A steering guidance method, system and vehicle

Abstract

This invention relates to the field of vehicle guidance and control technology, and provides a steering guidance method, system, and vehicle. The method includes the following steps: S1, acquiring an image of the road surface ahead and identifying lane lines in the road surface image; S2, fitting the curve equation of the lane lines within a predetermined distance ahead to obtain the turning radius of the lane lines ahead; S3, when a turn occurs within the predetermined distance ahead, using the turning radius and the turn of the lane lines ahead as the steering guidance radius and turn, respectively. This invention, by fitting the lane line curve of the road segment ahead in real time and extracting the curvature radius of the lane lines, uses the curvature radius of the lane lines as the turning guidance radius when a turn occurs ahead. The curvature radius of the steering guidance adaptively changes with the curvature radius of the road ahead, providing the driver with more precise steering prompts and greatly improving the driver's driving experience.

Description

Technical Field

[0001] This invention relates to the field of vehicle guidance and control technology, and provides a steering guidance method, system and vehicle. Background Technology

[0002] HUD stands for Head-Up Display, which can be understood as a head-up display or a head-up display device. It is also called a head-up display system, which refers to a driver-centric, blind-operated, multi-functional instrument panel.

[0003] Traditional HUD guidance uses fixed curvatures to guide vehicle steering. Common fixed curvatures include 90° for left turns and 180° for U-turns. However, in real-world driving environments, there are many non-standard intersections. For example, some ramps have a 20° curvature, while others have a 30° curvature. Some Y-shaped intersections have a 40° curvature, while others have a 30° curvature. The curvature radii involved in circular road sections are dynamically changing in real time. Existing HUD steering guidance can only roughly indicate vehicle steering using fixed curvatures.

[0004] Based on the above analysis, it can be seen that the existing HUD guidance has the problem of mismatch between steering guidance and actual steering. The steering guidance is not accurate enough when the driver is seated. The driver cannot intuitively feel the steering range of the road ahead through the HUD guidance, which affects the actual driving experience. Summary of the Invention

[0005] In view of this, this application provides a steering guidance method aimed at improving the above-mentioned problems.

[0006] Specifically, the following technical solutions are included:

[0007] On the one hand, embodiments of this application provide a steering guidance method, the method comprising the following steps:

[0008] S1. Acquire images of the road surface ahead and identify lane lines in the road surface images;

[0009] S2. Fit the curve equation of the lane line within the set distance ahead to obtain the turning radius of the lane line ahead;

[0010] S3. When a turn is detected within a set distance ahead, the turning radius and turn of the lane line ahead are used as the turning radius and turn for steering guidance, respectively.

[0011] In some embodiments, the method for identifying the lane lines ahead in the road surface image is as follows:

[0012] (1) Perform grayscale processing on the acquired road surface image and extract the lane lines of the road surface image based on the set grayscale value;

[0013] (2) Check whether the lane lines within the set distance ahead are complete. If the detection result is yes, the lane lines ahead are considered to have been successfully extracted.

[0014] In some embodiments, the method for determining whether lane lines are complete is as follows:

[0015] (1) Determine the ROI area within a set distance ahead of the vehicle;

[0016] (2) Detect whether there are lane lines on both sides of the lane where the vehicle is located within the ROI area. If they do not exist, the lane lines are considered incomplete. If they do exist, extract the lane line point set on both sides of the lane where the vehicle is located.

[0017] (3) Detect whether the distance between adjacent lateral coordinates on both sides of the lane where the vehicle is located exceeds the distance threshold. If it does, the lane line is considered incomplete; if it does not, the lane line is considered complete.

[0018] In some embodiments, when the lane line ahead is not extracted, the turning radius of the road segment ahead is extracted from the navigation map data, that is, the curve equation of the road segment ahead is read from the navigation data, and the turning radius A2 of the lane line ahead is extracted from the curve equation.

[0019] In some embodiments, a quadratic equation is used: y = A0 + A1x + (A2 / 2)x 2 Fit the discrete set of lane line points to obtain fitting coefficients A0, A1, and A2.

[0020] The radius of curvature r satisfies: y″=A2=1 / r.

[0021] In some embodiments, the method for determining whether a turn is possible within a predetermined distance ahead is as follows:

[0022] If the turning radius of the road segment within the set distance ahead is less than the set turning radius threshold, then it is determined that there is a turn within the set distance ahead.

[0023] In some embodiments, when turning from a straight line, the steering guidance is divided into two segments: a straight segment and a turning segment; wherein the turning segment is displayed based on the turning radius of the road segment ahead.

[0024] In some embodiments, when turning continuously on a road segment, the lane line curve within a set distance ahead is fitted in real time, and the turning guidance for the current cycle is performed based on the radius of curvature in the lane line curve. The end point of the current turning guidance is used as the starting point of the next cycle for the next turning guidance.

[0025] On the other hand, embodiments of this application provide a steering guidance system, the system comprising:

[0026] A camera located at the front of the vehicle and a navigation system integrated into the vehicle;

[0027] The camera, navigator, and control unit are connected for communication.

