JP6570424B2 - Electronic equipment - Google Patents

Description

  The present invention relates to an electronic device having a function of displaying information useful to a driver on a windshield of a vehicle or a screen thereof, and in particular, an image is displayed by a head up display (hereinafter abbreviated as HUD). The present invention relates to correction of a projection position when projecting.

  Conventionally, a HUD that projects an image in the direction of the driver's line of sight has been put to practical use. The HUD projects an image from the projection optical system installed in the vehicle onto the windshield or the screen (or combiner) provided there, and creates a virtual image as if an object exists in the real space that can be seen through the screen. It is a display system that projects. The driver can reduce the number of times of visually recognizing the display device in the vehicle by viewing the virtual image through the screen.

  In the HUD, when the driver's posture or the vehicle posture changes, the projected image may deviate from the driver's viewing direction. Therefore, in the vehicle travel guidance device disclosed in Patent Document 1, a section in which a braking force of a predetermined value or more is predicted to be continuously generated in the vehicle is set as a correction target section in which the vehicle attitude is predicted to change. During the travel of the correction target section, the display position of the HUD is corrected in consideration of the vehicle posture. Further, the HUD of Patent Document 2 includes a front camera for detecting vehicle vibration and a driver camera for imaging the driver, and corrects the image projection position according to vehicle vibration and driver attitude change. doing.

Japanese Patent No. 5327025 JP 2010-70066 A

  The projection position of the HUD can usually be set by user input such as a driver or a passenger. FIG. 16 is an example of a projection position setting method. As shown in FIG. 16A, when the menu screen is displayed on the display 1 of the vehicle-mounted device different from the HUD and the user selects the head-up display, as shown in FIG. Setting items are displayed. The user can set the projection position or projection angle of the HUD according to the height and posture of the driver by selecting “height” from those items.

  As described in Patent Documents 1 and 2, the set projection position can be corrected in accordance with a change in the driver's attitude or a change in the attitude of the vehicle. When the projection position is corrected by the above, the projected image frequently fluctuates, and on the contrary, it becomes difficult to visually recognize. For example, if the driver's head is changing in small increments while traveling on an uneven road, it becomes difficult to see if the projection position is corrected in small increments accordingly.

  The present invention solves such a conventional problem, and an object of the present invention is to provide an electronic device that improves visibility while correcting the projection position in accordance with the vibration of the vehicle or the change in the driver's posture. To do.

  An electronic apparatus having a display function according to the present invention includes an image generation unit that generates an image, a projection unit that projects an image generated by the image generation unit on a screen, and a posture detection unit that detects the posture of a viewer. Vibration detecting means for detecting the vibration of the vehicle, analyzing means for analyzing whether or not the displacement amount of the vibration detected by the vibration detecting means is greater than or equal to a threshold value, detection results of the posture detecting means and the analysis Correction means for correcting the projection position of the image by the projection means based on the analysis result of the means, and the correction means detects the posture detected by the posture detection means when vibrations greater than the threshold continue. The projection position is corrected according to the change.

  Preferably, when vibration equal to or greater than the threshold value continues, the image generation unit changes an image such as a character, a symbol, or a number to an image emphasized more than usual. Preferably, when vibration is less than a threshold value, the correction unit does not correct the projection position, and the image generation unit makes an image such as a character, a symbol, and a number more emphasized than usual. change. Preferably, the correction means thins out a constant value from the change amount of the posture detected by the posture detection means, and corrects the projection position according to the thinned change amount. Preferably, the correction unit thins out a predetermined interval from the posture interval detected by the posture detection unit, and corrects the projection position according to the thinned interval. Preferably, the electronic device further includes a rough road determination unit that determines whether or not the host vehicle is traveling on a rough road, and the correction unit is determined to be traveling on the rough road by the rough road determination unit. The projection position is corrected on the condition. Preferably, the electronic device further includes position calculating means for calculating the current location of the host vehicle, and obtaining means for obtaining map data including at least information related to the rough road, wherein the rough road determining means includes the current location and the map data. Whether or not the vehicle is traveling on a rough road is determined based on the above. Preferably, the electronic device further includes air pressure detection means for detecting air pressure, and calculation means for calculating a contact area between the tire and the road surface based on the detected air pressure, wherein the rough road determination means includes the calculated contact area. To determine whether or not the vehicle is traveling on a rough road. Preferably, the electronic device further includes a radar for detecting unevenness on the road surface, and the rough road determination means determines whether or not the vehicle is traveling on a bad road based on a detection result of the laser.

