AR (Augmented Reality) equipment and method for golf motion guidance

Abstract

The invention discloses AR (Augmented Reality) equipment and method for golf motion guidance, the equipment comprises an AR terminal display, a position sensor, an attitude sensor, an image acquisition device, a processor and a court information database, the position sensor and the attitude sensor respectively have a relatively fixed position relationship and a relatively fixed space relationship with the image acquisition device; the position sensor and the attitude sensor respectively acquire position information and attitude information of the image acquisition device, the image acquisition device acquires real-time image information, and the processor is used for receiving data acquired by the position sensor, the attitude sensor and the image acquisition device. And obtaining the position of the golf ball, calling information in the ball field information database to obtain topographic data and the position of a target ball hole, generating an initial motion condition and a reference motion track of the golf ball, and then overlapping the information and a real ball field and presenting the information and the real ball field in an AR terminal display. The problem that the ball hitting track of a player deviates from a target curve is solved, and motion guidance is provided in golf training and daily motion.

Description

Technical Field

[0001] The present invention relates to a movement guidance system for golf.

[0002] More specifically, the present invention relates to presenting sports guidance and predicted golf movement information to players on AR devices through augmented reality technology during golf movement. Background Art

[0003] Golf is a healthy sport. Besides entertaining the body and mind, playing golf also allows you to enjoy the sunshine and fresh air. Therefore, golf has become a popular sport worldwide. The smart devices provided for golf in the prior art have added convenience and fun to the sport. The patent with application number 202111534187.X introduces a motion pattern processing method and a wearable device that can display the motion path of a golf ball after being hit, which is beneficial for users to review golf to improve the stability of their own performance. However, the golf swing action seems simple, but it requires the coordination of various parts of the body. In the time from swing to hit, which is less than one second, the action is very important to the trajectory of the golf ball. The hitting point and the direction of the shot directly affect the trajectory of the golf ball. These two points are difficult for novice golfers to grasp, so they often hit shots that deviate from the target line. Summary of the Invention

[0004] In response to the problems mentioned in the background technology, the purpose of the present invention is to provide an AR device and method for golf sports guidance to overcome the problem that the golfer's hitting trajectory deviates from the target curve and provide sports guidance in golf training and daily exercise.

[0005] The present invention provides an AR device for golf sports guidance, comprising: an AR terminal display, a position sensor, a posture sensor, an image acquisition device, a processor, and a golf course information database.

[0006] The AR terminal display is used to present sports guidance information to the golfer;

[0007] The processor is used to receive data acquired by the position sensor, posture sensor and image acquisition device, retrieve information from the court information database, and further calculate the information required by the user;

[0008] The image acquisition device and the position sensor have a relatively fixed positional relationship, and the image acquisition device and the attitude sensor have a relatively fixed spatial relationship; the position sensor acquires position information of the image acquisition device, the attitude sensor acquires attitude information of the image acquisition device, and the image acquisition device acquires real-time image information. A processor processes the acquired information to obtain the position of the golf ball, and then establishes a golf ball dynamics model. A numerical optimization problem is constructed using the initial motion conditions of the golf ball as independent variables and minimizing the distance deviation between the golf ball's motion trajectory and the target hole as the objective function. The initial motion conditions that make the golf ball's motion trajectory pass through the target point are solved and a reference motion trajectory is generated.

[0009] The course information database collects the terrain of the golf course. Furthermore, the terrain includes the height information of the golf course, the location of the holes, the location and shape of the obstacles and greens. The height information is represented by the function z=h(x,y); further, it can also include the golfer's shot history data.

[0010] The present invention provides a method for golfing guidance, which specifically includes:

[0011] The first step is to obtain the position of the golf ball by:

[0012] a. Establish a three-dimensional course coordinate system with any position on the golf course as the origin, establish a three-dimensional camera coordinate system with the optical center of the image acquisition device as the origin, and establish a two-dimensional image coordinate system on the image obtained by the image acquisition device;

[0013] b. The position sensor obtains the position data of the image acquisition device, and the position coordinates in the court coordinate system are marked as P cam ; The posture sensor acquires posture data of the image acquisition device; the image acquisition device acquires an image;

[0014] c. Obtain the two-dimensional coordinates of the golf ball in the image coordinate system based on the target detection method, and calculate the standard equation of the ray from the optical center of the image acquisition device to the golf ball in the course coordinate system;

[0015] d. Calculate the position of the golf ball based on ray tracing or depth estimation.

