Display control method, display control device, and recording medium

Abstract

A controller (20) acquires a captured image (Im1) captured by a first camera (10) mounted in front of a vehicle (50), generates a corrected image (Im2) by performing correction processing for correcting distortion of the captured image (Im1), generates a display image (Im4) on the basis of the corrected image (Im2), and displays the display image (Im4) on a display unit (15). The correction processing corrects the distortion such that the distortion of the image at a position shifted in an image lateral direction from an image center in the image lateral direction is smaller than the distortion of the image at the image center.

Description

Display control method, display control device, and recording medium

[0001] The present invention relates to a display control method, a display control device, and a recording medium.

[0002] Patent Literature 1 discloses an image processing device. The first region is a ground region that the vehicle is predicted to pass through when traveling a predetermined distance during a first travel in which the vehicle travels from an arbitrary position at a steering angle that causes the vehicle to travel straight. The second region is a ground region that the vehicle is predicted to pass through when traveling a predetermined distance during a second travel in which the vehicle travels from an arbitrary position at a steering angle that causes the vehicle to travel other than straight. The third region is a region of the second region that is not included in the first region. The image processing device performs image conversion processing so that distortion of the third region in an image output from the image processing device during the second travel is smaller than distortion of the third region in an image output from the image processing device during the first travel.

[0003] JP 2018-148491 A

[0004] However, the technique of Patent Document 1 may not be able to correctly recognize an object located in a blind spot of a passenger in real space in an image.

[0005] An object of the present invention is to provide a display control method, a display control device, and a recording medium that enable an occupant to correctly recognize an object in a blind spot.

[0006] A display control method according to one aspect of the present invention includes generating a corrected image by performing a correction process to correct distortion of a captured image, generating a display image based on the corrected image, and displaying the display image on a display. The correction process corrects distortion so that distortion at positions laterally shifted from the center of the image in the image horizontal direction is smaller than distortion at the center of the image.

[0007] According to one aspect of the present invention, an object in a blind spot of an occupant in real space can be correctly recognized in a display image displayed on a display.

[0008] FIG. 1 is a diagram schematically showing the configuration of a display control device according to this embodiment. FIG. 2 is a diagram showing an environment in which a vehicle travels. FIG. 3 is a flowchart showing a display control method. FIG. 4 is a conceptual diagram showing a captured image. FIG. 5 is a conceptual diagram showing image distortion. FIG. 6 is a conceptual diagram showing image distortion. FIG. 7 is a conceptual diagram showing a corrected image. FIG. 8 is a conceptual diagram showing a clipped image clipped from the corrected image. FIG. 9 is a diagram showing the relationship between the clipped image and a display image clipped from the clipped image. FIG. 10 is a conceptual diagram showing a display image enlarged to the size of a display. FIG. 11 is a conceptual diagram showing a display image enlarged to the size of a display. FIG. 12 is a diagram schematically showing a display image displayed on a display.

[0009] A display control device 1 according to this embodiment will be described with reference to Fig. 1. The display control device 1 is mounted on a vehicle and includes a first camera 10, a second camera 11, a vehicle sensor 12, a GPS receiver 13, a map database 14, a display unit 15, and a controller 20.

[0010] As shown in FIG. 2 , the first camera 10 is mounted in front of the vehicle 50, specifically at the front end of the vehicle 50. The first camera 10 is equipped with a fisheye lens with a wide angle of view, and the imaging range of the first camera 10 covers an area Ra of approximately 180° in front of the vehicle 50. For example, the first camera 10 is positioned so that the center of the optical axis of the fisheye lens is parallel to the longitudinal direction of the vehicle 50 and is at a predetermined depression angle. The first camera 10 is equipped with a solid-state imaging element such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The first camera 10 captures an image of the scenery ahead of the vehicle 50 and outputs the captured image. The first camera 10 captures images at a predetermined imaging period.

