A road marking method based on visual standard points

Abstract

The present invention relates to a road marking method based on visual marking points, the method comprising: marking a plurality of marking points on a road to be marked, starting a marking operation, obtaining a current posture of a marking mechanism, and obtaining a current posture error based on the current posture; when the current posture error is less than a preset threshold value and exceeds an allowable error range for marking, performing image acquisition on the marking points through a camera to obtain an initial image; performing image processing on the initial image to obtain an HSV color image, marking the contours of the marking points based on the HSV color image, and calculating the characteristic center of the marking points; constructing a bounding circle with the characteristic center of the marking points as the center and a preset threshold as the radius, determining the positional relationship between the image anchor point and the bounding circle, and adjusting the posture of the marking mechanism based on the determination result to perform road marking. Through the present application, a road marking operation with high precision and high stability can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic road marking in road construction, and in particular to a road marking method based on visual marking points. Background Art

[0002] Traditional road marking is done manually, which relies on human operation and judgment. The quality and efficiency of road marking are affected by the skills and experience of the operators. It is difficult to meet the current heavy workload of road marking in my country. Therefore, road marking can be combined with modern science and technology to improve the efficiency and quality of road marking.

[0003] However, some existing technologies have certain defects. For example, GPS (Global Positioning System) has difficulty achieving accurate positioning in urban areas, tunnels, and indoor environments, and it is difficult to achieve high-precision and high-stability positioning in complex urban environments. Traditional sensors such as WO (wheel odometer) and IMU (inertial measurement unit) are easily affected by problems such as ground slippage and accumulated system errors during long-term operation, resulting in reduced positioning accuracy.

[0004] Therefore, there is an urgent need for a road marking method that can solve the problems of high cost, low efficiency, and long time consumption of traditional road marking methods, as well as the limitations of various positioning and navigation sensors on environmental factors and cumulative errors. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a road marking method based on visual marking points to solve the shortcomings of the existing technology.

[0006] To achieve the above object, the present invention provides a road marking method based on visual marker points, the method comprising:

[0007] Marking multiple sample points on the road to be marked, starting the marking operation, obtaining the current posture of the marking mechanism based on the fusion data of the wheel odometer and the IMU, and obtaining the current posture error based on the current posture;

[0008] When the current posture error is less than a preset threshold and exceeds the allowable error range of marking, an image of the standard point is captured by a camera to obtain an initial image, wherein the camera is provided on the marking mechanism;

[0009] Performing image processing on the initial image to obtain an HSV color image, marking the outline of the standard sample point based on the HSV color image, and calculating the characteristic center of the standard sample point;

[0010] A defining circle is constructed with the characteristic center of the standard point as the center and the preset threshold as the radius, the positional relationship between the image anchor point and the defining circle is determined, and the posture of the marking mechanism is adjusted based on the determination result to perform road marking.

[0011] The beneficial effects of the present invention are as follows: by marking multiple reference points on a road to be marked, after starting the road marking operation, the current posture of the road marking mechanism is obtained based on the fusion data of the wheel odometer and the IMU, and the current posture error is obtained based on the current posture. When the current posture error is less than a preset threshold and exceeds the allowable error range of road marking, the camera on the road marking mechanism is used to capture an image of the reference points to obtain an initial image, and the initial image is processed to obtain an HSV color image. The contours of the reference points are marked using the HSV color image, and the characteristic centers of the reference points are calculated and obtained. Then, a defining circle is constructed with the characteristic centers of the reference points as the circle center and a preset threshold as the radius. By determining the positional relationship between the image anchor point and the defining circle, the posture of the road marking mechanism is adjusted to achieve accurate and stable road marking operation. The problem of time-consuming, labor-intensive and inefficient road marking operation caused by relying on manual operation and judgment is solved, and the problem of inaccurate road marking caused by various positioning and navigation sensors being limited by environmental factors and accumulated errors is solved.

[0012] Furthermore, the method further comprises:

[0013] The defined circle is divided into eight regions by determining one region every π / 4 in a clockwise direction, wherein the eight regions are a first region, a second region, a third region, a fourth region, a fifth region, a sixth region, a seventh region, and an eighth region;

[0014] A rectangular coordinate system is established with the center of the defined circle as the origin, the axis of symmetry of the first region or the fifth region as the Y axis, and the axis of symmetry of the third region or the seventh region as the X axis.