[0016] Preferably, in step c, the image acquisition device transmits the captured real-time image to the processor for target detection. When a golf ball is detected in the field of view of the image acquisition device, the next step of calculation is performed; the position of the golf ball in the image coordinate system is recorded as a two-dimensional coordinate (u b ,v b );

[0017] Preferably, in step c, the conversion matrix from the image coordinate system to the camera coordinate system is obtained based on the intrinsic parameter matrix K of the image acquisition device; the conversion matrix from the camera coordinate system to the course coordinate system is obtained based on the posture data obtained in step b, denoted as R. Then, the direction vector from the optical center of the image acquisition device to the golf ball in the course coordinate system is The standard equation for the ray from the optical center of the image acquisition device to the golf ball is

[0018] Preferably, the target detection method is a target detection algorithm based on traditional computer vision or a target detection method based on deep learning; further preferably, the target detection method based on deep learning is a CNN model or a Transformer-based deep learning model, and further preferably, the CNN model is a YOLO series model;

[0019] Preferably, in step d, the step of calculating the position of the golf ball by using the ray method is:

[0020] 1. Obtain the course terrain function z = h (x, y) from the course information database;

[0021] 2. Combine the terrain function z = h(x, y) and the ray equation Solve the equation about δ and get the intersection of the ray and the ground, which is the position P of the golf ball. b .

[0022] Preferably, in step d, the step of calculating the position of the golf ball by depth estimation method is:

[0023] I. Use the depth estimation model to generate the depth map Depth(u,v) of the image;

[0024] II. Extract target coordinates (u b ,v b ) at a depth value d = Depth(u b ,v b );

[0025] III. Substitute the depth value d into the standard equation of the ray to calculate the three-dimensional coordinates P of the golf ball in the course coordinate system b .

[0026] The second step is to calculate the initial motion conditions and reference motion trajectory of the golf ball: a golf ball dynamics model is established, and a numerical optimization problem is constructed with the initial motion conditions of the golf ball as the independent variable and minimizing the distance deviation between the golf ball's motion trajectory and the target hole as the objective function. The initial motion conditions that make the golf ball's motion trajectory pass through the target point are solved and a reference motion trajectory is generated. The specific steps are as follows:

[0027] 1. Constructing numerical optimization problems:

[0028] When a golf ball is hit, its motion process includes flying until it lands. After landing, whether it bounces or rolls is determined based on its motion state and the terrain at the landing point. The dynamic constraints of the numerical optimization problem include flight dynamics model, bounce dynamics model and rolling dynamics model. The independent variables are the initial motion conditions, the path constraint is that the trajectory of the golf ball has no intersection with obstacles, and the objective function is to minimize the distance between the stopping point of the golf ball and the target hole.

[0029] Preferably, the initial motion conditions include the initial speed, launch angle, azimuth angle and rotational angular velocity of the golf ball;

[0030] When a golf ball rolls after being hit, the dynamic constraint is a rolling dynamics model, the independent variable is the initial motion condition, and the objective function is to minimize the distance between the motion trajectory and the target hole. It is also necessary to satisfy that the speed when the motion trajectory takes the minimum distance with the target hole is less than a preset threshold.

[0031] Preferably, the preset threshold is a value within the range of 0.01-0.2 m / s, and further preferably the preset threshold is 0.02 m / s, 0.03 m / s, 0.04 m / s, 0.05 m / s, 0.06 m / s, 0.07 m / s, 0.08 m / s, 0.09 m / s, and 0.1 m / s;

[0032] Preferably, the golf ball dynamics model is a classical physical model: based on Newton's second law, taking into account gravity, aerodynamics, Magnus force and other forces, an ordinary differential dynamics equation is established to describe the flight of a golf ball in the air; considering the motion state of a golf ball when it falls on different terrains such as sand or grass, a bouncing dynamics equation is established to describe the instantaneous speed and angular velocity changes of the golf ball when it bounces on the ground; considering the effects of gravity, green slope, grass friction and other factors, an ordinary differential dynamics equation is established to describe the rolling of a golf ball on the grass.