  According to the present invention, when the vibration of the vehicle equal to or greater than the threshold value continues, the projection position is corrected in accordance with the change in posture detected by the posture detection means, so that the visibility can be improved while correcting the projection position. Can be suppressed.

It is a block diagram which shows the structure of the vehicle-mounted apparatus which concerns on 1st Example of this invention. It is a block diagram which shows the structural example of HUD of a present Example. It is a figure which shows the example of a display of HUD of a present Example. It is a block diagram which shows the functional structure of the projection control program of a present Example. It is a flow which shows the correction | amendment operation | movement of the projection position of HUD of a present Example. It is a figure which shows the example of the correction | amendment operation | movement of the projection position of HUD of a present Example. It is a block diagram which shows the functional structure of the projection control program which concerns on 2nd Example of this invention. FIG. 8A shows an analysis example of a large vibration, and FIG. 8B shows an analysis example of a small vibration. FIG. 9A shows an example of font display during normal driving, and FIG. 9B shows an example of font display when emphasized. It is a flow which shows the correction | amendment operation | movement of the projection position of HUD which concerns on 2nd Example of this invention. It is a figure explaining operation | movement of the projection position correction | amendment part which concerns on the 4th Example of this invention. It is a block diagram which shows the functional structure of the projection control program which concerns on the 4th Example of this invention. It is an illustration of the uneven | corrugated state of the road surface detected by the radar detection part by the 5th Example of this invention. It is a flow which shows the correction | amendment operation | movement of the projection position of HUD which concerns on the 5th Example of this invention. It is an example of the image for performing the correction | amendment of the projection position which concerns on the 6th Example of this invention. It is a figure explaining the setting method of the conventional HUD.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. In a preferred embodiment, the electronic device according to the present invention can be an in-vehicle device mounted in a moving body such as a vehicle. In a further preferred aspect, the display function of the electronic device includes a HUD that projects an image on a windshield or the like. Furthermore, the electronic apparatus according to the present invention can include functions provided in a conventional in-vehicle apparatus such as a navigation function, a radio / TV reception function, and a multimedia playback function.

  FIG. 1 is a block diagram showing a configuration of an in-vehicle device according to a first embodiment of the present invention. The in-vehicle device 10 includes an input unit 100, a position information calculation unit 110, a navigation unit 120, an imaging unit 130, a vehicle state detection unit 140, an audio output unit 150, a display unit 160, a HUD 170, a communication unit 180, a storage unit 190, and a control. The unit 200 is configured to be included.

  The input unit 100 receives an instruction from a user through an input key device, a voice input recognition device, a touch panel, and the like, and provides this to the control unit 200. For example, as illustrated in FIG. 16, the initial setting of the HUD is performed via the input unit 100. The position information calculation unit 110 calculates the vehicle position using a GPS signal transmitted from a GPS satellite, a detection signal from a self-contained navigation sensor such as a gyro sensor, an acceleration sensor, or the like. The navigation unit 120 searches for a route to the destination, displays a road map around the vehicle position on the display unit 160 and the HUD 170, and outputs voice guidance from the voice output unit 150.

  The imaging unit 130 includes at least an imaging camera that images the driver, and provides the captured image data to the control unit 200. This image data is used to detect the driver's posture (in particular, the head, neck, and line-of-sight position).

  The vehicle state detection unit 140 detects the speed of the vehicle, the steering angle of the steering, etc. in addition to the gyro sensor and the acceleration sensor described above. Further, the vehicle state detection unit 140 may include an air pressure detection sensor that detects tire air pressure, a radar that detects road surface unevenness, and the like. A signal detected by the vehicle state detection unit 140 is provided to the control unit 200.

  The audio output unit 150 and the display unit 160 output audio data and image data when the navigation unit 120 and other multimedia functions are executed. Furthermore, in-vehicle device 10 includes HUD 170 as another display function in addition to display unit 160.

  The HUD 170 projects an image on a windshield or a screen (or combiner) attached thereto. FIG. 2 is a block diagram illustrating a configuration example of the HUD 170. The HUD 170 includes a light source 210, an illumination optical system 220, a light modulation unit 230, a projection optical system 240, a mirror 250, and an actuator 260. The light source 210 is composed of, for example, a light emitting diode array. The illumination optical system 220 focuses the light from the light source 210 and illuminates the light modulation means 230 with the collected light. The light modulation unit 230 includes, for example, a liquid crystal device or a digital mirror device in which a plurality of variable mirrors are two-dimensionally arranged, and the liquid crystal device or the digital mirror device based on image data provided from the control unit 200 or the like. To spatially modulate the illuminated light. The projection optical system 240 collects the modulated light, and the mirror 250 reflects the collected light toward the windshield.