[0015] Furthermore, the step of adjusting the posture of the marking mechanism based on the judgment result includes:

[0016] When the image anchor point is located within the first area and close to the right side of the Y-axis, controlling the marking mechanism to move leftward;

[0017] When the image anchor point is located within the first area and close to the left side of the Y-axis, controlling the marking mechanism to move rightward;

[0018] When the image anchor point is located within the second area and close to the symmetry axis of the second area, controlling the marking mechanism to move leftward;

[0019] When the image anchor point is located within the third area and close to the symmetry axis of the third area, controlling the marking mechanism to move leftward;

[0020] When the image anchor point is located within the fourth region and close to the symmetry axis of the fourth region, controlling the marking mechanism to move leftward;

[0021] When the image anchor point is located within the fifth area and close to the right side of the Y-axis, controlling the scribing mechanism to move leftward;

[0022] When the image anchor point is located within the fifth area and close to the left side of the Y-axis, controlling the scribing mechanism to move rightward;

[0023] When the image anchor point is located within the sixth region and close to the axis of symmetry of the sixth region, controlling the marking mechanism to move rightward;

[0024] When the image anchor point is located within the seventh region and close to the symmetry axis of the seventh region, controlling the marking mechanism to move rightward;

[0025] When the image anchor point is located within the eighth region and close to the symmetry axis of the eighth region, the scribing mechanism is controlled to move rightward.

[0026] Furthermore, the method further comprises:

[0027] The lateral deviation of the marking mechanism is obtained, the lateral deviation is compared with a preset initial condition, and the proportional gain of the adaptive PID controller is adjusted based on the comparison result to perform a regulation operation on the marking mechanism.

[0028] Furthermore, the calculation formula of the feature center is as follows:

[0029]

[0030] Among them, max(d) represents the distance between the two farthest point sets M and point set N. represents the circumcircle, Represents the characteristic center of the standard sample point, m1 and m2 both represent elements in the point set M, and n1 and n2 both represent elements in the point set N.

[0031] Furthermore, before starting the marking operation, the method further includes:

[0032] For wheel odometry calibration, the camera and IMU are jointly calibrated using the Kalibr toolkit;

[0033] The position of the marking mechanism is adjusted according to the driving direction, and the marking distance between the marking mechanism and the standard sample point is set. The expression of the marking distance is as follows:

[0034]

[0035] in, represents the stroke distance, Indicates the lateral offset between the camera and the reference point. Indicates the lateral offset between the camera and the center of motion, It represents the lateral deviation between the center of motion and the marking mechanism.

[0036] Furthermore, the method further comprises:

[0037] When the current posture error is less than the preset threshold and exceeds the line-marking allowable error range, resetting the fusion data of the wheel odometer and the IMU;

[0038] When the current posture error is smaller than the preset threshold and smaller than the line marking allowable error range, a normal line marking operation is performed.

[0039] Furthermore, the method further comprises:

[0040] When the current posture error is greater than the preset threshold, a buzzer warning is activated and the marking operation is stopped. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a flow chart of a road marking method based on visual landmark points according to an embodiment of the present invention;

[0042] Figure 2 is a schematic diagram of a scribing mechanism according to an embodiment of the present invention;

[0043] Figure 3 A schematic diagram illustrating the positional relationship between different regions of a defined circle and an image anchor point according to an embodiment of the present invention;

[0044] Figure 4 A schematic diagram of a characteristic center of a standard sample point according to an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of a self-adaptive PID controller controlling the marking mechanism to perform posture adjustment operation according to an embodiment of the present invention;

[0046] Figure 6 Schematic diagram of an application of a road marking method based on visual landmark points according to an embodiment of the present invention.

[0047] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely used to explain this application and are not intended to limit this application. Based on the embodiments provided in this application, all other embodiments obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of this application.

[0049] Obviously, the drawings described below are merely examples or embodiments of the present application. Those skilled in the art can, without inventive effort, apply the present application to other similar scenarios based on these drawings. Furthermore, it is also understood that, although the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, changes in design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as an insufficiency of the content disclosed in this application.

[0050] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments unless there is a conflict.

