JP6573218B2 - VEHICLE IMAGE DISPLAY DEVICE AND SETTING METHOD - Google Patents

Description

  The present invention relates to a vehicular image display device and a setting method, and more particularly to a vehicular image display device and a setting method that are mounted on a vehicle and support driving of a driver.

  2. Description of the Related Art Conventionally, there has been known a vehicle image display device that assists driving of a driver by capturing the surroundings of a vehicle with a camera provided outside the vehicle and displaying the captured image on a monitor installed in the vehicle. For example, when a driver parks, this device assists the driver in confirming safety around the vehicle by imaging the surroundings of the vehicle, which is a blind spot of the driver, and displaying it on a monitor. For this reason, a camera having a wide-angle lens (such as a fisheye lens) that can capture a wide range is used.

  The image captured by the wide-angle lens camera is compressed as the distance from the optical axis increases, resulting in “distortion”. Due to this “distortion”, it was difficult to visually recognize the peripheral portion of the image. In order to solve this problem, there is known a vehicle image display device in which an image captured by a wide-angle lens camera is coordinate-transformed and displayed on a monitor as a flat image without “distortion” (for example, Patent Document 1). Or 2).

JP-A-2006-14381 JP 2006-167772 A

  However, a flat image obtained by coordinate transformation of a screen imaged by a wide-angle lens camera has a smaller number of pixels in the periphery of the image than in the center, so “blurring” occurs in a portion away from the optical axis. To do. For this reason, the driver still has a problem that it is difficult to visually recognize the peripheral portion. Further, the installation position of the camera with respect to the vehicle is determined in consideration of the vehicle exterior design and peripheral components, and no consideration is given to “blurring” of the image displayed on the monitor. That is, even if the surroundings of the vehicle that the driver should pay attention to for safety are displayed on the monitor, there is a case where “blurred” has occurred in that portion, which makes it difficult for the driver to visually recognize. In addition, the driver is distracted by checking the portion where the “blurring” has occurred, and there is a problem that the driver's attention to driving may be reduced.

  Therefore, the present invention provides an image display device for a vehicle that can prevent a driver's attention from being reduced when displaying an image captured by a wide-angle lens camera to the driver, and can support a driver's safe driving. The purpose is to provide a setting method.

In order to solve the above-described problem, an image display device for a vehicle according to the present invention is a vehicle image display device that is mounted on a vehicle and supports driving of a driver, and is installed at a front portion or a rear portion outside the vehicle. In addition, a camera that captures the front or rear of the vehicle with a wide-angle lens, a processing unit that corrects the wide-angle image captured by the camera and generates a planar image, and a central area that is suitable for the driver to visually recognize the imaging body And a display unit that displays a planar image including an unsuitable peripheral area on the screen, and the optical axis of the wide-angle lens is on the vehicle traveling side of the vehicle and moves until the vehicle at the set vehicle speed stops. The road surface portion of the section is set toward a predetermined position on the road surface portion so that it is included in the central area, and the moving section in the vehicle traveling direction is obtained based on the set vehicle speed. Open Empty vehicle traveling direction run distance and driver until it is characterized in that the vehicle is defined based on the braking distance of the vehicle traveling direction to a stop from the start of the braking operation.

In the present invention configured as described above, even if “blurring” that is not suitable for the driver to visually recognize the imaging body occurs in the planar image displayed on the display unit, the road surface portion that the driver should pay attention to for safety Is displayed on the central area of the planar image in which no “blurring” occurs. Therefore, in the image captured by the wide-angle lens camera, the driver can visually recognize the road surface portion without “blurring”, preventing the driver's attention from being scattered and assisting the driver's safe driving. be able to.
Further, in the present invention, the travel section in the vehicle traveling direction is obtained based on the set vehicle speed, and the free running distance in the vehicle traveling direction until the driver recognizes the object and starts the braking operation and the driver performs the braking operation. Since it is defined based on the braking distance in the vehicle traveling direction from the start to the stop of the vehicle, the road surface portion in the vehicle traveling direction can be accurately determined, and the road surface portion is a plane where no “blurring” occurs It can be displayed in the center area of the image.

  In the present invention, preferably, the central region is a region where the contrast ratio of the planar image is 30% or more. In the present invention configured as described above, the driver can visually recognize the road surface portion on a central region having a contrast ratio of 30% or more.

  In the present invention, preferably, the optical axis of the wide-angle lens is set so as to intersect with the approximate center of the road surface. In the present invention configured as described above, since the road surface portion can be kept away from the optical axis, the road surface portion can be reliably displayed in the central area of the planar image in which no “blurring” occurs. Can do.

  In the present invention, preferably, the camera is further installed at a position close to the outside of the blind spot area in the blind spot area of the front part or the rear part when the driver is driving. In the present invention configured as described above, since the camera is installed in the vicinity of the extension line of the driver's line of sight, the camera can be reliably directed to the road surface portion.

  In the present invention, it is preferable that the moving section in the vehicle width direction is further obtained based on the set vehicle speed and the maximum steering angle of the vehicle, in the vehicle width direction until the driver recognizes the object and starts the braking operation. It is defined based on the free running distance and the braking distance in the vehicle width direction from when the driver starts the braking operation until the vehicle stops. In the present invention configured as described above, the road surface portion in the vehicle width direction can be accurately determined, and the road surface portion can be displayed in the central region of the planar image in which no “blurring” occurs.

