Vehicle attitude calculation device and headlight optical axis control device

Abstract

To solve such problems that a cost becomes a problem since an optical axis of a headlight is automatically adjusted with the detected inclination by detecting the posture of a vehicle, a vehicle height sensor is generally used for detection of the posture and sensors are required in front and rear portions, and also, a correct inclination value cannot be output when the posture and road surface inclination change due to transportation by a trailer and a ship during a period from ignition ON to OFF in the posture detection using an acceleration sensor.SOLUTION: A vehicle posture calculation device acquires the position and orientation of a vehicle from information of a GPS receiver, extracts an in-image position of a landmark from an image acquired by a camera as a feature point, acquires a calculated reference point by calculating the position of the landmark to be captured in the image of the camera from a 3D map and the acquired position and orientation of the vehicle, and calculates an inclination angle of the vehicle from a deviation between the feature point and the calculated reference point.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle attitude calculation device that detects the inclination of a vehicle and a headlight optical axis control device. [Background technology]

[0002] The headlight beam axis must be directed within a legally defined range. This range is set to prevent the headlights from shining onto the driver's seat or other areas of oncoming vehicles. The beam axis must be adjusted for each vehicle because variations in headlight and body tolerances and vehicle posture can cause the headlights to be installed out of position. For this reason, vehicles are equipped with a mechanism for adjusting the beam axis using screws or other devices. However, uneven distribution of luggage inside the vehicle or centrifugal force acting on the suspension can cause the vehicle to tilt relative to the road surface. In such cases, even if the beam axis is within the legally defined range, the headlights may still irradiate the driver's seat or other areas of oncoming vehicles. In recent years, headlight beams have become stronger, and even if the beam axis is not directed toward the driver's seat or other areas, the driver of an oncoming vehicle may feel dazzled simply by the beam axis approaching. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-192673 [Patent Document 2] Patent Publication No. 2021-62866 Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, a method is being developed in which the vehicle's attitude is detected and the optical axis of the headlights is automatically adjusted based on the detected tilt. As shown in Patent Document 1, a vehicle height sensor is generally used to detect the vehicle's attitude, but this requires sensors at the front and rear, which creates a cost issue. Also, as shown in Patent Document 2, attitude detection using an acceleration sensor is becoming more common. However, because the sensor value is temporarily stored when the ignition is turned off, if the vehicle's attitude or road inclination changes during transportation by trailer or ship between the time the ignition is turned off and on, an accurate tilt value cannot be output. [Means for solving the problem]

[0005] The present invention provides a vehicle attitude calculation device that calculates the vehicle's tilt angle from information from a GPS receiver and an image acquired by a camera. [Effects of the Invention]

[0006] According to the present invention, data indicating the tilt of a vehicle can be obtained without increasing the number of dedicated detection devices or the like. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a system configuration diagram showing an embodiment of the present invention. [Figure 2] FIG. 4 is an explanatory diagram of feature points and calculation reference points according to an embodiment of the present invention. [Figure 3] FIG. 4 is an explanatory diagram for determining an inclination angle in one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] A vehicle 1 according to an embodiment of the present invention has an ECU 2, which is a vehicle attitude calculation device. As shown in Fig. 1, the ECU 2 is connected to an on-board camera 3, a car navigation system 4, and a headlight beam axis adjustment device 51. The camera 3 is a camera used for a drive recorder or an advanced safety device. The car navigation system 4 is also a camera used for a drive recorder or an advanced safety device.

[0009] The ECU 2 acquires information on the latitude, longitude, and direction of the vehicle 1, as well as a 3D map of the vicinity of the vehicle 1, from the car navigation system 4. The car navigation system 4 receives the latitude and longitude information of the vehicle 1 from the GPS receiver 41, and calculates the direction of the vehicle 1 from the latitude and longitude movement data. The 3D map contains data on the 3D shapes of landmarks such as buildings and traffic signs, and the altitude and inclination of roads.

[0010] ECU2 also acquires an image from camera 3. ECU2 selects two landmarks from the image and extracts the coordinates of the feature points in the image from each landmark. Figure 2 shows the situation where the coordinates of feature points a and b have been extracted from two landmarks A and B. For landmark A, the center of the top is extracted as the coordinate of feature point a, and for landmark B, the top is extracted as the coordinate of feature point b. These coordinates are on the image. The coordinate axes on the coordinate plane of the screen are indicated by dotted lines in Figure 2.

[0011] Meanwhile, ECU2 calculates the position of landmarks that should be captured in the image based on 3D map data and the latitude, longitude, and direction of vehicle 1, and acquires a calculated reference point. The 3D map data includes the 3D shapes of landmarks such as buildings and traffic signs, as well as data on road altitude and road surface inclination. Using the road surface inclination data in the 3D map, the position of the landmark that should be captured at the position of camera 3 when vehicle 1 is level with the road is set as the calculated reference point. In FIG. 2, a1 is the calculated reference point acquired by calculating the coordinates of the center of the top of landmark A. Furthermore, b1 is the calculated reference point acquired by calculating the coordinates of the center of the top of landmark B.