[0028] The camera captures real-time images of the road ahead of the vehicle and sends them to the control unit. The control unit reads navigation data of the road ahead from the navigator in real time and guides the vehicle's steering based on the aforementioned steering guidance method.

[0029] On the other hand, embodiments of this application provide a vehicle that integrates the aforementioned steering guidance system.

[0030] This invention fits the lane curve of the road ahead in real time and extracts the curvature radius of the lane line. When there is a turn ahead, the curvature radius of the lane line is used as the curvature radius for turn guidance. The curvature radius for turn guidance changes adaptively with the curvature radius of the road ahead, providing the driver with more accurate turn prompts and greatly improving the driver's driving experience. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A flowchart of a steering guidance method provided in an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the steering guidance system provided in an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of the lane line curve equation provided in an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of a steering guide arrow provided in an embodiment of the present invention;

[0036] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] Figure 1 The flowchart of the steering guidance method provided in the embodiment of the present invention includes the following steps:

[0039] S1. Acquire images of the road surface ahead and identify lane lines in the road surface images;

[0040] In this embodiment of the invention, the method for extracting lane lines is as follows:

[0041] (1) The acquired road surface image is processed into grayscale. Since the lane line color is different from the road surface color, the grayscale value of the pixels on the lane line is different from that of the pixels on the road surface. Therefore, the lane line of the road surface image can be extracted based on the set grayscale value.

[0042] (2) Check whether the lane lines of the road ahead are complete. If the detection result is yes, the lane lines ahead are successfully extracted and step S2 is executed. If the detection result is no, the lane lines ahead are failed to be extracted.

[0043] In this embodiment of the invention, the method for determining whether lane lines are complete is as follows:

[0044] (1) Determine the ROI area in front of the vehicle. The ROI area is a rectangle. The rectangular area 300m in front of the vehicle and 25m to the left and right is taken as the ROI area.

[0045] (2) Detect whether there are lane lines on both sides of the lane where the vehicle is located within the ROI area. If they do not exist, the lane lines are considered incomplete. If they do exist, extract the lane line point set on both sides of the lane where the vehicle is located.

[0046] (3) Detect whether the distance between adjacent lateral coordinates on both sides of the lane where the vehicle is located exceeds the distance threshold. If it does, the lane line is considered incomplete; if it does not, the lane line is considered complete.

[0047] It should be noted that the vehicle coordinate system uses the longitudinal direction of the vehicle as the x-axis and the lateral extension direction of the vehicle as the y-axis.

[0048] In this embodiment of the invention, during driving, there may be obstructions ahead, resulting in incomplete lane lines. In this case, it is impossible to extract the lane lines ahead based on the road surface image. Instead, the turning radius of the road segment ahead can only be extracted from the navigation map data.

[0049] In this embodiment of the invention, the method for determining the turning radius based on navigation data is as follows:

[0050] Read the curve equation of the road segment ahead from the navigation data, and extract the turning radii A2 and A1 of the lane ahead from the curve equation.

[0051] S2. Fit the curve equation of the lane line ahead to obtain the turning radius of the lane line ahead;

[0052] In this embodiment of the invention, a quadratic equation is used: y = A0 + A1x + (A2 / 2)x 2 By fitting a discrete set of lane line points, the values ​​of the three coefficients A0, A1, and A2 are obtained. The radius of curvature is extracted and mapped to the turning radius in the equation y = A0 + A1x + (A2 / 2)x. 2 In this equation, A2 can be approximated as the curvature of the lane line ahead, i.e., y″ = A2 = 1 / r; A1 is the tan value of the trigonometric function of the angle between the lane line ahead and the x-axis. This curvature is substituted into the trajectory of the steering guide arrow, and the equation of motion for the steering arrow on the head-up display is set as y″. j =A0′+A′1x c +(A2′ / 2)(x c ) 2 Where A′1=A1, A′2=A2, as shown Figure 3 As shown;

[0053] S3. Determine whether there is a turn within the set distance ahead based on the turning radius. If the detection result is yes, proceed to step S4. If the detection result is no, determine that the road ahead is straight and do not display turn guidance.

[0054] In this embodiment of the invention, if the turning radius of the lane ahead is less than a set turning radius threshold, it is determined that there is a turn ahead; if the turning radius of the lane ahead is greater than or equal to the set turning radius threshold, it is determined that there is no turn ahead.

[0055] S4. Use the turning radius and direction of the lane ahead as the turning radius and direction for steering guidance, respectively.

[0056] In this embodiment of the invention, steering guidance is achieved through the dynamic display of the traction arrow. To ensure a smooth display of the steering guide line, when transitioning from a straight line to a turn, the steering guide line is divided into two segments: a straight segment and a turning segment. The turning segment provides steering guidance based on the turning radius of the lane markings ahead, such as... Figure 4 As shown;

[0057] If one cycle of the steering guidance is 5 seconds, and a traction arrow appears every second, then the specific display strategy for straight-ahead steering is as follows:

[0058] When t∈(0,2], the line segment is displayed as follows:

[0059]

[0060] That is, when t∈(2,5], the curve segment is displayed based on the turning radius of the road segment ahead, as follows:

[0061]

[0062] In this embodiment of the invention, if the current road segment is in a continuous turning phase, such as a spiral road, the radius of curvature A2 of the lane ahead is constantly changing. The lane line curve within a set distance ahead is fitted in real time, and the turning guidance for the current cycle is performed based on the radius of curvature in the lane line curve. The end point of the current turning guidance is used as the starting point of the next cycle for the turning guidance of the next cycle.