In order to solve the above-described problems, a setting method of the present invention is a setting method for an image display device for a vehicle that supports driving of a driver, and includes a step of setting a vehicle setting vehicle speed and a maximum steering angle, And a step of defining the road surface portion of the moving section that is on the vehicle traveling direction side from the vehicle and until the vehicle at the set vehicle speed stops, and a wide-angle lens of a camera that the vehicle image display device has In the flat image generated by correcting the wide-angle image captured via the driver, a step for defining a central region suitable for the driver to visually recognize the imaging body and a peripheral region not suitable for the driver, and a road surface portion are included in the central region have a step of setting a predetermined position of the road surface portion for directing the optical axis of the wide-angle lens as the mobile segment in the traveling direction of the vehicle is obtained based on the set vehicle speed, the driver is aware of the object braking Idling-run distance and a driver of the vehicle traveling direction until the start of work, characterized in that the said vehicle from the start of the braking operation is defined based on the braking distance of the vehicle traveling direction to a stop.

In the present invention configured as described above, it is possible to provide a setting method for allowing a driver to visually recognize a road surface portion without “blurring” in an image captured by a wide-angle lens camera.
Further, in the present invention, the travel section in the vehicle traveling direction is obtained based on the set vehicle speed, and the free running distance in the vehicle traveling direction until the driver recognizes the object and starts the braking operation and the driver performs the braking operation. Since it is defined based on the braking distance in the vehicle traveling direction from the start to the stop of the vehicle, the road surface portion in the vehicle traveling direction can be accurately determined, and the road surface portion is a plane where no “blurring” occurs It can be displayed in the center area of the image.

  The vehicle image display apparatus and setting method according to the present invention can prevent a driver's attention from being lowered when an image captured by a wide-angle lens camera is displayed on the driver, and can support the driver's safe driving. it can.

Fig.1 (a) is a side view which shows the whole vehicle carrying the image display apparatus for vehicles of embodiment of this invention, FIG.1 (b) is a top view of Fig.1 (a). 1 is a basic configuration diagram showing a vehicle image display device according to an embodiment of the present invention. FIG. 3A is a diagram showing a vehicle state when the vehicle image display device according to the present embodiment is used, and FIG. 3B is a display of a liquid crystal screen in the case of FIG. It is a figure showing a state. FIG. 4A is a diagram illustrating an image of a wide-angle image captured by a camera having a wide-angle lens, and FIG. 4B is a diagram illustrating an image of a planar image obtained by correcting the wide-angle image of FIG. is there. It is a figure for demonstrating the relationship between "blurring" and contrast ratio. It is a side view showing the direction of the optical axis and the road surface portion of the wide-angle lens of the vehicle image display device according to the embodiment of the present invention. FIG. 7 is a plan view of FIG. 6. It is a flowchart which shows the setting method of the image display apparatus for vehicles by embodiment of this invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, with reference to FIGS. 1 and 2, a basic configuration of a vehicle image display apparatus according to an embodiment of the present invention will be described. FIG. 1A is a side view showing the entire vehicle on which the vehicle image display device is mounted, and FIG. 1B is a plan view of FIG. FIG. 2 is a basic configuration diagram showing a vehicle image display apparatus.

  In this specification, the vehicle forward side is referred to as front, the vehicle reverse side is referred to as rear, and the vehicle width direction of the vehicle is referred to as left and right, and the vertical direction is referred to as up and down.

  As shown in FIGS. 1 and 2, the vehicle image display device 1 is mounted on a vehicle 2 and includes a front camera 3, a rear camera 5, a left side camera 7, a right side camera 9, a display unit 11, a switch 13, and a processing unit. 15 is provided. The vehicular image display device 1 acquires sensor data from various sensors. The various sensors include a gear position sensor 17, a vehicle speed sensor 19, and a steering angle sensor 21.

  Referring to FIG. 1, a front camera 3 is installed at a front portion 4 outside the vehicle 2 at the front end of the vehicle 2 and in the center in the vehicle width direction. Specifically, the front camera 3 is installed above an ornament arranged between the left and right headlights of the front portion 4. The front camera 3 includes a wide-angle lens and is installed so as to face forward and downward. As the wide-angle lens, for example, a fish-eye lens, a super-wide-angle lens, or the like is used, and a wide-angle image having a field angle range (about 180 degrees) wider than the field angle of view of the driver can be captured. Thereby, the front camera 3 can image the vehicle periphery ahead of the vehicle 2 in a wide range via the wide-angle lens. The front camera 3 is communicably connected to the processing unit 15 and transmits captured wide-angle image data to the processing unit 15.

