JP2020104847A - Display device, control method, program, and storage medium - Google Patents

Abstract

To provide a display device capable of suitably suppressing deterioration of visibility due to vibration.SOLUTION: A head-up display 2 includes a light source part 4 and a combiner 9. A control part of the light source part 4 displays on the combiner 9 a guide image indicating a letter or a graphic so that the guide image appears to overlap scenery visible from a vehicle Ve. On the basis of a detection signal received from a vibration sensor and traveling speed of the vehicle, the control part obtains a smoothness determination index that is information on degree of smoothness of a road surface on which the vehicle is traveling. The control part then changes size of the letter or the graphic to be displayed on the combiner 9 in accordance with the smoothness determination index.SELECTED DRAWING: Figure 3

Description

The present invention relates to a display technology that takes into account vibration of a vehicle.

Conventionally, there is a technique for reducing the influence of vehicle vibration in a head-up display. For example, Patent Document 1 has a front camera that captures a scene that is in the line of sight of the driver to detect vibration of the vehicle, and a driver camera that captures changes in the relative position of the driver and the vehicle. There is disclosed a head-up display that improves visibility by changing the position of information projected on a combiner based on information acquired by a driver camera.

JP, 2010-70066, A

According to Japanese Patent Laid-Open No. 2004-242242, deterioration of visibility due to vibration can be reduced, but on the other hand, a front camera and a driver camera are required, so that there is a problem that the system construction cost becomes high.

The present invention has been made to solve the above problems, and a main object of the present invention is to provide a display device capable of suitably suppressing deterioration of visibility with respect to vibration.

The invention according to claim is a display device, and a display control means for displaying a character or a graphic on the display means so as to apparently overlap the scenery visually recognized from the vehicle, and a road surface on which the vehicle is traveling. And a road surface condition acquisition unit that acquires information about the smoothness, wherein the display control unit deteriorates as the smoothness of the road surface indicated by the information about the smoothness acquired by the road condition acquisition unit deteriorates, It is characterized in that the size of the character or figure is increased.
The invention as set forth in the claims is a display device, and a display control means for displaying a character or a graphic on the display means so as to apparently overlap the scenery visually recognized from the vehicle, and vibration of the vehicle is detected. A vibration amount acquisition unit that acquires the vibration amount detected by the sensor, and the display control unit increases the size of the character or figure as the vibration amount acquired by the vibration amount acquisition unit increases. It is characterized by doing.

Further, the invention described in the claims is a control method executed by a display device, comprising a display control step of displaying a character or a graphic on the display means so as to apparently overlap the scenery visually recognized from the vehicle, A road surface condition acquisition step of acquiring information on the smoothness of a road surface on which the vehicle is traveling; and the display control step, wherein the road surface indicated by the information on the smoothness acquired by the road surface condition acquisition step. It is characterized in that the size of the character or figure is increased as the smoothness of is deteriorated.

Further, the invention described in the claims is a program executed by a computer, and a display control means for displaying a character or a graphic on the display means so as to apparently overlap the scenery visually recognized from the vehicle, and the vehicle. The computer is made to function as a road surface condition acquisition unit that acquires information about the smoothness of the road surface that is running, and the display control unit indicates the road surface indicated by the information about the smoothness acquired by the road surface condition acquisition unit. It is characterized in that the size of the character or figure is increased as the smoothness deteriorates.

1 shows a schematic configuration of a display system. 1 shows a schematic configuration of a navigation device. The schematic structure of a head-up display is shown. 1 shows a schematic configuration of a light source unit. The graph which shows the relationship between the traveling speed of a vehicle and the amount of vibrations of a vehicle is shown. 9 is a table visually showing the relationship between the judgment level and the font size and graphic size of the guide image. It is a graph which shows the time-dependent change of the smoothness determination index and the determination level of the road where the vehicle has traveled for a predetermined period. It is a flow chart which shows the display processing of the guidance image concerning the 1st example. The display example of a combiner is shown. The schematic structure of the display system which concerns on 2nd Example is shown. 6 is a graph showing a relationship between a traveling speed of a vehicle and an estimated vibration amount when traveling on a road corresponding to a predetermined smoothness determination index. It is a flow chart which shows the display processing of the guidance image concerning the 3rd example.

In a preferred embodiment of the present invention, the display device includes display control means for displaying a character or a graphic on the display means so as to apparently overlap the scenery viewed from the vehicle, and a road on which the vehicle is traveling. Road surface condition acquisition means for acquiring information on surface smoothness, wherein the display control means determines the size of the character or figure according to the information on smoothness acquired by the road surface condition acquisition means. Change.

The display device includes a display control unit and a road surface condition acquisition unit. The display control means causes the display means to display a character or a graphic so as to apparently overlap the scenery visually recognized from the vehicle. The road surface condition acquisition means acquires information regarding the smoothness of the road surface on which the vehicle is traveling. Then, the display control means changes the size of the character or figure to be displayed on the display means in accordance with the information on the smoothness acquired by the road surface condition acquisition means. By doing so, the display device can change the display size of the characters and graphics to be displayed on the display means in accordance with the road surface condition of the road surface, and allow the driver to visually recognize them suitably.