[0033] 2. Solve the numerical optimization problem: Solve the numerical optimization problem using a numerical optimization algorithm. If the problem is solvable, a reference trajectory of the golf ball and its initial conditions that satisfies the constraints are obtained. If the problem fails to converge, indicating that the golf ball cannot be holed in a single shot, then add waypoints to replace the target hole in the corresponding objective function and re-solve the problem until the problem converges.

[0034] Preferably, the system recommends waypoints based on the golfer's preferences, and the golfer can also manually set waypoints;

[0035] In the third step, the AR terminal display displays the motion guidance information: the processor converts the reference motion trajectory into the camera coordinate system, superimposes it on the real golf course, and presents it on the AR terminal display. The AR terminal display also displays the initial motion conditions of the golf ball.

[0036] Preferably, the AR terminal display also displays information such as the distance to the target hole, course information, shot history information, and the current best score on the course.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. Compared to existing technologies that record and display the trajectory of a golf ball, this invention provides guidance before a golfer hits the golf ball, calculates the optimal initial motion conditions for the golf ball, and generates a reference trajectory for the golf ball. This provides golfers with real-time, interactive reference information, real-time dynamic visualization, and interactive feedback, breaking through the static limitations of traditional tools and helping golfers accurately grasp the golf ball's position on the course and the course information near the golf ball.

[0039] 2. The AR device for golf guidance according to the present invention can locate a golf ball on a course without installing a positioning device on the golf ball. It displays information about the golf ball and the course on the AR terminal display, and also provides statistics on past shot data. The device is simple and easy to use. Using augmented reality technology, the AR device overlays the predicted golf ball trajectory, calculated based on dynamic equations, onto the real field of view in real time, creating a dynamic, visual reference path. Athletes can intuitively visualize the effects of shots at different initial speeds and angles, achieving a closed-loop "what you see is what you practice" training, significantly improving training efficiency.

[0040] 3. The golf ball positioning method provided by the present invention cleverly obtains the real-time position information of a golf ball using information from an image acquisition device and a posture sensor. It has the advantages of simple equipment, low cost, and high real-time performance. Compared to traditional positioning methods, this method can obtain real-time position information of a golf ball without installing a positioning sensor inside the golf ball. Based on an efficient target detection algorithm and the posture of the image acquisition device, it effectively combines visual information, posture information, and terrain information, eliminating the need to modify the golf ball. In this application scenario, the golf ball and the grass have a sharp color contrast, and the target detection algorithm is highly accurate and computationally efficient. The golf ball position information obtained by this method is real-time and accurate, with a computational speed and accuracy comparable to traditional positioners.

[0041] 4. Existing golf training aids (such as swing trainers, putting mirrors, and alignment sticks) mainly provide feedback through physical devices or offline data analysis. For example, putting aids only focus on the starting line of the shot or posture calibration, and cannot dynamically adjust the strategy during the shot. The AR glasses of the present invention use augmented reality technology to superimpose the golf ball trajectory prediction results calculated based on the dynamic equation into the real field of view in real time, forming a dynamic visual reference line, such as displaying the trajectory correction curve under the influence of the fairway slope and wind speed. Athletes can intuitively see the effects of hitting the ball at different initial speeds and angles. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0043] Figure 1 This is an appearance diagram of the AR glasses provided in Example 1 of the present application;

[0044] Figure 2 The golf guidance method provided in Example 2 of the present application;

[0045] Figure 3 A schematic diagram of a golf ball position calculation method provided in Example 2 of the present application;

[0046] Figure 4 The process for solving the golf ball numerical optimization problem provided in Example 2 of this application;

[0047] Figure 5 A schematic diagram of the force and trajectory of a golf ball in flight in Example 2 of the present application;

[0048] Figure 6 This is a schematic diagram of reconstructing the optimization problem by adding path points when the numerical optimization problem provided in Example 2 of the present application cannot converge;

[0049] Figure 7 This is the AR interactive display effect provided in Example 2 of this application. DETAILED DESCRIPTION

[0050] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments, and they do not constitute a limitation of the present invention, but are merely examples. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] Example 1: Reference Figure 1 , AR glasses for golf guidance, including:

[0052] a) Frame 101: The frame serves as the main structure and is used to install and fix other components.