[0063] In another embodiment of the invention, a U-turn is a special type of steering where the U-turn area lacks lane markings and cannot be performed using the aforementioned steering guidance method. Therefore, before steering guidance, it is first determined whether a U-turn is possible within a predetermined distance ahead.

[0064] S4. Based on navigation data, determine whether there is a U-turn situation within the set distance ahead. If the detection result is no, proceed to step S1. If the detection result is yes, turn 180 degrees based on the current driving direction as a U-turn guide.

[0065] Figure 2 This is a schematic diagram of a steering guidance system provided in an embodiment of the present invention. For ease of explanation, only the parts relevant to the embodiment of the present invention are shown. The system includes:

[0066] A camera located at the front of the vehicle and a navigation system integrated into the vehicle;

[0067] The camera, navigator, and control unit are connected for communication.

[0068] The camera captures real-time images of the road ahead of the vehicle and sends them to the control unit. The control unit reads navigation data of the road ahead from the navigator in real time and guides the vehicle's steering based on the aforementioned steering guidance method.

[0069] In this embodiment of the invention, the control unit can be located in the vehicle's existing controller, such as the vehicle control unit (VCU), or a separate controller specifically for steering control can be set up in the vehicle, with the control unit integrated into the separately set controller.

[0070] In another embodiment of the invention, a vehicle is also provided that integrates the above-described steering guidance system.

[0071] Unless otherwise defined, all technical terms used in the embodiments of this application have the same meaning as commonly understood by one of ordinary skill in the art.

[0072] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.

[0073] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A steering guidance method, characterized in that, The method includes the following steps: S1. Acquire images of the road surface ahead and identify lane lines in the road surface images; S2. Fit the curve equation of the lane line within the set distance ahead to obtain the turning radius of the lane line ahead; S3. When a turn is detected within a set distance ahead, the turning radius and turn of the lane line ahead are used as the turning radius and turn for steering guidance, respectively. The specific method for identifying the lane lines ahead in the road surface image is as follows: (1) Perform grayscale processing on the acquired road surface image and extract lane lines from the road surface image based on the set grayscale value; (2) Detect whether the lane lines within the set distance ahead are complete. If the detection result is yes, then extract the lane lines ahead. The specific method for determining whether lane lines are complete is as follows: (1) Determine the ROI area within a set distance ahead of the vehicle; (2) Detect whether there are lane lines on both sides of the lane where the vehicle is located within the ROI area. If they do not exist, the lane lines are considered incomplete. If they do exist, extract the lane line point set on both sides of the lane where the vehicle is located. (3) Detect whether the distance between adjacent lateral coordinates on both sides of the lane where the vehicle is located exceeds the distance threshold. If it does, the lane line is considered incomplete; if it does not, the lane line is considered complete. Using the quadratic equation y = A0 + A1x + (A2 / 2)x 2 Fit the discrete set of lane line points to obtain fitting coefficients A0, A1, and A2. Wherein, the radius of curvature r satisfies: y″=A2=1r; If there are continuous turns in the current road segment, the lane line curve within a set distance ahead is fitted in real time. The turning guidance for the current cycle is based on the radius of curvature in the lane line curve. The end point of the current turning guidance is used as the starting point of the next cycle for the next turning guidance.

2. The steering guidance method as described in claim 1, characterized in that, If the lane line ahead is not extracted, the turning radius of the road segment ahead is extracted from the navigation map data. That is, the curve equation of the road segment ahead is read from the navigation data, and the turning radius A2 of the lane line ahead is extracted from the curve equation.

3. The steering guidance method as described in claim 1, characterized in that, The specific method for determining whether a turn is possible within a predetermined distance ahead is as follows: If the turning radius of the lane line within the set distance ahead is less than the set turning radius threshold, then it is determined that there is a turn within the set distance ahead.

4. The steering guidance method as described in claim 1, characterized in that, When turning from a straight line, the steering guidance is divided into two segments: the straight segment and the turning segment. Among them, the steering guidance for the steering segment is based on the turning radius of the lane line ahead.

5. A steering guidance system, characterized in that, The system includes: A camera located at the front of the vehicle and a navigation system integrated into the vehicle; The camera, navigator, and control unit are connected for communication. The camera captures images of the road surface ahead of the vehicle in real time and sends them to the control unit. The control unit reads navigation data of the road ahead from the navigator in real time. The control unit guides the vehicle's steering based on the steering guidance method described in any one of claims 1 to 4.

6. A vehicle, characterized in that, The vehicle is equipped with the steering guidance system as described in claim 5.

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