[0012] Due to the vehicle 1 tilting relative to the road surface due to the deflection of the suspension, etc., the coordinates of image a are shifted from the calculated a1, and the coordinates of image b are shifted from the calculated b1. From the positional shift between the feature points of the image taken by camera 3 and the calculation reference point calculated from the 3D data, the vehicle inclination angle relative to the road surface, which is the inclination of the vehicle 1 relative to the road surface, can be calculated.

[0013] As shown in Figure 3, the intersection of the perpendicular bisector of the line connecting a and a1 and the perpendicular bisector of the line connecting b and b1 on the coordinate plane of the screen is defined as center C. The interior angle of the line connecting center C with a and a1 is the inclination angle Ta with respect to the road surface. Although center C is outside the image in Figure 3, it can be described as coordinates existing on a plane extending from the image. In this embodiment, to reduce errors, the interior angle of the line connecting center C with b and b1 is also calculated and defined as inclination angle Tb, and the average of this and Ta is calculated as (Ta + Tb) / 2, which is the inclination angle T with respect to the road surface. The inclination angle T is the inclination angle in the roll direction of the vehicle. The inclination angle in the pitch direction can also be obtained from the coordinates of center C.

[0014] The ECU 2 then instructs the optical axis adjuster 51 to adjust the headlights 5 in a direction that offsets the inclination angle T. For example, if the vehicle 1 is in an attitude where the left side is lowered relative to the road surface, the optical axis of the right headlight 5 is lowered. This makes it possible to prevent the light from being directed at the driver of an oncoming vehicle due to the inclination of the vehicle 1. In this way, the optical axis of the headlights is controlled by an optical axis control device that inputs the vehicle inclination angle relative to the road surface obtained by the ECU 2, which is a vehicle attitude calculation device, into the optical axis adjuster 51, and the direction of the optical axis relative to the road surface can be kept within a predetermined range.

[0015] In the embodiment, the tilt angles in the roll direction and pitch direction are obtained from the feature points of two landmarks and the calculation reference point, but the tilt angles may also be obtained from three or more landmarks. By extracting two or more calculation reference points and feature points, the tilt angles can be obtained quickly and accurately. Furthermore, the tilt angle T may be determined by sequentially changing the tilt angle T for a feature point of one landmark so that the deviation from the calculation reference point obtained from 3D data or the like becomes smaller. In this case, assuming that there is no tilt in the pitch direction, for example, the calculation reference point is obtained while sequentially shifting the tilt angle T in the roll direction, and the tilt angle T is obtained when the feature point and the calculation reference point are closest.

[0016] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to the embodiments, and the present invention also includes design changes within the scope of the present invention. Furthermore, the above-described embodiments can be combined by utilizing each other's technology as long as there are no particular contradictions or problems in their purpose, configuration, etc.

[0017] For example, in the embodiment, the amount of vehicle tilt is used to control the beam axis of headlights, but it can also be used for various vehicle controls, such as displaying the vehicle tilt inside the vehicle or controlling active suspension. Furthermore, the road surface tilt may be calculated from the curvature of the road recorded on the 3D map. In the embodiment, the vehicle altitude is obtained from the altitude data recorded on the 3D map at the latitude and longitude position where the vehicle is located. However, altitude data obtained by a GPS receiver may also be used, or both the altitude data on the 3D map and the altitude data obtained by the GPS receiver may be averaged and used. [Explanation of symbols]

[0018] 1 vehicle 2 ECU 3 Camera 4. Car navigation system 41 GPS receiver 5. Headlights 51 Optical axis adjustment device

Claims

1. Obtain the vehicle's position and orientation from the GPS receiver information, The positions of landmarks in the image are extracted as feature points from the image acquired by the camera; A vehicle attitude calculation device characterized by calculating the position of a landmark that should be captured in the image of the camera from a 3D map and the acquired position and orientation of the vehicle to obtain a calculated reference point, and calculating the vehicle's tilt angle from the intersection of each perpendicular bisector at two or more landmarks with respect to the perpendicular bisector of a line connecting the feature point and the calculated reference point.

2. A vehicle attitude calculation device as described in claim 1, characterized in that the pitch direction tilt angle of the vehicle is obtained from the position of the intersection.

3. 3. The vehicle attitude calculation device according to claim 1, wherein the altitude of the vehicle is obtained from altitude data stored in the 3D map at the latitude and longitude where the vehicle is located.

4. 3. The vehicle attitude calculation device according to claim 1, wherein the vehicle altitude data is obtained from the GPS receiver.

5. 5. The vehicle attitude calculation device according to claim 1, further comprising: a road-to-vehicle tilt angle, which is an angle of tilt of the vehicle relative to the road surface, obtained from the road surface tilt and the calculated tilt angle.

6. 6. The vehicle attitude calculation device according to claim 5, wherein the road surface inclination is recorded on the 3D map.

7. 6. The vehicle attitude calculation device according to claim 5, wherein the road surface inclination is calculated from the curvature of the road depicted on the 3D map.

8. 8. A headlight optical axis control device comprising: the vehicle attitude calculation device according to claim 5; and an optical axis adjustment device for adjusting an optical axis of a headlight, wherein the vehicle inclination angle with respect to a road surface is input to the optical axis adjustment device to control the optical axis of the headlight, and the direction of the optical axis with respect to the road surface is kept within a predetermined range.

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