In one aspect of the display device, the display control unit increases the size of the character or figure as the smoothness of the road surface indicated by the information about the smoothness deteriorates. According to this aspect, even when the vehicle is traveling on a road surface with poor smoothness, it is possible to increase the size of the characters or figures to be displayed, and allow the driver to appropriately recognize them.

In another aspect of the display device, the display device includes a speed acquisition unit that acquires a traveling speed of the vehicle, and a vibration amount acquisition unit that acquires a magnitude of vibration of the vehicle. The means acquires information regarding the smoothness based on the traveling speed and the vibration amount. According to this aspect, the display device can appropriately estimate the smoothness of the road surface.

In another aspect of the display device, the road surface condition acquisition unit acquires the information regarding the smoothness from map data in which the information regarding the smoothness is recorded in advance in association with each road. Also according to this aspect, the display device can appropriately acquire the information about the smoothness of the road surface and appropriately determine the display size of the character or graphic to be displayed.

In another aspect of the display device, the display device includes a speed acquisition unit that acquires a traveling speed of the vehicle, and the display control unit is estimated based on the smoothness information and the traveling speed. The size of the character or figure is changed according to the estimated vibration amount. According to this aspect, the display device can appropriately estimate the vibration amount of the vehicle, and can appropriately change the size of the character or figure to be displayed according to the estimated vibration amount.

In another aspect of the display device, the road surface condition acquisition unit acquires, as the information regarding the smoothness, a vibration amount detected by a sensor that detects vibration of the vehicle, and the display control unit includes the road surface condition. The size of the character or figure is changed according to the vibration amount acquired by the acquisition means. According to this aspect, the display device can appropriately change the size of the character or figure to be displayed according to the detected vibration amount.

In another preferred embodiment of the present invention, a control method executed by the display device, comprising a display control step of displaying a character or a graphic on the display means so as to apparently overlap the scenery visually recognized from the vehicle, A road surface condition acquisition step of acquiring information on the smoothness of the road surface on which the vehicle is traveling, and the display control step, in accordance with the information on the smoothness acquired by the road surface condition acquisition step, Change the size of characters or figures. By executing this control method, the display device can change the display size of the characters and graphics to be displayed on the display means in accordance with the road surface condition of the road surface, and allow the driver to visually recognize them suitably.

In still another embodiment of the present invention, a program executed by a computer, the display control means for displaying a character or a graphic on the display means so as to apparently overlap with a landscape viewed from the vehicle, and the vehicle The computer is caused to function as a road surface condition acquisition unit that acquires information about the smoothness of the road surface that is running, and the display control unit determines the character according to the information about the smoothness acquired by the road surface condition acquisition unit. Or change the size of the figure. By executing this program, the computer can change the display size of the characters and figures to be displayed on the display means in accordance with the road surface condition of the road surface, and can appropriately make them visible to the driver. Preferably, the program is stored in a storage medium.

Hereinafter, preferred first to third embodiments of the present invention will be described with reference to the drawings.

<First embodiment>
First, the first embodiment will be described.

[Schematic configuration]
(1) System Configuration FIG. 1 shows a configuration example of a display system 100 according to the embodiment. As shown in FIG. 1, the display system 100 is mounted on a vehicle Ve and includes a navigation device 1, a head-up display 2, and a vibration sensor 3.

The navigation device 1 has a function of providing route guidance from a departure place to a destination. The navigation device 1 may be, for example, a stationary navigation device installed in the vehicle Ve, a PND (Portable Navigation Device), or a mobile phone such as a smartphone.

The head-up display 2 generates an image (also referred to as a “guidance image”) that displays map information including the current position, route guidance information, the traveling speed of the vehicle Ve, facility marks, and other guidance information for assisting driving, This is a device for visually recognizing the guide image as a virtual image from the driver's eye position (eye point). As will be described later, the head-up display 2 adjusts the size of the guide image according to the road surface condition so that the driver can visually recognize the guide image even when the vehicle Ve is vibrating.

The vibration sensor 3 detects the amount of vibration of the vehicle Ve. Then, the vibration sensor 3 supplies a detection signal Sd indicating the detected vibration amount to the head-up display 2.

When the navigation device 1 is a mobile phone such as a smartphone, the navigation device 1 may be held by a cradle or the like. In this case, the navigation device 1 may exchange information with the head-up display 2 via a cradle or the like. Further, the vibration sensor 3 may be connected to the navigation device 1 instead of the head-up display 2. In this case, when the navigation device 1 receives the detection signal Sd from the vibration sensor 3, the navigation device 1 transfers the detection signal Sd to the head-up display 2.

(2) Configuration of Navigation Device FIG. 2 shows the configuration of the navigation device 1. As shown in FIG. 2, the navigation device 1 includes an autonomous positioning device 10, a GPS receiver 18, a system controller 20, a disk drive 31, a data storage unit 36, a communication interface 37, a communication device 38, an interface 39, and a display unit 40. , Audio output unit 50, and input device 60.

