JP6778620B2 - Road marking device, road marking system, and road marking method - Google Patents

Description

The present invention relates to a technique for detecting a lane marking indicating a parking lot.

An in-vehicle image processing device has been proposed in which two marking lines indicating a parking lot are detected from two pairs of parallel straight lines in an image captured by a camera and a parking target position is determined based on the detected marking lines (for example, Patent Document). 1). Specifically, for each of the two pairs of parallel straight lines (four straight lines), the distance between the end points on the own vehicle side and the end points on the own vehicle side is the predetermined distance. Positions (four positions) are determined, and the position determined from the four positions is determined as the parking target position.

Japanese Unexamined Patent Publication No. 2014-126921

Since the in-vehicle image processing device proposed in Patent Document 1 detects two lane markings indicating the parking lot from two pairs of parallel straight lines in the image captured by the camera, the two lane markings indicating the parking lot If they are not parallel, the target parking position cannot be determined.

In view of the above problems, the present invention provides a lane marking technique capable of appropriately setting a target parking position based on the two lane markings even when the two lane markings indicating the parking lot are not parallel. The purpose is to provide.

The lane marking detection device according to the present invention includes a detection unit that detects a first lane marking and a second lane marking from a photographed image obtained by a camera that photographs the periphery of the vehicle, and a vehicle of the first lane marking. A first reference line having an end point corresponding to a side end portion and parallel to the average direction of the first division line and the second division line, and an end point corresponding to the vehicle side end portion of the second division line. To generate a second reference line parallel to the average direction of the first marking line and the second marking line, the end points and directions of the first reference line, and the second reference line. The position calculation unit that calculates the target parking position based on the end points and directions of the lines, and the first reference line based on the target parking position and the average direction of the first reference line and the second reference line. The detection unit includes the end point coordinates of the first reference line and the end point coordinate calculation unit for calculating the end point coordinates of the second reference line, and the detection unit includes the end point coordinates of the first reference line calculated by the end point coordinate calculation unit and the above. This is a configuration (first configuration) in which the region of interest is set based on the end point coordinates of the second reference line. The average direction of a plurality of lines can be defined by a vector obtained by normalizing the sum of the normalized direction vectors of each line. For example, the normalized direction vector indicating the average direction of the first division line and the second division line includes the normalized direction vector indicating the direction of the first division line and the second division. It is a vector obtained by normalizing the sum with the normalized direction vector indicating the direction of the line. Similarly, the normalized direction vector indicating the average direction of the first reference line and the second reference line includes the normalized direction vector indicating the direction of the first reference line and the second reference line. It is a vector obtained by normalizing the sum with the normalized direction vector indicating the direction of the reference line.

Further, in the lane marking device having the first configuration, the position calculation unit is separated by a predetermined length from the end point of the first reference line in the direction of the first reference line toward the side opposite to the vehicle. The first coordinates are calculated, and the second coordinates that are separated by a predetermined length from the end point of the second reference line toward the opposite side of the vehicle in the direction of the second reference line are calculated. , Half of the distance between the end point of the first reference line and the second reference line from the first coordinate toward the second reference line side in a direction perpendicular to the direction of the first reference line. The third coordinates that are separated from each other are calculated, and the first reference line moves from the first coordinate in a direction perpendicular to the direction of the first reference line toward the side opposite to the second reference line. The fourth coordinate, which is half the distance between the end point and the second reference line, is calculated, and the first reference line side from the second coordinate in a direction perpendicular to the direction of the second reference line. The fifth coordinate, which is half the distance between the end point of the first reference line and the second reference line, is calculated toward, and the second coordinate is perpendicular to the direction of the second reference line. The sixth coordinate, which is half the distance between the end point of the first reference line and the second reference line, is calculated from the coordinates of the above toward the side opposite to the first reference line, and the third coordinate is calculated. Coordinates to the sixth coordinate, the two coordinates that minimize the distance between the two points are selected, and the coordinate of the two selected coordinates that is closer to the vehicle is used as the coordinate of the target parking position. The second configuration) may be used.

Further, in the lane marking detection device having the first or second configuration, the area of interest is the first interest set based on the end point coordinates of the first reference line calculated by the end point coordinate calculation unit. The first area of interest and the second area of interest include a region and a second area of interest set based on the end point coordinates of the second reference line calculated by the end point coordinate calculation unit. May be a configuration (third configuration) separated from each other.

