, it is set parallel to the front, rear, left, and right directions of the vehicle 1 (it may roughly coincide with the road surface 6). The drawing module 510 displays the image M that is the source of the virtual image V21 on the display unit 50, so as to display the image (in this case, the virtual image V21) obtained by projecting the content FU onto the virtual image display area VS1 with respect to the virtual viewpoint VP1. Here, D0 is the distance along the virtual plane 100 from the virtual viewpoint VP1 to the first area 110, and h0 is the distance (height) from the virtual plane 100 to the virtual viewpoint VP1. 【0044】 Figure 7A shows the virtual image after the first position adjustment process. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen by the observer when facing forward. In Figure 7A, the vehicle posture AT10 is assumed to be AT12, in which the vehicle 1 is tilted forward by a relatively small pitching angle α12 compared to the vehicle posture AT11 before the first position adjustment process. Here, tilting forward means that the front of the vehicle 1 is lower (in other words, the rear of the vehicle 1 is higher) relative to the vehicle posture AT11 shown in Figure 6. When the vehicle 1 tilts forward from the state in Figure 6 to the state in Figure 7A, the virtual image display area VS seen from the observer's viewpoint shifts B12 downward relative to the actual scenery (road surface) 6 due to the change in posture. If the first position adjustment process is not performed, the virtual image V21 shown in Figure 6 will shift downward by an image shift amount B12 due to the change in the orientation of the virtual image display area VS, to position G2 in the right diagram of Figure 7A. In other words, the virtual image V21 will be misaligned from the target position MP1 where the content FU should be placed, as seen from the observer's viewpoint. In some embodiments, the processor 33 performs the first position adjustment process to correct the position G2 of the virtual image upward (positive Y-axis direction) by a first position adjustment amount C12 (C10) in order to suppress (cancel out) the image shift amount B12 due to the change in orientation (displaying the adjusted virtual image V22). Preferably, the first position adjustment amount C12 (C10) is made equal to the image shift amount B12 (B10) due to the change in orientation (C10 = B10), so that the virtual image V20 after the change in orientation can be maintained in the first area 110 (target position MP1). According to this, the image shift amount B10 due to attitude changes is offset by the first position adjustment amount C10 and is not perceived by the observer. However, the first position adjustment amount C10 only needs to be small enough to reduce the image shift amount B10 due to attitude changes. According to this, positional displacement of virtual images based on changes in vehicle attitude can be suppressed. 【0045】 FIG. 7B is a diagram showing a virtual image after the second position adjustment process. The left diagram shows the relationship between the virtual image and the virtual plane, and the right diagram shows the foreground and the virtual image that are visually recognized when the observer faces forward. In FIG. 7B, it is assumed that the vehicle posture AT10 is AT13 in which the vehicle 1 is tilted forward by a pitching angle α13 (>α12) that is relatively large for the vehicle 1 compared to the vehicle posture AT11 before the second position adjustment process. When the vehicle 1 tilts forward from the state of FIG. 6 to the state of FIG. 7B, the virtual image display area VS viewed from the viewpoint of the observer shifts downward (negative Y-axis direction) by B13 relative to the actual scene (road surface) 6 due to the posture change. If no position adjustment is performed, the virtual image V21 shown in FIG. 6 shifts by the image shift amount B13 to the position G3 in the right diagram of FIG. 7B along with the image shift amount B13 of the virtual image display area VS due to the posture change. In order to cancel the downward image shift amount B13 due to this posture change, the virtual image V20 may be moved upward by the image shift amount B13, but if the virtual image V20 is moved upward by the image shift amount B13, it will go outside the virtual image display area VS13. 【0046】 In some embodiments, when the posture change of the vehicle 1 is large (an example of a predetermined condition described later), the processor 33 executes the second position adjustment process, so that the downward image shift amount B13 of the virtual image display area VS due to the posture change is smaller than the first position adjustment amount C13 (C10) in the first position adjustment process. The position G3 of the virtual image is corrected upward (positive Y-axis direction) by a second position adjustment amount C23 (C20) (the adjusted virtual image V23 is displayed). By making the second position adjustment amount C23 (C20) smaller than the image shift amount B13 (B10) due to the posture change (C20 < B10), although it deviates more greatly to the second area 120 (a position different from the target position MP1) closer to the first area 110 (target position MP1) than in the first position adjustment process, the virtual image V23 can be maintained within the virtual image display area VS13. According to this, since the image shift amount B13 (B10) due to the posture change is not canceled by the second position adjustment amount C23 (C20), it is recognized by the observer. 【0047】 The content FU is positioned with a predetermined angular relationship to the road surface 6. Specifically, for example, the content FU is positioned so that it is visible parallel to the road surface 6. However, if the pitching angle α of the vehicle 1 changes, the angular relationship between the content FU and the road surface 6 will change. Specifically, if the virtual image V20 was displayed parallel to the road surface 6, the parallel relationship between the virtual image V20 and the road surface 6 will shift by the pitching angle α. This shift in the angular relationship between the virtual image V20 and the road surface 6 due to the attitude change (pitching) of the vehicle 1 can be corrected by adjusting the angle β of the virtual image V20 with respect to the left-right direction (the downward angle (depression angle) of the virtual image V20). 【0048】 In some embodiments, the processor 33 may adjust the depression angle β of the virtual image V20 (content FU) in response to changes in the attitude of the vehicle 1 during the second position adjustment process. The processor 33 dynamically increases the depression angle β in accordance with an increase in the pitching angle α in the forward tilt direction. Conversely, the processor 33 dynamically decreases the depression angle β in accordance with an increase in the pitching angle α in the backward tilt direction. 【0049】 In some embodiments, the processor 33 may also adjust the depression angle β of the virtual image V20 (content FU) in response to changes in the attitude of the vehicle 1 when executing the first position adjustment process (first depression angle adjustment process). Similar to when executing the second position adjustment process, the processor 33 dynamically increases the depression angle β in accordance with the increase in the pitching angle α in the forward tilt direction. Conversely, the processor 33 dynamically decreases the depression angle β in accordance with the increase in the pitching angle α in the backward tilt direction. 【0050】 In some embodiments, the processor 33 can adjust the depression angle β by the same angle as the change in pitching angle α when executing the first position adjustment process (an example of the first depression angle adjustment process). Specifically, when the vehicle 1 tilts forward from the state in Figure 6 to the state in Figure 7A, the change in pitching angle α is α12. The virtual viewpoint VP1 shown in Figure 6 changes the angle of the virtual viewpoint VP2 with respect to the virtual plane 100 by α12 based on the change in pitching angle α12 of the forward tilt shown in Figure 7A. As a result, the depression angle β12 looking down at the content FU placed at the target position MP1 with respect to the virtual viewpoint VP2 becomes α12 larger than the depression angle β11. In addition, in some embodiments, the processor 33 can adjust the depression angle β by an angle obtained by multiplying the change in pitching angle α by a predetermined coefficient (an example of the first depression angle adjustment process). 【0051】 Furthermore, in some embodiments, the processor 33 may adjust the depression angle β by the same angle as the change in pitching angle α when executing the second position adjustment process (an example of the first depression angle adjustment process). Specifically, when the vehicle 1 tilts forward from the state in Figure 6 to the state in Figure 7B, the change in pitching angle α is α13. The virtual viewpoint VP1 shown in Figure 6 moves to the virtual viewpoint VP3 position due to the change in pitching angle α13 of the forward tilt shown in Figure 7B, and the angle of the virtual viewpoint VP3 with respect to the virtual plane 100 changes by α13. Accordingly, the processor 33 may increase the depression angle β of the content FU represented by the virtual image V23 by the change in pitching angle α13 of the forward tilt. Furthermore, in some embodiments, the processor 33 may adjust the depression angle β by an angle obtained by multiplying the change in pitching angle α by a predetermined coefficient (an example of the first depression angle adjustment process). 