The self-supporting positioning device 10 includes an acceleration sensor 11, an angular velocity sensor 12, and a distance sensor 13. The acceleration sensor 11 includes, for example, a piezoelectric element, detects the acceleration of the vehicle Ve, and outputs acceleration data. The angular velocity sensor 12 is composed of, for example, a vibration gyro, detects the angular velocity of the vehicle Ve at the time of changing the direction of the vehicle Ve, and outputs the angular velocity data and the relative azimuth data. The distance sensor 13 measures a vehicle speed pulse composed of a pulse signal generated as the wheels of the vehicle Ve rotate.

The GPS receiver 18 receives radio waves 19 carrying downlink data including positioning data from a plurality of GPS satellites. The positioning data is used to detect the absolute position (also called “current position”) of the vehicle Ve from latitude and longitude information and the like.

The system controller 20 includes an interface 21, a CPU (Central Processing Unit) 22, a ROM (Read Only Memory) 23, and a RAM (Random Access Memory) 24, and controls the entire navigation device 1.

The interface 21 performs an interface operation with the acceleration sensor 11, the angular velocity sensor 12, the distance sensor 13, and the GPS receiver 18. Then, from these, vehicle speed pulses, acceleration data, relative azimuth data, angular velocity data, GPS positioning data, absolute azimuth data, etc. are input to the system controller 20. The CPU 22 controls the entire system controller 20. The ROM 23 has a non-volatile memory (not shown) in which a control program for controlling the system controller 20 is stored. The RAM 24 readably stores various data such as route data preset by the user via the input device 60, and provides a working area to the CPU 22.

The system controller 20, a disk drive 31 such as a CD-ROM drive or a DVD-ROM drive, a data storage unit 36, a communication interface 37, a display unit 40, an audio output unit 50 and an input device 60 are mutually connected via a bus line 30. It is connected to the.

Under the control of the system controller 20, the disc drive 31 reads content data such as music data and video data from a disc 33 such as a CD or a DVD and outputs it. The disc drive 31 may be either a CD-ROM drive or a DVD-ROM drive, or may be a CD and DVD compatible drive.

The data storage unit 36 is a unit configured of, for example, an HDD, and stores various data used for navigation processing such as map data. The map data includes road data represented by links corresponding to roads and nodes corresponding to road connection parts, facility information regarding each facility, and the like.

The communication device 38 is configured by, for example, an FM tuner, a beacon receiver, a mobile terminal, a dedicated communication module, and the like, and traffic congestion and the like delivered from a VICS (registered trademark, Vehicle Information Communication System) center via the communication interface 37. Receive road traffic information such as traffic information and other information. Further, the communication device 38 heads various information used for navigation processing, such as information on a guide route, information on the current position acquired from the GPS receiver 18, information on a vehicle speed pulse acquired from the self-contained positioning device 10, and map data. Send to up display 2.

The display unit 40 displays various display data on a display device such as a display under the control of the system controller 20. Specifically, the system controller 20 reads the map data from the data storage unit 36. The display unit 40 displays the map data and the like read from the data storage unit 36 by the system controller 20 on the display screen. The display unit 40 includes a graphic controller 41 that controls the entire display unit 40 based on control data sent from the CPU 22 via the bus line 30, and a memory such as a VRAM (Video RAM) to display image information that can be immediately displayed. A buffer memory 42 for temporary storage, a display control unit 43 for controlling display of a display 44 such as a liquid crystal, a CRT (Cathode Ray Tube) based on image data output from the graphic controller 41, and a display 44. .. The display 44 functions as an image display unit, is composed of, for example, a liquid crystal display device having a diagonal of about 5 to 10 inches, and is mounted near the front panel in the vehicle.

The audio output unit 50, under the control of the system controller 20, performs D/A (Digital to Analog) conversion of audio digital data sent from the CD-ROM drive 31, the DVD-ROM 32, the RAM 24, or the like via the bus line 30. A D/A converter 51 for performing, an amplifier (AMP) 52 for amplifying a voice analog signal output from the D/A converter 51, and a speaker 53 for converting the amplified voice analog signal into voice and outputting the voice. It is equipped with.

The input device 60 includes keys, switches, buttons, a remote controller, a voice input device, etc. for inputting various commands and data. The input device 60 is arranged around the front panel and the display 44 of the main body of the vehicle-mounted electronic system mounted in the vehicle. When the display 44 is a touch panel type, a touch panel provided on the display screen of the display 44 also functions as the input device 60.

(3) Configuration of Head-up Display FIG. 3 is a schematic configuration diagram of the head-up display 2. As shown in FIG. 3, the head-up display 2 according to the present embodiment is a vehicle Ve that includes a light source unit 4 and a combiner 9, and includes a front window 25, a ceiling 27, a hood 28, a dashboard 29, and the like. It is attached.

The light source unit 4 is installed on the ceiling portion 27 in the vehicle interior through the support members 5a and 5b, and emits light forming a guide image indicating information for assisting driving toward the combiner 9 to cause the combiner 9 to exit. The driver visually recognizes the virtual image “Iv” via.