Further, in the lane marking detection device having the third configuration, the top view area of the first area of interest and the top view area of the second area of interest are smaller than the top view area of the vehicle (fourth). The configuration of) may be used.

Further, the lane marking detection device having any of the first to fourth configurations includes an output unit that outputs information related to the first reference line and the second reference line to the outside (fifth). Configuration) may be used.

Further, in the lane marking detection device having the fifth configuration, the output unit has the coordinates of the target parking position and the average direction of the first reference line and the second reference line with respect to the front-rear direction of the vehicle. The angle may be output to the outside as information related to the first reference line and the second reference line (sixth configuration).

The lane marking detection system according to the present invention has a configuration (seventh configuration) including a camera for photographing the periphery of the vehicle and a lane marking device having any of the first to sixth configurations.

The lane marking detection method according to the present invention includes a detection step of detecting a first lane marking and a second lane marking from a photographed image obtained by a camera that photographs the periphery of the vehicle, and a vehicle of the first lane marking. A first reference line having an end point corresponding to a side end portion and parallel to the average direction of the first division line and the second division line, and an end point corresponding to the vehicle side end portion of the second division line. And a generation step of generating a second reference line parallel to the average direction of the first marking line and the second marking line, the end points and directions of the first reference line, and the second reference. The first reference line based on the position calculation step of calculating the target parking position based on the end points and directions of the lines and the average direction of the target parking position and the first reference line and the second reference line. The end point coordinate calculation step for calculating the end point coordinates and the end point coordinates of the second reference line, and the end point coordinates of the first reference line and the end point coordinates of the second reference line calculated in the end point coordinate calculation step. It is a configuration (eighth configuration) including a step of setting an area of interest based on the above.

According to the lane marking detection technique of the present invention, the first reference line parallel to the average direction of the first lane marking and the second lane marking and parallel to the averaging direction of the first lane marking and the second lane marking line. A second reference line is generated, and the target parking position is calculated based on the end points and directions of the first reference line and the end points and directions of the second reference line. Even when the two lane markings indicating the parking lot are not parallel, the target parking position can be appropriately set based on the two lane markings.

The figure which shows the configuration example of the lane marking device Top view of the parking lot Flow chart showing an operation example of the lane marking ECU Top view showing the relationship between the marking line and the reference line Flowchart showing the calculation procedure of the target parking position Top view showing the relationship between the reference line and the coordinate candidates of the target parking position Top view showing the relationship between the reference line and the coordinate candidate of the target parking position in the case of imitating Patent Document 1. Flowchart showing the calculation procedure of the end point coordinates of the reference line Top view showing the relationship between the target parking position and the end point coordinates of the reference line Top view showing the relationship between the reference line and the region of interest

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the direction in which the vehicle travels straight from the driver's seat to the steering wheel is referred to as "forward direction". Further, the direction in which the vehicle travels straight from the steering wheel to the driver's seat is called "rear direction". Further, the direction from the right side to the left side of the driver facing forward, which is the direction perpendicular to the straight traveling direction and the vertical straight line of the vehicle, is referred to as "left direction". Further, the direction from the left side to the right side of the driver facing forward, which is the direction perpendicular to the straight line and the vertical direction of the vehicle, is referred to as "right direction".

Further, in the present embodiment, a coordinate system (world coordinate system) with a specific point of the vehicle equipped with the lane marking detection device as the origin is used. The specific point of the vehicle is that it is separated from the front end of the vehicle in the rear direction by the effective length (the length obtained by subtracting the rear overhang from the total length of the vehicle) and is the center in the left-right direction of the vehicle. The front-rear direction of the vehicle is the Z-axis direction (the rear direction is the positive direction of the Z-axis), and the left-right direction of the vehicle is the X-axis direction (the left direction is the positive direction of the X-axis).

<1. Configuration of lane marking device>
FIG. 1 is a diagram showing a configuration example of a lane marking detection device. The lane marking ECU (Electric Control Unit) 1 which is an example of the lane marking detection device is connected to the photographing unit 2 and is also connected to the vehicle control ECU 3 or the like via an in-vehicle network 4 such as CAN (Controller Area Network). Ru. Then, the lane marking detection system 1 is configured by the lane marking ECU 1 and the photographing unit 2.