[0051] Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by persons of ordinary skill in the art to which this application belongs. The terms "a," "an," "an," "the," and similar expressions used herein do not denote quantitative limitations and may refer to either the singular or the plural. The terms "comprise," "include," "have," and any variations thereof, used herein, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or modules (units) is not limited to the listed steps or units but may also include steps or units not listed, or may include other steps or units inherent to the process, method, product, or apparatus. The terms "connected," "connected," "coupled," and similar expressions used herein are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. As used herein, "plurality" means two or more. "And / or" describes an association between associated objects, indicating that three possible relationships exist. For example, "A and / or B" may mean: A exists alone; A and B exist simultaneously; or B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0052] Example 1

[0053] See also Figures 1-6 , the road marking method based on visual sample points in the first embodiment of the present invention, such as Figure 1 As shown, the method includes the following steps:

[0054] Step S101: Mark multiple sample points on the road to be marked, start the marking operation, obtain the current posture of the marking mechanism based on the fusion data of the wheel odometer and the IMU, and obtain the current posture error based on the current posture;

[0055] The number of standard points is determined based on the road marking plan. Both the wheel odometer and IMU (Inertial Measurement Unit) are mounted on the marking mechanism. The wheel odometer is equipped with a high-precision encoder that can measure the rotational speed of the marking mechanism's encoder motor, thereby inferring the mechanism's position (displacement and attitude). The IMU contains an accelerometer and gyroscope, which respectively measure the acceleration and angular velocity of each axis of the marking mechanism, thereby measuring the mechanism's attitude. However, in actual applications, wheel odometers and IMUs are subject to slippage, temperature drift, noise, and other factors, resulting in cumulative system errors. Therefore, it is necessary to fuse their data to reduce the impact of these errors and obtain a more accurate attitude.

[0056] It should be noted that the step of obtaining the current posture error based on the current posture is specifically as follows: the horizontal deviation can be solved by obtaining the current posture, and the projections in each direction are calculated by constructing a vector triangle to obtain the current posture error.

[0057] Step S102: When the current posture error is less than a preset threshold and exceeds the allowable error range of marking, an image of the standard point is captured by a camera to obtain an initial image, wherein the camera is provided on the marking mechanism;

[0058] The current posture error is first compared with the preset threshold, and when the current posture error is smaller than the preset threshold, the current posture error is then compared with the line drawing allowable error range.

[0059] Furthermore, the method further comprises:

[0060] When the current posture error is greater than the preset threshold, a buzzer warning is activated and the marking operation is stopped.

[0061] Step S103: performing image processing on the initial image to obtain an HSV color image, marking the contours of the standard points based on the HSV color image, and calculating the feature centers of the standard points;

[0062] RGB (red, green, and blue) is a hardware-based color representation, while HSV (hue, saturation, and value) is more consistent with the human eye's intuitive perception of color. The value (V) channel in the HSV space is directly related to light intensity, while the hue (H) and saturation (S) channels are relatively insensitive to changes in lighting. This makes color segmentation and recognition using the HSV space more stable under changing lighting conditions. Furthermore, in image processing algorithms, using the HSV space can simplify the calculation process and improve computational efficiency. Therefore, in this application, the original image is adjusted and processed into an HSV color image in the HSV space.

[0063] Furthermore, the step of performing image processing on the initial image includes:

[0064] The initial image is sequentially subjected to distant image filtering, near image processing, bilateral filtering and color conversion processing.

[0065] Furthermore, the circumscribed contour of the standard point is obtained, and the maximum diameter circumscribed circle in the circumscribed contour is calculated. The coordinates of the pixel point in the HSV color image where the center of the maximum diameter circumscribed circle lies are the feature center of the standard point.

[0066] The calculation formula of the characteristic center of the standard sample point is as follows:

[0067]

[0068] in, is the characteristic center of the standard sample point, is the maximum diameter of the circumscribed contour, is the circumcircle of maximum diameter.

[0069] Step S104: constructing a bounding circle with the feature center of the standard point as the center and the preset threshold as the radius, determining the positional relationship between the image anchor point and the bounding circle, and adjusting the posture of the marking mechanism based on the determination result to perform road marking.

[0070] The preset threshold determines the degree of deviation of the marking mechanism. Therefore, a bounding circle is constructed with the preset threshold as its radius. When the image anchor point is within the bounding circle, this indicates that the deviation between the marking mechanism and the line segment to be marked is within a reasonable adjustment range. It should be noted that different marking scenarios have different marking standards. In some areas with high marking accuracy, the error is between 1 cm and 3 cm. The preset threshold is determined based on these marking standards to ensure that the marking accuracy meets the standard.

