Display system and vibration detection system

Abstract

This display system comprises an orientation detection device that detects the amount of orientation change of a mobile object, and a correction processing device including a vibration detection unit that determines, on the basis of the amount of orientation change, whether or not an orientation change of the mobile object having a specific frequency band component is occurring in an ongoing way for a certain time or longer. If the vibration detection unit determines that the orientation change of the mobile object having the specific frequency band component is not occurring in an ongoing way for a certain time or longer, the correction processing device updates the correction quantity of an image display position on the basis of the amount of orientation change, whereas if the vibration detection unit determines that the orientation change of the mobile object having the specific frequency band component is occurring in an ongoing way for a certain time or longer, the correction processing device makes the absolute value of the correction quantity less than or equal to the absolute value of the correction quantity in the previous determination.

Description

[Technical Field]

[0001] The present disclosure relates to a display system that controls the display position of an image in response to vibrations of a moving body, and a vibration detection system that detects vibrations occurring in a moving body. [Background technology]

[0002] Patent Document 1 discloses a vehicle information projection system that uses a head-up display (HUD) device to perform augmented reality (AR) display. The HUD device projects light representing a virtual image onto the vehicle windshield, allowing the viewer, a vehicle occupant, to view the virtual image along with the real view outside the vehicle. For example, a virtual image representing the vehicle's guide route is displayed in association with a display object (e.g., a road) within the real view. This allows the occupant to confirm the guide route while viewing the real view. The vehicle information projection system of Patent Document 1 is equipped with a vehicle speed sensor and corrects the display position of the virtual image according to acceleration. This prevents the virtual image from shifting position when the vehicle suddenly decelerates or accelerates. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-101311 Summary of the Invention [Problem to be solved by the invention]

[0004] When a vehicle vibrates due to the condition of the road on which the vehicle is traveling, the real view appears to the occupants as vibrating. When correcting the display position of a virtual image in accordance with the vehicle vibration, a time lag occurs between the correction of the virtual image's display position and the vehicle vibration. For example, in the case of vibration in a specific frequency band that is higher than a certain frequency, if the ratio of the time lag between calculating the correction amount of the virtual image and displaying it relative to the vehicle vibration period exceeds a certain level, the display misalignment may increase. Therefore, it is necessary to detect vibration in a specific frequency band that occurs in a moving object such as a vehicle, and to suppress the increase in the display misalignment correction error when vibration in the specific frequency band occurs in the moving object.

[0005] The present disclosure provides a display system that suppresses the increase in correction error and a vibration detection system that detects vibrations occurring in a moving body. [Means for solving the problem]

[0006] The display system disclosed herein includes a display processing device that controls the display of an image, a posture detection device that detects a posture change amount of a moving object, and a correction processing device having a vibration detection unit that determines whether a posture change of the moving object having a specific frequency band component has occurred continuously for a certain period of time or more based on the posture change amount. The correction processing device updates a correction amount for the display position of the image based on the posture change amount when the vibration detection unit determines that a posture change of the moving object having the specific frequency band component has not occurred continuously for a certain period of time or more, and sets the absolute value of the correction amount to be equal to or less than the absolute value of the correction amount at the previous determination when the vibration detection unit determines that a posture change of the moving object having the specific frequency band component has occurred continuously for a certain period of time or more. The vibration detection unit includes a threshold crossing detection unit that detects when the posture change amount or a fluctuation amount calculated based on the posture change amount crosses a predetermined threshold, a counter that measures the number of times the posture change amount or the fluctuation amount crosses the threshold per unit time, and a vibration determination unit that determines that a posture change of the moving object having the specific frequency band component has occurred continuously for a certain period of time or more when the number of times measured by the counter is equal to or greater than the count threshold. The display processing device controls the display position of the image based on the correction amount.

[0007] In addition, the vibration detection system disclosed herein includes an attitude detection device that detects the amount of attitude change of a moving body, a threshold crossing detection unit that detects when the amount of attitude change or a fluctuation amount calculated based on the amount of attitude change crosses a predetermined threshold, a counter that measures the number of times the amount of attitude change or the fluctuation amount crosses the threshold in a unit time, and a vibration determination unit that determines that an attitude change of a moving body having a specific frequency band component has occurred continuously for a certain period of time or more when the number of times measured by the counter is equal to or greater than the count threshold.

[0008] These general and specific aspects may be realized by a system, a method, and a computer program, as well as combinations thereof. [Effects of the Invention]

[0009] According to the display system and vibration detection system of the present disclosure, it is possible to provide a display system that suppresses the increase in correction error and a vibration detection system that detects vibrations occurring in a moving body. [Brief explanation of the drawings]

[0010] [Figure 1] Diagram to explain the head-up display (HUD) [Figure 2] FIG. 1 is a block diagram showing the internal configuration of a display system according to a first embodiment. [Figure 3A] A diagram showing an example when the vehicle is not tilted [Figure 3B] A diagram showing an example of the view from the windshield [Figure 3C] A diagram showing an example in which a virtual image is displayed at a reference position. [Figure 3D] A diagram showing an example of an augmented reality (AR) display [Figure 4A] Diagram showing the vehicle's backward tilt [Figure 4B] FIG. 10 is a diagram illustrating an example in which a positional deviation of a virtual image occurs when a vehicle is tilted backward. [Figure 4C] A diagram showing an example of a virtual image after correction. [Figure 5] 1 is a flowchart showing a display process in the first embodiment; [Figure 6] 1 is a flowchart showing a correction process in the first embodiment; [Figure 7A] 7A and 7B are explanatory diagrams showing the effect of an offset removal filter, in which FIG. 7A(a) shows the offset error of the fluctuation amount, and FIG. 7A(b) shows the fluctuation amount after the offset error has been removed. [Figure 7B] 7B(a) shows an example of the fluctuation of the amount of fluctuation, and FIG. 7B(b) shows a counted flag. [Figure 8A] FIG. 10 is an explanatory diagram showing an example of resetting the correction amount to zero. [Figure 8B] Graph showing the effectiveness of detecting specific frequencies [Figure 8C] Graph showing fluctuations in compensation error [Figure 9] 10 is a flowchart showing a correction process in the second embodiment. [Figure 10] FIG. 10 is an explanatory diagram showing an example in which the correction amount is not updated; [Figure 11] FIG. 10 is a block diagram showing the internal configuration of a display system according to a third embodiment. [Figure 12] 10 is a flowchart showing a correction process in the third embodiment. [Figure 13] FIG. 10 is a block diagram showing the configuration of a vibration detection system according to a fourth embodiment. [Figure 14] 14A and 14B are explanatory diagrams showing an example of counting using a threshold value, where FIG. 14A shows an example of counting using a positive threshold value, and FIG. 14B shows an example of counting using a negative threshold value. [Figure 15] FIG. 10 is a block diagram showing the internal configuration of a display system according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Findings that formed the basis of this disclosure) The amount of change in the attitude of the moving body is detected by an attitude detection device. The amount of change in attitude is, for example, an angular velocity. Furthermore, a fluctuation amount, which is a value obtained by calculating the amount of change in attitude, is detected. Note that the fluctuation amount may be a value obtained by using the amount of change in attitude directly.

[0012] For example, a gyro sensor can be used to detect the attitude of a moving body with high accuracy. The angles around the three axes of the moving body (roll angle, pitch angle, and yaw angle), which are the amount of fluctuation of the moving body, can be obtained by integrating the angular velocity around each of the three axes as the amount of attitude change detected by the gyro sensor. When the pitch angle is used as the amount of fluctuation of the moving body, for example, the pitch angle is 0° when the moving body is in a horizontal state, so the amount of fluctuation of the moving body is the amount of rotation in the pitch direction based on the horizontal state of the moving body. The pitch direction refers to the direction of rotation around an axis in the left-right direction perpendicular to the moving direction of the moving body.