The photographing unit 2 includes three cameras 21 to 23. The camera 21 is provided at the rear end of the vehicle. Therefore, the camera 21 is also referred to as a back camera 21. The optical axis of the back camera 21 is along the front-rear direction of the vehicle in a top view. The back camera 21 captures the rear direction of the vehicle. The mounting position of the back camera 21 is preferably at the center of the left and right of the vehicle, but may be slightly deviated from the center of the left and right in the left and right direction.

The camera 22 is provided on the left door mirror of the vehicle. Therefore, the camera 22 is also referred to as a left side camera 22. The optical axis of the left side camera 22 is along the left-right direction of the vehicle in a top view. The left side camera 22 photographs the left direction of the vehicle. The camera 23 is provided on the right door mirror of the vehicle. Therefore, the camera 23 is also referred to as a right side camera 23. The optical axis of the right side camera 23 is along the left-right direction of the vehicle in a top view. The right side camera 23 captures the right direction of the vehicle.

In the present embodiment, the lane marking ECU 1 acquires the captured images of the cameras 21 to 23, but the lane marking ECU 1 excludes the left side camera 22 and the right side camera 23 from the photographing unit 2 and only the captured images of the back camera 21. It may be configured to acquire.

The marking line detection ECU 1 includes a video acquisition unit 10, a detection unit 11, a generation unit 12, a position calculation unit 13, and an end point coordinate calculation unit 14. The lane marking ECU 1 can be composed of, for example, a control unit and a storage unit. The control unit is a computer including a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The storage unit non-volatilely stores the computer programs and data required for the lane marking ECU 1 to operate as the video acquisition unit 10, the detection unit 11, the generation unit 12, the position calculation unit 13, and the end point coordinate calculation unit 14. .. As the storage unit, for example, EEPROM, flash memory, or the like can be used.

The image acquisition unit 10 continuously acquires analog or digital captured images from the cameras 21 to 23 at a predetermined cycle (for example, a 1/30 second cycle). Then, when the acquired time-continuous captured image (acquired video) is analog, the video acquisition unit 10 converts the analog captured image into a digital captured image (A / D conversion).

The detection unit 11 detects the first division line and the second division line indicating the parking zone from the captured image output from the image acquisition unit 10 by using image processing such as edge extraction. The first lane markings and the second lane markings are drawn with white lines or the like on the road surface of the parking lot. In the top view of the parking lot illustrated in FIGS. 2 (a) to 2 (d), the portion surrounded by the gray dotted line D1 is detected as the first division line, and the portion surrounded by the gray dotted line D2 is the second. Detected as a lane marking.

In the first detection, the detection unit 11 sets the entire area of the captured image as the region of interest (the range in which the marking line can be detected), and in the second and subsequent detections, the first reference calculated by the end point coordinate calculation unit 14. The region of interest is set based on the end point coordinates of the line and the end point coordinates of the second reference line.

The generation unit 12 generates a first reference line corresponding to the first marking line and a second reference line corresponding to the second marking line.

The position calculation unit 13 calculates the target parking position based on the end points and directions of the first reference line and the end points and directions of the second reference line.

The end point coordinate calculation unit 14 calculates the end point coordinates of the first reference line and the end point coordinates of the second reference line. The details of the calculation method will be described later.

The vehicle control ECU 3 controls, for example, the direction and speed of the vehicle according to the operation by the driver, and controls, for example, the direction of the vehicle according to the information sent from the lane marking ECU 1 via the vehicle-mounted network 4.

The generation unit 12 and the position calculation unit 13 of the lane marking ECU 1 have a function of outputting information related to the first reference line and the second reference line to the vehicle control ECU 3. In the present embodiment, the generation unit 12 outputs the angle of the average direction of the first reference line and the second reference line with respect to the front-rear direction of the vehicle, and the position calculation unit 13 outputs the coordinates of the target parking position to the vehicle control ECU 3. To do. Thereby, for example, when the vehicle is moved to the parking lot, the vehicle control ECU 3 can automatically control the direction of the vehicle (steering angle).

<2. Operation of road marking device>
FIG. 3 is a flowchart showing an operation example of the lane marking ECU 1 which is an example of the lane marking detection device. When the operation start event of the lane marking ECU 1 occurs, the lane marking ECU 1 starts the operation of the flowchart shown in FIG. Examples of the operation start event of the lane marking ECU 1 include switching the position of the shift lever of the vehicle to the reverse range. The photographing unit 2 also starts operating at the same time as the operation of the lane marking ECU 1 starts.