【0052】 In some preferred embodiments, the processor 33 may set the amount of adjustment of the depression angle β with respect to the change in pitching angle α in the depression angle adjustment process (second depression angle adjustment process) performed together with the second position adjustment process (second depression angle adjustment process) to be greater than the amount of adjustment of the depression angle β with respect to the change in pitching angle α in the depression angle adjustment process (first depression angle adjustment process) performed together with the first position adjustment process (first depression angle adjustment process) (depression angle adjustment amount E10). The virtual image V23 that has undergone the second position adjustment process will be perceived as being shifted from the target position MP1 more than the virtual image V22 that has undergone the first position adjustment process. Specifically, when leaning forward, the virtual image V23 that has undergone the second position adjustment process will be perceived as being shifted to a position 120 that overlaps with the actual scenery (road surface 6) closer to the observer, relative to the target position MP1 (110), more than the virtual image V22 that has undergone the first position adjustment process. When the content FU is positioned near the observer along a virtual plane 100 parallel to the road surface 6, the downward angle β of the content FU relative to the virtual viewpoint VP becomes large. Conversely, when the content FU is positioned far from the observer, the downward angle β of the content FU relative to the virtual viewpoint VP becomes small. Therefore, in some more preferred embodiments, the processor 33 may use as the amount of adjustment of the downward angle β of the content FU in the downward angle adjustment process (second downward angle adjustment process) performed together with the second position adjustment process, which is a sum of the downward angle adjustment amount due to the change in the pitching angle α of the vehicle 1 and the downward angle adjustment amount due to the shift of the content FU in the near and far directions of the virtual plane 100 (which is set, for example, to roughly coincide with the road surface 6). The depression angle β13 in Figure 7B is calculated by correcting the depression angle β11 in Figure 6, which serves as the reference for attitude changes, with a depression angle adjustment amount that is the sum of the depression angle adjustment amount due to the shift of the content FU from the first region 110 on the virtual plane 100 to the nearby second region 120, and the depression angle adjustment amount due to the change in the pitching angle α of the vehicle 1. 【0053】 Figure 8A shows the virtual image after the first position adjustment process and the first depression angle adjustment process. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen by an observer facing forward. In Figure 8A, the vehicle posture AT10 is assumed to be AT14, in which the vehicle 1 is tilted backward by a relatively small pitching angle α14 compared to the vehicle posture AT11 before the first position adjustment process. Here, tilting backward means that the front of the vehicle 1 rises (in other words, the rear of the vehicle 1 falls) relative to the vehicle posture AT11 shown in Figure 6. When the vehicle 1 tilts backward from the state in Figure 6 to the state in Figure 8A, the virtual image display area VS shifts B14 relative to the actual scenery (road surface) 6 by B14 relative to the actual scenery (road surface) 6 due to the change in posture. If the first position adjustment process is not performed, the virtual image V21 shown in Figure 6 will shift upward by an image shift amount B14 due to the change in the orientation of the virtual image display area VS, to position G4 in the right diagram of Figure 8A. In other words, the virtual image V21 will be misaligned from the target position MP1 where the content FU is to be placed. In some embodiments, the processor 33 performs the first position adjustment process to suppress (cancel out) the image shift amount B14 due to the change in orientation by correcting the position G4 of the virtual image downward (negative Y-axis direction) by a first position adjustment amount C14 (C10) (displaying the adjusted virtual image V24). Preferably, by making the first position adjustment amount C14 (C10) equal to the image shift amount B14 (B10) due to the change in orientation (C10 = B10), the virtual image V21 that would otherwise be displayed at position G4 after the change in orientation can be maintained in the first area 110 (target position MP1). According to this, the image shift amount B14 (B10) due to attitude changes is offset by the first position adjustment amount C14 (C10) and is not perceived by the observer. However, the first position adjustment amount C10 only needs to be small enough to reduce the image shift amount B10 due to attitude changes. According to this, positional displacement based on changes in vehicle attitude can be suppressed. 【0054】 In some embodiments, the processor 33 can adjust the depression angle β in the first depression angle adjustment process by the same angle as the change in the pitching angle α in the rearward tilting direction of the vehicle 1. Specifically, when the vehicle 1 tilts backward from the state in Figure 6 to the state in Figure 8A, the change in the pitching angle α is α14. The virtual viewpoint VP1 shown in Figure 6 changes in angle of the virtual viewpoint VP4 with respect to the virtual plane 100 by α14 due to the change in the pitching angle α14 of the rearward tilt shown in Figure 8A. As a result, the depression angle β14 looking down at the content FU placed at the target position MP1 with respect to the virtual viewpoint VP4 becomes α14 smaller than the depression angle β11. In addition, in some embodiments, the processor 33 can adjust the depression angle β by an angle obtained by multiplying the change in the pitching angle α by a predetermined coefficient. 【0055】 Figure 8B shows the virtual image after the second position adjustment process and the second depression angle adjustment process. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen by the observer when facing forward. In Figure 8B, the vehicle posture AT10 is assumed to be AT15, where the vehicle 1 is tilted backward by a relatively large pitching angle α15 (α14>) compared to the vehicle posture AT11 before the second position adjustment process. When the vehicle 1 tilts backward from the state in Figure 6 to the state in Figure 8B, the virtual image display area VS shifts upward (positive Y-axis direction) by B15 relative to the actual scenery (road surface) 6 due to the change in posture. If no position adjustment is performed, the virtual image V21 shown in Figure 6 will shift by an image shift amount B15 to the position G5 shown in the right figure of Figure 8B, due to the image shift amount B15 caused by the change in the posture of the virtual image display area VS. To counteract the upward image shift amount B15 caused by this attitude change, the virtual image displayed at position G5 should be moved downward by an image shift amount B15. However, moving the virtual image displayed at position G5 downward by an image shift amount B15 would cause it to move outside the virtual image display area VS15. 【0056】 In some embodiments, when the posture variation is large (an example of a predetermined condition described later), the processor 33 executes the second position adjustment process, so that the second position adjustment amount C25 (C20) is smaller than the first position adjustment amount C15 (C10) in the first position adjustment process with respect to the upward image shift amount B15 of the virtual image display area VS due to the posture variation. The position G5 of the virtual image is corrected downward (in the positive Y-axis direction) by C25 (C20) (the adjusted virtual image V25 is displayed). By making the second position adjustment amount C25 (C20) smaller than the image shift amount B15 (B10) due to the posture variation (C20 < B10), although it deviates more greatly to the fifth area 150 (a position different from the target position MP1) farther from the first area 110 (target position MP1) than in the first position adjustment process, the virtual image V25 can be maintained within the virtual image display area VS15. According to this, since the image shift amount B10 due to the posture variation is not offset by the second position adjustment amount C20, it is recognized by the observer. The processor 33 in the present embodiment dynamically decreases the depression angle β as the pitching angle α in the backward tilt direction increases. 【0057】 In some preferred embodiments, the processor 33 may set the amount of adjustment of the depression angle β with respect to the change in pitching angle α in the second depression angle adjustment process performed together with the second position adjustment process (depression angle adjustment amount E20) to be greater than the amount of adjustment of the depression angle β with respect to the change in pitching angle α in the first depression angle adjustment process performed together with the first position adjustment process (depression angle adjustment amount E10). The virtual image V25 that has undergone the second position adjustment process will be perceived as being shifted from the target position MP1 more than the virtual image V23 that has undergone the first position adjustment process. Specifically, in the case of a backward tilt, the virtual image V25 that has undergone the second position adjustment process will be perceived as being shifted to a position 150 that overlaps with the actual scenery (road surface 6) further away from the observer, relative to the target position MP1 (110), more than the virtual image V24 that has undergone the first position adjustment process. When the content FU is positioned away from the observer along a virtual plane 100 parallel to the road surface 6, the downward angle β of the content FU relative to the virtual viewpoint VP becomes smaller. Therefore, the downward angle β15 in Figure 8B may be calculated by correcting the downward angle β11 in Figure 6, which serves as the reference for attitude changes, with a downward angle adjustment amount that is a sum of the downward angle adjustment amount due to the content FU shifting from the first region 110 to the farther third region 130 on the virtual plane 100, and the downward angle adjustment amount due to the change in the pitching angle α of the vehicle 1. 