  The actuator 260 includes a drive mechanism (for example, a motor) for making the angle of the mirror 250 variable. The actuator 260 outputs a drive signal for adjusting the angle of the mirror 250 based on the control signal S1 from the control unit 200. By changing the angle of the mirror 250, the vertical position or angle of the projected image can be corrected.

  FIG. 3A shows a display example of HUD. The HUD 170 is accommodated in the front dashboard, and an image is projected on the screen 272 of the windshield 270 therefrom. The image includes, for example, information such as a guide image indicating a distance to the next intersection, an estimated arrival time to the destination, and a vehicle speed. FIG. 3B is an example when the projection position is corrected downward by the actuator 250. The projection position is changed by changing the angle of the mirror 250 as described above.

  Returning to FIG. 1 again, the communication unit 180 enables wired or wireless data communication with an external network or an external device. The storage unit 190 can store application software executed by the in-vehicle device 10, a program executed by the control unit 200, map data executed by the navigation unit 120, and the like. Further, the storage unit 190 can store image data projected by the HUD 170. In a preferred embodiment, the map data can include information regarding bad roads. The rough road is a road having a large unevenness on the road surface, for example, an unpaved road, a gravel road in a mountainous area, or the like. For example, a flag for identifying whether the road is a bad road is set in the link data included in the map data.

  In a preferred embodiment, the control unit 200 includes a microcontroller including a ROM, a RAM, and the like, and the ROM or the RAM can store various programs for controlling the operation of each unit of the in-vehicle device 10. In the first embodiment, the control unit 200 executes a projection control program that controls the projection of the HUD 170.

  FIG. 4 is a diagram illustrating a functional configuration example of the projection control program 300 according to the first embodiment. The projection control program 300 includes a setting unit 310, an image generation unit 320, a posture detection unit 330, a posture change determination unit 340, and a projection position correction unit 350.

  The setting unit 310 sets, for example, the projection position of the HUD 170 by a method as shown in FIG. In a preferred embodiment, when setting the HUD 170, the posture of the driver during normal driving is also registered at the same time. Registration of the driver's posture is performed by the imaging unit 130 imaging the driver. However, the registration of the driver's posture does not necessarily have to be performed at the same time as the setting of the projection position. For example, the driver's posture may be registered by imaging the driver while traveling. Such setting information is held in the storage unit 190, for example.

  The image generation unit 320 generates an image projected by the HUD 170. Although the image generation method is not particularly limited, in one aspect, the image generation unit 320 can receive image data to be generated from the control unit 200. In another aspect, the image generation unit 320 may be an image that generates image data read from the storage unit 190. For example, the image generation unit 320 generates an image representing the speed of the host vehicle based on the vehicle speed information acquired from the vehicle state detection unit 140 while the host vehicle is traveling, or when the navigation unit 120 is activated. A guide image of the next intersection and an image representing the expected arrival time of the destination are generated.

  The posture detection unit 330 detects the driver's posture imaged by the imaging unit 130. Preferably, the position of the driver's head, neck, line of sight, and the like are detected as the driver's posture. These detections are detected, for example, by analyzing image data.

  The posture change determination unit 340 compares the driver's posture detected by the posture detection unit 330 with the registered driver's posture, and determines whether or not the posture has changed. This determination includes a posture change amount and a posture change direction (hereinafter referred to as posture change vectors). The posture change determination unit 340 provides the determination result to the projection position correction unit 350.

  When the posture change determination unit 330 determines that the posture has changed, the projection position correction unit 350 corrects a preset projection position or projection angle in accordance with the posture change vector. As shown in FIG. 2, the projection position correcting unit 350 outputs a control signal S1 corresponding to the posture change vector to the actuator 260, and the actuator 260 adjusts the angle of the mirror 250 based on the control signal S1. For example, when the posture change determining unit 330 determines that the driver's posture is tilted forward, the projection position is corrected downward as shown in FIG.