[0013] When correcting the display position of an image according to the attitude state of a moving object detected based on the detection results of an attitude detection device, pitch-direction vibrations of the moving object due to the surface condition of the road are detected as fluctuations in the pitch angle, and the display position of the image is corrected according to these fluctuations in the pitch angle. The vibration frequency of the moving object varies depending on the unevenness of the road. If the vibration period of the moving object due to road unevenness is sufficiently short compared to the time lag from calculation of the image correction amount to display, the display vibration can be suppressed. However, if the vibration period of the moving object due to road unevenness is close to the time lag for display position correction, the display misalignment may be amplified.

[0014] The display system of the present disclosure detects the amount of change in the posture of a moving object, and adjusts the amount of correction for the image display position if the amount of variation calculated based on the amount of change in posture contains components in a specific frequency band. This makes it possible to reduce the expansion of correction errors even when the vibration period of the moving object due to unevenness in the road is close to the time lag for correcting the display position.

[0015] (First embodiment) A first embodiment will be described below with reference to the drawings. In the first embodiment, a moving body is a vehicle such as an automobile, and a display system is a head-up display system (hereinafter referred to as a HUD system) that displays a virtual image in front of the windshield of the vehicle.

[0016] 1. Display system configuration Fig. 1 is a diagram for explaining the HUD system. In Fig. 1, the roll axis of the vehicle 200 is the X axis, the pitch axis of the vehicle 200 is the Y axis, and the yaw axis of the vehicle 200 is the Z axis. That is, the X axis is orthogonal to the Y axis and the Z axis and is an axis along the line of sight of the occupant D viewing the virtual image Iv. The Y axis is an axis along the left-right direction as seen by the occupant D viewing the virtual image Iv, and is an axis along the left-right direction with respect to the traveling direction of the vehicle 200. The Z axis is an axis along the height direction of the vehicle 200.

[0017] The display system 100 of this embodiment is a HUD system that performs so-called augmented reality (AR) display by superimposing a virtual image Iv on a real view ahead of the windshield 210 of the vehicle 200. The virtual image Iv represents predetermined information. For example, the virtual image Iv is graphics and text that indicate a route to a destination, an estimated time of arrival at the destination, a direction of travel, a speed, various warnings, and the like. The display system 100 is installed in the vehicle 200 and projects a display light Lc representing the virtual image Iv into a display area 220 of the windshield 210 of the vehicle 200. In this embodiment, the display area 220 is a partial area of ​​the windshield 210. Note that the display area 220 may be the entire area of ​​the windshield 210. The display light Lc is reflected by the windshield 210 toward the interior of the vehicle. As a result, an occupant (viewer) D inside the vehicle 200 visually recognizes the reflected display light Lc as a virtual image Iv in front of the vehicle 200.

[0018] The display system 100 includes a projection device 10, an information acquisition device 20, a display processing device 30, an attitude detection device 40, and a correction processing device 50. The attitude detection device 40 and a vibration detection unit 52c of a correction control unit 52 of the correction processing device 50 constitute a vibration detection system 60.

[0019] The projection device 10 projects display light Lc representing the virtual image Iv into the display area 220. The projection device 10 includes, for example, a liquid crystal display element that displays an image of the virtual image Iv, a light source such as an LED that illuminates the liquid crystal display element, and a mirror and a lens that reflect the display light Lc of the image displayed by the liquid crystal display element onto the display area 220. The projection device 10 is installed, for example, in the dashboard of the vehicle 200.

[0020] The information acquisition device 20 acquires vehicle position information. Specifically, the information acquisition device 20 measures the position of the vehicle 200 and generates position information indicating the position. The information acquisition device 20 outputs vehicle-related information including at least the position information of the vehicle 200. Note that the information acquisition device 20 may acquire vehicle exterior information indicating an object, a distance to the object, and the like. The vehicle-related information may include the acquired vehicle exterior information.

[0021] The display processing device 30 controls the display of the virtual image Iv based on the vehicle-related information obtained from the information acquisition device 20, and outputs image data of the virtual image Iv to the projection device 10. The display processing device 30 may control the display of the virtual image Iv based on the display timing (display time) of the virtual image Iv or a combination of the vehicle-related information and the display timing. The display timing may be, for example, repeating a 10-second display and a 1-second non-display.

[0022] The attitude detection device 40 acquires the amount of change in attitude of the vehicle 200. In this embodiment, the attitude detection device 40 includes, for example, a gyro sensor 41 that detects the angular velocity of the vehicle 200. The gyro sensor 41 outputs the detected angular velocity to the correction processing device 50 as an amount of change in attitude indicating the attitude of the vehicle 200.

[0023] The correction processing device 50 calculates the amount of correction for the display position of the virtual image Iv based on the amount of change in the attitude of the vehicle 200 detected by the attitude detection device 40.

[0024] FIG. 2 is a block diagram showing the internal configuration of the display system 100. As shown in FIG.

[0025] In this embodiment, the information acquisition device 20 includes a GPS (Global Positioning System) module 21 that detects a position indicating the current location of the vehicle 200 in a geographic coordinate system. Specifically, the GPS module 21 receives radio waves from GPS satellites and determines the latitude and longitude of the received point. The GPS module 21 generates location information indicating the determined latitude and longitude. The information acquisition device 20 may further include a camera that captures an external scene and generates image data. The information acquisition device 20 may, for example, identify an object from the image data using image processing and measure the distance to the object. In this case, the information acquisition device 20 may generate information indicating the object and the distance to the object as outside vehicle information. The information acquisition device 20 outputs vehicle-related information including the location information to the display processing device 30. Note that image data generated by the camera may also be output to the display processing device 30.

[0026] The display processing device 30 includes a communication unit 31 , a display control unit 32 , and a storage unit 33 .

[0027] The communication unit 31 includes a circuit that communicates with external devices in accordance with a predetermined communication standard (e.g., LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark), USB, HDMI (registered trademark), CAN (controller area network), SPI (Serial Peripheral Interface)).

[0028] The display control unit 32 can be realized by a semiconductor element or the like. The display control unit 32 can be configured by, for example, a microcomputer, a CPU, an MPU, a GPU, a DSP, an FPGA, or an ASIC. The functions of the display control unit 32 may be configured by hardware alone, or may be realized by combining hardware and software. The display control unit 32 realizes predetermined functions by reading data and programs stored in the storage unit 33 and performing various arithmetic processing.

[0029] The storage unit 33 is a storage medium that stores programs and data necessary to realize the functions of the display processing device 30. The storage unit 33 can be realized by, for example, a hard disk (HDD), an SSD, a RAM, a DRAM, a ferroelectric memory, a flash memory, a magnetic disk, or a combination of these.

[0030] The storage unit 33 stores a plurality of image data 33i representing the virtual image Iv. The display control unit 32 determines the virtual image Iv to be displayed based on vehicle-related information obtained from the information acquisition device 20. The display control unit 32 reads out the image data 33i of the determined virtual image Iv from the storage unit 33 and outputs it to the projection device 10. Furthermore, the display control unit 32 sets the display position of the virtual image Iv. The display control unit 32 outputs display information indicating whether or not the virtual image Iv should be displayed or whether or not it is currently being displayed to the correction processing device 50.

[0031] The correction processing device 50 includes a communication unit 51 , a correction control unit 52 , and a storage unit 53 .

[0032] The communication unit 51 includes a circuit that communicates with external devices in accordance with a predetermined communication standard (e.g., LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark), USB, HDMI (registered trademark), CAN (controller area network), SPI (Serial Peripheral Interface)).

[0033] The correction control unit 52 is a calculation device that can be realized using semiconductor elements or the like. The correction control unit 52 can be configured with, for example, a microcomputer, a CPU, an MPU, a GPU, a DSP, an FPGA, or an ASIC. The functions of the correction control unit 52 may be configured with hardware alone, or may be realized by combining hardware and software. The correction control unit 52 realizes predetermined functions by reading data and programs stored in the memory unit 53 in the correction processing device 50 and performing various calculation processes.

[0034] The correction control unit 52 includes, as functional components, a deviation amount calculation unit 52a, a correction amount calculation unit 52b, a vibration detection unit 52c, and a correction amount adjustment unit 52d.