[0071] In addition, the defining circle is determined by the marking points, and the marking points are precise points placed in advance on the line segment to be marked. If the relative position of the image anchor point and the defining circle remains unchanged, the posture of the marking mechanism at each point is guaranteed to be correct, thereby ensuring the accuracy of the marking. Therefore, the position of the image anchor point can be judged with reference to the defining circle.

[0072] Through the above steps, multiple reference points are marked on the road to be marked. After the marking operation is started, the current posture of the marking mechanism is obtained based on the fusion data of the wheel odometer and the IMU, and the current posture error is obtained based on the current posture. When the current posture error is less than a preset threshold and exceeds the allowable error range for marking, the camera on the marking mechanism captures an image of the reference point to obtain an initial image. The initial image is processed to obtain an HSV color image. The contours of the reference points are marked using the HSV color image, and the feature centers of the reference points are calculated. Then, a defining circle is constructed with the feature centers of the reference points as the circle center and a preset threshold as the radius. The posture of the marking mechanism is adjusted by determining the positional relationship between the image anchor point and the defining circle to achieve accurate and stable road marking operations. This solves the problem of time-consuming, labor-intensive, and inefficient road marking operations caused by manual operation and judgment in existing road marking. It also solves the problem of inaccurate marking caused by various positioning and navigation sensors being limited by environmental factors and accumulated errors.

[0073] Furthermore, before starting the marking operation, the method further includes:

[0074] For wheel odometry calibration, the camera and IMU are jointly calibrated using the Kalibr toolkit;

[0075] The linear parameters and angular parameters of the wheel odometer are calibrated by the marking machine traveling a straight distance and rotating in place, until the errors of the right-angle parameters and the angular parameters reach the corresponding wheel odometer thresholds, and the calibration operation of the wheel odometer is completed.

[0076] The position of the marking mechanism is adjusted according to the driving direction, and the marking distance between the marking mechanism and the standard sample point is set. The expression of the marking distance is as follows:

[0077]

[0078] in, represents the stroke distance, represents the lateral offset between the camera head and the reference point, Indicates the lateral offset between the camera head and the center of motion, It represents the lateral deviation between the motion center and the marking mechanism. The marking mechanism is a differential mobile robot. The motion center refers to the center of the line connecting the left and right independent drive wheels on the mobile robot.

[0079] It should be noted that if Figure 2 As shown, the marking mechanism includes a circumferential slide 1, a rectangular slide 2, a telescopic arm 3 and a marking structure 4. The marking structure 4 can adjust its position and lateral offset relative to the center of motion according to the circumferential slide 1, the rectangular slide 2 and the telescopic arm 3. , assuming the total length of the rectangular slide rail 2 and the telescopic arm 3 is , the angle between the rectangular slide 2 and the travel direction is ,but .

[0080] Furthermore, the method further comprises:

[0081] When the current posture error is less than the preset threshold and exceeds the line-marking allowable error range, resetting the fusion data of the wheel odometer and the IMU;

[0082] When the current posture error is smaller than the preset threshold and smaller than the line marking allowable error range, a normal line marking operation is performed.

[0083] Furthermore, the method further comprises:

[0084] The defined circle is divided into eight regions by determining one region every π / 4 in a clockwise direction, wherein the eight regions are a first region, a second region, a third region, a fourth region, a fifth region, a sixth region, a seventh region, and an eighth region;

[0085] A rectangular coordinate system is established with the center of the defined circle as the origin, the axis of symmetry of the first region or the fifth region as the Y axis, and the axis of symmetry of the third region or the seventh region as the X axis.

[0086] Among them, such as Figure 3 As shown, the symmetry axis of the first region is defined as the 0 position or the 2π position relative to the bounding circle. Similarly, the symmetry axis of the second region is defined as Position, the symmetry axis of the third region is defined as Position, the symmetry axis of the fourth region is defined as The symmetry axis of the fifth region is defined as Position, the symmetry axis of the sixth region is defined as The symmetry axis of the seventh region is defined as Position, the symmetry axis of the eighth region is defined as Location.