  The rear camera 5 is installed at the rear end 6 outside the vehicle 2 and at the rear end of the vehicle 2 and at the center in the vehicle width direction. Specifically, the rear camera 5 is installed above a license plate disposed between the left and right backlights of the rear portion 6. In other words, the rear camera 5 is positioned at substantially the same height as the lower edge of the rear glass 8, that is, the uppermost edge of the rear portion 6 that becomes a blind spot when the driver views the rear glass 8 (the blind spot area and the blind spot outside area). Near the boundary). As a result, it is possible to capture an image as if the driver is visually recognizing the blind spot area through the rear glass 8. The rear camera 5 includes a wide-angle lens having the same specifications as the front camera 3 and is installed so as to face rearward and downward. As a result, the rear camera 5 can capture a wide area around the vehicle behind the vehicle 2 via the wide-angle lens. The rear camera 5 is communicably connected to the processing unit 15 and transmits captured wide-angle image data to the processing unit 15.

  The left side camera 7 and the right side camera 9 are installed below the left and right door mirrors 10 disposed on the side portion 12 outside the vehicle 2. The left and right side cameras 7 and 9 have wide-angle lenses having the same specifications as the front camera 3 and are installed so as to face outward and downward. As a result, the left and right side cameras 7 and 9 can image the vehicle periphery on the side of the vehicle 2 in a wide range via the wide-angle lens. The left and right side cameras 7 and 9 are communicably connected to the processing unit 15 and transmit the captured wide-angle image data to the processing unit 15.

  The display unit 11 includes a liquid crystal screen that displays an image, and is installed on a dashboard in front of the vehicle. The display unit 11 may also be used as a liquid crystal screen for a car navigation system. The liquid crystal screen faces the driver's seat and is installed so that the driver who is driving can visually recognize the screen. The display unit 11 is communicably connected to the processing unit 15 and receives image data via the processing unit 15. Wide-angle images captured by various cameras are converted into planar images by the processing unit 15 and displayed on the liquid crystal screen.

  The gear position sensor 17 is electrically connected to a speed change mechanism including a plurality of gears. The transmission mechanism includes a back gear for the vehicle 2 to move backward, and a plurality of drive gears for the vehicle to move forward. When the driver operates the operation lever to select one gear, the vehicle 2 travels according to the selected vehicle traveling direction and speed. The gear position sensor 17 is communicably connected to the processing unit 15, detects the position of the operation lever, and transmits gear position data to the processing unit 15.

  The vehicle speed sensor 19 detects the absolute speed of the vehicle 2. The vehicle speed sensor 19 is communicably connected to the processing unit 15, and transmits absolute speed data of the vehicle 2 to the processing unit 15.

  The steering angle sensor 21 detects the steering angle of the steering. The steering angle sensor 21 is communicably connected to the processing unit 15 and transmits steering angle data of the steering to the processing unit 15.

  The switch 13 is installed in the vicinity of the display unit 11 or the driver's seat in the vehicle, and includes a power switch 18 that activates or terminates the display unit 11 and various cameras, and an image changeover switch 20 that switches an image type of the display unit 11. When the operation lever is in the drive gear, the driver uses the image switch 20 to move the front image taken by the front camera 3, the front wide image taken from a wider area, or the side image taken by the left and right side cameras 7, 9. Either of these can be selected and displayed on the liquid crystal screen. When the operation lever is in the back gear, the driver uses the image changeover switch 20 to select either the rear image captured by the rear camera 5 or the rear wide image captured from a wider area and display it on the liquid crystal screen. Can do. Each switch is communicably connected to the processing unit 15, and transmits data from each switch to the processing unit 15.

  The processing unit 15 is a CMU (Connectivity Master Unit) or / and an ECU (Electronic Control Unit) that integrates each signal and each data. The processing unit 15 receives wide-angle image data captured by various cameras. The processing unit 15 generates a planar image in real time by performing coordinate conversion on the wide-angle image and performing correction. The processing unit 15 transmits the data of the planar image to the display unit 11. As a result, wide-angle images captured by various cameras are corrected and displayed on the display unit 11 as a planar image. Further, the processing unit 15 controls the type and content of each camera image displayed on the liquid crystal screen of the display unit 11 based on each data from the various sensors and the switch 13.

  Next, the basic concept of the vehicle image display apparatus according to this embodiment of the present invention will be described with reference to FIGS. FIG. 3A is a diagram illustrating a vehicle state when the vehicular image display device is used, and FIG. 3B is a diagram illustrating a display state of the liquid crystal screen in FIG. 3A. 4A is a diagram showing an image of a wide-angle image captured by a camera having a wide-angle lens, and FIG. 4B is a diagram showing an image of a planar image obtained by correcting the wide-angle image of FIG. 4A.

  As shown in FIG. 3, the vehicle image display device 1 is used, for example, when the driver moves the vehicle 2 backward to perform parking (see FIG. 3A). The vehicular image display device 1 is activated when the driver turns on the power switch 18. Next, when the driver puts the operation lever into the back gear, the processing unit 15 causes the display unit 11 to display a rear surrounding image of the vehicle 2 captured by the rear camera 5. On the liquid crystal screen of the display unit 11, a bird's eye image display unit 22, each direction image display unit 24 that displays various planar images, an icon 26 that indicates a use state, a power switch 18, and an image changeover switch 20 are displayed. (See FIG. 3B).