[0035] The deviation amount calculation unit 52a calculates the amount of deviation in the angle of the vehicle 200 based on the amount of attitude change output by the attitude detection device 40. The amount of deviation in the angle is the attitude angle with respect to the reference attitude state of the moving body. The reference attitude state of the moving body is, for example, a horizontal state. For example, the deviation amount calculation unit 52a calculates the angle around the pitch axis (pitch angle) of the vehicle 200 by integrating the pitch angular velocity detected by the gyro sensor 41. This makes it possible to detect the amount of deviation (angle) of the vehicle 200 in the direction of rotation about the Y axis (pitch axis) shown in FIG. 1 as the central axis. Note that although the pitch angle is calculated in this embodiment, a yaw angle or a roll angle may also be calculated. For example, angles around the X axis, Y axis, and Z axis may all be calculated.

[0036] The correction amount calculation unit 52b calculates the correction amount for the display position of the virtual image Iv according to the amount of deviation in the angle of the vehicle 200. Specifically, the correction amount calculation unit 52b converts the amount of deviation in the angle (pitch angle) calculated by the deviation amount calculation unit 52a into the number of pixels and determines a correction amount that will restore the number of deviated pixels (hereinafter also referred to as the "number of deviated pixels"). The correction amount calculation unit 52b outputs the calculated correction amount to the display processing device 30. Note that, in this embodiment, the correction amount around the pitch axis is calculated, but correction amounts around the yaw axis and the roll axis may also be calculated. For the roll angle, a correction amount is determined that will restore the amount of deviation in the roll angle while leaving the angle unchanged.

[0037] The vibration detection unit 52c detects whether the input signal contains a specific frequency band component and includes a fluctuation amount calculation unit 52m, an offset removal filter 52e, a threshold crossing detection unit 52f, a counter 52g, and a vibration determination unit 52h.

[0038] The change amount calculation unit 52m calculates the change amount of the vehicle 200 based on the posture change amount output by the posture detection device 40. For example, the change amount calculation unit 52m calculates the angle (pitch angle) around the pitch axis of the vehicle 200 by integrating the pitch angular velocity detected by the gyro sensor 41 as the change amount. Thereby, the change amount (pitch angle) of the vehicle 200 in the rotation direction centered on the Y axis (pitch axis) shown in FIG. 1 can be detected. In the present embodiment, the pitch angle is calculated, but the yaw angle or the roll angle may be calculated. For example, the angles around the X axis, Y axis, and Z axis may all be calculated. Note that since both the deviation amount calculated by the deviation amount calculation unit 52a and the change amount calculated by the change amount calculation unit 52m are angle information, they may be shared or calculated as separate angle information. Note that the change amount may be a value using the posture change amount as it is. Also, when the posture change amount is directly used as the change amount, the change amount calculation unit may be omitted.

[0039] [[ID=৪]]The offset removal filter 52e removes the offset component of the input signal (change amount), and as a result, attenuates the low-frequency band component of the input signal. The offset removal filter 52e is, for example, a high-pass filter. The relationship between the cut-off frequency Fc of the offset removal filter 52e and the lower limit F of the frequency band to be detected satisfies, for example, the following formula (1). Fc < F ≤ 1 / (2×T [sec]) ··· (1) formula T is the total delay time (time lag) [sec] from the calculation of the correction amount of the virtual image to the display. However, the method of setting the frequency is not limited to formula (1) and may be adjusted as appropriate. The lower limit F of the frequency band to be detected is, for example, 2.5 Hz.

[0040] The threshold crossing detector 52f detects when an input value crosses a predetermined threshold. Here, "detecting when the input value crosses the threshold" means, for example, detecting when the input value changes from below the threshold to above the threshold, or from above the threshold to below the threshold. When the threshold crossing detector 52f detects when the input value crosses the threshold, it outputs a detection signal to the counter 52g. The threshold is, for example, zero or an arbitrary specific value. The arbitrary specific value is, for example, the value of the offset error.

[0041] The counter 52g measures the number of times that the input value to the threshold crossing detector 52f crosses a predetermined threshold, i.e., the counter 52g counts the number of detection signals input to the counter 52g from the threshold crossing detector 52f.

[0042] The vibration determination unit 52h determines whether a specific frequency band component has occurred in the fluctuation amount for a certain period of time or longer based on the number of times counted by the counter 52g per unit time. The vibration determination unit 52h, for example, sets a time window and determines the occurrence of vibration having a specific frequency band component based on the amount of change in the count value over a certain period of time. In this way, it is possible to detect the occurrence of vibration having a frequency band component of 2.5 Hz or higher, for example. The determination result is sent from the vibration determination unit 52h to the correction amount calculation unit 52b and the correction amount adjustment unit 52d.

[0043] The correction amount adjuster 52d adjusts the correction amount based on the determination result of the vibration determination unit 52h. When the vibration determination unit 52h determines that an attitude change of the vehicle 200 having a specific frequency band component has occurred continuously for a certain period of time or more, the correction amount is adjusted by setting the sign of the correction amount to the same as the sign of the correction amount determined previously by the vibration determination unit 52h and setting the absolute value of the correction amount to be equal to or less than the absolute value of the correction amount determined previously. In the first embodiment, when adjustment of the correction amount is necessary, the correction amount is adjusted to zero.

[0044] The storage unit 53 is a storage medium that stores programs and data necessary to realize the functions of the correction control unit 52. Therefore, for example, programs and data necessary to cause an arithmetic device such as a processor to function as the correction amount calculation unit 52b are also stored in the storage unit 53. The storage unit 53 can be realized by, for example, a hard disk drive (HDD), an SSD, a RAM, a DRAM, a ferroelectric memory, a flash memory, a magnetic disk, or a combination of these.

[0045] The correction processing device 50 outputs the amount of correction to the display processing device 30 .

[0046] Next, AR display will be described with reference to Fig. 3A to Fig. 3D. Fig. 3A shows an example when vehicle 200 is not tilted. Fig. 3B shows an example of an actual scene seen through windshield 210 of vehicle 200 shown in Fig. 3A. Fig. 3C shows an example of a virtual image Iv seen from display area 220. Fig. 3D shows an example in which virtual image Iv shown in Fig. 3C is superimposed on the actual scene shown in Fig. 3B.

[0047] The display system 100 superimposes a virtual image Iv shown in FIG. 3C on the actual scene shown in FIG. 3B. The reference position (initial position) P0 of the virtual image Iv is determined based on the type of virtual image Iv, the state (position and attitude) of the vehicle 200, map data, and the like, and the reference position P0 is determined by an external device. For example, if the display object 230 is a driving lane and the virtual image Iv is an arrow indicating the direction of travel, the reference position P0 is the display position on the liquid crystal display when the tip of the arrow points to the center of the driving lane. For example, in FIG. 3C, the reference position P0 is set at the position of a pixel on the liquid crystal display corresponding to the Y coordinate and Z coordinate values ​​within the display area 220. The reference position P0 is acquired from the external device.

[0048] The external device may be configured with, for example, a microcomputer, a CPU, an MPU, a GPU, a DSP, an FPGA, or an ASIC, and a GPS module 21. The functions of the external device may be configured with hardware alone, or may be realized by combining hardware and software. The reference position P0 output from the external device may change based on changes in posture due to factors such as the number of occupants, changes in load, and a decrease in gasoline, and therefore may differ from, for example, the reference position (initial position) initially acquired. Therefore, the display processing device 30 may change the reference position P0 acquired from the external device based on changes in posture due to factors such as the number of occupants, changes in load, and a decrease in gasoline. The display processing device 30 may set the reference position P0 based on vehicle-related information, map data, and the like. The display processing device 30 may set the size of the virtual image Iv based on vehicle-related information.

[0049] Fig. 4A shows an example of a state in which the vehicle 200 is tilted backward. Fig. 4B shows an example in which the display position of the virtual image Iv is shifted from the display target 230 in response to a change in the posture of the vehicle 200. Fig. 4C shows the display position of the virtual image Iv after correction.