[0087] Furthermore, the step of adjusting the posture of the marking mechanism based on the judgment result includes:

[0088] When the image anchor point is located within the first area and close to the right side of the Y-axis, controlling the marking mechanism to move leftward;

[0089] When the image anchor point is located within the first area and close to the left side of the Y-axis, controlling the marking mechanism to move rightward;

[0090] When the image anchor point is located within the second area and close to the symmetry axis of the second area, controlling the marking mechanism to move leftward;

[0091] When the image anchor point is located within the third area and close to the symmetry axis of the third area, controlling the marking mechanism to move leftward;

[0092] When the image anchor point is located within the fourth region and close to the symmetry axis of the fourth region, controlling the marking mechanism to move leftward;

[0093] When the image anchor point is located within the fifth area and close to the right side of the Y-axis, controlling the scribing mechanism to move leftward;

[0094] When the image anchor point is located within the fifth area and close to the left side of the Y-axis, controlling the scribing mechanism to move rightward;

[0095] When the image anchor point is located within the sixth region and close to the axis of symmetry of the sixth region, controlling the marking mechanism to move rightward;

[0096] When the image anchor point is located within the seventh region and close to the symmetry axis of the seventh region, controlling the marking mechanism to move rightward;

[0097] When the image anchor point is located within the eighth region and close to the symmetry axis of the eighth region, the scribing mechanism is controlled to move rightward.

[0098] If the image anchor point is within the defined circle and close to position 0, if it is close to the right side of position 0, the marking mechanism moves to the left, and if it is close to the left side of position 0, the marking mechanism moves to the right; if the image anchor point is within the defined circle and close to position 0, the marking mechanism moves to the right. Position, the lateral deviation of the marking mechanism is to the right, and the marking mechanism needs to move to the left; if the image anchor point is within the defined circle and close to Position, the lateral deviation of the marking mechanism is to the right, and the marking mechanism needs to move to the left; if the image anchor point is within the defined circle and close to Position, the lateral deviation of the marking mechanism is to the right, and the marking mechanism needs to move to the left; if the image anchor point is within the defined circle and close to Location, if close If the marking mechanism is on the right side of the position, it needs to move to the left. If the image anchor point is within the defined circle and close to the left of the position, the marking mechanism moves to the right; Position, the lateral deviation of the marking mechanism is to the left, and the marking mechanism needs to move to the right; if the image anchor point is within the defined circle and close to Position, the lateral deviation of the marking mechanism is to the left, and the marking mechanism needs to move to the right; if the image anchor point is within the defined circle and close to position, the lateral deviation of the marking mechanism is to the left, and the marking mechanism needs to be moved to the right.

[0099] It should be noted that the deviation value between the image anchor point and the feature center is first calculated, and the deviation value is compared with the preset threshold to determine whether the image anchor point is within the defined circle, and then the next step of judgment is performed, wherein the deviation value between the image anchor point and the feature center of the standard sample point is The calculation formula is as follows:

[0100]

[0101] in, represents the coordinates of the image anchor point, Represents the characteristic center of the standard sample point.

[0102] When it is determined that the image anchor point is within the defined circle and the image anchor point is not the center of the defined circle, the deviation value Preset threshold , and the deviation value , and then based on the complementary angle between the line connecting the image anchor point and the center of the defined circle and the horizontal angle , to adjust the posture of the marking mechanism. Specifically, define the preset small amount as , we can get the following: If , and in ,exist like , then keep to the left, if , then keep to the left, if , then keep to the left, if , and in ,exist ;like , then keep to the right, if , then keep to the right, if , then keep to the right.

[0103] Furthermore, the calculation formula of the feature center is as follows:

[0104]

[0105] Among them, max(d) represents the distance between the two most distant point sets M and N, that is, the maximum diameter of the circumscribed contour. represents the circumcircle, Represents the characteristic center of the standard sample point, m1 and m2 both represent elements in the point set M, and n1 and n2 both represent elements in the point set N.

[0106] It should be noted that if Figure 4 , which is a schematic diagram of the characteristic center of the standard sample point.

[0107] Furthermore, the method further comprises:

[0108] The lateral deviation of the marking mechanism is obtained, the lateral deviation is compared with a preset initial condition, and the proportional gain of the adaptive PID controller is adjusted based on the comparison result to perform a regulation operation on the marking mechanism.