  The bird's-eye image display unit 22 displays an image of a viewpoint that looks down at the vehicle 2 from the sky. This image is obtained by combining images captured by the front camera 3, the rear camera 5, and the left and right side cameras 7 and 9 by the processing unit 15. In the bird's-eye view image display unit 22, a vehicle width extension line 28 is displayed on this image together with a composite image around the vehicle. The vehicle width extension line 28 is a line indicating a vehicle width extension guideline predicted by the processing unit 15 based on the steering angle of the steering detected by the steering angle sensor 21.

  Each direction image display unit 24 displays a planar image captured by the front camera 3 or the rear camera 5 and the left and right side cameras 7 and 9 and corrected by the processing unit 15. Further, a vehicle width extension line 28 and a distance guide line 30 are displayed together with the planar image. The distance guide line 30 is a line drawn at an interval of about 1 m from the rear end of the vehicle 2. A rear image is displayed on each direction image display unit 24 in FIG. 3B, but can be switched to a rear wide area image by the image switch 20. Further, when the driver puts the operation lever into the drive gear, either the front image, the front wide image, or the side image can be displayed on each direction image display unit 24 according to the image changeover switch 20.

  The icon 26 represents a camera that captures an image being displayed on each direction image display unit 24.

  In this manner, the vehicle surrounding image that is the blind spot of the driver imaged by various cameras is displayed on the liquid crystal screen of the display unit 11. Thereby, the driver can drive the vehicle 2 while confirming safety around the vehicle by the liquid crystal screen of the display unit 11.

  Desirably, when the processing unit 15 determines that the absolute vehicle speed detected by the vehicle speed sensor 17 exceeds 15 km / h, the processing unit 15 stops the screen display of the display unit 11. As a result, the images of the bird's-eye image display unit 22 and the directional image display unit 24 are turned off.

  As shown in FIG. 4A, the lens used in the camera of the vehicle image display device 1 is a wide-angle lens, for example, a fish-eye lens, a super-wide-angle lens, etc., and the captured wide-angle image 31 is displayed as a circular image. . Since the peripheral portion 34 of the wide-angle image 31 is compressed in comparison with the central portion 32, “distortion” occurs as the distance from the optical axis 36 increases. As a result, the wide-angle image 31 is difficult to visually recognize in the peripheral portion 34 where “distortion” occurs.

  As shown in FIG. 4B, in order to eliminate “distortion” of the wide-angle image 31, the processing unit 15 corrects the wide-angle image 31 by coordinate transformation to generate a planar image 37. Since the peripheral area 40 of the planar image 37 has a smaller number of pixels than the central area 38, the number of pixels is insufficient when correction is performed by coordinate transformation. For this reason, the flat image 37 becomes more “blurred” as the distance from the optical axis 42 increases. That is, the peripheral region 40 is a region in which the contrast ratio is smaller than 30% and “blurring” has occurred, and thus is not suitable for the driver to visually recognize the image pickup body. Further, the central area 38 of the planar image 37 is an area suitable for the driver to visually recognize the image pickup body because the contrast ratio is 30% or more and “blurring” hardly occurs.

  In the planar image 37 obtained by correcting the wide-angle image 31, the central area 38 is suitable for the driver to visually recognize the imaging body, and the peripheral area 40 is not suitable for the driver to visually recognize the imaging body. A road surface portion and an object (for example, a vehicle, a pedestrian, an obstacle, etc.) to be watched when the driver drives on a road surface (for example, a road, a lane, a white line, a curb, etc.) are displayed in the central area 38. In this case, the driver can instantly see the driver. However, when they are displayed in the peripheral area 40, since “blurring” has occurred, the visibility with respect to them decreases. As described above, when the road surface portion or the object is displayed in the peripheral area 40, the driver is distracted by the confirmation of the peripheral area 40, so that the driver's attention to driving may be reduced.

  Conventionally, it has been considered to improve camera performance (number of pixels, wide angle of view, etc.) as a design concept for this. However, adopting a high-performance camera leads to an increase in the product cost of the entire vehicle. Therefore, the present inventors pay attention to the fact that the vehicle speed during parking is lower than that during normal driving (about 5 km / h or less) and the road surface portion to be watched when the driver is driving is narrow, and the road surface portion is It has been found that the driver's attention can be prevented from being lowered if the driver is surely recognized and the other parts are not visually recognized.

  Next, the definition of “blurring” according to the present embodiment will be described with reference to FIG. FIG. 5 is a diagram for explaining the relationship between “blurring” and the contrast ratio.

“Blur” is defined by, for example, a contrast ratio. The contrast ratio is a value obtained by dividing the minimum luminance value L _min of a pixel within a predetermined width range from an arbitrary boundary by the maximum luminance value L _max of the pixel within a predetermined width range (contrast ratio (%) = L _min / L _max x 100)). As shown in FIG. 5, when the contrast ratio is 100% (FIG. 5A), no “blurring” occurs, and the driver can clearly see the imaging body. When the contrast ratio is 50% (FIG. 5B), some “blurring” occurs, but this is the limit that allows the driver to clearly see the imaging body. When the contrast ratio is 10% (FIG. 5C), “blurring” has occurred considerably, and it is difficult for the driver to visually recognize the image pickup body. That is, if the contrast ratio is 30% or more, the driver is suitable for visually recognizing the image pickup body.