[0050] Vehicle 200 may tilt due to an uneven road surface, sudden acceleration or deceleration of vehicle 200, or the like. For example, as shown in FIG. 4A, when vehicle 200 runs over a convex portion 303 on road surface 301, vehicle 200 tilts backward. In this case, as shown in FIG. 4B, the position of display target 230 visible through windshield 210 varies depending on the inclination θ1 of vehicle 200 with respect to the road. Therefore, when virtual image Iv is displayed at reference position P0, virtual image Iv is displaced from display target 230.

[0051] For example, when the vehicle 200 leans backward due to a protrusion 303 on the road surface 301, the position of the display object 230 shifts downward compared to normal driving, as shown in FIG. 4B. Therefore, the tip of the arrow of the virtual image Iv displayed at the reference position P0 shifts outside the lane. Therefore, the display system 100 adjusts the display position of the virtual image Iv in a direction to correct the shift according to the attitude of the vehicle 200.

[0052] Specifically, as shown in FIG. 4C , the correction processing device 50 calculates a correction amount C so that the display position is at position P1 where there is no deviation due to the angle of the vehicle 200. That is, the display processing device 30 sets the display position of the virtual image Iv to "reference position P0 + correction amount C." This allows the projection device 10 to display the virtual image Iv at position P1 corresponding to the display target 230. In this way, even if the vehicle 200 is tilted, by changing the display position of the virtual image Iv from the reference position P0 based on the correction amount C, the virtual image Iv can be displayed at position P1 corresponding to the display target 230 in the real scene.

[0053] 4A, if there are successive convex portions 303 on the road surface 301 or depending on the condition of the road surface 301, the vehicle 200 vibrates continuously. In this case, the display position of the virtual image Iv also vibrates. Since there is a time lag between the detection of a change in the posture of the vehicle 200 and the display of the virtual image Iv, if the timing of a new change in the posture of the vehicle 200 coincides with the display position corrected for a previously detected vibration, the display misalignment due to the correction error will increase. A method for suppressing the increase in this display misalignment will be described later.

[0054] 2. Operation of the display processing device Fig. 5 shows a display process performed by the display control unit 32 of the display processing device 30. The display process shown in Fig. 5 is started, for example, when the engine of the vehicle 200 is started or when a button for instructing the start of display of the virtual image Iv is operated.

[0055] The display control unit 32 acquires vehicle-related information from the information acquisition device 20 (S101). The display control unit 32 determines a virtual image Iv to be displayed based on the vehicle-related information (S102). The display control unit 32 acquires a reference position P0 of the virtual image Iv from an external device (S103). The display control unit 32 acquires a correction amount C of the display position output from the correction processing device 50 (S104).

[0056] The display control unit 32 causes the projection device 10 to display the virtual image Iv based on the reference position P0 and the correction amount C (S105). For example, the display control unit 32 reads out image data 33i of the virtual image Iv corresponding to the display target from the storage unit 33, sets the display position of the virtual image Iv to "reference position P0+correction amount C," and outputs the image data 33i to the projection device 10.

[0057] The display control unit 32 determines whether to continue the display process (S106). For example, when the engine of the vehicle 200 is stopped or when a button for instructing to end the display of the virtual image Iv is operated, the display control unit 32 ends the display process. If the display process is to be continued, the process returns to step S101.

[0058] 3. Operation of the correction processing device Fig. 6 shows the correction process performed by the correction control unit 52 of the correction processing device 50. The correction process shown in Fig. 6 is started, for example, when the engine of the vehicle 200 is started or when a button for instructing the start of display of the virtual image Iv is operated. The correction process of Fig. 6 is started, for example, together with the display process of Fig. 5. Note that the correction process shown in Fig. 6 may also be started when a button for instructing the start of position correction of the virtual image Iv is operated.

[0059] The correction control unit 52 acquires an attitude change amount indicating an angular velocity output from the gyro sensor 41 (S201). The deviation amount calculation unit 52a of the correction control unit 52 calculates the attitude of the vehicle 200, for example, the deviation amount which is an angle with respect to the pitch direction, based on the acquired attitude change amount (S202). Specifically, the deviation amount calculation unit 52a calculates the pitch angle of the vehicle 200 by integrating the angular velocity. The calculated deviation amount is sent to the correction amount calculation unit 52b.

[0060] The fluctuation amount calculation unit 52m of the vibration detection unit 52c of the correction control unit 52 calculates the amount of fluctuation in the attitude of the vehicle 200, for example, the angle relative to the pitch direction, based on the acquired amount of attitude change (S203). Specifically, the fluctuation amount calculation unit 52m calculates the pitch angle of the vehicle 200 by integrating the angular velocity. The calculated amount of fluctuation is sent to the offset removal filter 52e.

[0061] The offset removal filter 52e of the vibration detection unit 52c removes the offset component from the detected amount of fluctuation, thereby attenuating the low-frequency band component of the amount of fluctuation. For example, if the amount of fluctuation fluctuates as shown in FIG. 7A(a), the offset removal filter 52e can remove the offset component OF1 included in the amount of fluctuation to obtain the amount of fluctuation oscillating around 0 as the center of amplitude, as shown in FIG. 7A(b). The amount of fluctuation from which the offset component OF1 has been removed and the low-frequency band component has been attenuated is sent to the threshold crossing detection unit 52f. Note that the offset removal filter 52e may first remove the offset component from the amount of posture change acquired by the vibration detection unit 52c from the posture detection device 40, and then the amount of fluctuation may be calculated by the fluctuation amount calculation unit 52m from the amount of posture change from which the offset has been removed.

[0062] The threshold crossing detector 52f detects when the input fluctuation amount crosses a predetermined threshold. For example, when the fluctuation amount fluctuates as shown in FIG. 7B(a), the threshold crossing detector 52f detects that the threshold has changed from less than zero to greater than or equal to zero, and outputs a detection signal to the counter 52g as shown in FIG. 7B(b). The threshold crossing detector 52f may halve the detection cycle and count not only an increase in the fluctuation amount from less than zero to greater than or equal to zero, but also a decrease in the fluctuation amount from greater than or equal to zero to less than zero.

[0063] The counter 52g counts the number of detection signals input within a predetermined period of time. The predetermined period of time may be, for example, a time window or the most recent predetermined time.

[0064] The vibration determination unit 52h determines whether or not a component of a specific frequency band is present in the amount of fluctuation (S204). The vibration determination unit 52h determines whether or not a component of a specific frequency band is present in the amount of fluctuation, for example, by comparing the number of times the amount of fluctuation crosses a threshold within a predetermined period with a count threshold. The vibration determination unit 52h compares the number of times counted by the counter 52g with the count threshold.

[0065] If the vibration determination unit 52h determines that the number of counts by the counter 52g is smaller than the count threshold, it determines that the amount of fluctuation does not include a specific frequency band component for a certain period of time or longer, and recognizes based on this determination result that the vibration of the vehicle 200 does not include vibration of a specific frequency (No in S205). In this case, the vibration determination unit 52h sends an instruction to the correction amount calculation unit 52b to calculate a correction amount.

[0066] The correction amount calculation unit 52b calculates a correction amount C for the display position of the virtual image Iv based on the amount of deviation (S206). Specifically, the correction amount calculation unit 52b converts the amount of deviation of the vehicle 200 into the number of pixels and determines the correction amount C that cancels out the amount of deviation expressed by the number of pixels.

[0067] In this embodiment, the correction amount C is defined as "correction amount C = - (current deviation amount) + (deviation amount at zero reset)." Hereinafter, the deviation amount at zero reset is also referred to as a deviation offset value. An initial value of the deviation offset value is zero, for example. The deviation offset value is a deviation amount detected in a reference posture state of the moving object. In calculating the correction amount in step S206, the deviation amount calculation unit 52a may calculate "-current posture (angle) + deviation offset value (angle)" in angle units and output the result to the correction amount calculation unit 52b, and the correction amount calculation unit 52b may convert the input value into the number of pixels. Alternatively, the deviation amount calculation unit 52a may output the current posture (angle) to the correction amount calculation unit 52b, and the correction amount calculation unit 52b may convert the posture (angle) into the number of pixels and then calculate "-current deviation amount (number of pixels) + deviation offset value (number of pixels)."