First, the detection unit 11 attempts to detect the first lane marking and the second lane marking (step S1). As described above, in the first detection, the entire area of the captured image is the region of interest, and in the second and subsequent detections, the end point coordinates of the first reference line and the second reference calculated by the end point coordinate calculation unit 14. The region of interest is set based on the end point coordinates of the line.

When the first lane marking and the second lane marking are detected, the generation unit 12 generates the first reference line corresponding to the first lane marking and the second reference line corresponding to the second lane marking. (Step S2). Specifically, the generation unit 12 has an end point corresponding to the vehicle side end of the first lane marking, and has a first reference line parallel to the average direction of the first lane marking and the second lane marking, and A second reference line having an end point corresponding to the vehicle side end of the second marking line and parallel to the average direction of the first marking line and the second marking line is generated. Therefore, for example, not only when the first division line and the second division line are parallel as shown in FIG. 4A, but also when the first division line and the second division line are parallel as shown in FIG. 4B. Even if the marking lines are not parallel to each other, the first reference line LN1 and the second reference line LN2 are parallel to each other. As a result, by setting the target parking position based on the first reference line LN1 and the second reference line LN2, even if the two lane markings indicating the parking lot are not parallel, the two lane markings can be set. Based on this, the target parking position can be set appropriately. As shown in FIG. 4, the end point EP1 of the first reference line LN1 is superimposed on the vehicle side end portion E1 of the first lane marking, and the end point EP2 of the second reference line LN2 is the second lane marking. It overlaps with the vehicle side end E2.

In step S3 following step S2, the position calculation unit 13 calculates the target parking position based on the end points and directions of the first reference line and the end points and directions of the second reference line. The specific processing contents of step S3 will be described with reference to the flowchart shown in FIG. 5 and the top view shown in FIG. 6A.

First, the position calculation unit 13 has an effective length L0 (the length obtained by subtracting the rear overhang from the total length of the vehicle) from the end point EP1 of the first reference line toward the opposite side of the vehicle in the direction of the first reference line. The first coordinate A1 that is separated is calculated (step S3_1). Next, the position calculation unit 13 calculates the second coordinate A2 which is separated from the end point EP2 of the second reference line in the direction of the second reference line by the effective length L0 toward the opposite side of the vehicle (step). S3_2).

Next, the position calculation unit 13 has the end points EP1 and the second reference line of the first reference line from the first coordinate A1 toward the second reference line side in the direction perpendicular to the direction of the first reference line. The third coordinate A3, which is half the distance W from, is calculated, and the distance W is calculated from the first coordinate A1 in the direction perpendicular to the direction of the first reference line toward the side opposite to the second reference line. The fourth coordinate A4, which is half apart from the above, is calculated (step S3_3). Further, the position calculation unit 13 calculates the fifth coordinate A5, which is half the distance W from the second coordinate A2 toward the first reference line side in the direction perpendicular to the direction of the second reference line. , Calculate the sixth coordinate A6, which is half the distance W from the second coordinate A2 in the direction perpendicular to the direction of the second reference line toward the side opposite to the first reference line (step S3_4). ..

Then, the position calculation unit 13 selects the two coordinates that minimize the distance between the two points from the third coordinates A3 to the sixth coordinates A6 (step S3_5), and is closer to the vehicle among the two selected coordinates. The coordinates (the coordinates with the smaller distance from the origin) are set as the coordinates of the target parking position (step S3_6), and the calculation process of the coordinates of the target parking position is completed.

In both the case where the first lane marking and the second lane marking are parallel and the case where the first lane marking and the second lane marking are not parallel, the target parking position is obtained by processing the flowchart shown in FIG. From the vehicle side end (entrance of the parking lot) of the first and second road markings, the coordinates of are entered in the depth direction of the parking lot by the effective length L0, and the first road marking and the second road markings It can be located in the center of the lane markings. Here, for example, by imitating Patent Document 1, the first coordinate A1 is calculated by moving the effective length L0 along the direction of the first marking line, and the effective length L0 along the direction of the second marking line is calculated. When the second coordinate A1 is calculated by moving, if the first lane marking and the second lane marking are not parallel as shown in FIG. 4 (b), the coordinate of the target parking position is parked. There arises a problem that the vehicle is biased to either the right direction or the left direction after completion and is biased to either the front direction or the rear direction of the vehicle after parking is completed (see FIG. 6B).