[0053] b) Temples 102: A pair of temples are provided on both sides of the frame for supporting and fixing the glasses when worn.

[0054] c) Lens 103: Two lenses are mounted on the frame for optical imaging and display functions.

[0055] d) Camera 104: The camera is located at the connection position between the two lenses and is used to collect image data.

[0056] e) The processor 105 is connected to the temple 102 via a data cable to complete data interaction and calculation. The processor 105 can read the court terrain database from the cloud or local memory card.

[0057] f) RTK GNSS positioning module:

[0058] 1) The RTK GNSS positioning module is a mobile GNSS receiver in a dynamic environment. It receives satellite signals and differential data from the base station, and calculates its own coordinates in real time using a relative positioning algorithm. It is installed on the mirror frame and has lightweight and high-precision characteristics.

[0059] 2) The RTKGNSS positioning module has a positioning accuracy of better than ±2cm in the horizontal and vertical directions;

[0060] 3) The positioning module is installed in the frame or temple and has a relatively fixed position relationship with the camera to provide real-time high-precision position information.

[0061] g) 9-axis inertial sensor unit:

[0062] 1) The 9-axis inertial sensor unit is installed in the frame or temple of the glasses, and has a relatively fixed spatial relationship with the camera. It includes the following submodules: a three-axis accelerometer for measuring acceleration data; a three-axis gyroscope for measuring angular velocity data; and a three-axis magnetometer for measuring the direction of the Earth's magnetic field.

[0063] 2) The three-axis gyroscope works in conjunction with the three-axis magnetometer to output high-precision camera attitude data, including pitch, roll, and yaw angles, as well as quaternions;

[0064] 3) The data from the three-axis accelerometer and the RTKGNSS positioning module are processed through a fusion algorithm to achieve higher-precision dynamic positioning.

[0065] Example 2: Basic process reference for using AR glasses for golf guidance Figure 2 The specific implementation steps are as follows:

[0066] Step 1: Establish three coordinate systems: 1. With a teeing point on the golf course as the origin, establish the right-handed course coordinate system O-XYZ with the east as the X-axis, the north as the Y-axis, and the upward as the Z-axis; 2. With the optical center of the camera on the AR glasses as the origin o, establish the camera coordinate system o-xyz with the right direction as the positive direction of the x-axis, the forward direction as the positive direction of the y-axis, and the upward direction as the positive direction of the z-axis; 3. With the center point of the image as the origin, establish the image coordinate system with the right direction as the positive direction of the u-axis and the upward direction as the positive direction of the v-axis.

[0067] Step 2: Data Acquisition: The camera captures an image of the golfer's field of view, and the RTKGNSS module acquires position data. This data is derived from the relative position between the camera and the camera, and then integrated with the accelerometer data in the 9-axis inertial measurement unit (IMU) for even higher positioning accuracy. The 3-axis gyroscope and 3-axis magnetometer in the 9-axis IMU work together to obtain high-precision attitude information. When worn by the golfer, the 9-axis IMU maintains a relatively fixed spatial attitude relationship with the camera, resulting in high-precision camera attitude data. The image, position, and attitude data are then transmitted to the processor via a data line.

[0068] Step 3, target detection: The processor uses the improved YOLOv8 algorithm suitable for small target detection to perform target detection on the image, determine whether there is a golf ball in the image, and output the bounding box of the golf ball. The center of the rectangular bounding box is used as the characteristic position of the golf ball in the image, and its two-dimensional coordinates in the image coordinate system are marked as (u b ,v b The improved YOLOv8 algorithm can achieve a detection speed of 30 frames per second and a detection accuracy of 82.5% AP for small golf ball targets, meeting both real-time and precision requirements.

[0069] Step 4, calculate the ray equation from the camera's optical center to the golf ball:

[0070] The camera intrinsic parameter matrix can be obtained through the checkerboard calibration method, and its expression is as follows:

[0071]

[0072] Among them, f u ,f v are the equivalent focal lengths in the u and v axis directions (in pixels), reflecting the imaging scale of the camera; u0 and v0 are the coordinates of the principal point (the projection of the optical center on the image plane), which are usually close to the center of the image; s is the coordinate axis tilt parameter, which is ideally 0, indicating that the pixel rows and columns are strictly orthogonal.