[0068] The correction control unit 52 outputs the correction amount C calculated by the correction amount calculation unit 52b to the display processing device 30 (S207). As a result, the display processing device 30 causes the projection device 10 to display the virtual image Iv based on the reference position P0 and the correction amount C, and the virtual image Iv is displayed at the position indicated by "reference position P0+correction amount C."

[0069] In step S205, if the vibration determination unit 52h determines that the number of times counted by the counter 52g is equal to or greater than the count threshold, it recognizes that the amount of fluctuation includes vibration of a specific frequency (Yes in S205). In this case, a signal indicating that the amount of fluctuation includes vibration of a specific frequency is sent to the correction amount adjustment unit 52d.

[0070] When the correction amount adjustment unit 52d receives a signal from the vibration determination unit 52h indicating that the amount of variation includes vibration of a specific frequency, the correction amount adjustment unit 52d sets the correction amount C to zero (S209). Specifically, for example, the deviation amount calculation unit 52a sets the deviation offset value (angle) to "deviation offset value (angle) = attitude (angle)". As a result, the deviation amount calculation unit 52a outputs an angle indicated by "- attitude (angle) + deviation offset value (angle)", i.e., 0 degrees, to the correction amount calculation unit 52b. Alternatively, the correction amount calculation unit 52b converts the amount of attitude change (angle) calculated by the deviation amount calculation unit 52a into the number of pixels (number of deviation pixels) and sets the deviation offset value (number of pixels) to "deviation offset value (number of pixels) = number of deviation pixels". As a result, the correction amount C calculated by "- deviation amount (number of pixels) + deviation offset value (number of pixels)" becomes zero. The correction control unit 52 outputs the correction amount C that the correction amount calculation unit 52b has set to zero to the display processing device 30 (S207). Fig. 8A is an explanatory diagram illustrating an example of resetting the correction amount C to zero. For example, when it is determined that the amount of variation includes a component in a specific frequency band, the correction amount C is immediately reset to zero and the display position is returned to the reference position P0.

[0071] The correction control unit 52 determines whether to continue the correction process (S208). For example, when the engine of the vehicle 200 is stopped or when a button for instructing to end the display of the virtual image Iv is operated, the correction control unit 52 ends the correction process. If the correction process is to be continued, the process returns to step S201.

[0072] As described above, in this embodiment, when a component of a specific frequency band occurs in the amount of variation, the correction amount C is set to zero by setting "deviation offset value = deviation amount." In other words, when a component of a specific frequency band occurs in the amount of variation, the display position is reset to the reference position P0.

[0073] 4. Effects and Supplements The vibration detection system 60 of the present disclosure includes an attitude detection device 40 that detects the amount of attitude change of the vehicle 200, a threshold crossing detection unit 52f that detects when the amount of change calculated based on the amount of attitude change crosses a predetermined threshold, a counter 52g that measures the number of times the amount of change crosses the threshold per unit time, and a vibration determination unit 52h that determines whether or not a specific frequency band component is included in the attitude change of the vehicle 200 for a certain period of time or more based on the number of times measured by the counter 52g.

[0074] Because the frequency band and amplitude of vibrations generated in vehicle 200 vary depending on road conditions, for example, when determining whether vibrations having specific frequency band components are occurring for a certain period of time or longer using filtering such as a high-pass filter, low-pass filter, or band-pass filter, the amplitude of the vibration must be included in the determination criteria. However, it is difficult to predict the amplitude of the vibration, and it is also difficult to set an optimal threshold for the filtering. In contrast, according to the present disclosure, the high-frequency band components contained in the fluctuation amount are detected using the counter value, so the amplitude of the vibration does not need to be included in the determination criteria, and the high-frequency band components can be detected with high accuracy.

[0075] The display system 100 of the present disclosure also includes a display processing device 30 that controls the display of a virtual image, an attitude detection device 40 that detects an amount of attitude change of the vehicle 200, and a correction processing device 50 having a vibration detection unit 52c that determines whether an attitude change of the vehicle 200 having a specific frequency band component has occurred continuously for a certain period of time or more based on the amount of attitude change of the vehicle 200. When the vibration detection unit 52c determines that an attitude change of the vehicle 200 having a specific frequency band component has not occurred continuously for a certain period of time or more, the correction processing device 50 updates a correction amount C for the display position of the virtual image Iv based on the amount of attitude change. When the vibration detection unit 52c determines that an attitude change of the vehicle 200 having a specific frequency band component has occurred continuously for a certain period of time or more, the correction processing device 50 sets the sign of the correction amount C to the same as the sign of the correction amount C determined previously and sets the absolute value of the correction amount C to be equal to or less than the absolute value of the correction amount C determined previously. The vibration detection unit 52c also has a threshold crossing detection unit 52f that detects whether the posture change amount or a fluctuation amount calculated based on the posture change amount has crossed a predetermined threshold, a counter 52g that measures the number of times the posture change amount or the fluctuation amount has crossed the threshold per unit time, and a vibration determination unit 52h that determines that a posture change of the vehicle 200 having a specific frequency band component has been occurring continuously for a certain period of time or more when the number of times measured by the counter 52g is equal to or greater than the count threshold. The display processing device 30 controls the display position of the virtual image based on the correction amount C.

[0076] This suppresses the expansion of display misalignment caused by a change in the vehicle's posture that has a specific frequency band component, thereby enabling the virtual image Iv to be displayed appropriately. When the vehicle's posture changes for a certain period of time or longer, the vibration correction amount corresponding to the change in the vehicle's posture is adjusted. This suppresses discomfort and erroneous recognition felt by the occupant D due to the vibration of high-frequency components being increased by the correction. FIG. 8B is an explanatory diagram showing the effect of correction by detecting a specific frequency in frequency characteristics. In FIG. 8B, the solid line graph shows the amount of correction error of the display misalignment when the amount of correction is adjusted based on the detection of vibration in a specific frequency band, while the dashed line graph shows the amount of correction error of the display misalignment when the amount of correction is not adjusted based on the detection of vibration in the specific frequency band. In FIG. 8B, the horizontal axis is a logarithmic scale. As shown in FIG. 8B, for example, the error correction amplitude of the display misalignment is reduced at a specific frequency occurring near 5 Hz, which is higher than the threshold value Tf, which is the lower limit F of the frequency band in Equation (1).

[0077] FIG. 8C is an explanatory diagram showing the effect of correction by specific frequency detection on a time waveform. FIG. 8C shows a period T1 during which a specific frequency component occurs and a period T2 during which the specific frequency component is detected. The dashed line graph shows the amount of correction error for display misalignment when the amount of correction is not adjusted based on vibration detection of a specific frequency band, while the solid line graph shows the amount of correction error for display misalignment when the amount of correction is adjusted based on vibration detection of a specific frequency band. Compared to when the amount of correction is not adjusted based on vibration detection, the amount of correction error for display misalignment in period T2 is reduced when the amount of correction is adjusted based on vibration detection.

[0078] Furthermore, since the vibration detection unit 52c detects that the amount of fluctuation contains high-frequency band components based on the counter value, there is no need to include the amplitude of vibration in the judgment criteria, and it is possible to accurately detect that the amount of fluctuation contains high-frequency band components.

[0079] The correction processing device 50 also includes a correction amount calculation unit 52b that calculates the amount of correction for the display position of the virtual image based on the amount of posture change, and a correction amount adjustment unit 52d that adjusts the amount of correction. The vibration detection unit 52c includes a fluctuation amount calculation unit 52m that calculates the amount of fluctuation based on the amount of posture change, and the correction amount adjustment unit 52d adjusts the amount of correction based on the judgment result of the vibration judgment unit 52h.

[0080] Furthermore, by setting the correction amount C to zero while high-frequency vibration is occurring in the vehicle 200, display misalignment due to the vehicle vibration occurs, but the display misalignment can be prevented from increasing. That is, when the vibration (misalignment) of the virtual image Iv relative to the external scene is corrected, if there is a long delay time from calculation of the correction amount to display, the correction can prevent the display misalignment from increasing. This makes it possible to prevent the display misalignment caused by high-frequency vibration, which has a significant impact on the display quality of the virtual image, such as deterioration of visibility and increased discomfort, from increasing.