【0058】 In some embodiments, the processor 33 performs a first image adjustment process (S151 described later) to adjust the position of the virtual image based on a first position adjustment amount C10 when the attitude of the vehicle 1 changes in a first direction of tilting forward or backward from a reference attitude, and performs a second image adjustment process (S152 described later) which suppresses the adjustment of the position of the virtual image in response to the change in the attitude of the vehicle 1 more than the first image adjustment process (S151 described later). 【0059】 Figure 9 illustrates the image adjustment process for attitude changes, showing an example of switching between the first and second image adjustment processes depending on the direction of the attitude change (or position adjustment amount). At times t11 to t12, the pitching angle α is a forward tilt smaller than the preset attitude threshold αTd. The position adjustment amount C is set to a first position adjustment amount C10 that dynamically corrects the position of the virtual image within the virtual image display area VS in the upward direction in accordance with the attitude change (forward tilt of pitching angle α) in order to strongly suppress (preferably cancel out) the downward displacement of the virtual image caused by the attitude change. As a result, the positional displacement of the virtual image is preferably canceled out (the position of the virtual image is maintained at the target position MP1). The depression angle adjustment amount E is set to a first depression angle adjustment amount E10 that dynamically increases the depression angle β of the virtual image in accordance with the attitude change (forward tilt of pitching angle α) in order to suppress (preferably cancel out) the depression angle misalignment between the real scene (road surface 6) and the virtual image caused by the attitude change (change in pitching angle α). If the positional misalignment of the virtual image is canceled out by the first position adjustment amount C10, the virtual image does not deviate from the target position MP1, and no size adjustment is necessary, so the size adjustment amount F becomes zero. 【0060】 Between times t12 and t13, the pitching angle α is a forward tilt greater than the preset attitude threshold αTd. The position adjustment amount C is set to a second position adjustment amount C20, which is smaller than the first position adjustment amount C10 that strongly suppresses (preferably cancels out) the downward displacement of the virtual image caused by attitude changes, and fixes the position of the virtual image within the virtual image display area VS regardless of attitude changes (forward tilt of pitching angle α). As a result, a downward displacement of the virtual image occurs due to attitude changes (forward tilt of pitching angle α) (in other words, the forward tilt causes the virtual image to shift closer to the observer). The depression angle adjustment amount E is set to a second depression angle adjustment amount E20, which dynamically increases the depression angle β of the virtual image in accordance with the attitude change (forward tilt of pitching angle α). This is achieved by adding a depression angle adjustment amount that corrects the depression angle discrepancy between the real scene (road surface 6) and the virtual image caused by attitude changes (changes in pitching angle α) and a depression angle adjustment amount that represents the shift of the virtual image closer to the observer. Here, the second depression angle adjustment amount E20 is larger than the first depression angle adjustment amount E10 because it also adds a depression angle adjustment amount that represents the shift of the virtual image closer to the observer. The size adjustment amount F is set to dynamically increase the size of the virtual image in accordance with the attitude change (changes in pitching angle α) in order to represent the shift of the virtual image closer to the observer. 【0061】 At times t13-t14, the pitching angle α is a forward tilt smaller than the preset attitude threshold αTd, and at times t14-t15, the pitching angle α is a backward tilt smaller than the preset attitude threshold αTu. The position adjustment amount C is set to a first position adjustment amount C10 that dynamically corrects the position of the virtual image within the virtual image display area VS in the upward direction (downward direction at t14-t15) in accordance with the attitude change (forward tilt of pitching angle α (backward tilt at t14-t15)), in order to strongly suppress (preferably cancel out) the downward (upward) displacement of the virtual image caused by the attitude change. As a result, the positional displacement of the virtual image is preferably canceled out (the position of the virtual image is maintained at the target position MP1). The depression angle adjustment amount E is set to a first depression angle adjustment amount E10 that dynamically increases (decreases at t14-t15) the depression angle β of the virtual image in accordance with the attitude change (forward tilt of pitching angle α (backward tilt at t14-t15)) in order to suppress (preferably cancel out) the depression angle misalignment between the real scene (road surface 6) and the virtual image caused by the attitude change (change in pitching angle α). If the positional misalignment of the virtual image is canceled out by the first position adjustment amount C10, the virtual image does not deviate from the target position MP1, and no size adjustment is necessary, so the size adjustment amount F becomes zero. 【0062】 Between times t15 and t16, the pitching angle α is a greater backward tilt than the preset attitude threshold αTu. The position adjustment amount C is set to a second position adjustment amount C20, which is smaller than the first position adjustment amount C10 that strongly suppresses (preferably cancels out) the upward shift of the virtual image caused by attitude fluctuations, and fixes the position of the virtual image within the virtual image display area VS regardless of attitude fluctuations (backward tilt of pitching angle α). As a result, an upward shift of the virtual image occurs due to attitude fluctuations (backward tilt of pitching angle α) (in other words, the backward tilt causes the virtual image to shift further away from the observer). The depression angle adjustment amount E is set to a second depression angle adjustment amount E20, which dynamically increases the depression angle β of the virtual image in accordance with the posture change (backward tilt of pitching angle α). This is achieved by adding a depression angle adjustment amount that corrects the depression angle difference between the real scene (road surface 6) and the virtual image caused by the attitude change (change in pitching angle α) and a depression angle adjustment amount that represents the shift of the virtual image to a distance from the observer. Here, the second depression angle adjustment amount E20 is larger than the first depression angle adjustment amount E10 because it also adds a depression angle adjustment amount that represents the shift of the virtual image to a distance from the observer. The size adjustment amount F is set to a size adjustment amount that dynamically decreases the size of the virtual image in accordance with the attitude change (change in pitching angle α) in order to represent the shift of the virtual image to a distance from the observer. The image processing at times t16~t19 is the same as the image processing at times t11~t12 and t13~t15, so the explanation is omitted. 【0063】 Figure 10 illustrates the image adjustment process in several embodiments, showing an example of switching between the first and second image adjustment processes depending on the direction of the attitude change (or position adjustment amount). At times t21 to t22, the pitching angle α is a forward tilt smaller than a preset attitude threshold αTd (an example of attitude change in the first direction). The position adjustment amount C is set to a first position adjustment amount C10 that dynamically corrects the position of the virtual image within the virtual image display area VS in the upward direction in accordance with the attitude change (forward tilt of pitching angle α) in order to strongly suppress (preferably cancel out) the downward displacement of the virtual image caused by the attitude change. As a result, the positional displacement of the virtual image is preferably canceled out (the position of the virtual image is maintained at the target position MP1). The depression angle adjustment amount E is set to a first depression angle adjustment amount E10 that dynamically increases the depression angle β of the virtual image in accordance with the attitude change (forward tilt of pitching angle α) in order to suppress (preferably cancel out) the depression angle misalignment between the real scene (road surface 6) and the virtual image caused by the attitude change (change in pitching angle α). If the positional misalignment of the virtual image is canceled out by the first position adjustment amount C10, the virtual image does not deviate from the target position MP1, and no size adjustment is necessary, so the size adjustment amount F becomes zero. 