The combiner 9 projects the display image emitted from the light source unit 4 and reflects the display image to the driver's eye point “Pe” to display the display image as the virtual image Iv. The combiner 9 has the support shaft portion 8 installed on the ceiling portion 27, and rotates about the support shaft portion 8 as a spindle. The support shaft portion 8 is installed, for example, near a ceiling portion 27 near the upper end of the front window 25, in other words, near a position where a driver-not-illustrated sun visor is installed. The support shaft portion 8 may be installed in place of the sun visor described above. The combiner 9 is an example of the "display means" in the present invention.

(4) Configuration of Light Source Unit FIG. 4 is a diagram schematically showing the configuration of the light source unit 4. As shown in FIG. 4, the light source unit 3 includes a light source 54, a control unit 55, and a communication unit 56.

The light source 54 has, for example, red, blue, and green laser light sources, and emits light (also referred to as “display light”) that forms a display image to be irradiated on the combiner 9 under the control of the controller 55. ..

The communication unit 56 receives various types of information used for navigation processing from the navigation device 1 under the control of the control unit 55. For example, the communication unit 56 receives, from the navigation device 1, information necessary for generating a guide image such as guide route information, current position information, and vehicle speed information. Further, the communication unit 56 receives the detection signal Sd from the vibration sensor 3.

The control unit 55 includes a CPU, a ROM that stores control programs and data executed by the CPU, a RAM that sequentially reads and writes various data as a work memory when the CPU operates, and the like. Control.

The control unit 55 generates a guide image based on the information transmitted from the navigation device 1, and causes the light source 54 to emit the display light forming the guide image. Further, in the present embodiment, the control unit 55, based on the information on the traveling speed acquired from the navigation device 1 and the vibration amount indicated by the detection signal Sd acquired from the vibration sensor 3, drives the road on which the vehicle Ve is traveling (simply simply Recognize the road surface condition of the road. Then, the control unit 55 changes the display size of the guide image according to the recognized road surface condition of the traveling road. This will be discussed in more detail in the Adjust Display Size section.

Then, the control unit 55 functions as a computer that executes the “road surface condition acquisition unit”, the “display control unit”, the “speed acquisition unit”, the “vibration amount acquisition unit” and the program according to the present invention.

[Display size adjustment]
Next, a method of adjusting the display size of the guide image showing characters and figures will be described. Schematically, the control unit 55 calculates an index (also referred to as “smoothness determination index α”) indicating the smoothness degree of the traveling road based on the traveling speed of the vehicle Ve and the vibration amount indicated by the detection signal Sd. , The display size of the guide image is changed stepwise according to the smoothness determination index α. As a result, the control unit 55 improves the visibility of the guide image on a road with large unevenness and improves the visibility of the front on a smooth road. The smoothness determination index α is an example of “information regarding smoothness” in the present invention, and in this embodiment, the smoother the road surface, the lower the value.

(1) Method for calculating smoothness determination index First, a method for calculating the smoothness determination index α will be described. In the present embodiment, the control unit 55 regards the vibration amount of the vehicle Ve as being proportional to the smoothness determination index α of the traveling road and the traveling speed of the vehicle Ve. That is, the control unit 55 considers that the following expression (1) is established, where the traveling speed of the vehicle Ve is “X” and the vibration amount of the vehicle Ve is “Y”.
Y=α·X formula (1)

The relationship represented by Expression (1) will be described in more detail with reference to FIG. FIG. 5 shows graphs G1 to G3 when the traveling speed of the vehicle Ve is on the X axis and the vibration amount of the vehicle Ve is on the Y axis. Here, the graph G1 shows the relationship between the traveling speed and the vibration amount when the smoothness determination index α is “α1” which is relatively low, that is, when the paving condition of the traveling road is good. Further, the graph G3 shows the relationship between the traveling speed and the vibration amount when the smoothness determination index α is “α3” which is relatively high, that is, when the paving condition of the traveling road is poor, and the graph G2 shows the smoothness determination. The relationship between the traveling speed and the vibration amount when the index α is an intermediate value “α2” between “α1” and “α3” is shown.

As shown in FIG. 5, the vibration amount increases in proportion to the traveling speed, and the larger the smoothness determination index α, the larger the inclination of change. Therefore, the control unit 55 can calculate the smoothness determination index α corresponding to the inclination of the graph based on the traveling speed and the vibration amount.

Further, in the present embodiment, the control unit 55 controls the traveling speed in time series (also referred to as “speed average Xa”) and the detected vibration amount in time series as moving average (also referred to as “vibration average Ya”). .) and the smoothness determination index α is calculated by the following equation (2).
α=Ya/Xa Formula (2)

In the example of FIG. 5, the control unit 55 calculates the smoothness determination index α2 using the velocity average Xa and the vibration average Ya. Here, the control unit 55 calculates the speed average Xa based on the traveling speed information for the predetermined number immediately before acquired from the navigation device 1, and the vibration average Ya for the predetermined number immediately before acquired from the vibration sensor 3. It is calculated based on the detection signal Sd. The above-mentioned predetermined number is set to a compatible value based on, for example, an experiment. In this way, by calculating the smoothness determination index α using the moving average and the traveling speed and the vibration amount, the control unit 55 preferably removes the sudden noise component.