[0081] Furthermore, by providing the vibration detection unit 52c with an offset removal filter 52e whose cutoff frequency is set to be lower than a specific frequency band of the fluctuation amount, the influence of the offset error of the fluctuation amount can be suppressed, and the detection accuracy of the high frequency band components can be improved.

[0082] The display system 100 of this embodiment further includes a projection device 10 that projects light representing a virtual image. In this embodiment, the moving object is a vehicle, and the image is a virtual image displayed in front of the vehicle's windshield. This embodiment can suppress the increase in correction deviation of the display position of the virtual image due to road surface conditions.

[0083] Note that in step S209, the method for setting the correction amount C to zero is arbitrary. In this embodiment, "correction amount C = - deviation amount + offset value" is used, but the correction amount C may be "correction amount C = - deviation amount". In this case, the deviation amount itself is set to zero, thereby setting the correction amount C to zero. Specifically, when calculating the vehicle attitude based on the output of the gyro sensor 41, the integral amount of the angular velocity calculated by the deviation amount calculation unit 52a is set to zero.

[0084] In this way, the correction processing device 50 sets the correction amount C to zero, so that the virtual image Iv is maintained at a constant position. Although the position of the virtual image Iv is displaced by the amount of vehicle vibration, the display displacement is not increased by the correction, so the occupant D does not see abrupt vibrational changes due to the display position displacement of the virtual image Iv, and fatigue can be reduced. In other words, the increase in display displacement caused by high-frequency vibrations that have a significant impact on the display quality of the virtual image can be reduced, and the visual discomfort caused by the vibration of the display position can be reduced.

[0085] 6, instead of setting the correction amount C to zero, the correction amount C may be decreased by a predetermined amount so that it does not become zero. In this case, the correction processing device 50 may decrease the correction amount C by a predetermined amount (a value smaller than the correction amount C) so that the correction amount C does not become zero. Specifically, for example, the correction amount calculation unit 52b sets the "offset value = predetermined amount" in "correction amount C = - (deviation amount - offset value)". The predetermined amount may be set according to the display position of the virtual image Iv within the display area 220. The correction amount C may also be decreased in stages. Note that the number of times the correction amount C is decreased may be three or more, and the offset value may be changed depending on the number of times. This makes it possible to more effectively suppress changes in the display position of the virtual image Iv and reduce the sense of incongruity in appearance, compared to suddenly setting the correction amount C to zero.

[0086] (Second embodiment) In the first embodiment, if the amount of variation includes a component in a specific frequency band, the correction amount C is set to zero. In the second embodiment, if the amount of variation includes a component in a specific frequency band, the updating of the correction amount C is stopped. Therefore, in the second embodiment, when the vibration determination unit 52h determines that an attitude change of the vehicle 200 having a component in a specific frequency band has occurred continuously for a certain period of time or more, the correction amount adjustment unit 52d sets the sign of the correction amount to the same as the sign of the correction amount determined previously, and maintains the absolute value of the correction amount at the same value as the correction amount determined previously.

[0087] Fig. 9 is a flowchart showing the flow of correction processing in the second embodiment. Steps S201 to S207 in Fig. 9 of the second embodiment are the same as those in the first embodiment. In the second embodiment, steps S201 to S204 are performed in the same way as in the first embodiment.

[0088] In the second embodiment, when the fluctuation amount includes a component of a specific frequency band (Yes in S205), the correction amount adjustment unit 52d does not update the correction amount C with the correction amount calculated by the correction amount calculation unit 52b (S211). Therefore, as shown in FIG. 10, the sign of the correction amount C becomes the same as the sign of the correction amount determined previously, and the absolute value of the correction amount C is maintained at the same value as the correction amount determined previously. In other words, the correction amount C when it is determined that a component of a specific frequency (high frequency) band is included is maintained. When it is determined that a component of the specific frequency band is not included, the calculated correction amount C is output, and the display position of the virtual image Iv that is shifted due to vibration of the vehicle 200 is corrected. Thereafter, steps S207 and S208 are performed as in the first embodiment.

[0089] In this way, even if a component of a specific frequency band is detected in the amount of fluctuation, the display position of the virtual image Iv does not suddenly move to the reference position, thereby reducing the sense of discomfort felt by the viewer. Furthermore, when the vehicle 200 is vibrating at a specific frequency, the display position of the virtual image Iv is constant, so the amount of deviation of the display position does not change, thereby reducing fatigue felt by the viewer.

[0090] (Third embodiment) In the first embodiment, when the amount of variation includes a component in a specific frequency band, the correction amount C is set to zero. In the third embodiment, when the amount of variation includes a component in a specific frequency band, the correction amount is multiplied by a coefficient and updated, thereby making it possible to further reduce the amplitude of the correction amount C. Therefore, in the third embodiment, when the vibration determination unit 52h determines that an attitude change of the vehicle 200 having a component in a specific frequency band has occurred continuously for a certain period of time or more, the absolute value of the correction amount is set to a value smaller than the absolute value of the correction amount determined previously.

[0091] 11 is a block diagram showing the internal configuration of a display system 100A according to the third embodiment. The display system 100A according to the third embodiment has a configuration in which a coefficient multiplication unit 52k as a correction amount adjustment unit is added to the correction control unit 52 of the correction processing device 50 in the display system 100 according to the first embodiment. Other than this point and points described below, the configuration of the display system 100A according to the third embodiment is the same as that of the display system 100 according to the first embodiment.

[0092] Fig. 12 shows the correction process in the third embodiment. Steps S201 to S208 in Fig. 12 of the third embodiment are the same as steps S201 to S208 in Fig. 11 of the first embodiment. In the third embodiment, steps S201 and S202 are performed as in the first embodiment. In Fig. 12, calculation of the correction amount in step S206 is shown between calculation of the deviation amount in step S202 and calculation of the variation amount in step S203, but step S206 and steps S203 to S205 from calculation of the variation amount to determination can be performed in parallel.

[0093] In the third embodiment, if vibration of a specific frequency occurs in the variation amount (Yes in S205), the coefficient multiplication unit 52k updates the correction amount by multiplying the calculated correction amount by a coefficient. The coefficient is a number greater than 0 and less than 1, for example, 0.5. As a result, while the variation amount includes a component of the specific frequency band, the amplitude of the display position of the corrected virtual image Iv is reduced, making the vibration of the virtual image Iv less noticeable. Thereafter, steps S207 and S208 are performed as in the first embodiment. Note that the coefficient multiplication unit 52k may multiply the calculated deviation amount by a coefficient instead of multiplying the calculated correction amount by a coefficient. In this case, the correction amount calculation unit 52b calculates a correction amount corresponding to the deviation amount that has been reduced by multiplication by the coefficient.

[0094] Furthermore, if the answer to step S205 is Yes, the coefficient multiplication unit 52k may update the correction amount by multiplying the correction amount previously determined by the vibration determination unit 52h by a coefficient greater than 0 and less than 1. As a result, while the amount of variation includes components in a specific frequency band, the amplitude of the display position of the corrected virtual image Iv becomes smaller, making it possible to make the vibration of the virtual image Iv less noticeable.

[0095] Furthermore, if the determination in step S205 is Yes, the coefficient multiplication unit 52k may update the current correction amount by multiplying the absolute value of the correction amount determined previously by a coefficient greater than 0 and less than 1, while setting the sign of the correction amount to the same as that determined previously by the vibration determination unit 52h. Therefore, when the vibration determination unit 52h determines that an attitude change of the vehicle 200 having a specific frequency band component has been occurring continuously for a certain period of time or more, the correction control unit 52A sets the sign of the correction amount to the same as that determined previously, and sets the absolute value of the correction amount to a value smaller than the absolute value of the correction amount determined previously. As a result, while the amount of change includes a component of the specific frequency band, the amplitude of the display position of the corrected virtual image Iv is significantly reduced, making it possible to make the vibration of the virtual image Iv less noticeable.