[0109] Among them, such as Figure 5, which is a schematic diagram of controlling the marking mechanism to perform posture adjustment operation by an adaptive PID controller. Specifically, the preset initial conditions include a first initial threshold value T1 and a second initial threshold value T2. When the image anchor point is located within the first area and the fifth area, the lateral deviation of the marking mechanism is small, that is, the lateral deviation E is less than the first initial threshold value T1, and the proportional gain is reduced.

[0110] When the image anchor point is located within the second area, the fourth area, the sixth area, and the eighth area, and the lateral deviation of the marking mechanism is moderate, that is, the lateral deviation E is greater than the first initial threshold value T1 and less than the second initial threshold value T2, the proportional gain is maintained or moderately increased;

[0111] When the image anchor point is located within the third area and the seventh area, the lateral deviation of the marking mechanism is large, that is, the lateral deviation value E is greater than the second initial threshold value T2, and the proportional gain is increased.

[0112] It should be noted that the proportional gain of the adaptive PID controller is adjusted and updated to obtain the latest system output value U. The system output U is also the input value of the left and right encoding motors of the marking mechanism, that is, after the adaptive PID algorithm, the speed difference of the left and right encoding motors is controlled, and the left and right encoding motors for controlling the independent drive wheels of the marking mechanism are controlled by the system output value U to control the posture adjustment of the marking mechanism. At the same time, the actual output value Y of the encoding motor (the actual image deviation value obtained after the left and right encoding motors adjust the speed difference) will be fed back to the adaptive PID controller to form a closed-loop control. It should be noted that the entire control system is in a cyclic adjustment process until the target value is reached, and the adaptive PID controller regulates the encoding motor through the joint action of proportional control, integral control and differential control.

[0113] Furthermore, the expression of the lateral deviation E is as follows:

[0114]

[0115] The expression of proportional control P is as follows:

[0116]

[0117] The expression of integral control I is as follows:

[0118]

[0119] The expression of differential control D is as follows:

[0120]

[0121] The expression of the total control Q of the adaptive PID controller is as follows:

[0122]

[0123] Where R is the expected value, is the actual output value of the encoder motor last time, t is the time, is the integral gain, is the differential gain, is the proportional gain.

[0124] Furthermore, the expression for filtering the distant image and processing the near image on the initial image is as follows:

[0125]

[0126] in, represents the acquired image, Indicates the height of the image, Indicates the width of the image, They all represent the pixels of the image.

[0127] The expression for converting the image color space is as follows:

[0128]

[0129]

[0130]

[0131]

[0132] in, Represents the normalized RGB value, Indicates the maximum value of RGB, Indicates the minimum RGB value, Indicates the difference between the maximum RGB value and the minimum RGB value. represents hue, S represents saturation, and V represents value.

[0133] Example 2

[0134] A second embodiment of the present invention is based on the same inventive concept and proposes a computer-readable storage medium. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the steps of the road marking method based on visual landmark points of the above embodiment are implemented.

[0135] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, "computer-readable medium" can be any device that stores, communicates, propagates, or transmits a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0136] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting, or processing it in another suitable manner as necessary, and then storing it in a computer memory.

[0137] The memory may include a large-capacity memory for data or instructions. By way of example, and not limitation, the memory may include a hard disk drive (HDD), a floppy disk drive, a solid-state drive (SSD), flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory may include removable or non-removable (or fixed) media. Where appropriate, the memory may be internal or external to the data processing device. In a specific embodiment, the memory is non-volatile memory. In a specific embodiment, the memory includes read-only memory (ROM) and random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically alterable ROM (EAROM) or a flash memory (FLASH), or a combination of two or more of these. Under appropriate circumstances, the RAM can be a static random access memory (SRAM) or a dynamic random access memory (DRAM), where the DRAM can be a fast page mode dynamic random access memory (FPMDRAM), an extended data out dynamic random access memory (EDODRAM), a synchronous dynamic random access memory (SDRAM), etc.

[0138] Example 3

[0139] A third embodiment of the present invention, based on the same inventive concept, proposes a terminal comprising: a processor and a memory; the processor and the memory communicate with each other; the memory is used to store instructions; the processor is used to execute the instructions in the memory to execute the road marking method based on visual sample points of the above embodiment.