(2) Method of Determining Display Size Next, a method of determining the display size of the guide image will be described. The control unit 55 recognizes the level (also referred to as “determination level Lv”) to which the calculated smoothing determination index α belongs, and determines the display size of the guide image according to the determination level Lv. Hereinafter, it is assumed that the determination level Lv exists in four stages of Level 1 to Level 4, and the higher the smoothness determination index α, the higher the determination level Lv.

FIG. 6 is a table visually showing the relationship between the determination level Lv and the font size and graphic size of the guide image. As shown in FIG. 6, the control unit 55 increases the font size of the character indicated by the guide image and the size of the figure indicated by the guide image as the determination level Lv is higher. Actually, the control unit 55 stores in advance a digitized table showing the relationship between the determination level Lv and the font size and graphic size of the guide image as shown in FIG. That is, the control unit 55 stores in advance numerical values indicating the font size and the graphic size of the guide image corresponding to each determination level Lv.

As described above, the control unit 55 determines that the guide image is difficult to see due to the vibration of the vehicle Ve on the traveling road where the determination level Lv is high and the pavement state is determined to be poor, and the guide image is displayed. The characters and figures shown are enlarged. As a result, the control unit 55 enhances the visibility of the guide image and allows the driver to appropriately view the guide image. Further, the control unit 55 determines that the guide image is easily visible on the traveling road where the determination level Lv is low and the smoothness is high, and displays the guide image in the standard size. Accordingly, the control unit 55 can prevent the visibility from being deteriorated due to the guide image being unnecessarily large, and can appropriately secure the visibility of the driver's forward scenery.

Further, in the determination of the determination level Lv, the control unit 55 gives hysteresis to the threshold value of the smoothing determination index α for determining the determination level Lv in order to prevent the size setting of the guide image from frequently changing. This will be described with reference to FIG.

FIG. 7 is a graph showing changes over time in the smoothness determination index α and the determination level Lv of the road on which the vehicle Ve has traveled for a predetermined period. In the example of FIG. 7, the control unit 55 moves one level below the threshold (α2, α4, α6) of the smoothing determination index α for determining whether or not to increase each level of the determination level Lv. The threshold values (α1, α3, α5) of the smoothing determination index α for determining whether or not to lower the value are set low. Hereinafter, the former threshold will be referred to as the “advance threshold” and the latter threshold will also be referred to as the “advance threshold”.

Specifically, the control unit 55 sets the advance threshold for increasing the determination level Lv from Level 1 to Level 2 to "α2", and the advance threshold for decreasing the determination level Lv from Level 2 to Level 1 to less than α2. α1”. Similarly, the control unit 55 sets the advance threshold for increasing the determination level Lv from Level 2 to Level 3 to "α4", and the advance threshold for decreasing the determination level Lv from Level 3 to Level 2 to α4, which is lower than α4. The advance threshold for increasing the determination level Lv from level 3 to level 4 is "α6", and the advance threshold for decreasing the determination level Lv from level 4 to level 3 is "α5", which is lower than α6. The control unit 55 sets the threshold values α1 to α6 of the smoothness determination index α to compatible values based on experiments or the like, and stores them in a memory or the like in advance.

Then, in the example of FIG. 7, the control unit 55 sets the determination level Lv from the level 1 from the level 1 because the smoothing determination index α calculated based on the equation (2) becomes equal to or larger than the carry threshold α2 at the time “t1”. Raise to 2. After that, the control unit 55 maintains the determination level Lv at the level 2 even when the smoothing determination index α is below the carry-up threshold α2 in a range where the carry-over determination threshold α is equal to or larger than the carry-down threshold α1. Next, the control unit 55 raises the determination level Lv from level 2 to level 3 at the time “t2” because the smoothing determination index α becomes equal to or higher than the carry-up threshold α4, and at the time “t3”, the smoothing determination index α. Since α becomes equal to or higher than the carry-up threshold value α6, the determination level Lv is raised from level 3 to level 4.

After that, at time “t4”, the control unit 55 lowers the determination level Lv from the level 4 to the level 3 because the smoothing determination index α is below the lowering threshold α5. Similarly, at time “t5”, the control unit 55 lowers the determination level Lv from Level 3 to Level 2 because the smoothing determination index α is below the lowering threshold α3.

As described above, in the example of FIG. 7, the control unit 55 lowers the carry-down threshold value for determining whether to lower the level from the relevant level to one level lower than the carry-up threshold value for determining whether to increase to each level of the determination level Lv. By setting, even if the smoothing determination index α fluctuates up and down, it is possible to preferably prevent the determination level Lv from frequently switching.