[0011] The second camera 11 is disposed closer to the center of the vehicle than the first camera 10 in the longitudinal direction of the vehicle, for example, near the rearview mirror. The second camera 11 has a narrower angle of view than the first camera 10, and the imaging range of the second camera 11 covers a certain range in front of the vehicle 50 that is narrower than the area Ra. For example, the imaging range of the second camera 11 corresponds to the field of view of an occupant (typically the driver) when facing forward. The second camera 11 is equipped with a solid-state imaging element such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The second camera 11 captures an image of the scenery in front of the vehicle and outputs the captured image. The second camera captures images at a predetermined imaging period. Note that the display control device 1 does not necessarily have to include the second camera 11.

[0012] 1 , the vehicle sensor 12 is a sensor that detects the state of the vehicle 50. In this embodiment, the vehicle sensor 12 detects the state of the turn signal of the vehicle 50. The GPS receiver 13 receives radio waves from a plurality of GPS satellites to calculate the position of the vehicle 50.

[0013] The map database 14 is a storage device that stores map data. The map data is data that indicates map information related to roads and structures attached to the roads. The road information includes, for example, information on the type, shape, and lanes of the road. The structure information includes information on the position and type of road markings such as stop lines at intersections, and information on the position, shape, and type of three-dimensional structures. Three-dimensional structures include traffic signs and traffic lights. The map database 14 may obtain map data from an external map data server using cloud computing.

[0014] The display unit 15 includes one or more displays for displaying information to the driver. In this embodiment, the display unit 15 includes a main display 16 and a meter display 17. The main display 16 displays information from the navigation system, information related to the audio equipment, etc. The meter display 17 is a display that displays gauges such as a speedometer, a tachometer, and a fuel gauge, as well as various warning lights.

[0015] The meter display 17 is located in front of the driver's seat on the instrument panel, taking into consideration the driver's visibility. The main display 16 is located in the center of the vehicle on the instrument panel, adjacent to the side of the meter display 17. The main display 16 and the meter display 17 can each display information individually, or the main display 16 and the meter display 17 may display information as a single continuous display. In the following description, unless otherwise specified, the term "display unit 15" will be used to refer to the main display 16.

[0016] The controller 20 is a general-purpose microcomputer equipped with a CPU (Central Processing Unit), memory, and input / output units. A computer program is installed in the microcomputer. By executing the computer program, the microcomputer functions as multiple information processing circuits equipped in the controller 20.

[0017] In this embodiment, an example is shown in which the multiple information processing circuits provided in the controller 20 are realized by software. Of course, it is also possible to configure the multiple information processing circuits for executing the information processing described below using dedicated hardware. Furthermore, the multiple information processing circuits may be configured using individual hardware.

[0018] The controller 20 displays a predetermined display image on the display unit 15 based on the image captured by the first camera 10. The controller 20 includes a distortion correction unit 21, a correction map storage unit 22, an image cropping unit 23, an image adjustment unit 24, a recognition processing unit 25, and a display control unit 26 as a plurality of information processing circuits.

[0019] The distortion correction unit 21 acquires the captured image captured by the first camera 10. The distortion correction unit 21 generates a corrected image by performing a correction process to correct distortion in the captured image. The image cropping unit 23 generates a cropped image that is larger than the vertical size of the display unit 15. The image adjustment unit 24 generates a display image by trimming the cropped image according to the shape of the display unit 15. The recognition processing unit 25 recognizes objects by performing image processing on the display image. The display control unit 26 displays the display image on the display unit 15 and displays an image that draws attention superimposed on the display image.

[0020] A display control method according to this embodiment will be described using an example of a T-shaped intersection 105 where a first road 101 and a second road 102 intersect, as shown in FIG. 2 . A vehicle 50 is about to enter the intersection 105 from the first road 101 connected to the intersection 105, and the front end of the vehicle 50 is located near the intersection 105. In the example shown in FIG. 2 , a second road 102, which is a cross road that intersects with the first road 101, intersects with the first road 101 at a right angle. At such an intersection 105, walls or buildings may be present on both sides of the first road 101, causing the second road 102 to be included in the driver's blind spot. In other words, it is difficult for the driver to visually check the traffic conditions on the second road 102. Therefore, the display control device 1 according to this embodiment displays, on the display unit 15, a display image that has been image-processed based on an image captured by the first camera 10, allowing the driver to correctly view objects on the second road 102.