[0073] The transformation matrix from the image coordinate system to the camera coordinate system is obtained based on the camera's intrinsic parameter matrix K. The transformation matrix from the camera coordinate system to the course coordinate system is obtained based on the camera's attitude data, denoted as R. Then, in the course coordinate system, the expression of the normalized direction vector from the camera optical center to the golf ball is: The standard equation for the ray from the camera's optical center to the golf ball is It represents an infinitely extended ray from the camera center point to the direction of the golf ball (refer to Figure 3 ). Where t is the time variable, P cam is the camera position, and δ is a variable representing the ray length.

[0074] Step 5, solve the golf ball position: the processor obtains the course terrain function z = h (x, y) from the course information database, which is a surface in three-dimensional space represented by X and Y coordinates; the terrain function z = h (x, y) and the ray equation are combined We get a one-variable equation about δ, and solving it gives the intersection of the ray and the ground, which is the three-dimensional position P of the golf ball. b , the coordinate value is expressed as (X, Y, Z).

[0075] The camera position accuracy obtained based on the RTK GNSS positioning module is at the centimeter level. Taking into account the attitude data error of the attitude sensor and the target detection error, the golf ball positioning accuracy can reach less than 5cm.

[0076] Step 6, establishing a dynamic model: This embodiment provides a physical model, including a flight dynamics model, a bouncing dynamics model, and a rolling dynamics model.

[0077] (1) Flight dynamics model

[0078] refer to Figure 5 When the ball is hit and flies in the air, it is mainly affected by gravity. air resistance and the Magnus force due to rotation Build a golf ball flight dynamics model, specifically a set of ordinary differential equations for position and angular velocity:

[0079]

[0080] in, is the position of the golf ball, m is the weight of the golf ball, is the gravity vector, I is the moment of inertia of the golf ball, τ is the net torque on the golf ball, ω is the angular velocity of the golf ball, and t is the time variable. The magnitudes of aerodynamic drag and Magnus force are:

[0081]

[0082] A is the reference area of ​​the golf ball, r is the radius of the golf ball, usually A=πr 2 , C d and C M are the drag coefficient and the Magnus force coefficient, respectively, which are related to factors such as air viscosity, sphere surface interface, air density, flight speed and rotation speed, and can be obtained through experiments; ρ is the atmospheric density, is the flight velocity vector.

[0083] (2) Bounce dynamics model

[0084] The impact of a golf ball on the ground involves energy dissipation and momentum transfer. A feasible dynamic model is as follows. It is assumed that the tangential velocity component remains unchanged after the collision, and the change in the normal velocity component is described by the normal collision restitution coefficient, which is defined as follows:

[0085]

[0086] v n,before ,v n,after are the normal velocities before and after the collision, v t,before is the tangential velocity component before collision; the tangential friction model is defined, and the change in rotation rate caused by friction is

[0087]

[0088] μ is the friction coefficient of the grass. The normal collision restitution coefficient and friction coefficient can be obtained statistically. The dynamic equations for the velocity and rotational speed after the collision are as follows:

[0089]

[0090] This dynamic model can predict the rolling distance and secondary bounce trajectory of a golf ball after it lands.

[0091] (3) Rolling dynamics model

[0092] Define the golf ball's local coordinate system, where the x-axis points in the direction of the green's main slope (maximum inclination), the y-axis is along the cross slope, and the z-axis is perpendicular to the green surface and upward.

[0093] Green slope parameters:

[0094] Main slope angle α: the angle between the x-axis and the horizontal plane

[0095] · Transverse slope angle β: the angle between the y-axis and the horizontal plane

[0096] Compound slope vector:

[0097] Gravity decomposition:

[0098]

[0099] The motion state of the ball is described by translation and rotation, and the coupling equation is established as follows:

[0100] Consider rolling resistance, sliding friction, and slope effects:

[0101]

[0102] in:

[0103] m: ball mass (standard ball 45.93g)

[0104] Rolling resistance F roll =μ roll mg z cosαcosβ

[0105] Sliding friction v t is the tangential velocity component

[0106] Rolling friction coefficient μ roll (Grassland ≈ 0.05-0.15, affected by grass density and humidity)

[0107] ·Spherical moment of inertia Angular acceleration:

[0108] F fric,x ,F fric,y are the components of sliding friction in the x and y directions, v x ,v y are the components of velocity in the x and y directions respectively. When the pure rolling condition v = rω is satisfied, the rotation and translation are coupled.