  In the present embodiment, the threshold value of the contrast ratio suitable for the driver's visual recognition is set to 30%. However, the threshold value can be changed depending on the size of the image pickup body, for example, 30% when a small image pickup body is imaged with a camera. It is desirable to set a larger value.

  Next, characteristics of the vehicle image display apparatus according to the present embodiment of the present invention will be described with reference to FIGS. 6 is a side view showing the direction of the optical axis and the road surface portion of the wide-angle lens of the vehicular image display device, and FIG. 7 is a plan view of FIG.

  As shown in FIGS. 6 and 7, a front camera 3 is installed at the front end of the vehicle at the front portion 4, and a rear camera 5 is installed at the rear end of the vehicle at the rear portion 6. On the road surface 51 on which the vehicle 2 travels, a rear side moving section 53 in which the vehicle 2 can move before the vehicle 2 at the set vehicle speed moves backward and stops, and until the vehicle 2 at the set vehicle speed moves forward and stops. The front side movement section 55 in which the vehicle 2 can move is set between. Further, on the road surface 51 on which the vehicle 2 travels, the rear side (reverse direction side) passes through the reference line 58 that passes through the rear end of the vehicle 2 and extends in the left-right direction (vehicle width direction) perpendicular to the vehicle center axis X. A rear road surface portion 57 is set. Further, on the road surface 51 on which the vehicle 2 travels, in the front side movement section 55, the front side of the reference line 60 that passes through the front end of the vehicle 2 and is perpendicular to the vehicle central axis X and extends in the left-right direction (vehicle width direction) ( A front road surface portion 59 is set in the forward direction).

  The rear movement section 53 or the front movement section 55 is a range in which the vehicle 2 moves from when the driver recognizes an object and starts a braking operation to when the vehicle 2 stops during backward or forward travel. The rear end line 52 of the rear movement section 53 is the farthest position where the rear end of the rear part 6 can reach before the vehicle 2 moves backward and stops within the range of the minimum steering angle and the maximum steering angle. . The left end line 54 and the right end line 56 of the rear side movement section 53 are farthest positions in the vehicle width direction at which the side portion 12 can reach the vehicle 2 from the reverse travel to the stop at the left and right maximum steering angle. . A range surrounded by the rear end line 52, the left end line 54, the right end line 56, and the outline of the vehicle 2 is a rear movement section 53. Similar to the rear movement section 53, a range surrounded by the front end line 61, the left end line 63, the right end line 65, and the outline of the vehicle 2 is the front movement section 55.

  The maximum distance L1 in the vehicle traveling direction of the rear movement section 53 is the distance in the vehicle traveling direction from the rear end (reference line 58) of the vehicle 2 at a certain reference position to the farthest position (rear end line 52). Specifically, the maximum distance L1 is the rear end of the vehicle 2 during the period from when the driver recognizes an object at a certain reference position and starts a braking operation while the vehicle is moving backward at the set vehicle speed V until the vehicle 2 stops. Is the distance traveled. The maximum distance L1 is obtained on the basis of the set vehicle speed V. The idle travel distance L2 in the vehicle traveling direction until the driver recognizes the object and starts the braking operation and the vehicle 2 after the driver starts the braking operation. It is calculated by the sum of the braking distance L3 in the vehicle traveling direction until the vehicle stops (L1 = L2 + L3).

  The set vehicle speed V is a fixed value specified in advance, and is set to 5 km / h on the assumption of parking.

  The free running distance L2 is a set vehicle speed with respect to the sum of a time t1 from when the driver sees the liquid crystal screen until the driver recognizes the object and a time t2 from when the driver recognizes the object until the driver starts the braking operation. The distance multiplied by V (L2 = (t1 + t2) × V). t1 and t2 are predetermined fixed values, and are set to 0.5 s and 0.75 s, respectively.

  The braking distance L3 is a distance obtained by dividing the set speed V by the value obtained by multiplying the friction coefficient μ by the gravitational acceleration G and multiplying by two (L3 = V / (2 × μ × G)).

  The maximum distance W1 in the vehicle width direction of the rear movement section 53 is a distance in the vehicle width direction from the outline of the side portion 12 of the vehicle 2 to the farthest position (the left end line 54 or the right end line 56). Specifically, the maximum distance W1 is determined by the vehicle from when the driver recognizes an object at a certain reference position and starts a braking operation at a certain reference position during reverse travel at the set vehicle speed V and the maximum steering angle until the vehicle 2 stops. This is the distance that the second side portion 12 moves in the vehicle width direction. The maximum distance W1 is obtained based on the set vehicle speed V and the maximum rudder angle, and the free running distance W2 in the vehicle width direction until the driver recognizes the object and starts the braking operation and the driver starts the braking operation. From the braking distance W3 in the vehicle width direction until the vehicle 2 stops (W1 = W2 + W3).

  The rear road surface portion 57 passes through the rear end of the vehicle 2 and is perpendicular to the vehicle central axis X and extends rearward (reverse direction side) from the reference line 58 extending in the left-right direction (vehicle width direction). It is. In other words, the rear road surface portion 57 is a range surrounded by the rear end line 52, the left and right end lines 54 and 56, and the reference line 58 of the rear side movement section 53. When the vehicle 2 is moved backward, the driver needs to pay the most attention to confirming the safety of the rear road surface portion 57.