[0096] (Fourth embodiment) In the first embodiment, vibrations of a specific frequency of the vehicle 200 are detected and the amount of variation is corrected in accordance with this vibration, but the fourth embodiment is not limited to a moving body such as the vehicle 200, and may be a movable body that changes posture or vibrates on the spot. The moving body also includes a movable body that can be displaced on the spot. An example of such a movable body is a digital camera that is displaced by a user's hand shake, and the vibration detection system 60 of the fourth embodiment detects vibrations of such a movable body 300.

[0097] 13 is a block diagram showing the configuration of a vibration detection system 60 in the fourth embodiment. A movable body 300 is equipped with the vibration detection system 60. The vibration detection system 60 is equipped with an attitude detection device 40 and a vibration detection unit 52c. The configurations of the attitude detection device 40 and the vibration detection unit 52c are the same as those in the first embodiment, so a description thereof will be omitted. Note that the movable body 300 may be, for example, an imaging unit, such as a digital camera or an in-vehicle camera.

[0098] According to the vibration detection system 60 of the fourth embodiment, vibrations of the movable body 300 in a specific frequency band can be detected with high accuracy, and therefore can be used for vibration correction.

[0099] (Other embodiments) As described above, the above embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which appropriate modifications, substitutions, additions, omissions, etc. are made. Therefore, other embodiments will be described below as examples.

[0100] In the above embodiment, the vibration detection unit 52c includes the offset removal filter 52e, but this may be omitted. In this case, the threshold crossing detection unit 52f detects whether the vibration of the fluctuation amount crosses the threshold when the fluctuation amount contains an offset component and a high-frequency component. In this case, as shown in FIG. 14(a), setting the threshold value TA as the offset value makes it possible to detect whether the fluctuation amount contains a vibration of a specific frequency. Furthermore, by using two threshold values, the positive and negative signs of the offset error can be taken into consideration even if the offset removal filter 52e is omitted. For example, as shown in FIGS. 14(a) and 14(b), by using a threshold value TA having a positive sign and a threshold value TB having a negative sign, it is possible to detect whether the fluctuation amount crosses the respective threshold values ​​TA and TB, even if a positive or negative offset error occurs in the posture fluctuation amount, and thus it is possible to detect whether the fluctuation amount contains a component of a specific frequency band.

[0101] In the above embodiment, the correction control unit 52 includes the deviation amount calculation unit 52a, and the angular velocity information output by the attitude detection device 40 is integrated into angle information. However, this is not limited to this. As shown in FIG. 15, the attitude detection device 40 may include the deviation amount calculation unit 52a, and angle information may be transmitted from the attitude detection device 40 to the correction processing device 50. Furthermore, if the vibration detection unit 52c detects vibrations in a specific frequency band while using the amounts of attitude change, such as the pitch angular velocity, roll angular velocity, and yaw angular velocity, detected by the gyro sensor 41 as the amount of variation, the variation amount calculation unit 52m may be omitted. In this case, the offset removal filter 52e and the threshold crossing detection unit 52f perform their respective processes using the angular velocity information, which is the amount of attitude change, as the amount of variation.

[0102] Furthermore, when the gyro sensor 41 of the attitude detection device 40 directly detects the pitch angle, roll angle, and yaw angle, the amount of attitude change detected by the gyro sensor 41 may be directly treated as the amount of fluctuation and the amount of deviation by the correction control unit 52. In this case, the fluctuation amount calculation unit 52m and the deviation amount calculation unit 52a can be omitted.

[0103] In the above embodiment, one count threshold is used, but two count thresholds may be set. Multiple count thresholds can be used to deal with cases where there is an offset in the amount of deviation.

[0104] In the above embodiment, the projection device 10, the information acquisition device 20, the display processing device 30, the orientation detection device 40, and the correction processing device 50 are each separate devices. However, multiple devices may be integrated into a single device. For example, the display processing device 30 and the correction processing device 50 may be integrated into a single device. The information acquisition device 20 and the display processing device 30 may be integrated into a single device. The orientation detection device 40 and the correction processing device 50 may be integrated into a single device. The separately formed devices are connected to each other via wire or wireless communication. Note that the projection device 10, the information acquisition device 20, the display processing device 30, the orientation detection device 40, and the correction processing device 50 may all be formed into a single device. In this case, the communication units 31 and 51 may be omitted.

[0105] In the above embodiment, an example has been described in which the information acquisition device 20 includes the GPS module 21. However, the information acquisition device 20 may also include a distance sensor that measures the distance and direction from the vehicle 200 to surrounding objects and may output distance information indicating the measured distance and direction to the display processing device 30. The information acquisition device 20 may also include a vehicle speed sensor that detects the speed of the vehicle 200 or a navigation system. The information acquisition device 20 may also include one or more of the GPS module 21, a distance sensor, a camera, an image processing device, an acceleration sensor, a radar, a sonic sensor, and a white line detection device of an ADAS (Advanced Driver-Assistance Systems). In this case, the GPS module 21, the distance sensor, the camera, and the like that function as the information acquisition device 20 may be built into a single device or may be individually attached to the vehicle 200.

[0106] In the above embodiment, an example has been described in which the attitude detection device 40 includes the gyro sensor 41. The attitude detection device 40 may further include an acceleration sensor that detects the acceleration of the vehicle 200 and may further output the detected acceleration as an attitude change amount. The attitude detection device 40 may further include a vehicle height sensor that detects the height from the road surface and may further output the detected height as an attitude change amount. The attitude detection device 40 may further include other known sensors. The attitude detection device 40 may include one or more of an acceleration sensor, a vehicle speed sensor, and the like in addition to the gyro sensor 41. In this case, the gyro sensor 41, the acceleration sensor, the vehicle height sensor, and the like that function as the attitude detection device 40 may be built into a single device or may be separately attached to the vehicle 200.

[0107] In the above embodiment, the mobile object is described as a vehicle 200 such as an automobile, or as a movable object such as a digital camera. However, the mobile object is not limited to the vehicle 200. The mobile object may be a vehicle that travels on the ground, such as a train or a motorcycle.

[0108] In the above embodiment, the image is displayed in front of the moving object. However, the position where the image is displayed is not limited to the front. For example, the image may be displayed to the side or rear of the moving object.

[0109] In the above embodiment, an example has been described in which the display system 100 is a HUD system. However, the display system 100 does not have to be a HUD system. The display system 100 may include a liquid crystal display or an organic EL display instead of the projection device 10. The display system 100 may include a screen and a projector.

[0110] (Outline of the embodiment) (1) The display system disclosed herein includes a display processing device that controls the display of an image, a posture detection device that detects a posture change amount of a moving object, and a correction processing device that has a vibration detection unit that determines whether a posture change of the moving object having a specific frequency band component has occurred continuously for a certain period of time or more based on the posture change amount. When the vibration detection unit determines that a posture change of the moving object having the specific frequency band component has not occurred continuously for a certain period of time or more, the correction processing device updates a correction amount for the display position of the image based on the posture change amount. When the vibration detection unit determines that a posture change of the moving object having the specific frequency band component has occurred continuously for a certain period of time or more, the correction processing device sets the absolute value of the correction amount to be equal to or less than the absolute value of the correction amount determined previously. The vibration detection unit includes a threshold crossing detection unit that detects when the posture change amount or a fluctuation amount calculated based on the posture change amount crosses a predetermined threshold, a counter that measures the number of times the posture change amount or the fluctuation amount crosses the threshold per unit time, and a vibration determination unit that determines that a posture change of the moving object having the specific frequency band component has occurred continuously for a certain period of time or more when the number of times measured by the counter is equal to or greater than the count threshold. The display processing device controls the display position of the image based on the correction amount.