[0109] The following table gives typical values ​​in the dynamic equation, which can also be statistically analyzed based on the conditions of the green to achieve higher accuracy.

[0110] Table 1 Typical parameter values

[0111] parameter Dry hard greens Wet and soft greens <![CDATA[Coefficient of rolling friction μ roll > 0.06 0.12 <![CDATA[Coefficient of kinetic friction μ kinetic > 0.18 0.25 <![CDATA[Normal restitution coefficient e n > 0.75 0.55

[0112] Step 7: Construct a numerical optimization problem:

[0113] The state variables x(t) of a golf ball include its position p(t), velocity v(t), and angular velocity ω(t), i.e., x(t) = [p(t), v(t), ω(t)], where t represents the time variable. The time when the ball is hit is t = 0, and the time when the golf ball stops moving is t. f , then the value range of t is t∈[0,t f ]. p(t) is a curve in space that describes the trajectory of the golf ball.

[0114] The numerical optimization problem is to minimize the objective function

[0115] min J

[0116] satisfy:

[0117] Dynamic constraints:

[0118] Path constraint: p(t)∈Ω

[0119] Initial position constraint: X(0)=X b ,Y(0)=Y b ,Z(0)=Z b

[0120] Where Ω is the feasible spatial position of the golf ball, which is usually the area within the boundary of the golf course, excluding obstacles; f(x) represents the ordinary differential equation, g(x(t + ),x(t - ))=0 is the dynamic constraint that describes the state of the golf ball at the time points before and after it bounces.

[0121] Determine whether the current position of the golf ball and the target hole can be reached by rolling alone. If so, construct numerical optimization problem a; otherwise, construct numerical optimization problem b.

[0122] Specifically, the numerical optimization problem a corresponds to the situation when the golf ball is on the green and can be pushed to reach the target hole by simply rolling. In this case, the objective function is to minimize the shortest distance between the trajectory and the target hole.

[0123] J=||p(t)-P h ||

[0124] The independent variables include the initial velocity and azimuth, and the dynamic constraints are the rolling dynamics model given in step 6.

[0125] For numerical optimization problem a: the initial position is known, and the independent variable is added to form the initial state. The rolling dynamics model is integrated using the Runge-Kutta 4th-order integral until the speed becomes 0, and the discrete state variable sequence x(t=t i )=[Pi ,V i ,ω i ], where i = 0, ..., N represents the discrete time point subscript, t f =t N .P i It is the discrete time representation of p(t). The continuous curve p(t) is obtained by performing cubic spline interpolation on Pi. The minimum distance between p(t) and the hole is the objective function.

[0126] Numerical optimization problem b, the objective function is to minimize the distance between the stopping point and the target hole

[0127] J=||p(t f )-P h ||

[0128] Among them, P h is the three-axis coordinate of the target hole, which is a constant and is therefore represented by capital letters. f ) is the moment when the movement ends t = t f The position of , which is a variable and is therefore represented by lowercase letters; the independent variables include initial velocity, azimuth, launch angle and angular velocity. Depending on the type of club, the initial velocity and angular velocity are also subject to certain constraints.

[0129] For numerical optimization problem b: the initial position is known, and the independent variable is added to form the initial state. The rolling dynamics model is integrated using the Runge-Kutta 4th-order integral until landing. The landing criterion can be simplified to P i and P i+1 They are located on opposite sides of the terrain surface z=h(x,y). After landing, the terrain of the landing point is determined. If it is located in bushes, woods, pools, sand pits, etc., the integration is stopped; if it lands on grass, the speed and angular velocity changes after the bounce are calculated based on the bouncing dynamics model. When the bounce falls below a certain speed, it turns into a rolling motion state, and the integration continues based on the rolling dynamics model until the speed is 0. The discrete state variable sequence x(t=t i )=[P i ,V i ,ω i ], through P i Perform cubic spline interpolation to obtain the continuous curve p(t).