  The maximum distance L4 in the vehicle traveling direction of the front side movement section 55 is the distance in the vehicle traveling direction from the front end (reference line 60) of the vehicle 2 at a certain reference position to the farthest position (front end line 61). Specifically, the maximum distance L4 is determined by the front portion of the vehicle 2 during a period from when the driver recognizes an object at a certain reference position and starts a braking operation while moving forward at the set vehicle speed V until the vehicle 2 stops. This is the distance that the front end of 4 moves. The maximum distance L4 is obtained based on the set vehicle speed V, and the vehicle idle travel distance L5 in the traveling direction until the driver recognizes the object and starts the braking operation and the vehicle 2 after the driver starts the braking operation. It is calculated by the sum of the vehicle braking distance L6 in the traveling direction until the vehicle stops (L4 = L5 + L6).

  The set vehicle speed V is a fixed value specified in advance, and is set to 5 km / h on the assumption of parking.

  The free running distance L5 is a set vehicle speed with respect to the sum of the time t1 from when the driver sees the liquid crystal screen until the driver recognizes the object and the time t2 from when the driver recognizes the object until the driver starts the braking operation. The distance multiplied by V (L5 = (t1 + t2) × V). t1 and t2 are predetermined fixed values, and are set to 0.5 s and 0.75 s, respectively.

  The braking distance L6 is a distance obtained by dividing the set speed V by the value obtained by multiplying the friction coefficient μ by the gravitational acceleration G and multiplying by two (L6 = V / (2 × μ × G)).

  The maximum distance W4 in the vehicle width direction of the front side movement section 55 is a distance in the vehicle width direction from the outline of the side portion 12 of the vehicle 2 to the farthest position (left end line 63 or right end line 65). Specifically, the maximum distance W4 is determined by the vehicle from when the driver recognizes an object at a certain reference position and starts a braking operation while moving forward at the set vehicle speed V and the maximum steering angle until the vehicle 2 stops. This is the distance that the second side portion 12 moves in the vehicle width direction. The maximum distance W4 is obtained based on the set vehicle speed V and the maximum steering angle, and the idle running distance W5 in the vehicle width direction until the driver recognizes the object and starts the braking operation, and the driver starts the braking operation. From the braking distance W6 in the vehicle width direction until the vehicle 2 stops (W4 = W5 + W6).

  The front road surface portion 59 is a front movement section 55 that passes through the front end of the vehicle 2 and is perpendicular to the vehicle central axis X and extends in the left-right direction (vehicle width direction) and on the front side (forward direction side). The front road surface portion 59 is a range surrounded by the front end line 61, the left and right end lines 63 and 65, and the reference line 60 of the front side movement section 55. When the vehicle 2 is moved forward, the driver needs to pay the most attention to confirming the safety of the front road surface portion 59.

  The optical axis 62 of the wide-angle lens of the rear camera 5 in the planar image 37 displayed on the display device 11 includes the entire rear side road surface portion 57 in the central region 38 suitable for the driver to visually recognize the imaging body. As described above, the predetermined angle α is inclined with respect to the vertical line and set toward a predetermined position of the rear road surface portion 57. As a result, the rear road surface portion 57 is displayed in the central area 38 of the planar image 37 and is not displayed in the peripheral area 40. Further, the central region 38 is configured with a contrast ratio of 30% or more, which is suitable for the driver to visually recognize the imaging body. Further, the optical axis 62 of the wide-angle lens of the rear camera 5 is rearward and crossed so as to intersect with the central portion 66 at the substantially center in the vehicle traveling direction (front-rear direction) and the vehicle width direction (left-right direction) in the rear road surface portion 57. It is set to face downward.

  The optical axis 64 of the wide-angle lens of the front camera 3 in the planar image 37 displayed on the display device 11 is such that the entire surface of the front road surface portion 59 is included in the central region 38 suitable for the driver to visually recognize the imaging body. Further, it is set toward a predetermined position of the front road surface portion 59 by being inclined by a predetermined angle β with respect to the vertical line. Thereby, the front road surface portion 59 is displayed in the central area 38 of the planar image 37 and is not displayed in the peripheral area 40. The central region 38 is configured with a contrast ratio of 30% or more, and is suitable for the driver to visually recognize the imaging body. Further, the optical axis 64 of the wide-angle lens of the front camera 3 is forward and downward so as to intersect with a central portion 68 at a substantially center in the vehicle traveling direction (front-rear direction) and the vehicle width direction (left-right direction) in the front road surface portion 59. Is set to face.

  Next, a flow of a setting method of the vehicle image display device according to the embodiment of the present invention will be described with reference to FIG. FIG. 8 is a flowchart showing a setting method of the vehicle image display apparatus. In FIG. 8, S indicates each step.

  In the vehicle image display device 1 that supports driving by displaying an image captured by a wide-angle lens camera on the display unit 11, an electronic computer or the like (not shown) is used before the camera is attached to the vehicle 2. Thus, the directions of the optical axes 62 and 64 of the wide-angle lens are set in advance.