(3) Process Flow FIG. 8 is a flowchart showing the guide image display process according to the first embodiment. The control unit 55 repeatedly executes the processing of the flowchart shown in FIG. 8 according to a predetermined cycle.

First, the control unit 55 acquires the detection signal Sd indicating the vibration amount detected from the vibration sensor 3 (step S101). Next, the control unit 55 acquires information on the traveling speed of the vehicle Ve measured by the distance sensor 13 and the like from the navigation device 1 (step S102). Then, the control unit 55 calculates a speed average Xa that is a moving average of traveling speeds of a predetermined number in the past and a vibration average Ya that is a moving average of vibration amounts indicated by the detection signal Sd of the past predetermined number (step). S103).

Next, the control unit 55 calculates the smoothness determination index α by referring to the equation (2) based on the calculated velocity average Xa and vibration average Ya (step S104). Next, the control unit 55 refers to the thresholds α1 to α6 described in FIG. 7 and determines the determination level Lv from the smoothing determination index α (step S105). Then, the control unit 55 determines the display size of each guide image based on the information indicating the correspondence between the determination level Lv and the display size of the guide image as shown in FIG. 6, and displays each guide image on the combiner 9. It is displayed (step S106).

(4) Display Example Next, a display example according to the first embodiment will be described with reference to FIG.

FIG. 9A shows a front view visually recognized by the driver via the combiner 9 during traveling on a road having high smoothness. In the example of FIG. 9(A), the control unit 55 uses, as guide images, an arrow image 81 indicating a traveling direction at a guide point to turn right next, a distance display image 82 indicating a distance to the guide point, and a current guide image. The speed display image 83 showing the traveling speed of the vehicle Ve is displayed on the combiner 9.

In FIG. 9A, the control unit 55 determines that the smoothing determination index α calculated by referring to the equation (2) based on the velocity average Xa and the vibration average Ya is lower than the carry-up threshold α2 described in FIG. 7. , The determination level Lv is set to level 1. Therefore, in this case, the control unit 55 displays the guide images 81 to 83 in the standard size.

FIG. 9B shows a front view visually recognized by the driver via the combiner 9 when the vehicle is traveling on a road with a poor pavement condition. In the example of FIG. 9B, the smoothing determination index α calculated by the control unit 55 based on the velocity average Xa and the vibration average Ya by referring to the equation (2) is equal to or greater than the carry threshold α4 described in FIG. 7. Then, the determination level Lv is set to level 3. Therefore, in this case, the control unit 55 enlarges the arrow image 81 by a predetermined rate over the standard size and enlarges the distance display image 82 by a predetermined rate over the standard font size. By doing so, even when the paving condition is poor, the arrow image 81 and the distance display image 82 can be suitably viewed by the driver.

Further, in the example of FIG. 9B, the control unit 55 does not enlarge the font size of the speed display image 83 indicating the information of relatively low importance. As described above, it is preferable that the control unit 55 appropriately magnify and display only the guide image with high priority to be visually recognized by the driver, and do not magnify and display the guide image with low priority to be visually recognized. As a result, the control unit 55 can appropriately secure the field of view of the driver's forward scenery. In this case, for example, the control unit 55 creates a table indicating the type of guide image whose display size is changed according to the determined determination level Lv and the type of guide image whose display size is fixed regardless of the determination level Lv. It is stored in advance and the display size of each guide image is determined by referring to the table.

As described above, the head-up display 2 according to this embodiment includes the light source unit 4 and the combiner 9. The control unit 55 of the light source unit 4 causes the combiner 9 to display a guide image showing characters or figures so as to apparently overlap the scenery visually recognized from the vehicle Ve. The control unit 55 acquires the smoothness determination index α, which is information regarding the smoothness of the road surface on which the vehicle Ve is traveling, based on the detection signal Sd received from the vibration sensor 3 and the traveling speed of the vehicle Ve. Then, the control unit 55 changes the size of the character or figure displayed on the combiner 9 according to the smoothness determination index α. By doing so, the head-up display 2 can change the display size of the characters and graphics according to the road surface condition of the road surface, and allow the driver to visually recognize them suitably.

<Second embodiment>
FIG. 10 shows a schematic configuration of the display system 100 according to the second embodiment. In the second embodiment, the control unit 55 uses the map data of the data storage unit 36 in advance instead of calculating the smoothness determination index α by referring to the equation (2) based on the detection signal Sd received from the vibration sensor 3 and the like. This is different from the first embodiment in that the smoothness determination index α is acquired by referring to the stored smoothness determination index α for each road. Other parts that are the same as those in the first embodiment are given the same reference numerals as appropriate, and description thereof is omitted.

In the second embodiment, the data storage unit 36 stores, as map data, the smoothing determination index α for each link data corresponding to each road in advance. Then, the control unit 55 recognizes the traveling road by acquiring the current position measured by the GPS receiver 18 or the like from the navigation device 1, and the smoothness determination index α associated with the link data corresponding to the recognized traveling road. From the map data stored in the data storage unit 36. After that, the control unit 55 determines the determination level Lv and changes the display size of the guide image according to the determination level Lv, as in the first embodiment.