[0021] In the following description, the area of ​​real space facing the vehicle 50, with the width of the vehicle 50 as its range, is referred to as the first area Rac. Specifically, the first area Rac is an area located inside two lines extending in the front-to-rear direction and spaced apart by the width of the vehicle 50. The areas of real space located to the left and right of the first area are referred to as the second areas Ral and Rar. In particular, the area to the left of the first area Rac is referred to as the left second area Ral, and the area to the right of the first area is referred to as the right second area Rar.

[0022] 3, a display control method according to this embodiment, specifically, a control method for displaying a display image on the display unit 15, will be described. The flowchart shown in FIG.

[0023] The display control unit 26 acquires the current position of the vehicle 50 from the GPS receiver 13. Points that meet certain conditions, such as intersections with poor visibility, are registered as registered points in the map data of the map database 14. Based on the current position of the vehicle 50 and the map data, the display control unit 26 determines whether the vehicle 50 is in the vicinity of the registered point, specifically, whether the vehicle 50 is within a predetermined radius of the registered point (S10). If the vehicle 50 is in the vicinity of the registered point, the display control unit 26 performs the processes from step S11 onwards.

[0024] The distortion correction unit 21 acquires the captured image Im1 output from the first camera 10 (S11). The position of each pixel in the captured image Im1 is specified by coordinate values ​​in a two-dimensional coordinate system. In the captured image Im1 shown in FIG. 4, the first virtual line La virtually represents the road edge 102a located far from the vehicle 50 on the second road 102 shown in FIG. 2. The second virtual line Lb virtually represents the road edge 102b located close to the vehicle 50 on the second road 102 shown in FIG. 2. As described above, the second road 102 in FIG. 2 intersects with the first road 101 at a right angle, and therefore each of the road edges 102a, 102b corresponds to a straight line perpendicular to the longitudinal direction of the vehicle 50. The first virtual line La corresponds to the straight road edge 102a perpendicular to the longitudinal direction of the vehicle 50, at a position spaced apart from the first camera 10 by the width (reference distance) of the second road 102 on the ground where the vehicle 50 is located. Similarly, the second virtual line Lb corresponds to a straight road edge 102b perpendicular to the fore-and-aft direction of the vehicle 50 at a position a certain distance away from the first camera 10 on the ground where the vehicle 50 is located.

[0025] As shown in FIG. 4 , the captured image Im1 is distorted by the fisheye lens. The distortion of the captured image Im1 increases as the distance from the center of the optical axis of the fisheye lens increases. The image region Rir shown in the captured image Im1 in FIG. 4 is a region that captures an arbitrary position on the second region Ral or Rar shown in FIG. 2 , specifically, the right second region Rar. This position is on the right side as viewed from the vehicle 50, and is a certain distance (e.g., 50 m) away from the first camera 10 on the second road 102. This position is also outside the field of view of the second camera 11, and is in the driver's blind spot. In contrast, the image region Ric is a region that captures an arbitrary position in front of the vehicle on the second road 102, specifically, the first region Rac shown in FIG. 2 .

[0026] 5 and 6 schematically show image distortion in each image region Rir and Ric. FIG. 5 schematically shows image distortion in image region Rir, and FIG. 6 schematically shows image distortion in image region Ric. When there is no distortion in the image, the "+" marks shown in FIGS. 5 and 6 are aligned at equal intervals in both the vertical and horizontal directions. Larger distortion occurs in image region Rir shown in FIG. 5 compared to image region Ric shown in FIG. 6.

[0027] The distortion correction unit 21 performs a correction process to correct the distortion of the captured image Im1, thereby generating a corrected image Im2 (S12). The distortion correction unit 21 performs coordinate transformation based on the captured image Im1, thereby generating a corrected image Im2 as shown in FIG. 7. The coordinate transformation is performed in accordance with a correction map stored in the correction map storage unit 22. The correction map describes the correspondence between the coordinate values ​​of each pixel of the captured image Im1 and the coordinate values ​​of a two-dimensional coordinate system (vertical and horizontal) that defines the corrected image Im2. By transforming the coordinate values ​​of each pixel of the captured image Im1, the captured image Im1 is rotated, enlarged or reduced, and translated.