  As shown in FIG. 8, first, in S1, each initial condition is set. Specifically, the computer calculates the set vehicle speed V when the vehicle 2 is parked (for example, 5 km / h), the maximum steering angle of the vehicle 2, the position where the camera is attached to the vehicle (the height in the vertical direction, the position in the vehicle width direction). , A position in the vehicle traveling direction), a time t1 from when the driver sees the liquid crystal screen until the driver recognizes the object, and a time t2 from when the driver recognizes the object until the driver starts the braking operation.

  Next, in S2, the computer calculates the free running distance and the braking distance in the vehicle traveling direction and the vehicle width direction based on each initial condition (set vehicle speed V, maximum steering angle, etc.) read in S1, A rear side movement section 53 or a front side movement section 55 from when the object is recognized until the vehicle 2 stops is defined. Further, a rear movement section 53 on the rear side (reverse direction side) from the rear end (reference line 58) of the vehicle 2 is defined as a rear road surface portion 57. Further, a front movement section 55 on the front side (forward direction side) from the front end (reference line 60) of the vehicle 2 is defined as a front road surface portion 59.

  In S <b> 3, the electronic computer captures an image by the rear camera 5 or the front camera 3 having a wide-angle lens, and in the planar image 37 corrected by the processing unit 15, the central region 38 that is suitable for the driver to visually recognize the imaging body. And a peripheral region 40 that is not suitable for the driver to visually recognize the image pickup body. The central region 38 is preferably a region where the contrast ratio of the planar image 37 is 30% or more.

  Next, in S <b> 4, the electronic computer directs the optical axes 62 and 64 of the wide-angle lens so that the entire road surface portions 57 and 59 are displayed in the central region 38 in the flat image 37 displayed on the liquid crystal screen of the display device 11. The predetermined positions of the road surface portions 57 and 59 are set. This completes the flow of the method for setting the vehicle image display device.

  The road surface portions 57 and 59 displayed on the liquid crystal screen do not need to be displayed so that the outer peripheral edge thereof completely coincides with the outer peripheral edge of the central region 38, and only a predetermined width with respect to the outer peripheral edge of the central region 38. You may display small.

Next, the (action) effect of this embodiment will be described.
The vehicle image display device 1 according to the present embodiment is installed at the front end of the front portion 4 outside the vehicle 2 or the rear end of the rear portion 6, and cameras 3 and 5 that capture the front or rear of the vehicle 2 with a wide-angle lens, A processing unit 15 that corrects the wide-angle image 31 captured by the cameras 3 and 5 by coordinate conversion to generate a planar image 37, and a central region 38 that is suitable for the driver to visually recognize the imaging body and a peripheral region 40 that is not suitable. It has the display part 11 which displays the plane image 37 including it on a liquid crystal screen. Road surface portions 57 of the moving sections 53, 55 that are on the front side or the rear side (vehicle traveling direction side) of the front end or rear end (reference lines 58, 60) of the vehicle 2 and until the vehicle 2 at the set vehicle speed V stops. , 59 are displayed in the central area 38, and the optical axes 62, 64 of the wide-angle lens are set toward predetermined positions of the road surface portions 57, 59.

  In such an embodiment, even if “blurring” that is not suitable for the driver to visually recognize the image pickup body occurs in the planar image 37 of the display unit 11, road surface portions 57 and 59 that the driver should pay attention to for safety. Is displayed on the central area 38 of the planar image 37 in which “blurring” has not occurred. Accordingly, in the image captured by the wide-angle lens camera, the driver can visually recognize the road surface portions 57 and 59 without “blurring”, preventing the driver's attention from being scattered, and driving the driver safely. Can help.

  In the present embodiment, preferably, the central region 38 is a region where the contrast ratio of the planar image 37 is 30% or more. In this embodiment, the driver can visually recognize the road surface portions 57 and 59 on the central region 38 having a contrast ratio of 30% or more.

  In the present embodiment, preferably, the optical axes 62 and 64 of the wide-angle lens are set so as to intersect with the central portions 66 and 68 at substantially the center of the road surface portions 57 and 59. In this embodiment, since the road surface portions 57 and 59 can be kept away from the optical axes 62 and 64 of the wide-angle lens, the road surface portions 57 and 59 are flat surfaces on which no “blurring” occurs. It can be reliably displayed in the central area 38 of the image 37.

  Further, in the present embodiment, preferably, the cameras 3 and 5 are further located at positions close to outside the blind spot area (front part 4) in the blind spot area of the front part 4 or the rear part 6 when the driver is driving. Near the uppermost edge of the front end or the rear end of the rear portion 6). In this embodiment, since the cameras 3 and 5 are installed in the vicinity of the extension line of the driver's line of sight, the cameras 3 and 5 can be reliably directed to the road surface portions 57 and 59.

  In the present embodiment, preferably, the movement sections 53 and 55 in the vehicle traveling direction are obtained based on the set vehicle speed V, and the free running distance in the vehicle traveling direction until the driver recognizes the object and starts the braking operation. L2 and L5 and the braking distances L3 and L6 in the vehicle traveling direction from when the driver starts the braking operation until the vehicle 2 stops. In this embodiment, the road surface portions 57 and 59 in the vehicle traveling direction can be accurately determined. Further, the road surface portions 57 and 59 can be accurately displayed in the central region 38 of the planar image 37 in which “blurring” has not occurred.