【0064】 Between times t22 and t23, the pitching angle α is a forward tilt greater than the preset attitude threshold αTd (an example of attitude variation in the first direction). The position adjustment amount C is set to a second position adjustment amount C20, which is smaller than the first position adjustment amount C10 that strongly suppresses (preferably cancels out) the downward displacement of the virtual image caused by the attitude variation, and fixes the position of the virtual image within the virtual image display area VS regardless of the attitude variation (forward tilt of pitching angle α). As a result, a downward displacement of the virtual image occurs due to the attitude variation (forward tilt of pitching angle α) (in other words, the forward tilt causes the virtual image to shift closer to the observer). The depression angle adjustment amount E is set to a second depression angle adjustment amount E20, which dynamically increases the depression angle β of the virtual image in accordance with the attitude change (forward tilt of pitching angle α). This is achieved by adding a depression angle adjustment amount that corrects the depression angle discrepancy between the real scene (road surface 6) and the virtual image caused by attitude changes (changes in pitching angle α) and a depression angle adjustment amount that represents the shift of the virtual image closer to the observer. Here, the second depression angle adjustment amount E20 is larger than the first depression angle adjustment amount E10 because it also adds a depression angle adjustment amount that represents the shift of the virtual image closer to the observer. The size adjustment amount F is set to dynamically increase the size of the virtual image in accordance with the attitude change (changes in pitching angle α) in order to represent the shift of the virtual image closer to the observer. 【0065】 At times t23-t24, the pitching angle α is a forward tilt smaller than the preset attitude threshold αTd (an example of attitude variation in the first direction). The position adjustment amount C is set to a first position adjustment amount C10 that dynamically corrects the position of the virtual image within the virtual image display area VS upward in accordance with the attitude variation (forward tilt of pitching angle α) in order to strongly suppress (preferably cancel out) the downward displacement of the virtual image caused by the attitude variation. As a result, the positional displacement of the virtual image is preferably canceled out (the position of the virtual image is maintained at the target position MP1). The depression angle adjustment amount E is set to a first depression angle adjustment amount E10 that dynamically increases (decreases at t24-t25) the depression angle β of the virtual image in accordance with the attitude variation (forward tilt of pitching angle α (rearward tilt at t24-t25)) in order to suppress (preferably cancel out) the depression angle displacement between the real scene (road surface 6) and the virtual image caused by the attitude variation (change in pitching angle α). If the positional shift of the virtual image is offset by the first positional adjustment amount C10, the virtual image will not shift from the target position MP1, and no size adjustment will be necessary, so the size adjustment amount F will be zero. 【0066】 Between times t24 and t25, the pitching angle α is tilted backward relative to a predetermined reference posture α0 (an example of posture variation in the second direction). The position adjustment amount C is set to a second position adjustment amount C20, which is smaller than the first position adjustment amount C10 that strongly suppresses (preferably cancels out) the upward displacement of the virtual image caused by the posture variation, and fixes the position of the virtual image within the virtual image display area VS regardless of the posture variation (backward tilt of the pitching angle α). Here, the second position adjustment amount C20 is zero. In other words, in this embodiment, when the vehicle tilts backward from a predetermined reference posture α0 (an example of posture variation in the second direction), no adjustment is made to the position of the virtual image in response to the change in the vehicle's posture (backward tilt, which is a posture variation in the second direction). As a result, an upward displacement of the virtual image occurs due to the posture variation (backward tilt of the pitching angle α) (in other words, the virtual image shifts to a distance from the observer due to the backward tilt). The depression angle adjustment amount E may be set to a second depression angle adjustment amount E20, which dynamically increases the depression angle β of the virtual image in accordance with the posture change (backward tilt of pitching angle α). This is achieved by adding a depression angle adjustment amount that corrects the depression angle difference between the real scene (road surface 6) and the virtual image caused by the posture change (change in pitching angle α) and a depression angle adjustment amount that represents the shift of the virtual image to a distance from the observer. Here, the second depression angle adjustment amount E20 may be larger than the first depression angle adjustment amount E10 because it also adds a depression angle adjustment amount that represents the shift of the virtual image to a distance from the observer. The size adjustment amount F may be set to a size adjustment amount that dynamically decreases the size of the virtual image in conjunction with the posture change (change in pitching angle α) in order to represent the shift of the virtual image to a distance from the observer. The image processing at times t26~t29 is the same as the image processing at times t21~t22 and t23~t25, so the explanation is omitted. The reference posture α0 is the vehicle's pitching angle α, which is stored in memory 37 beforehand. Typically, this is the state where the vehicle's pitching angle is zero (parallel to the road surface 6). The reference posture α0 may be variable. Specifically, if the vehicle's pitching angle α does not change much for a predetermined period of time, the stable pitching angle α at that time may be set (updated) as the reference posture α0 and stored in memory 37. 【0067】 The size adjustment process is described below. Figure 11 shows the virtual image before attitude change; the left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen when the observer is facing forward. In Figure 11, the vehicle attitude AT10 is assumed to be AT16. Looking at the first virtual image V21 from the virtual viewpoint VP6, the area that overlaps with an arbitrary virtual plane 100 parallel to the road surface 6 is defined as the first region 110, and the length of the first region 110 in the depth direction is defined as the first length L10. The arbitrary virtual plane 100 is a virtual plane on which the content FU is placed, and is set parallel to the front, rear, left, and right directions of the vehicle 1 (it may roughly coincide with the road surface 6). The drawing module 510 displays the image M that is the source of the virtual image V26 on the display unit 50 so as to display the image (in this case, the virtual image V26) which is a projection transformation of the content FU onto the virtual image display region VS16, based on the virtual viewpoint VP6. Here, let D0 be the distance from virtual viewpoint VP6 to the first region 110 along the virtual plane 100, and let h0 be the distance from virtual plane 100 to virtual viewpoint VP1. 【0068】 Figure 12A shows the virtual image after size adjustment processing when the virtual image display area is shifted downward relative to the real scene due to forward tilt. The left figure shows the relationship between the virtual image and the virtual plane, and the right figure shows the foreground and virtual image as seen when the observer is facing forward. In Figure 12A, the vehicle posture AT10 is assumed to be AT17, where the vehicle 1 is tilted forward more than the vehicle posture AT16 shown in Figure 11. In this case, the position of the virtual plane 100 over which the virtual image V27 overlaps shifts from the first region 110 (target position MP1) in Figure 11 to the second region 120, which is closer to the observer. That is, as shown in the right figure of Figure 12A, the virtual image V27 is seen overlapping with the region of the road surface 6 (second region 120) that is closer to the vehicle 1 (observer) than the first region 110. In this way, when it is estimated that the virtual image will be seen overlapping with a closer foreground, the processor 33 increases the size of the virtual image. In other words, based on the forward tilt of the vehicle 1, if it is determined that the position in which the virtual image overlaps with the second region 120, which is closer to the reference position than the first region 110 (target position MP1) on the virtual plane 100, is changed from the reference position (for example, the center 205 of the eye box 200) when viewed from the reference position, a virtual image V27 is displayed at the position overlapping with the second region 120, and the virtual image V27 is made larger than the virtual image V26 shown in Figure 11, such that the second length L20 in the depth direction of the second region 120 over which the virtual image V27 overlaps is the same as the first length L10 (L20 = L10). This makes it possible to express a sense of perspective as if a virtual image (virtual object) of a predetermined size were moving along the road surface. 