[0028] A feature of the image display according to this embodiment is that it allows the driver to correctly visually recognize the conditions of the second road 102. The first region Rac, which faces the vehicle 50, is an area visible to the driver, while the second regions Ral and Rar include areas that the driver cannot visually recognize. In particular, the farther away from the vehicle 50 the second regions Ral and Rar are from the vehicle 50, the more difficult it is for the driver to visually recognize them. Therefore, the distortion correction unit 21 corrects the distortion of the captured image Im1 so that objects present in the second regions Ral and Rar can be correctly recognized. Specifically, the distortion correction unit 21 corrects the distortion of the captured image Im1 so that the image distortion at positions laterally shifted from the image center in the corrected image Im2 is smaller than the image distortion at the image center. In other words, the image distortion of the second regions Ral and Rar in the corrected image Im2 is smaller than the image distortion of the first region Rac in the corrected image Im2.

[0029] Specifically, the distortion correction unit 21 corrects the distortion of the captured image Im1 so that the second road 102 approaches horizontality as it moves from the image center of the corrected image Im2 in the horizontal direction of the image. At this time, the distortion correction unit 21 corrects the distortion of the captured image Im1 using an object located 50 m away from the vehicle 50 on the second road 102 as a reference so that the aspect ratio of the object in the corrected image Im2 most closely resembles the aspect ratio of the object in real space. That is, the second regions Ral and Rar in the corrected image Im2 include actual size ratio regions in which the aspect ratio of the object in the corrected image Im2 most closely resembles the aspect ratio of the object in real space. The actual size ratio regions are set in the driver's blind spots, i.e., regions of the second regions Ral and Rar that are outside the angle of view of the second camera 11.

[0030] 4 and 5, the distortion correction unit 21 corrects the distortion of the captured image Im1 so that the top and bottom sides of the rectangle approach horizontal. In addition, the distortion correction unit 21 enlarges the size of the rectangle in the vertical direction so that the image appears closer to the object in real space, and then enlarges the size of the rectangle in the horizontal direction in accordance with the vertical enlargement ratio.

[0031] On the other hand, the distortion correction unit 21 corrects the distortion of the captured image Im1 so that the image shrinks in the horizontal direction in the corrected image Im2 as it approaches the center of the image in the horizontal direction. In the image region Ric shown in Figures 4 and 6, the distortion correction unit 21 corrects the distortion of the captured image Im1 so that the rectangle is compressed in the horizontal direction.

[0032] The distortion correction unit 21 also corrects the distortion in the corrected image Im2 so that the first virtual line La is positioned higher in the horizontal direction of the image from the image center of the corrected image Im2. The first virtual line La virtually represents the road edge 102 a on the far side of the second road 102.

[0033] The first virtual line La of the corrected image Im2 slopes downward toward the image center of the corrected image Im2, preferably at an angle of 1 to 8 degrees, and more preferably at an angle of 2 to 4 degrees. The first virtual line La curves downward in a certain region in the horizontal direction of the image that includes the image center of the corrected image Im2 (e.g., the first region Rac). The first virtual line La also extends linearly in a certain region (e.g., the second regions Ral and Rar) that is shifted from the image center of the corrected image Im2 in the horizontal direction.

[0034] However, if the distortion of the image in the actual-size region described above is brought too close to horizontal, i.e., if the distortion of the image in the actual-size region is completely eliminated, the center of the first virtual line La will be unnaturally large and depressed. Therefore, it is preferable to leave some distortion in the actual-size region. For this reason, in the corrected image Im2 in Figure 7, the right or left end of the first virtual line La is drawn as a straight line, but in reality, there is a region where the first virtual line La is curved and the slope gradually becomes gentler as it approaches the horizontal end of the image.

[0035] The above-mentioned correction map is set in advance based on this concept of correction. The correction map is created assuming that a straight virtual line perpendicular to the longitudinal direction of the vehicle 50 exists at a position on the ground where the vehicle 50 is located, a reference distance from the first camera 10, for example, a position that is a typical road width of 6 to 8 meters, and that this virtual line follows the same trajectory as the above-mentioned first virtual line La. The distortion correction unit 21 corrects the captured image Im1 by performing coordinate transformation in accordance with the correction map stored in the correction map storage unit 22. The distortion correction unit 21 then generates a corrected image Im2, which is the corrected captured image Im1.