  FIG. 5 shows a flow of the projection position correction operation. The HUD 170 projects the image generated by the image generation unit 320 onto the projection position set by the setting unit 310 (S100). While the projection by the HUD 170 is performed, the posture detection unit 330 detects the driver's posture at a constant detection cycle and monitors the driver's posture (S102). The posture change determination unit 340 compares the detected driver's posture with the registered driver's posture, and determines that there has been a posture change when a certain difference or more occurs between the two postures (S104). ). If it is determined that there has been a change in posture, the projection position correction unit 350 corrects the projection position in accordance with the posture change vector (S106). When the posture change is not determined by the posture change determination unit 340 (S108), the projection position correction by the projection position correction unit 350 is completed, and the projection position is returned to the original state (S110).

  FIG. 6 is a diagram illustrating an example of correction of the projection position according to the present embodiment. FIG. 6A illustrates the posture of the driver U during normal traveling, that is, when registered. The posture of the driver U when registered is the axis Y, and at this time, the projection position P1 is in the driver's line-of-sight direction E. FIG. 6B is an illustration of the posture of the driver U when traveling on a rough road. When driving on a rough road, the driver U pays attention to the front, so the driver leans forward Y1, the line-of-sight direction E faces downward, and the projection position P1 easily deviates from the line-of-sight direction E. When the posture change determination unit 340 determines that there is a change in the driver's posture (from the axis Y to the axis Y1), as shown in FIG. 6C, the projection position correction unit 350 matches the posture change vector. The projection position is corrected to P2. Thereby, the driver U is in a forward leaning posture during driving on a rough road, and the projected image can be viewed well.

  Next, a second embodiment of the present invention will be described. In the first embodiment, when the posture change of the driver occurs, the projection position is corrected in real time almost in synchronization with this, but if the projection position is corrected according to all posture changes, the projected image Sway frequently, and the image may be difficult to see. In the second embodiment, taking these into account, the projection position is corrected.

  FIG. 7 is a block diagram showing a functional configuration of the projection display program 300A according to the second embodiment. The projection display program 300A further includes a vibration detection unit 360, a vibration analysis unit 370, and a display image enhancement unit 380 in addition to the configuration of the first embodiment. The vibration detection unit 360 detects vehicle vibration based on the detection result of the vehicle state detection unit 140. More specifically, the acceleration component in the direction of gravity of the acceleration sensor mounted on the vehicle is detected. The vibration analysis unit 370 analyzes the vibration level detected by the vibration detection unit 360. Preferably, as shown in FIGS. 8A and 8B, the vibration analysis unit 370 compares the ± change amount of the vibration with the threshold values Th + and Th− (even by comparing the absolute value of the change amount with the threshold value). If the change amount is equal to or greater than the threshold value, it is analyzed that the vibration is relatively large, and if the change amount is less than the threshold value, the vibration is analyzed to be small. FIG. 8A shows a large vibration, and FIG. 8B shows a small vibration.

  The analysis result of the vibration analysis unit 370 is provided to the projection position correction unit 350 and the display image enhancement unit 380. For example, when a part or all of the image generated by the image generation unit 320 includes fonts such as characters, symbols, and numbers, the display image enhancement unit 380 emphasizes the images of those fonts. Change the image data as follows. The emphasis method is not particularly limited. For example, the line may be thickened, brightened so that the contrast with other images is increased, or the size may be increased. FIG. 9A shows an example of normal font display, and FIG. 9B shows an example of font display when the line thickness is emphasized.

  FIG. 10 is a flowchart for explaining the operation of correcting the projection position according to the second embodiment. Steps S200 and S202 are the same as steps S100 and S102 in the first embodiment. In the second embodiment, in addition to monitoring the posture change, the vibration of the vehicle is monitored by the vibration detection unit 360 (S204). The presence / absence of the driver's posture is determined by the posture change determination unit 340 (S206). If it is determined that there is a posture change, the vibration analysis unit 370 analyzes the vibration level (S208). That is, the vibration change amount is compared with the threshold value, and it is analyzed whether the vibration is large as shown in FIG. 8A or small vibration as shown in FIG. 8B. If it is analyzed that the vibration is large, the vibration analysis unit 370 further analyzes whether such vibration is continuous rather than sudden (S210). For example, when the detection period of the vibration detection unit 360 is Ts, continuous analysis is performed if the amount of vibration change is equal to or greater than a threshold value in at least a plurality of periods. For example, even if one sudden vibration A1 and A2 as shown in FIG. 8B occurs, this is not analyzed as continuous.