【0069】 FIG. 12B is a diagram showing a virtual image after size adjustment processing when the virtual image display area is shifted upward with respect to the real scene due to rearward tilt. The left diagram shows the relationship between the virtual image and the virtual plane, and the right diagram shows the foreground and the virtual image visible when the observer faces forward. In FIG. 12B, it is assumed that the vehicle posture AT10 is AT18 in which the vehicle 1 is more rearward tilted than the vehicle posture AT16 shown in FIG. 11. In this case, the position of the virtual plane 100 where the virtual image V28 overlaps shifts to the third region 130 farther from the observer than the first region 110 (target position MP1) in FIG. 11. That is, as shown in the right diagram of FIG. 12B, the virtual image V28 is visually recognized as overlapping the region of the road surface 6 (third region 130) farther from the vehicle 1 (observer) than the first region 110. Thus, when it is estimated that the virtual image is visually recognized as overlapping a nearer foreground, the processor 33 reduces the size of the virtual image. That is, based on the rearward tilt of the vehicle 1, when it is determined that the position where the virtual image overlaps changes from the first region 110 (target position MP1) in the virtual plane 100 to the third region 130 farther from the reference position when viewed from the reference position (for example, the center 205 of the instrument box 200), the virtual image V28 is displayed at the position overlapping the third region 130, and the virtual image V28 is made smaller than the virtual image V26 shown in FIG. 11 so that the third length L30 in the depth direction of the third region 130 where the virtual image V28 overlaps becomes the same as the first length L10 (L30 = L10). According to this, it is possible to express a sense of perspective as if a virtual image (virtual object) having a predetermined size moves along the road surface. However, in the case of forward tilt, the virtual image may be enlarged so that the second length L20 becomes longer than the first length L10 (L20 > L10). Also, in the case of rearward tilt, the virtual image may be reduced so that the third length L30 becomes shorter than the first length L10 (L30 < L10). The sense of perspective of the virtual image (virtual object) according to some embodiments is emphasized more than the same sense of perspective as the real space as if a virtual image (virtual object) having a predetermined size moves along the road surface while maintaining its size. Therefore, an impression of approaching or an impression of departing can be given to the observer more strongly. 【0070】 Figure 13 illustrates a first position adjustment process in which position adjustment is performed without size adjustment when vehicle 1 is tilted backward. The left figure shows the virtual image and foreground before the attitude change and before the first position adjustment process, and the right figure shows the virtual image and foreground after the attitude change and after the first position adjustment process. In Figure 13, the virtual image display area VS16 shifts upward (positive Y-axis direction) by B16 due to the attitude change. If no position adjustment process is performed, the first virtual image V31 (V20) shifts to position G6 in the right figure of Figure 13 due to the shift of the virtual image display area VS caused by tilting backward. In some embodiments, the processor 33 corrects the first virtual image V31 downward (negative Y-axis direction) by the first position adjustment amount C16 (C10) (displaying V31c) in order to suppress (preferably cancel out) the upward image shift amount B16 due to tilting backward by performing position adjustment. Preferably, the first position adjustment amount C16 (C10) is made equal to the image shift amount B16 due to attitude change (C16 = B16), so that the virtual image V31c after attitude change is maintained in a position that overlaps with the target position MP1. In this case, the image shift due to attitude change is canceled out by the first position adjustment amount C10 and is not perceived by the observer. However, the first position adjustment amount C16 (C10) only needs to decrease the image shift amount B16 (B10) due to attitude change, and may be smaller than the image shift amount B16 (B10). In this case, display misalignment based on changes in vehicle attitude is suppressed, so that the observer is less likely to feel any discomfort due to the change in the size of the virtual image in response to the display misalignment. 【0071】 Figure 14 illustrates a second position adjustment process in which size adjustment is performed without position adjustment when vehicle 1 tilts backward. The left figure shows the virtual image and foreground before attitude change and size correction, and the right figure shows the virtual image and foreground after attitude change and size correction. In Figure 14, the virtual image display area VS shifts upward (positive Y-axis direction) by B17 due to the backward tilt. If no position adjustment is performed, the first virtual image V32 also shifts upward (positive Y-axis direction) by B17, as shown in the right figure of Figure 14, along with the shift of the virtual image display area VS due to the attitude change. As a result, the virtual image V32a shifts to a position that overlaps with the foreground area further away from the observer than the first area 110 before the attitude change. In some embodiments, the processor 33 performs a size adjustment process when it is estimated that the virtual image will be seen superimposed on a more distant foreground, thereby making the displayed virtual image V32a (right in Figure 14) smaller than the virtual image V32 (left in Figure 14) before the attitude change. Even if the vehicle's attitude changes, the change in the size of the virtual image emphasizes the perspective of the virtual image in real space, which is expected to have the advantage of giving the observer the impression that the virtual image is moving away. 【0072】 Figure 15 illustrates the second position adjustment process, which performs position and size adjustment when vehicle 1 tilts backward. The left figure shows the virtual image and foreground before the attitude change and before the second position adjustment process, while the right figure shows the virtual image and foreground after the attitude change and after the second position adjustment process. In Figure 15, the virtual image display area VS shifts upward (positive Y-axis direction) by B18 due to the attitude change. If the second position adjustment process is not performed, the virtual image V32 shifts to position G8 in the right figure of Figure 15 due to the shift of the virtual image display area VS caused by the attitude change. In some embodiments, the processor 33 performs position adjustment to suppress the upward image shift amount B18 due to the backward tilt by correcting the virtual image V31 downward by a second position adjustment amount C28 that is smaller than the image shift amount B18 (displaying the virtual image V33c). Furthermore, when the processor 33 of this embodiment estimates that the virtual image will be seen superimposed on a more distant foreground, it performs a size adjustment process to make the displayed virtual image V33c (Figure 15, right) smaller than the virtual image V33 before the rearward tilt (Figure 15, left). This reduces image misalignment due to changes in the vehicle's attitude while also mitigating the sense of size discrepancy caused by image misalignment. 【0073】 The position adjustment process shown in Figure 16 is performed by the processor 33 executing the image adjustment module 520 stored in memory 37. In step S110, the image adjustment module 520 acquires drawing data generated by the drawing module 510. In step S120, the image adjustment module 520 sets the limit CT of the position adjustment amount of the virtual image V20 (the image M that forms the basis of the virtual image V20) from the information indicating the display position of the image M before the position adjustment process is performed (information indicating the reference position PO) contained in the acquired drawing data. Specifically, for example, the image adjustment module 520 sets the position adjustment range VT and sets the limit CT of the position adjustment amount C based on the position adjustment range VT and the reference position PO. 【0074】 Figure 17 is a diagram illustrating the limit CT of the position adjustment amount. If the lower end of the position adjustment range VT is set close to the reference position PO of the virtual image V20, the limit CTd of the downward position adjustment amount of the virtual image V20 is set to be short. On the other hand, if the upper end of the position adjustment range VT is set far from the reference position PO of the virtual image V20, the limit CTu of the upward position adjustment amount of the virtual image V20 is set to be long. The image adjustment module 520 may set the position adjustment range VT individually for each of the multiple virtual images V20 displayed in the virtual image display area VS, or it may be set in common for all virtual images V20. The position adjustment range VT may be the virtual image display area VS (the entire virtual image display area VS may be set as the position adjustment range VT). The image adjustment module 520 has table data (not shown) that associates the attitude change of the vehicle 1 (pitching angle α) with the position adjustment amount C of the virtual image V20. Based on this table data, the module may set the limit of the backward tilt pitching angle (attitude threshold) αTu that is expected when the position adjustment amount C of the virtual image V20 reaches the limit CTd of the downward position adjustment amount, and the limit of the forward tilt pitching angle (attitude threshold) αTd that is expected when the position adjustment amount C of the virtual image V20 reaches the limit CTu of the upward position adjustment amount. 