[0036] The image cropping unit 23 performs cropping processing on the corrected image Im2 (S13). As shown in Fig. 7, due to the coordinate transformation performed in the correction processing, there are areas in the corrected image Im2 where no image corresponding to the captured image Im1 exists (areas indicated by hatching). Therefore, as shown in Fig. 8, the image cropping unit 23 trims the area outside the corrected image Im2 to generate a cropped image Im3 by removing the area where no image exists from the corrected image Im2. This cropped image Im3 is cropped to a size larger than the vertical size of the display unit 15.

[0037] The image adjuster 24 generates a display image Im4 by cropping the cropped image Im3 according to the shape of the display unit 15 (S14: first image processing). The display mode of the display unit 15 includes a mode in which the display image Im4 is displayed only on the main display 16, and a mode in which the display image Im4 is displayed on the main display 16 and the meter display 17. The display mode is selected, for example, by a setting operation by the user. As shown in FIG. 9 , the image adjuster 24 generates the display image Im4 based on a shape according to the display mode.

[0038] The correction process described above prioritizes reducing distortion in the second regions Ral and Rar in the corrected image Im2, leaving distortion in the first region Rac in the corrected image Im2. In the correction process, the image in the first region Rac in the corrected image Im2 is compressed horizontally, and the virtual line La is corrected to bend downward. As a result, the road width near the center of the cropped image Im3 stretches vertically, giving the driver an impression of perspective that differs from that in real space. Therefore, the image adjustment unit 24 trims the cropped image Im3 by removing a lower region within a certain distance from the bottom edge. As a result, the proportion of the second road 102 in the vertical direction near the center of the image in the displayed image Im4 is reduced, giving the driver an impression of perspective closer to that in real space.

[0039] The image adjustment unit 24 enlarges the display image Im4 to fit the size of the display unit 15 (S15: second image processing). As shown in Fig. 10 , when a mode in which the display image Im4 is displayed only on the main display 16 is selected, the image adjustment unit 24 enlarges the display image Im4 to fit the size of the main display 16. As shown in Fig. 11 , when a mode in which the display image Im4 is displayed on the main display 16 and the meter display 17 is selected, the image adjustment unit 24 enlarges the display image Im4 to fit the size of a virtual display that combines the main display 16 and the meter display 17.

[0040] The recognition processing unit 25 processes the display image Im4 using a known image processing technique to recognize objects present on the second road 102 (S16). From the recognized objects, the recognition processing unit 25 recognizes a moving object moving on the second road 102. At this time, the recognition processing unit 25 may determine the type of the moving object, such as a pedestrian, bicycle, or automobile, and the speed or direction of movement.

[0041] The display control unit 26 performs a display process to display a display image Im4 on the display unit 15 (S17). Fig. 12 shows an example of the display image Im4 displayed on the main display 16. This display image Im4 is a single image in which the first region Rac and the second regions Ral and Rar in real space are continuous. In this embodiment, the single continuous image is generated using the first camera 10, which is a single camera.

[0042] As described above, in the correction process, the closer to the center of the corrected image Im2, the more the image is compressed in the horizontal direction. Therefore, in the display image Im4 cut out from this corrected image Im2, the width corresponding to the first region Rac is smaller than the width corresponding to the second regions Ral and Rar in real space. The width of the region corresponding to the second regions Ral and Rar in real space refers to the combined width of the width corresponding to the left second region Ral and the width corresponding to the right second region Rar.

[0043] Furthermore, when the recognition processing unit 25 recognizes a moving object, the display control unit 26 displays an image (hereinafter referred to as an "attention drawing image") that draws attention to the moving object superimposed on the display image Im4. In the example shown in Fig. 12, the attention drawing image is a rectangular frame Iwc that surrounds the periphery of the moving object. The attention drawing image may also include an image indicating the direction of movement of the moving object, such as an arrow image Iwa.