[0111] This makes it possible to suppress the expansion of display misalignment caused by a change in the posture of a moving object having a specific frequency band component, and to display the image appropriately. When a change in posture of a moving object continues for a certain period of time or more, the absolute value of the correction amount is set to be equal to or less than the absolute value of the correction amount determined previously, thereby suppressing the increase in the vibration of high-frequency components due to correction in relation to the vibration of the correction amount corresponding to the change in posture of the moving object, and suppressing discomfort and false recognition felt by the viewer of the image.

[0112] (2) In the display system of (1), the correction processing device includes a correction amount calculation unit that calculates a correction amount for the display position of the image based on the amount of posture change, and a correction amount adjustment unit that adjusts the correction amount, the vibration detection unit includes a fluctuation amount calculation unit that calculates a fluctuation amount based on the amount of posture change, and the correction amount adjustment unit adjusts the correction amount based on the judgment result of the vibration judgment unit.

[0113] (3) In the display system of (2), the vibration detection unit includes an offset removal filter that removes low-frequency components of the posture change or fluctuation amount that are lower than a specific frequency band.

[0114] (4) In the display system of (2) or (3), the correction amount adjustment unit sets the correction amount to zero when the vibration determination unit determines that a change in the posture of the moving body having a specific frequency band component has continued for a certain period of time or more.

[0115] (5) In the display system of (2) or (3), the correction amount adjustment unit stops updating the correction amount when the vibration determination unit determines that a change in the posture of the moving body having a specific frequency band component has continued for a certain period of time or more.

[0116] (6) In the display system of (2) or (3), when the vibration determination unit determines that a change in the posture of the moving body having a specific frequency band component has occurred continuously for a certain period of time or more, the correction amount adjustment unit multiplies the correction amount by a coefficient greater than 0 and less than 1.

[0117] (7) In any of the display systems (1) to (6), the threshold crossing detector detects when the input value changes from below the threshold to above the threshold, or from above the threshold to below the threshold.

[0118] (8) In any of the display systems (1) to (7), the threshold value is zero or a specific value indicating the offset value of the attitude detection device.

[0119] (9) In any of the display systems (1) to (8), the specific frequency band components are components in a high frequency band higher than a predetermined frequency.

[0120] (10) In the display system of any one of (1) to (8), the specific frequency band component is a high-frequency band component higher than a frequency F that satisfies the following relational expression: F=1 / (2×T) Here, T is the total delay time from calculation of the image correction amount to display.

[0121] (11) In any of the display systems (1) to (8), the specific frequency band components are components in a high frequency band higher than 2.5 Hz.

[0122] (12) The display system according to any one of (1) to (11), further comprising a projection device for projecting light representing an image.

[0123] (13) In any of the display systems (1) to (12), the moving object is a vehicle, and the image is a virtual image displayed in front of the vehicle's windshield.

[0124] (14) The vibration detection system disclosed herein includes an attitude detection device that detects an attitude change amount of a moving body, a threshold crossing detection unit that detects whether the attitude change amount or a fluctuation amount calculated based on the attitude change amount has crossed a predetermined threshold, a counter that measures the number of times the attitude change amount or the fluctuation amount has crossed the threshold in a unit time, and a vibration determination unit that determines that an attitude change of the moving body having a specific frequency band component has occurred continuously for a certain period of time or more when the number of times measured by the counter is equal to or greater than the count threshold.

[0125] As a result, the correction amount corresponding to the posture change amount is adjusted while vibrations having specific frequency band components in the posture change amount or fluctuation amount occur for a certain period of time or more, thereby suppressing the expansion of correction errors caused by vibrations having specific frequency band components.

[0126] (15) The vibration detection system of (14) further includes a fluctuation amount calculation unit that calculates a fluctuation amount based on the posture change amount.

[0127] (16) In the vibration detection system of (14), the specific frequency band component is a component in a high frequency band higher than a predetermined frequency.

[0128] The display system described in the present disclosure is realized by hardware resources, such as a processor, a memory, and cooperation with a program. [Industrial Applicability]

[0129] The present disclosure is applicable to a display system that displays a virtual image in front of a windshield. [Explanation of symbols]

[0130] 10 Projection device 20 Information acquisition device 21 GPS module 30 Display processing device 31, 51 Communications Department 32 Display control unit 33 Storage section 33i Images 40 Attitude detection device 41 Gyro sensor 50 Correction processing device 52 Correction control section 52a Deviation amount calculation unit 52b Correction amount calculation section 52c Vibration detection unit 52d Correction amount adjustment section 52e Offset Removal Filter 52f Threshold crossing detection unit 52g counter 52h Vibration judgment section 52k coefficient multiplier 60 Vibration Detection System 100 Display System 200 vehicles 210 Windshield 220 display area IV Virtual Image lc display light P0 reference position P1 corresponding position

Claims

1. a display processing device for controlling the display of the image; an attitude detection device for detecting an amount of attitude change of a moving object; a correction processing device having a vibration detection unit that determines whether a posture change of the moving body having a specific frequency band component has occurred continuously for a certain period of time or more based on the posture change amount, the correction processing device updates the correction amount of the display position of the image based on the amount of change in attitude when the vibration detection unit determines that a change in attitude of the moving body having a specific frequency band component has not occurred continuously for a certain period of time or more, and sets the absolute value of the correction amount to be equal to or less than the absolute value of the correction amount determined previously when the vibration detection unit determines that a change in attitude of the moving body having a specific frequency band component has occurred continuously for a certain period of time or more, The vibration detection unit a threshold crossing detection unit that detects whether the posture change amount or a fluctuation amount calculated based on the posture change amount crosses a predetermined threshold; a counter that measures the number of times the posture change amount or the fluctuation amount crosses the threshold value within a unit time; a vibration determination unit that determines that a posture change of the moving body having the specific frequency band component has occurred continuously for a certain period of time or more when the number of times measured by the counter is equal to or greater than a count threshold value, the display processing device controls the display position of the image based on the correction amount. Display system.

2. The correction processing device includes: a correction amount calculation unit that calculates a correction amount for the display position of the image based on the posture change amount; a correction amount adjustment unit that adjusts the correction amount; Equipped with the vibration detection unit includes a fluctuation amount calculation unit that calculates the fluctuation amount based on the posture change amount, the correction amount adjustment unit adjusts the correction amount based on the determination result of the vibration determination unit. The display system of claim 1 .

3. the vibration detection unit includes an offset removal filter set to a cutoff frequency lower than the specific frequency band of the posture change amount or the fluctuation amount, The display system of claim 2 .

4. the correction amount adjustment unit sets the correction amount to zero when the vibration determination unit determines that a change in the posture of the moving body having a specific frequency band component has occurred continuously for a certain period of time or more.

4. A display system according to claim 2 or 3.

5. the correction amount adjustment unit stops updating the correction amount when the vibration determination unit determines that a change in the posture of the moving body having a specific frequency band component has occurred continuously for a certain period of time or more.

4. A display system according to claim 2 or 3.

6. the correction amount adjustment unit multiplies the correction amount by a coefficient greater than 0 and less than 1 when the vibration determination unit determines that a posture change of the moving body having a specific frequency band component has occurred continuously for a certain period of time or more.

4. A display system according to claim 2 or 3.

7. the threshold crossing detector detects a change in the input value from less than the threshold to greater than or equal to the threshold, or from greater than or equal to the threshold to less than the threshold; A display system according to any one of claims 1 to 6.

8. the threshold value is zero or a specific value indicating an offset value of the attitude detection device; A display system according to any one of claims 1 to 7.

9. The specific frequency band component is a component in a high frequency band higher than a predetermined frequency. A display system according to any one of claims 1 to 8.

10. The specific frequency band component is a high-frequency band component higher than a frequency F that satisfies the following relational expression: F = 1 / (2 x T) where: T is the total delay time from the calculation of the image correction amount to the display. A display system according to any one of claims 1 to 8.

11. The specific frequency band components are components in a high frequency band higher than 2.5 Hz. A display system according to any one of claims 1 to 8.

12. further comprising a projection device for projecting light representing the image; A display system according to any one of claims 1 to 11.

13. the moving body is a vehicle, The image is a virtual image displayed in front of the vehicle's windshield. A display system according to any one of claims 1 to 12.

Images