[0140] It should be understood that various components of the present invention may be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof may be used: a discrete logic circuit having logic gate circuits for implementing logic functions on data signals, an application-specific integrated circuit having suitable combinational logic gate circuits, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0141] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0142] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0143] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A road marking method based on visual sample points, characterized in that: The method comprises: Marking multiple sample points on the road to be marked, starting the marking operation, obtaining the current posture of the marking mechanism based on the fusion data of the wheel odometer and the IMU, and obtaining the current posture error based on the current posture; When the current posture error is less than a preset threshold and exceeds the allowable error range of marking, an image of the standard point is captured by a camera to obtain an initial image, wherein the camera is provided on the marking mechanism; Performing image processing on the initial image to obtain an HSV color image, marking the outline of the standard sample point based on the HSV color image, and calculating the characteristic center of the standard sample point; Constructing a bounding circle with the characteristic center of the standard point as the center and the preset threshold as the radius, determining the positional relationship between the image anchor point and the bounding circle, and adjusting the posture of the marking mechanism based on the determination result to perform road marking; The calculation formula of the feature center is as follows: Among them, max(d) represents the distance between the two farthest point sets M and point set N. represents the circumcircle, Represents the characteristic center of the standard sample point, m1 and m2 both represent elements in the point set M, and n1 and n2 both represent elements in the point set N.

2. The road marking method based on visual sample points according to claim 1, characterized in that: The method further comprises: The defined circle is divided into eight regions by determining one region every π / 4 in a clockwise direction, wherein the eight regions are a first region, a second region, a third region, a fourth region, a fifth region, a sixth region, a seventh region, and an eighth region; A rectangular coordinate system is established with the center of the defined circle as the origin, the axis of symmetry of the first region or the fifth region as the Y axis, and the axis of symmetry of the third region or the seventh region as the X axis.

3. The road marking method based on visual sample points according to claim 2, characterized in that: The step of adjusting the posture of the marking mechanism based on the judgment result includes: When the image anchor point is located within the first area and close to the right side of the Y-axis, controlling the marking mechanism to move leftward; When the image anchor point is located within the first area and close to the left side of the Y-axis, controlling the marking mechanism to move rightward; When the image anchor point is located within the second area and close to the symmetry axis of the second area, controlling the marking mechanism to move leftward; When the image anchor point is located within the third area and close to the symmetry axis of the third area, controlling the marking mechanism to move leftward; When the image anchor point is located within the fourth region and close to the symmetry axis of the fourth region, controlling the marking mechanism to move leftward; When the image anchor point is located within the fifth area and close to the right side of the Y-axis, controlling the scribing mechanism to move leftward; When the image anchor point is located within the fifth area and close to the left side of the Y-axis, controlling the scribing mechanism to move rightward; When the image anchor point is located within the sixth region and close to the axis of symmetry of the sixth region, controlling the marking mechanism to move rightward; When the image anchor point is located within the seventh region and close to the symmetry axis of the seventh region, controlling the marking mechanism to move rightward; When the image anchor point is located within the eighth region and close to the symmetry axis of the eighth region, the scribing mechanism is controlled to move rightward.

4. The road marking method based on visual sample points according to claim 2, characterized in that: The method further comprises: The lateral deviation of the marking mechanism is obtained, the lateral deviation is compared with a preset initial condition, and the proportional gain of the adaptive PID controller is adjusted based on the comparison result to perform a regulation operation on the marking mechanism.

5. The road marking method based on visual sample points according to claim 1, characterized in that: Before starting the marking operation, the method further includes: For wheel odometry calibration, the camera and IMU are jointly calibrated using the Kalibr toolkit; The position of the marking mechanism is adjusted according to the driving direction, and the marking distance between the marking mechanism and the standard sample point is set. The expression of the marking distance is as follows: in, represents the stroke distance, Indicates the lateral offset between the camera and the reference point. Indicates the lateral offset between the camera and the center of motion, It represents the lateral deviation between the center of motion and the marking mechanism.

6. The road marking method based on visual sample points according to claim 1, characterized in that: The method further comprises: When the current posture error is less than the preset threshold and exceeds the line-marking allowable error range, resetting the fusion data of the wheel odometer and the IMU; When the current posture error is smaller than the preset threshold and smaller than the line marking allowable error range, a normal line marking operation is performed.

7. The road marking method based on visual sample points according to claim 1, characterized in that: The method further comprises: When the current posture error is greater than the preset threshold, a buzzer warning is activated and the marking operation is stopped.

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