In the display system 100 according to the second example, it is not necessary to acquire the detection signal Sd from the vibration sensor 3 and it is not necessary to acquire the information on the traveling speed of the vehicle Ve from the navigation device 1, so the control unit 55 The display size of the guide image can be determined more easily.

Note that the map data is stored in an external server (not shown), and the head-up display 2 may acquire the map information indicating the vicinity of the current position of the vehicle Ve and the smoothness determination index α via the network. ..

<Third embodiment>
In the third embodiment, in addition to the second embodiment, the control unit 55 uses the smoothing determination index α acquired from the map data and the traveling speed of the vehicle Ve to estimate the vibration amount of the vehicle Ve (“estimated vibration”). (Also referred to as the amount Ye”), and the determination level Lv is determined according to the estimated vibration amount Ye.

Specifically, the control unit 55 uses the smoothness determination index α corresponding to the traveling road acquired from the map data and the speed average Xa calculated in the same manner as in the first embodiment, according to the following formula (3), The estimated vibration amount Ye is calculated.
Ye=α·Xa Formula (3)

Then, the control unit 55 determines the determination level Lv based on the calculated estimated vibration amount Ye. FIG. 11 is a graph showing the relationship between the average speed Xa and the estimated vibration amount Ye when the smoothness determination index α is fixed. In the example of FIG. 11, similarly to the example of FIG. 7, the estimated vibration amount Ye for determining whether to increase to each level of the determination level Lv is one level lower than the carry-up threshold value (Ye2, Ye4, Ye6). The lowering thresholds (Ye1, Ye3, Ye5) of the estimated vibration amount Ye for determining whether or not to lower the level are set low. By doing so, the control unit 55 preferably suppresses frequent switching of the determination level Lv even when the estimated vibration amount Ye calculated based on the equation (3) frequently fluctuates up and down.

FIG. 12 is a flowchart showing a guide image display process according to the third embodiment. The control unit 55 repeatedly executes the processing of the flowchart shown in FIG. 12 according to a predetermined cycle.

First, the control unit 55 acquires the current position measured by the GPS receiver 18 or the like from the navigation device 1, thereby acquiring the link data corresponding to the traveling road from the map data (step S201). Then, the control unit 55 determines whether or not the acquired link data is stored in association with the smoothness determination index α (step S202).

When the acquired link data is stored in association with the smoothness determination index α (step S202; Yes), the control unit 55 acquires the smoothness determination index α (step S203). After that, the control unit 55 calculates the velocity average Xa (step S204) as in the first embodiment and the like, and calculates the estimated vibration amount Ye based on the equation (3) (step S205).

After that, the control unit 55 determines the determination level Lv according to the estimated vibration amount Ye (step S206). Specifically, the control unit 55 determines the determination level Lv based on the estimated vibration amount Ye calculated in step S204 and the threshold value (Ye1 to Ye6 in the example of FIG. 7) for determining the determination level Lv. .. Then, the control unit 55 displays the guide image in a size according to the determined determination level Lv (step S207). In this case, as described in the display example shown in FIG. 9 of the first embodiment, the control unit 55 may change the display size only for some guide images.

On the other hand, in step S202, when the control unit 55 determines that the corresponding link data is not stored in association with the smoothing determination index α (step S202; No), the control unit 55 uses the standard size, that is, the determination level Lv. The guide image is displayed with the same display size as when the level is level 1 (step S208).

As described above, according to the third embodiment, the display system 100 can display the guide image with an appropriate display size according to the vibration without using the vibration sensor.

[Modification]
Hereinafter, modified examples suitable for the above embodiment will be described. The following modifications may be applied to the above-described embodiment in any combination.

(Modification 1)
In the first embodiment, the control unit 55 may determine the determination level Lv based on the vibration amount acquired from the vibration sensor 3 as in the third embodiment. In this case, the control unit 55 determines a vibration amount carry-up threshold value for determining whether or not the level is increased to each level of the determination level Lv, and a vibration amount carry-down threshold value for determining whether or not the level is lowered by one level. And are stored in advance. Then, in the flowchart of FIG. 8, the control unit 55 obtains the vibration amount from the vibration sensor 3 in step S101 and then executes the above-described vibration amount in step S105 without executing steps S102 to S104. The determination level Lv is determined using the threshold value. According to this aspect as well, the control unit 55 can allow the driver to appropriately view the guide image regardless of the vibration amount of the vehicle Ve.

(Modification 2)
In the second embodiment, the data storage unit 36 stores the determination level Lv in association with each road instead of or in addition to storing the smoothness determination index α as map data for each road. Good. In this case, the control unit 55 determines the display size of the guide image by acquiring the determination level Lv corresponding to the traveling road from the data storage unit 36. Also according to this aspect, the control unit 55 can allow the driver to visually recognize the guide image regardless of the pavement state of the traveling road.

(Modification 3)
In the third embodiment, the control unit 55 may make the raising threshold and the lowering threshold of the estimated vibration amount Ye different for each road.