Returning to FIG. 3, the operation after the calculation process of the coordinates of the target parking position is completed will be described. In step S4 following step S3, the end point coordinate calculation unit 14 calculates the end point coordinates of the first reference line and the end point coordinates of the second reference line. The specific processing contents of step S4 will be described with reference to the flowchart shown in FIG. 7 and the top view shown in FIG.

First, the end point coordinate calculation unit 14 calculates the midpoint coordinate Pw that is separated from the target parking position A0 toward the vehicle side by the effective length L0 in the average direction of the first reference line LN1 and the second reference line LN2 ( Step S4-1).

Next, the end point coordinate calculation unit 14 first refers from the midpoint coordinate Pw toward the first reference line LN1 side in a direction perpendicular to the average direction of the first reference line LN1 and the second reference line LN2. The end point coordinates P1 of the first reference line LN1 which is half the distance W between the end point EP1 of the line LN1 and the second reference line LN2 are calculated (step S4_2).

Finally, the end point coordinate calculation unit 14 is half the distance W from the midpoint coordinate Pw toward the second reference line LN2 in the direction perpendicular to the average direction of the first reference line LN1 and the second reference line LN2. The end point coordinates P2 of the second reference line LN2 that is separated are calculated (step S4_3).

Returning to FIG. 3, the operation after the calculation process of the end point coordinates is completed will be described. In step S5 following step S4, the detection unit 11 sets the region of interest based on the end point coordinates of the first reference line and the end point coordinates of the second reference line calculated by the end point coordinate calculation unit 14. As a result, the range of the region of interest can be narrowed, so that erroneous detection by the detection unit 11 can be reduced.

As shown in FIG. 9, for example, the detection unit 11 sets a first region of interest R1 including the end point coordinates P1 of the first reference line LN1 calculated by the end point coordinate calculation unit 14, and the end point coordinate calculation unit 14 A second region of interest R2 including the end point coordinates P2 of the second reference line LN2 calculated by is set.

In the example shown in FIG. 9, the first region of interest R1 and the second region of interest R2 are separated from each other. As a result, the range of the region of interest can be further narrowed, so that erroneous detection by the detection unit 11 can be further reduced. Then, in order to effectively reduce the false detection in the detection unit 11, the top view area of the first interest region R1 and the top view area of the second interest region R2 are at least larger than the top view area of the vehicle. It is desirable to keep it small. Further, in the example shown in FIG. 9, the top view shape of the first region of interest R1 is rectangular, the longitudinal direction of the first region of interest R1 is made to coincide with the direction of the first reference line LN1, and the second region of interest R1. The top view shape of R2 is rectangular, and the longitudinal direction of the second region of interest R2 coincides with the direction of the second reference line LN2. By devising this shape, the top view area of the first area of interest R1 and the top view area of the second area of interest R2 are reduced.

In step S6 following step S5, the lane marking ECU 1 confirms whether or not the end event of the lane marking ECU 1 has occurred. The operation end event of the lane marking ECU 1 includes, for example, that the distance between the coordinates of the target parking position and the origin is equal to or less than a predetermined value, which is substantially zero, and the position of the shift lever of the vehicle is changed from the reverse range to another range. It can be mentioned that it has been switched.

If the operation end event of the lane marking ECU 1 has not occurred, the process returns to step S1. On the other hand, if the operation end event of the lane marking ECU 1 has occurred, the lane marking ECU 1 ends the operation of the flowchart shown in FIG.

Instead of executing step S6, the lane marking ECU 1 constantly monitors whether or not the operation end event of the lane marking ECU 1 has occurred during the operation of the flowchart, and the operation end event of the lane marking ECU 1 occurs. If so, the operation of the flowchart may be terminated immediately. In this case, when the process of step S5 is completed, the process may return to step S1.

<3. Notes>
In addition to the above-described embodiment, various technical features disclosed in the present specification can be modified in various ways without departing from the spirit of the technical creation. That is, it should be considered that the above embodiments are exemplary in all respects and are not restrictive, and the technical scope of the present invention is not the description of the above embodiments but the claims. It is shown and should be understood to include all modifications that fall within the meaning and scope of the claims.

For example, the lane marking ECU 1 outputs information related to the first reference line and the second reference line to the display device, and the display device superimposes the first reference line and the second reference line on the camera image. May be displayed. This superimposed display allows the driver of the vehicle to clearly recognize the parking lot.