【0075】 Figure 18 is a diagram illustrating the limit CT of the position adjustment amount. Multiple position adjustment ranges VT may be provided within the virtual image display area VS for each content FU. When the virtual image V20 or virtual image V30 is shifted downward within the position adjustment range VT, the virtual image V20 or virtual image V30 will dynamically shift in response to attitude changes until it reaches the limit CTd of the downward position adjustment amount. However, for attitude changes larger than this, it will be fixed and displayed at the position adjusted by the limit CTd of the downward position adjustment amount. Conversely, when the virtual image V20 or virtual image V30 is shifted upward within the position adjustment range VT, the virtual image V20 or virtual image V30 will dynamically shift in response to attitude changes until it reaches the limit CTu of the upward position adjustment amount. However, for attitude changes larger than this, it will be fixed and displayed at the position adjusted by the limit CTu of the upward position adjustment amount. 【0076】 Next, in step S130 of Figure 16, the image adjustment module 520 acquires information indicating the attitude change of the vehicle 1 (attitude change information) from the attitude detection unit 415. The attitude detection unit 415 includes one or more sensors, such as a gyro sensor, an acceleration sensor, and a height sensor. The attitude detection unit 415 may calculate the vehicle attitude, such as pitching angle and roll angle, and the frequency of changes in the vehicle attitude, as attitude change information from sensor values ​​such as angular velocity, acceleration, and height of the moving body, and output it to the display control device 30. That is, the attitude change information may include not only the vehicle attitude (pitching angle, roll angle, etc.) but also the frequency of changes in the vehicle attitude (vibration frequency). Some or all of the function by which the attitude detection unit 415 calculates the attitude change information may be provided in the display control device 30. 【0077】 In step S140, the image adjustment module 520 calculates a first position adjustment amount C10 to be used in the first image adjustment process S151, which will be described later. First, the image adjustment module 520 calculates the amount of attitude change (angle deviation) of the vehicle 1 based on the attitude change information obtained from the attitude detection unit 415. For example, the image adjustment module 520 calculates the angle (pitching angle) α around the pitch axis of the vehicle 1 by integrating the angular velocity detected by the attitude detection unit 415. This makes it possible to calculate the amount of deviation (angle) of the vehicle 1 in the rotational direction around the Y axis (the pitch axis) as shown in Figure 1. In this embodiment, the pitching angle is calculated, but the yaw angle or roll angle may also be calculated. For example, angles around the X axis, Y axis and Z axis may all be calculated. However, some or all of the functions for calculating the attitude change amount (angle deviation) in the image adjustment module 520 may be provided by a device other than the display control device 30 that can communicate with the display control device 30, and the display control device 30 may receive information indicating the attitude change amount (angle deviation) of the vehicle 1 from the other device via the I / O interface 31. In other words, some display control devices 30 may omit the function for calculating the attitude change amount (angle deviation) in the image adjustment module 520. 【0078】 In step S140, the image adjustment module 520 further calculates a first position adjustment amount C10 to correct the display position of the virtual image V20 based on the amount of attitude change (angle shift) of the vehicle 1. Specifically, the image adjustment module 520 converts the amount of shift (pitching angle) into the number of pixels and determines an adjustment amount that restores the number of pixels that have shifted (image shift amount B10 due to attitude change) to its original value. Preferably, in order to restore the position shift of the virtual image V20 due to the attitude change of the vehicle 1, the image adjustment module 520 calculates a position adjustment amount (first position adjustment amount C10) in the opposite direction that is equal to the image shift amount B10 due to attitude change. 【0079】 In step S150 of some embodiments, the image adjustment module 520 generates image data by performing image adjustments on the drawing data acquired in step S110. In S150, the image adjustment module 520 rearranges the pixels of the drawing data as pixels of the image data based on the position adjustment amount C, the downward angle adjustment amount E, and the size adjustment amount F. In S160, the image adjustment module 520 outputs the image data generated (adjusted) in S150 to the display 50. 【0080】 In step S150 of some embodiments, the image adjustment module 520 performs a first image adjustment process to adjust the position of the virtual image based on a first position adjustment amount C10 when the attitude change of the vehicle 1 changes in a first direction of tilting forward or backward from the reference posture, and performs a second image adjustment process that suppresses the adjustment of the position of the virtual image in response to the change in the attitude of the vehicle 1 more than the first image adjustment process when the attitude change of the vehicle 1 changes in a second direction opposite to the first direction of tilting forward or backward from the reference posture. 【0081】 In the first image adjustment process S151, the image adjustment module 520 adjusts the position of the virtual image V20 (the image M that forms the basis of the virtual image V20) based on a first position adjustment amount C10 (position adjustment amount C) that is dynamically set in step S140 in accordance with the attitude changes acquired in step S130. Preferably, the first position adjustment amount C10 is set to cancel out the positional shift of the image caused by the attitude changes. 【0082】 In the first image adjustment process S151 in some embodiments, the image adjustment module 520 may, in addition to the position adjustment, dynamically change the first depression angle adjustment amount E10 (depression angle adjustment amount E) in accordance with the attitude change acquired in step S130, and adjust the depression angle of the virtual image V20 (image M which is the basis of the virtual image V20) based on this first depression angle adjustment amount E10 (depression angle adjustment amount E). 【0083】 In the first image adjustment process S151 in some embodiments, if the first position adjustment amount C10 is not set to cancel out the positional shift of the image caused by the attitude change (in other words, if it causes the positional shift of the image due to the attitude change), the image adjustment module 520 may, in addition to the position adjustment, dynamically change the size adjustment amount F in accordance with the attitude change acquired in step S130, and adjust the size of the virtual image V20 (the image M that forms the basis of the virtual image V20) based on this size adjustment amount F. 【0084】 In the second image adjustment process S152, the image adjustment module 520 dynamically changes the second depression angle adjustment amount E20 (depression angle adjustment amount E) in accordance with the attitude change acquired in step S130, and adjusts the depression angle of the virtual image V20 (the image M that forms the basis of the virtual image V20) based on this second depression angle adjustment amount E20 (depression angle adjustment amount E). The depression angle adjustment amount E20 in the second image adjustment process S152 is a depression angle adjustment amount that corrects the depression angle discrepancy between the real scene (road surface 6) and the virtual image caused by the attitude change (change in pitching angle α). Preferably, the depression angle adjustment amount E20 in the second image adjustment process S152 may be an amount that corrects the depression angle misalignment between the real scene (road surface 6) and the virtual image caused by attitude changes (changes in pitching angle α), plus an amount that expresses a shift to the vicinity (or a shift to the distance) due to attitude changes (changes in pitching angle α). 【0085】 Furthermore, in the second image adjustment process S152 in some embodiments, the image adjustment module 520 may dynamically change the second position adjustment amount C20 (position adjustment amount C) in accordance with the attitude change acquired in step S130 (position adjustment process in the second image adjustment process S152). The image adjustment module 520 may include table data, calculation formulas, etc., for setting the second position adjustment amount C20 (position adjustment amount C) from the attitude change acquired in step S130. In the second image adjustment process S152 in some embodiments, in addition to the depression angle adjustment, the image adjustment module 520 may adjust the position of the virtual image V20 (image M which is the basis of the virtual image V20) based on the second position adjustment amount C20 (smaller than the first position adjustment amount C10) which is dynamically set in accordance with the attitude change acquired in step S130. 