For example, in this case, the data storage unit 36 stores, for each link data, the above-described threshold value information for determining the determination level Lv in addition to the smoothing determination index α. Then, when executing the flowchart of FIG. 12, the control unit 55 acquires the above-described threshold value together with the smoothing determination index α from the link data in step S202, and performs the determination processing of the determination level Lv in step S205.

In another example, the data storage unit 36 stores the above-mentioned threshold value information for determining the determination level Lv for each road type such as a general road and a toll road. Then, when executing the flowchart of FIG. 12, the control unit 55 further recognizes the type of the traveling road in step S205, and determines the determination level Lv by referring to the threshold of the determination level Lv corresponding to the recognized road type. To do.

In the above example, the number of levels of the determination level Lv may be different for each road. For example, the judgment level Lv may be two levels on a general road, and the judgment level Lv may be five levels on an expressway.

Similarly, also in the first and second embodiments, the control unit 55 may change the carry-up threshold value and the carry-back threshold value of the smoothness determination index α for each road.

(Modification 4)
In the first embodiment, the control unit 55 sets the determination level Lv to level 1 without calculating the smoothness determination index α when the speed average Xa is equal to or less than a predetermined value (for example, 5 km/h). Good. Accordingly, the control unit 55 can prevent the smoothness determination index α from being unable to be calculated due to the denominator of Expression (2) becoming 0.

(Modification 5)
In the first embodiment, the control unit 55 calculates the smoothness determination index α based on the equation (2), but the method of calculating the smoothness determination index α to which the present invention is applicable is not limited to this. Instead of this, for example, the control unit 55 uses a more sophisticated formula or map defined based on experiments or the like to calculate the smoothness determination index α that is more accurate according to the actual road surface condition, and then performs the smoothness determination. The index α may be calculated.

(Modification 6)
In the first and second embodiments, the control unit 55 changes the display size of the guide image stepwise based on the determination level Lv. Instead of this, the control unit 55 may continuously change the display size of the guide image according to the smoothness determination index α. That is, the control unit 55 may continuously increase the display size of the guide image as the smoothness determination index α increases. Similarly, in the third embodiment, the control unit 55 continuously changes the display size according to the estimated vibration amount Ye, instead of changing the display size of the guide image stepwise based on the determination level Lv. You may.

(Modification 7)
In FIG. 3, the head-up display 2 has the combiner 9 and makes the driver visually recognize the virtual image Iv based on the emitted light of the light source unit 4 reflected by the combiner 9. However, the configuration to which the present invention is applicable is not limited to this. Alternatively, the head-up display 2 may not have the combiner 9, and the driver may visually recognize the virtual image Iv based on the emitted light of the light source unit 4 reflected by the windshield 25. In this case, the windshield 25 is an example of the “display device” in the present invention.

Further, the position of the light source unit 4 is not limited to the case where it is installed on the ceiling 27. Alternatively, the light source unit 4 may be installed on the dashboard 29 or inside the dashboard 29. When installed on the dashboard 29, the combiner 9 is provided on the dashboard 29 or the windshield 25 reflects light directly from the light source unit 4 so that the driver recognizes the virtual image Iv. When installed in the dashboard 29, the dashboard 29 is provided with an opening for allowing light to pass through the combiner 9 or the windshield 25.

Further, the display system 100 may display the guide image by superposing it on the front landscape by the wearable head mounted display, instead of superimposing it on the front landscape by the head-up display 2.

(Modification 8)
The system controller 20 may execute a part of the processing of the control unit 55. For example, the system controller 20 may generate a guide image to be displayed by the head-up display 2, and the light source unit 4 of the head-up display 2 may receive the guide image. In this case, the system controller 20 determines the determination level Lv by executing the flowcharts shown in FIG. 8 and FIG. 12, and the signal for designating the display size of the guide image or the light source 54 necessary for emitting the display light. Information is transmitted to the head-up display 2. Therefore, in this modified example, the system controller 20 functions as a computer that executes the “road surface condition acquisition unit”, the “display control unit”, the “speed acquisition unit”, the “vibration amount acquisition unit” and the program according to the present invention.

Further, the head-up display 2 may have some or all of the functions of the navigation device 1. In this case, the light source unit 4 may include, for example, a memory that stores map data, sensors such as a GPS receiver, and the like.

(Modification 9)
In the display example of FIG. 9, the control unit 55 does not change the display size of the speed display image 83, but instead of this, the display sizes of all the guide images including the speed display image 83 are set according to the determination level Lv. You may change it.

1 Navigation device 2 Head-up display 4 Light source unit 9 Combiner 25 Windshield 28 Bonnet 29 Dashboard 100 Display system

Claims (1)

Display control means for displaying a character or a graphic on the display means so as to apparently overlap the scenery viewed from the vehicle,
A road surface condition acquisition means for acquiring information on the smoothness of the road surface on which the vehicle is traveling,
Equipped with
A display device, wherein the display control unit increases the size of the character or figure as the smoothness of the road surface indicated by the information about the smoothness acquired by the road surface condition acquisition unit deteriorates. ..

Images