1 Road marking ECU
10 Video acquisition unit 11 Detection unit 12 Generation unit 13 Position calculation unit 14 End point coordinate calculation unit 2 Imaging unit 21-23 Camera 3 Vehicle control ECU
4 In-vehicle network

Claims (8)

A detection unit that detects the first and second lane markings from the captured image obtained by the camera that captures the surroundings of the vehicle.
A first reference line having an end point corresponding to a vehicle-side end of the first lane marking and parallel to the average direction of the first lane marking and the second lane marking, and the second lane marking. A generation unit having an end point corresponding to the vehicle side end and generating a second reference line parallel to the average direction of the first division line and the second division line.
A position calculation unit that calculates a target parking position based on the end points and directions of the first reference line and the end points and directions of the second reference line.
End point coordinate calculation for calculating the end point coordinates of the first reference line and the end point coordinates of the second reference line based on the target parking position and the average direction of the first reference line and the second reference line. With a department,
The detection unit sets an area of interest based on the end point coordinates of the first reference line and the end point coordinates of the second reference line calculated by the end point coordinate calculation unit. .. The position calculation unit
The first coordinates that are separated by a predetermined length from the end point of the first reference line toward the side opposite to the vehicle in the direction of the first reference line are calculated.
The second coordinates that are separated by the predetermined length from the end point of the second reference line toward the side opposite to the vehicle in the direction of the second reference line are calculated.
Half the distance between the end point of the first reference line and the second reference line from the first coordinate toward the second reference line side in a direction perpendicular to the direction of the first reference line. Calculate the third coordinate that is
The distance between the end point of the first reference line and the second reference line from the first coordinate in a direction perpendicular to the direction of the first reference line toward the side opposite to the second reference line. Calculate the fourth coordinate, which is half away from
Half the distance between the end point of the first reference line and the second reference line from the second coordinate toward the first reference line side in a direction perpendicular to the direction of the second reference line. Calculate the fifth coordinate that is
The distance between the end point of the first reference line and the second reference line from the second coordinate in a direction perpendicular to the direction of the second reference line toward the side opposite to the first reference line. Calculate the sixth coordinate, which is half away from
Of the third coordinate to the sixth coordinate, the two coordinates that minimize the distance between the two points are selected, and the coordinate of the two selected coordinates that is closer to the vehicle is used as the coordinate of the target parking position. The lane marking detection device according to claim 1, wherein the lane markings are detected. The region of interest is a first region of interest set based on the end point coordinates of the first reference line calculated by the end point coordinate calculation unit, and the second reference calculated by the end point coordinate calculation unit. Includes a second region of interest, which is set based on the end point coordinates of the line,
The lane marking detection device according to claim 1 or 2, wherein the first region of interest and the second region of interest are separated from each other. The lane marking detection device according to claim 3, wherein the top view area of the first area of interest and the top view area of the second area of interest are each smaller than the top view area of the vehicle. The lane marking detection device according to any one of claims 1 to 4, further comprising an output unit that outputs information related to the first reference line and the second reference line to the outside. The output unit sets the coordinates of the target parking position and the angle of the average direction of the first reference line and the second reference line with respect to the front-rear direction of the vehicle to the first reference line and the second reference line. The lane marking detection device according to claim 5, which outputs information related to the reference line of the above to the outside. A camera that shoots the area around the vehicle,
A lane marking detection system comprising the lane marking detection device according to any one of claims 1 to 6. A detection process for detecting the first lane markings and the second lane markings from the captured images obtained by a camera that photographs the surroundings of the vehicle, and
A first reference line having an end point corresponding to a vehicle-side end of the first lane marking and parallel to the average direction of the first lane marking and the second lane marking, and the second lane marking. A generation step of generating a second reference line having an end point corresponding to the vehicle side end and parallel to the average direction of the first lane marking and the second lane marking.
A position calculation step of calculating a target parking position based on the end points and directions of the first reference line and the end points and directions of the second reference line.
End point coordinate calculation for calculating the end point coordinates of the first reference line and the end point coordinates of the second reference line based on the target parking position and the average direction of the first reference line and the second reference line. Process and
A lane marking detection method comprising: a step of setting an area of interest based on the end point coordinates of the first reference line calculated in the end point coordinate calculation step and the end point coordinates of the second reference line. ..