【0086】 In the position adjustment process in the second image adjustment process S152, the image adjustment module 520 calculates a second position adjustment amount C20 that is dynamically changed based on the attitude change amount of the vehicle 1. For example, the second position adjustment amount C20 is obtained by multiplying the first position adjustment amount C10, which is determined based on the attitude change amount of the vehicle 1, by a coefficient less than 1. In addition, the position adjustment module 522 of some embodiments may read a second position adjustment amount C20 stored in the memory 37 that is not based on the attitude change amount of the vehicle 1. In this embodiment, the adjustment amount in the pitch axis direction is calculated, but the adjustment amounts in the yaw axis direction and the roll direction may also be calculated. For the roll angle, the adjustment amount is determined such that the amount of deviation of the roll angle is restored to its original value, while keeping the angle as it is. However, some or all of the function for calculating the second position adjustment amount C20 of the image adjustment module 520 may be provided by a device other than the display control device 30 that can communicate with the display control device 30, and the display control device 30 may receive display parameters (second position adjustment amount C20) for adjusting the position of the virtual image from the other device via the I / O interface 31. 【0087】 Furthermore, in the second image adjustment process S152 in some embodiments, the image adjustment module 520 may, in addition to the position adjustment, dynamically change the size adjustment amount F in accordance with the attitude change acquired in step S130, and perform size adjustment processing of the virtual image V20 (the image M that forms the basis of the virtual image V20) based on this size adjustment amount F. The image adjustment module 520 may include table data, calculation formulas, etc., for setting the size adjustment amount F from the attitude change acquired in step S130. 【0088】 In this embodiment, the display control device 30 (processor 33), when certain conditions are met, performs a second position adjustment process (step S152) to adjust the depression angle β of the virtual image V20 according to the displacement of the virtual image due to the change in the attitude of the moving object. Below is an example of calculating the depression angle β of the virtual image V20 according to the change in the attitude (angle shift) of the vehicle 1 using a calculation formula. However, in the model space where the content (virtual object) FU is placed, the position and angle of the virtual viewpoint VP may be changed according to the change in the attitude of the vehicle 1, and the position, angle (depression angle β), and size of the image M that is the basis of the virtual image V20 may be changed by rendering according to the content (virtual object) FU as seen from the virtual viewpoint VP. 【0089】 The image adjustment module 520 (depression angle adjustment module 524) calculates the depression angle β of the virtual image V20 (content FU) according to the attitude change (angle shift) of the vehicle 1. 【0090】 First, as shown in Figures 6 to 8B, we define α as the angle around the pitch axis of vehicle 1 (pitching angle) (a negative value for forward tilt and a positive value for backward tilt), h as the height from the virtual viewpoint VP to the virtual plane 100 (h0 is the height h when the angular deviation α is zero), and D as the distance in the depth direction Z from the virtual viewpoint VP to the nearest edge of the area on the virtual plane 100 where the virtual image V20 appears to overlap (D0 is the distance D when the angular deviation α is zero). 【0091】 The image adjustment module 520 (depression angle adjustment module 524) may calculate the distance D corresponding to the pitching angle α using the following formula 1 (but is not limited to this). 【number】 【0092】 Furthermore, the image adjustment module 520 (depression angle adjustment module 524) may calculate the depression angle β corresponding to the distance D using the following formula 2 (but is not limited to this). 【number】 【0093】 Furthermore, the image adjustment module 520 (angle adjustment module 524) is not limited to the above calculation method, as long as it can adjust the angle of depression β of the virtual image V20 according to the attitude (angle deviation) of the vehicle 1. For example, the image adjustment module 520 (angle adjustment module 524) may pre-store table data in memory 37 that associates the correction coefficient of the angle of depression β of the virtual image V20 with the attitude fluctuation (angle deviation) of the vehicle 1, read the correction coefficient based on the input information (signal) indicating the attitude fluctuation (angle deviation) of the vehicle 1, and adjust the angle of depression β of the content FU (virtual image V20). 【0094】 Furthermore, the image adjustment module 520 (depression angle adjustment module 524) may calculate the depression angle adjustment amount Δβ based on the distance D to the content (virtual object) FU on the virtual plane 100 using the following formula 3 (but is not limited to this). 【number】 【0095】 More preferably, the image adjustment module 520 (depression angle adjustment module 524) may calculate the depression angle adjustment amount Δβ using the following formula 4, taking into account that the tilt angle θt of the virtual image display area VS is tilted by the amount of angular displacement α. 【number】 【0096】 Furthermore, in some embodiments, the display control device 30 (processor 33) adjusts the size of the virtual image V20 according to the displacement of the virtual image due to changes in the attitude of the moving object. Below is an example of calculating the size of the virtual image V20 according to the attitude change (angle shift) of the vehicle 1 using a calculation formula. However, in the model space where the content (virtual object) FU is placed, the position and angle of the virtual viewpoint VP may be changed according to the attitude change of the vehicle 1, and the position, angle (depression angle β), and size of the image M that forms the basis of the virtual image V20 may be changed by rendering according to the content (virtual object) FU as seen from the virtual viewpoint VP. 【0097】 The image adjustment module 520 (size adjustment module 526) calculates the size of the virtual image V20 (content FU) according to the attitude change (angle shift) of the vehicle 1. Here, the size of the virtual image V20 is defined as the vertical angle (field of view) of the virtual image V20 as seen from the reference position. The field of view is the angle between the line connecting the upper end of the virtual image V20 from a predetermined reference position (for example, the center 205 of the eye box 200) and the line connecting the lower end of the virtual image V20 from the predetermined reference position, and corresponds to the vertical size (Y-axis direction) of the virtual image V20 as seen by the observer. 【0098】 The image adjustment module 520 (size adjustment module 526) may calculate the size corresponding to the distance D using the following formula 5, where L is the length in the depth direction Z of the region on the virtual plane 100 where the virtual image V20 appears to overlap from the virtual viewpoint VP1. 【number】 【0099】 The image adjustment module 520 (size adjustment module 526) only needs to be able to adjust the size of the virtual image V20 according to the posture (angle deviation) of the vehicle 1, and is not limited to the above calculation method. For example, the image adjustment module 520 (size adjustment module 526) may pre-store table data in memory 37 that associates a correction coefficient for the size of the virtual image V20 with the posture (angle deviation) of the vehicle 1, read the correction coefficient based on the input information (signal) indicating the posture (angle deviation) of the vehicle 1, and adjust the size of the virtual image V20. However, some or all of the functions of the image adjustment module 520 (size adjustment module 526) may be provided by a device other than the display control device 30 that can communicate with the display control device 30, and the display control device 30 may input display parameters for adjusting the size of the virtual image from the other device via the I / O interface 31. In other words, some display control devices 30 may omit the image adjustment module 520 (size adjustment module 526). 【0100】 The head-up display device 20 described herein comprises a display control device 30 in any of several embodiments, a display surface 50a that emits display light, and a relay optical system 80 that directs the display light from the display surface 50a towards the projection unit 2. In this case as well, the same advantages as described above are expected. 【0101】 The operation of the processing steps described above can be carried out by having one or more functional modules of an information processing device, such as a general-purpose processor or an application-specific chip, execute. All of these modules, combinations of these modules, and / or combinations with known hardware that can substitute for their functions are all within the scope of protection of the present invention. 