[0044] At this time, the display control unit 26 may dynamically increase the size of the rectangular frame Iwc as the moving object approaches the vehicle 50. The display control unit 26 may dynamically change the color or display form of the rectangular frame Iwc and the arrow image Iwa so that the moving object is emphasized as it approaches the vehicle 50. Changing the display form means, for example, changing from a lit display to a flashing display or changing the transparency. In addition, when the recognition processing unit 25 determines the type and speed of the moving object, the display control unit 26 may change the color or display form of the attention-attention image depending on the type and speed of the moving object so that differences in the type and speed of the moving object can be recognized.

[0045] The display control unit 26 may display an attention alert image for all moving objects on the second road 102, or may display an attention alert image only for moving objects that satisfy certain conditions. For example, the display control unit 26 may select moving objects that satisfy certain conditions based on the state of the turn signal of the vehicle 50. For example, in a traffic environment where the vehicle 50 keeps left-hand traffic, when the turn signal of the vehicle 50 is activated for a left turn, the display control unit 26 displays an attention alert image only for moving objects that are present on the right side of the vehicle 50 and are moving toward the vehicle 50. On the other hand, when the turn signal of the vehicle 50 is activated for a right turn, the display control unit 26 displays an attention alert image for moving objects that are present on the right and left sides of the vehicle 50 and are moving toward the vehicle 50. Furthermore, when the display control unit 26 determines that a moving object is present within a predetermined target range, for example, a range visible to the driver, the display control unit 26 may prohibit the display of an attention alert image for the moving object.

[0046] 12, the display control unit 26 displays a display menu Iwm for switching the content displayed on the display unit 15, superimposed on the display image Im4. The display control unit 26 displays the display menu Iwm in a transparent state. This prevents the content of the display image Im4 from being obscured by the display menu Iwm.

[0047] As described above, display image Im4 is an image in which the lower region of cropped image Im3 has been cropped, and therefore a portion of intersection 105 (second road 102) in front of vehicle 50 is not reflected in display image Im4. Therefore, the driver cannot determine from display image Im4 whether the front end of vehicle 50 is entering the intersection 105. Therefore, display control unit 26 may perform image processing based on cropped image Im3 to determine whether the front end of vehicle 50 is entering the intersection 105. Then, when the front end of vehicle 50 is entering the intersection 105, display control unit 26 may display an image or output a sound on display unit 15 to notify the driver of the entrance to intersection 105.

[0048] When the controller 20 determines that the display has ended, for example, when the intersection 105 has been passed, the series of processes ends (S18: YES). On the other hand, when the display has not ended, the process returns to step S11.

[0049] As described above, in the display control method of this embodiment, the controller 20 corrects the distortion of the captured image Im1 so that the image distortion at positions laterally shifted from the image center in the corrected image Im2 is smaller than the image distortion at the image center. This reduces the distortion of objects in the driver's blind spot, specifically the second regions Ral and Rar in real space, in the corrected image Im2 and, ultimately, in the display image Im4 cropped from the corrected image Im2. As a result, the driver can correctly recognize objects in the driver's blind spot in real space.

[0050] In the display control method of this embodiment, the controller 20 corrects distortion in the corrected image Im2 so that the first virtual line La is positioned higher in the horizontal direction of the image from the image center. The first virtual line La extends linearly in a certain range of area that is shifted from the image center of the corrected image Im2 in the horizontal direction of the image. The first virtual line La has a shape that curves downward in a certain range of area in the horizontal direction of the image that includes the image center of the corrected image Im2. This method can create a visual effect in the corrected image Im2, and ultimately in the display image Im4 cut out from the corrected image Im2, that a moving object approaching the vehicle 50 on the second road 102 appears to be moving toward the vehicle 50, thereby enabling the driver to correctly recognize the moving object.

[0051] In the display control method of this embodiment, the horizontal width of the first region Rac in real space in the display image Im4 is smaller than the horizontal width of the second regions Ral and Rar in real space. Specifically, the controller 20 corrects the distortion of the captured image Im1 so that the image shrinks in the horizontal direction in the corrected image Im2 as it approaches the center of the image in the horizontal direction. This method allows the images of the noteworthy second regions Ral and Rar to be displayed widely in the display image Im4. This allows moving objects moving on the second road 102 to be correctly recognized.