  In the present embodiment, preferably, the movement sections 53 and 55 in the vehicle width direction are obtained based on the set vehicle speed V and the maximum steering angle of the vehicle 2, and the driver recognizes the object and performs a braking operation. It is defined based on the idle running distances W2 and 5 in the vehicle width direction until the start and the braking distances W3 and 6 in the vehicle width direction from when the driver starts the braking operation until the vehicle 2 stops. In this embodiment, the road surface portions 57 and 59 in the vehicle width direction can be accurately determined. Further, the road surface portions 57 and 59 can be accurately displayed in the central region 38 of the planar image 37 in which “blurring” has not occurred.

  The setting method of the present embodiment is a setting method of the vehicle image display device 1 that assists the driving of the driver, the step of setting the set vehicle speed V and the maximum steering angle of the vehicle 2, the set vehicle speed V and the maximum steering angle. The road surface portions 57 and 59 of the moving sections 53 and 55 between the front end of the vehicle 2 and the rear side of the vehicle 2 and the vehicle 2 at the set vehicle speed V until the vehicle stops. In the planar image 37 generated by correcting the wide-angle image 31 captured through the wide-angle lens included in the image display device 1, the center region 38 suitable for the driver to visually recognize the image pickup body and the unsuitable peripheral region 40 And a step of setting predetermined positions of the road surface portions 57 and 59 to which the optical axes 66 and 68 of the wide-angle lens are directed so that the road surface portions 57 and 59 are included in the central region 38.

  In this embodiment, there is provided a setting method for allowing the driver to visually recognize the road surface portions 57 and 59 without “blurring” in images taken by the wide-angle lens cameras 3 and 5. Can do.

  Without being limited to the above-described embodiment of the present invention, various changes and modifications can be made within the scope of the technical idea described in the claims.

DESCRIPTION OF SYMBOLS 1 Vehicle image display apparatus 2 Vehicle 3 Front camera 5 Rear camera 11 Display part 15 Processing part 31 Wide-angle image 37 Plane image 38 Central area 40 Peripheral area 53 Rear side movement area 55 Front side movement area 57 Rear side road surface part 59 Front side road surface part 62, 64 Center portion of optical axis 66, 68 of wide angle lens

Claims (6)

An image display device for a vehicle that is mounted on a vehicle and supports driving of a driver,
A camera that is installed at a front part or a rear part outside the vehicle and images the front or rear of the vehicle via a wide-angle lens;
A processing unit that corrects a wide-angle image captured by the camera to generate a planar image;
A display unit for displaying on the screen the planar image including a central area suitable for the driver to visually recognize the image pickup body and an unsuitable peripheral area;
The optical axis of the wide-angle lens is closer to the vehicle traveling direction than the vehicle, and a predetermined portion of the road surface portion is included in the central region so that a road surface portion of a moving section until the vehicle stops at a set vehicle speed. Set towards the position ,
The moving section in the vehicle traveling direction is obtained based on the set vehicle speed, and the free running distance in the vehicle traveling direction until the driver recognizes the object and starts the braking operation, and after the driver starts the braking operation. An image display device for a vehicle , which is defined based on a braking distance in a vehicle traveling direction until the vehicle stops .   The vehicle image display device according to claim 1, wherein the central region is a region in which a contrast ratio of the planar image is 30% or more.   The vehicular image display device according to claim 1, wherein an optical axis of the wide-angle lens is set so as to intersect with a substantially center of the road surface portion.   The said camera is installed in the position which adjoins the outside of this blind spot area | region in the blind spot area | region of the said front part or the said rear part when the driver is driving | operating. Vehicle image display device. The moving section in the vehicle width direction is obtained based on the set vehicle speed and the maximum steering angle of the vehicle, and the driver travels in the vehicle width direction until the driver recognizes the object and starts the braking operation. wherein from the start of the braking operation the vehicle is defined based on the braking distance in the vehicle width direction to a stop, the vehicle image display device according to any one of claims 1 to 4. A method for setting an image display device for a vehicle that supports driving of a driver,
Setting the vehicle speed and maximum steering angle of the vehicle;
Based on the set vehicle speed and the maximum steering angle, defining a road surface portion of a moving section that is closer to the vehicle traveling direction than the vehicle and until the vehicle at the set vehicle speed stops;
In the plane image generated by correcting the wide angle image captured through a wide-angle lens of the camera included in the VEHICLE image display device, a peripheral region the driver is unsuitable as the central region suitable for viewing the imaged A process of defining
Have a step of setting a predetermined position of the road surface portion where the road surface portion directs the optical axis of the wide-angle lens so as to be included in the central region,
The moving section in the vehicle traveling direction is obtained based on the set vehicle speed, and the free running distance in the vehicle traveling direction until the driver recognizes the object and starts the braking operation, and after the driver starts the braking operation. The setting method is defined based on a braking distance in a vehicle traveling direction until the vehicle stops .