  When it is analyzed that a large vibration is continuous, the projection position correction unit 350 corrects the projection position according to the posture change vector of the driver as in the first embodiment, and the display image enhancement unit 380 executes font emphasis (S212). Accordingly, the driver can see the emphasized font at the projection position corrected according to the posture, and thus visibility is improved. On the other hand, when it is analyzed that the vibration is small, or when it is analyzed that the vibration is large but not continuous, the projection position correction unit 350 does not correct the projection position according to the change in the driver's posture. The display image enhancement unit 380 executes font enhancement (S214). At small vibrations, the change in posture is also small, so if the projection position is corrected according to all of the changes in posture, the projection image shakes frequently, making it difficult to see the image. Such frequent shaking of the image is prevented, while the font is emphasized to improve visibility. Although an example of emphasizing the font is shown here, a display image other than the font can be emphasized as necessary at the time of small vibration.

  Next, a third embodiment of the present invention will be described. In the first and second embodiments, the projection position correction unit 350 corrects the projection position in accordance with the change amount of the driver's posture. In other words, the correction amount of the projection position is directly proportional to the change amount of the posture. However, in the third embodiment, the projection position is corrected by thinning out the amount of change in posture. As shown in FIGS. 6B and 6C, when the posture of the driver U changes from Y to Y1, the amount of change is represented by a function of Y−Y1. For example, in the first embodiment, the projection position is corrected according to the amount of change of Y−Y1, but in the third embodiment, the projection position is corrected according to the amount of change of (Y−Y1) −C. Is done. C is a constant for thinning out the amount of change, and is defined in advance. Thus, even if the projection position correction amount is relaxed or attenuated by thinning out a fixed value from the detected change amount, and the projection position is corrected in synchronization with the posture change amount, Can suppress frequent shaking.

  Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the projection position correction unit 350 corrects the projection position by thinning out the detection interval of the posture detection unit 330 at a constant interval. FIG. 11 shows an operation example of the projection position correction. The posture detection unit 33 detects the driver's posture at the detection cycle Tp, and detects the driver's posture at, for example, times t1, t2, t3, t4, t5,. The posture change determination unit 340 determines whether there is a change in posture at the same cycle as the detection cycle Tp, that is, determines whether there is a change in posture at times t1, t2, t3, t4, t5,. The projection position correction unit 350 can correct the projection position in synchronization with the determination period of the posture change determination unit 340. However, in the fourth embodiment, for example, times t1, t3, t5. As described above, the projection position is corrected at a timing at which a certain interval is thinned out. That is, the projection position correction unit 350 corrects the projection position at a cycle 2 × Tp that is twice the detection cycle Tp. Accordingly, it is possible to suppress frequent image shaking that may occur when the projection position is corrected in real time according to all changes in the driver's posture, and to improve visibility.

  Note that by combining the third and fourth embodiments, it is possible to correct the projection position by thinning out the constant value C from the change amount and thinning out the constant interval from the detection interval. Furthermore, the third and fourth embodiments can be combined with the first and second embodiments.

  Next, a fifth embodiment of the present embodiment will be described. FIG. 12 is a diagram illustrating a functional configuration of the projection display program 300B according to the fifth embodiment. In the fifth embodiment, in addition to the configurations of the first to fourth embodiments, a rough road determination is performed. Part 390. The rough road determination unit 390 determines whether the host vehicle is traveling on a rough road and provides the determination result to the projection position correction unit 350. In a preferred embodiment, the rough road determination unit 390 refers to the vehicle position calculated by the position information calculation unit 110 and the map data, and a flag indicating that the road on which the vehicle is traveling is a bad road is linked. When the data is set, it is determined that the vehicle is traveling on a rough road.

  As another preferable aspect, the rough road determination unit 390 refers to an air pressure sensor that detects the tire air pressure included in the vehicle state detection unit 140. Specifically, the rough road determination unit 390 calculates the contact area between the tire and the road surface from the detection result of the air pressure sensor, and determines whether the road is a bad road based on the contact area. For example, on a rough road surface, the contact area will be larger than that on a regular paved road, or the change in the contact area will be larger. In such a case, determine that you are traveling on a bad road. Can do.

  As yet another preferred mode, the rough road determination unit 390 refers to a radar that detects road surface unevenness included in the vehicle state detection means 140. FIG. 13 shows a road surface unevenness detection state 400 when the road surface is scanned by a radar. Where the unevenness is large, large distortion occurs in the grid-like line shape. The rough road determination unit 390 can determine that the road is rough when the unevenness of the road surface detected by the radar is greater than or equal to a certain level.