[0052] In the display control method of this embodiment, the second regions Ral and Rar in the corrected image Im2 include an actual size ratio region in which the aspect ratio of the object in the corrected image Im2 most closely resembles the aspect ratio of the object in real space. According to this method, the corrected image Im2, and in turn the display image Im4 cropped from the corrected image Im2, includes a region in which the object in the image is displayed with an aspect ratio that most closely resembles the aspect ratio of the object in real space. This allows the object to be displayed in a natural manner, enabling it to be correctly recognized. In this embodiment, the actual size ratio region is set in the second regions Ral and Rar outside the field of view of the second camera 11. This allows objects in the driver's blind spot to be correctly recognized.

[0053] In this embodiment, the actual size ratio area is set at a predetermined position in the corrected image Im2. However, the distortion correction unit 21 may dynamically modify the correction map to dynamically change the position of the actual size ratio area. For example, the recognition processing unit 25 may recognize an intersecting road extending in a direction intersecting the traveling direction of the vehicle 50 through image processing. Then, the distortion correction unit 21 may set the actual size ratio area on the intersecting road in the second area Ral, Rar. This allows moving objects on the intersecting road to be correctly recognized.

[0054] In the display control method of this embodiment, the display image Im4 is a single image in which the first region Rac and the second regions Ral and Rar in real space are continuous. This method makes it possible to seamlessly display an image of the region Ra in a wide range ahead of the vehicle 50.

[0055] In the display control method of this embodiment, the controller 20 generates a cropped image Im3 from the corrected image Im2, the cropped image having a size larger than the vertical size of the display unit 15. This method ensures a wide range of options for cropping a display image Im4 to be displayed on the display unit 15.

[0056] In the display control method of this embodiment, the controller 20 generates the display image Im4 by trimming the cropped image Im3 in accordance with the shape of the display unit 15 so as to remove the lower region of the cropped image Im3. According to this method, the intersecting road reflected in the display image Im4 can be displayed with a natural perspective.

[0057] In the display control method of this embodiment, when a moving object is detected within the imaging range of the first camera 10, the controller 20 displays an attention-calling image superimposed on the display image Im4 based on the state of the turn signal of the vehicle 50. This method allows the driver to correctly recognize moving objects that require the driver's attention.

[0058] In the display control method of this embodiment, the controller 20 recognizes, through image processing, intersecting roads extending in a direction intersecting the traveling direction of the vehicle 50. The controller 20 determines whether the vehicle 50 is entering the intersecting road. Although the intersecting road near the front end of the vehicle 50 is not displayed in the display image Im4, by performing the above determination, it is possible to determine that the front end of the vehicle 50 is entering the intersecting road. This makes it possible to alert the driver.

[0059] In the above-described embodiment, the first and second cameras 10 and 11 are disposed in front of the vehicle 50. However, the first and second cameras 10 and 11 may be disposed in rear of the vehicle 50.

[0060] In the present embodiment, when the vehicle 50 is in the vicinity of the registration point, the controller 20 displays the display image Im4 on the display unit 15. However, the controller 20 may display the display image Im4 on the display unit 15 when a display request is received from the driver.

[0061] Also included as part of this embodiment is a display control device 1 including a first camera 10 and a controller 20 that displays a display image Im4 on a display unit 15 based on an image captured by the first camera 10. The controller 20 performs the above-described display control method. Similarly, this embodiment also includes a program that causes a computer to execute the above-described display control method, and a computer-readable recording medium storing this program. With this display control device 1, program, and recording medium, distortion of objects in the driver's blind spot, specifically the second regions Ral and Rar in real space, is reduced in the corrected image Im2, making it possible to correctly recognize objects in the driver's blind spot in real space.

[0062] Although the embodiments of the present invention have been described above, the descriptions and drawings that form part of this disclosure should not be understood to limit the present invention. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure.