【0102】 The functional blocks of the vehicle display system 10 are optionally implemented by hardware, software, or a combination of hardware and software to carry out the principles of the various embodiments described. Those skilled in the art will understand that the functional blocks described in Figure 3 may be optionally combined, or one functional block may be separated into two or more subblocks, to carry out the principles of the embodiments described. Therefore, the description herein optionally supports any possible combination or division of the functional blocks described herein. [Explanation of symbols] 【0103】 1: Vehicle 2:Projected area 6: Road surface 10: Vehicle display system 20: HUD device (Head-Up Display device) 30: Display control device 31: I / O Interface 33: Processor 35: Image processing circuit 37: Memory 40: Image display device 50: Display 50a:Display surface 100: Virtual plane 200: ibox 205: Center 401: Vehicle ECU 403: Road Information Database 405: Vehicle position detection unit 407: Operation detection unit 409: Eye position detection unit 411: External vehicle sensor 413: Brightness detection unit 415: Attitude detection unit 417: Mobile Information Terminal 419: External communication devices 510: Drawing Module 520: Image adjustment module 522: Position adjustment module 524: Depression angle adjustment module 526: Size adjustment module 700: Observer 700L: Left eye 700R: Right eye B10: Image shift amount B12: Image shift amount B13: Image shift amount B14: Image shift amount B15: Image shift amount B16: Image shift amount B18: Image shift amount C:Position adjustment amount C10: 1st position adjustment amount C20: 2nd position adjustment amount CT: limit CTd: limit CTu :Limit E: Depression angle adjustment amount E10: 1st depression angle adjustment amount E20: 2nd depression angle adjustment amount F: Size adjustment amount FU: Content K:Display light V20: Illusion VP: Virtual Viewpoint VS: Virtual image display area VT: Position adjustment range Δβ: Depression angle adjustment amount α: Pitching angle α0 :Reference posture αTd: Posture threshold αTu: Posture threshold β : depression angle θt: Tilt angle

Claims

[Claim 1] A display control device for controlling a head-up display device mounted in a vehicle, having a display unit that displays an image on its display surface, and directing the light of the image towards the projection area to superimpose a virtual image within a virtual image display area that overlaps with the road surface in front of the vehicle, thereby allowing the user to view the virtual image. One or more processors, Memory and The system comprises one or more computer programs stored in the memory and configured to be executed by the one or more processors, The aforementioned processor, Information on the amount of attitude change indicating the attitude change of the vehicle is acquired. In order to suppress the relative positional shift between the virtual image and the road surface due to the attitude fluctuations of the vehicle, a first position adjustment amount is set that changes dynamically in accordance with the attitude fluctuation amount information. 1) When the vehicle's posture changes from its reference posture in a first direction of tilting forward or backward, a first image adjustment process is performed to adjust the position of the virtual image based on the first position adjustment amount. 2) If the vehicle's posture changes from the reference posture in a second direction opposite to the first direction, such as tilting forward or backward, a second image adjustment process is performed that suppresses the adjustment of the virtual image's position in response to the change in the vehicle's posture more than the first image adjustment process. A display control device characterized by the following: [Claim 2] The aforementioned processor, 1) In the first image adjustment process, if the vehicle's attitude is less than a first attitude change amount in the first direction, the position of the virtual image is adjusted based on the first position adjustment amount; if the vehicle's attitude is greater than the first attitude change amount in the first direction, the position of the virtual image is adjusted based on a constant second position adjustment amount that is less than the first position adjustment amount. 2) In the second image adjustment process, if the vehicle's attitude is less than the second attitude change amount in the second direction, the position of the virtual image is adjusted based on the first position adjustment amount; if the vehicle's attitude is greater than the second attitude change amount in the second direction, the position of the virtual image is adjusted based on a constant third position adjustment amount which is smaller than the first position adjustment amount for the change in the vehicle's attitude. The second change in posture is smaller than the first change in posture. The display control device according to feature 1. [Claim 3] The aforementioned processor, If the vehicle's posture changes from the reference posture in the second direction faster than a predetermined speed, the position of the virtual image is fixed relative to the change in the vehicle's posture. The display control device according to claim 2. [Claim 4] The aforementioned processor, If the vehicle's posture changes from the reference posture in the second direction faster than a predetermined speed, the position of the virtual image relative to the change in the vehicle's posture is fixed until it is determined that the vehicle's posture is in a predetermined stable state. The display control device according to claim 3. [Claim 5] The second direction is the direction in which the vehicle's posture tilts backward from the reference posture. The virtual image includes a first virtual image and a second virtual image displayed closer to the lower edge of the virtual image display area than the first virtual image. The processor can set the second position adjustment amount and the third position adjustment amount for each virtual image. The second position adjustment amount of the second virtual image is set to be smaller than the second position adjustment amount of the first virtual image, and the third position adjustment amount of the second virtual image is set to be smaller than the third position adjustment amount of the first virtual image. The display control device according to claim 2. [Claim 6] The processor reduces the visibility of the virtual image while adjusting the position of the virtual image based on the third position adjustment amount. The display control device according to claim 2. [Claim 7] The aforementioned processor, Based on the attitude change amount information, a downward angle adjustment amount is set to suppress the discrepancy in the relative angle (hereinafter referred to as the downward angle) between the virtual image and the road surface due to the attitude change of the vehicle. During the second image adjustment process described above, the depression angle of the virtual image is further adjusted based on the depression angle adjustment amount. The display control device according to feature 1. [Claim 8] The aforementioned processor, During the second image adjustment process, avoid changing the shape of the virtual image. After the second image adjustment process, the form of the virtual image is changed. The display control device according to feature 1. [Claim 9] A display unit mounted on the vehicle that displays an image on its surface, A relay optical system that directs the display light from the display unit towards the projection unit, One or more processors, Memory and The system comprises one or more computer programs stored in the memory and configured to be executed by the one or more processors. A head-up display device that superimposes a virtual image within a virtual image display area that overlaps with the road surface in front of the vehicle, The aforementioned processor, Information on the amount of attitude change indicating the attitude change of the vehicle is acquired. In order to suppress the relative positional shift between the virtual image and the road surface due to the attitude fluctuations of the vehicle, a first position adjustment amount is set that changes dynamically in accordance with the attitude fluctuation amount information. 1) When the vehicle's posture changes from its reference posture in a first direction of tilting forward or backward, a first image adjustment process is performed to adjust the position of the virtual image based on the first position adjustment amount. 2) If the vehicle's posture changes from the reference posture in a second direction opposite to the first direction, such as tilting forward or backward, a second image adjustment process is performed that suppresses the adjustment of the virtual image's position in response to the change in the vehicle's posture more than the first image adjustment process. A head-up display device characterized by the following features. [Claim 10] A display control method executed by a display control device that controls a head-up display device mounted in a vehicle, having a display unit that displays an image on its display surface, and directing the light of the image towards the projection area to superimpose a virtual image within a virtual image display area that overlaps with the road surface in front of the vehicle for viewing, To acquire attitude change amount information indicating the attitude change of the aforementioned vehicle, In order to suppress the relative positional shift between the virtual image and the road surface due to the attitude fluctuations of the vehicle, a first position adjustment amount is set that changes dynamically in accordance with the attitude fluctuation amount information, 1) When the vehicle's posture changes from a reference posture in a first direction of tilting forward or backward, a first image adjustment process adjusts the position of the virtual image based on the first position adjustment amount, 2) When the vehicle's posture changes from the reference posture in a second direction opposite to the first direction, such as tilting forward or backward, a second image adjustment process is included which suppresses the adjustment of the position of the virtual image in response to the change in the vehicle's posture more than the first image adjustment process. A display control method characterized by the following:

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