  In the fifth embodiment, the determination result of the rough road determination unit 390 can be used as a weighting requirement for correcting the projection position. FIG. 14 shows an operation flow of the fifth embodiment. The flow shown in the figure is the same as the flow in the first embodiment shown in FIG. 5 except that a rough road determination (S105) is added. That is, when it is determined that there is a change in the posture of the driver and it is determined that the vehicle is traveling on a rough road, the projection position is corrected. The fifth embodiment may be combined with other embodiments, for example, may be combined with the second embodiment shown in FIG. In this case, when it is determined that a large vibration is continuous and it is determined that the vehicle is traveling on a rough road, the correction of the projection position and the enhancement of the display image are executed, and the vehicle is traveling on the rough road. When it is determined that there is no correction, the display position may be emphasized without correcting the projection position.

  Next, a sixth embodiment of the present invention will be described. In the first embodiment, the actuator 260 corrects the projection position by changing the angle of the mirror 250. However, in the sixth embodiment, image data to be projected is changed without using the actuator. Thus, the projection position is corrected. FIG. 15A shows image data D1 at the time of normal traveling, in which information such as speed is arranged at the approximate center of the image frame, and FIG. 15B shows image data when the projection position is corrected downward. FIG. 15C shows image data D3 when the projection position is corrected upward, and information such as speed is arranged above the image frame. Is done. For example, when the driver's posture (head or line of sight) is tilted forward, the image data D2 shown in FIG. 15 (B) is projected, and when the driver's posture is tilted backward, FIG. 15 (C ) Is projected. Although the angle of the mirror 250 is constant, the actual projection position can be corrected by changing the projected image.

  The preferred embodiment of the present invention has been described in detail above. However, the present invention is not limited to the specific embodiment, and various modifications and variations are possible within the scope of the gist of the invention described in the claims. It can be changed.

1: Display 10: In-vehicle device 100: Input unit 110: Position information calculation unit 120: Navigation unit 130: Imaging unit 140: Vehicle state detection unit 150: Audio output unit 160: Display unit 170: HUD
180: Communication unit 190: Storage unit 200: Control unit

Claims (9)

An electronic device having a display function,
Image generating means for generating an image;
Projection means for projecting the image generated by the image generation means on a screen;
Posture detection means for detecting the posture of the viewer;
Vibration detecting means for detecting the vibration of the vehicle;
Analyzing means for analyzing whether or not a displacement amount of vibration detected by the vibration detecting means is greater than or equal to a threshold;
Correction means for correcting the projection position of the image by the projection means based on the analysis result of the analysis means when the posture detection means detects that the posture of the viewer has changed ,
The correction device corrects the projection position in accordance with a change in posture detected by the posture detection unit when vibration equal to or greater than the threshold value continues. 2. The electronic device according to claim 1, wherein when the vibration equal to or greater than the threshold value continues, the image generation unit changes an image such as a character, a symbol, or a number to an image emphasized more than usual. When the vibration is less than the threshold value, the correction unit does not correct the projection position, and the image generation unit changes the image of characters, symbols, numbers, and the like to an image emphasized more than usual. The electronic device according to claim 1. The said correction | amendment means thins out a fixed value from the variation | change_quantity of the attitude | position detected by the said attitude | position detection means, and correct | amends a projection position according to the decimated variation | change_quantity. Electronic equipment. 5. The electronic device according to claim 1, wherein the correction unit thins out a predetermined interval from the posture interval detected by the posture detection unit, and corrects the projection position according to the thinned interval. 6. . The electronic device further includes rough road determination means for determining whether or not the vehicle is traveling on a rough road,
The electronic device according to claim 1, wherein the correction unit corrects the projection position on the condition that the rough road determination unit determines that the vehicle is traveling on a rough road. The electronic device further includes a position calculating unit that calculates the current location of the vehicle, and an acquiring unit that acquires map data including at least information related to the rough road. The rough road determining unit is based on the current location and the map data. The electronic device according to claim 6, wherein it is determined whether the vehicle is traveling on a rough road. The electronic device further includes air pressure detection means for detecting air pressure, and calculation means for calculating a contact area between the tire and the road surface based on the detected air pressure, wherein the bad road determination means is based on the calculated contact area. The electronic device according to claim 6, wherein it is determined whether or not the vehicle is traveling on a rough road. The electronic device according to claim 6, further comprising a radar that detects unevenness of a road surface, wherein the rough road determination unit determines whether or not the vehicle is traveling on a bad road based on a detection result of the laser.

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