[0063] REFERENCE SIGNS LIST 1 display control device 10 first camera 11 second camera 12 vehicle sensor 13 GPS receiver 14 map database 15 display unit 16 main display 17 meter display 20 controller

Claims

1. A display control method executed by a display control device that displays an image on a display mounted on a vehicle, comprising: acquiring a captured image taken by a camera mounted on the front or rear of the vehicle; generating a corrected image by performing a correction process to correct distortion in the captured image; generating a display image based on the corrected image; and displaying the display image on the display, wherein the correction process corrects the distortion of the image at a position shifted from the center of the image in the horizontal direction of the image so that the distortion is smaller than the distortion of the image at the center of the image.

2. A display control method as described in claim 1, wherein, when a straight virtual line perpendicular to the longitudinal direction of the vehicle is imagined at a position a reference distance away from the camera on the ground where the vehicle is located, the correction process corrects the distortion so that the virtual line is positioned higher in the image as it moves from the center of the image in the lateral direction of the image.

3. A display control method according to claim 2, wherein the virtual line extends linearly within a certain range of area at a position shifted from the center of the image in the horizontal direction of the image.

4. The display control method according to claim 2, wherein the virtual line has a shape that curves downward in the image within a certain range of an area including the center of the image.

5. A display control method according to any one of claims 1 to 4, wherein, when a region of real space opposite the vehicle is defined as a first region, with the width of the vehicle as its range, and regions of real space to the right and left of the first region are defined as second regions, in the displayed image, the width of the image in the horizontal direction corresponding to the first region is smaller than the width of the image in the horizontal direction corresponding to the second region.

6. The display control method according to claim 5, wherein the correction process corrects the distortion so that the image shrinks in the horizontal direction of the image as it approaches the center of the image in the horizontal direction.

7. A display control method according to claim 5 or 6, wherein in the corrected image, the second region includes an actual size ratio region in which the aspect ratio of the object on the corrected image is most similar to the aspect ratio of the object in real space.

8. A display control method according to any one of claims 5 to 7, wherein the camera's angle of view includes the first area and the second area, and the display image is a single image in which the first area and the second area are continuous.

9. A display control method according to any one of claims 1 to 8, further comprising generating a cropped image from the corrected image, the cropped image having a size larger than the vertical size of the display.

10. The display control method according to claim 9, further comprising: generating the display image by cropping the cropped image in accordance with the shape of the display so that a lower region of the cropped image is removed.

11. A display control method according to any one of claims 1 to 10, further comprising: when a moving object is detected within the imaging range of the camera, superimposing an image that calls attention on the display image based on the state of the turn signal of the vehicle.

12. The display control method according to claim 7, further comprising: recognizing, by image processing, an intersecting road extending in a direction intersecting the traveling direction of the vehicle; and setting the actual size ratio area on the intersecting road in the second area.

13. A display control method as described in claim 7, wherein, when the camera is a first camera, the vehicle further comprises a second camera that is arranged closer to the center of the vehicle in the fore-and-aft direction of the vehicle than the first camera and has a smaller angle of view than the angle of view of the first camera, and the actual size ratio area is set to an area of ​​the second area that is outside the angle of view of the second camera.

14. A display control method according to any one of claims 1 to 13, further comprising: recognizing, by image processing, an intersecting road extending in a direction intersecting the traveling direction of the vehicle; and determining whether or not the vehicle is entering the intersecting road.

15. A display control device comprising: a camera mounted on the front or rear of a vehicle; and a controller that displays an image on a display mounted on the vehicle based on an image captured by the camera, wherein the controller performs a correction process to correct distortion in the captured image, thereby generating a corrected image; generating a display image based on the corrected image; and displaying the display image on the display, wherein the correction process corrects the distortion so that the distortion of the image at a position shifted laterally from the center of the image in the image's horizontal direction is smaller than the distortion of the image at the center of the image.

16. A computer-readable recording medium storing a program for causing a computer to execute the steps of: acquiring an image captured by a camera mounted on the front or rear of a vehicle; generating a corrected image by performing a correction process to correct distortion in the captured image; generating a display image based on the corrected image; and displaying the display image on a display mounted on the vehicle, wherein the correction process corrects distortion in an image at a position shifted laterally from the center of the image so that the distortion is smaller than the distortion in the image at the center of the image.

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