[0130] Step 8: Solve the numerical optimization problem.

[0131] Genetic algorithms are used to solve numerical optimization problems. First, the objective function of the numerical optimization problem is converted into a fitness function. Numerical solutions in the solution space are mapped to chromosomes (individuals) of the genetic algorithm through encoding. The population consists of multiple individuals, and the initial population is initialized through random generation to cover multiple regions of the solution space.

[0132] During the algorithm's iterations, the population is gradually optimized through selection, crossover, and mutation operations. The selection operation selects individuals with higher fitness based on their fitness values, giving them a higher probability of entering the next generation. The crossover operation generates new individuals by exchanging individual gene fragments, exploring the diversity of the solution space. The mutation operation randomly changes the values ​​of certain gene bits to prevent the algorithm from prematurely converging to a local optimal solution.

[0133] The genetic algorithm continuously iterates, gradually improving the average fitness of the population and eventually converging to a global optimal solution or a region close to the global optimal solution. For this embodiment, a typical set of genetic algorithm parameters is set as follows: an initial population of 100, a maximum number of iterations of 50, a crossover probability of 0.6, a mutation probability of 0.01, and a convergence criterion of J < 0.1 or a fitness change rate less than 1e-6.

[0134] Step 9, Figure 7 A reference motion trajectory and velocity of a push rod and a method for indicating its initial conditions are illustrated.

[0135] The reference motion trajectory p(t) and initial conditions are expressed in the course coordinate system. Coordinate system transformation can be used to convert indicative information such as the motion trajectory and initial conditions to the camera coordinate system. AR glasses can then render the motion trajectory and initial conditions into the field of view in real time and overlay them onto the actual course. The coordinate transformation matrix is ​​determined by the position and posture of the AR glasses, so the indicative information changes in the field of view as the golfer moves or rotates. Textual data such as the hole distance and course information moves with head rotation, but the reference trajectory and the arrow representing the initial velocity remain in the same position in space. Even if the golfer turns their head and the golf ball moves out of view, the motion trajectory curve can still be seen.

[0136] Example 3:

[0137] Step 5 in Example 2 can also use the depth estimation method to solve the golf ball position:

[0138] The position coordinates of the camera in the course coordinate system obtained by the RTK GNSS positioning module are marked as P cam =(X c ,Y c ,Z c ), the ray equation from the origin of the camera coordinate system (the camera optical center) to the golf ball is The distance from the camera optical center to the golf ball obtained based on the depth estimation method is recorded as d. Let t = d, the position coordinates of the golf ball can be obtained

[0139]

Claims

1. A method for golf guidance, characterized in that: The following steps are involved: S1. Get the location information of the golf ball; S2. Calculate the initial motion conditions and reference motion trajectory of the golf ball; S3. The AR terminal display displays exercise guidance information; Preferably, step S1 includes the following steps: a. Establish a three-dimensional golf course coordinate system with any position on the golf course as the origin, establish a three-dimensional camera coordinate system with the optical center of the image acquisition device as the origin, and establish a two-dimensional image coordinate system with any point in the image obtained by the image acquisition device as the origin; b. The position sensor obtains the position data of the image acquisition device, and the position coordinates in the court coordinate system are marked as P cam ; The posture sensor obtains the posture data of the image acquisition device; the image acquisition device obtains real-time image information; c. Obtain the two-dimensional coordinates of the golf ball in the image coordinate system based on the target detection method, and calculate the standard equation of the ray from the optical center of the image acquisition device to the golf ball in the course coordinate system; d. Calculate the position of the golf ball based on ray tracing or depth estimation; Preferably, step S2 includes the following steps: A golf ball dynamics model is established. A numerical optimization problem is constructed with the initial motion conditions of the golf ball as the independent variable and minimizing the distance deviation between the golf ball's motion trajectory and the target hole as the objective function. The initial motion conditions that make the golf ball's motion trajectory pass through the target point are solved, and a reference motion trajectory is generated.

2. A method for golf guidance according to claim 1, characterized in that: In step c, the image acquisition device transmits the captured real-time image to the processor for target detection. When a golf ball is detected in the field of view of the image acquisition device, the next step of calculation is performed; the position of the golf ball in the image coordinate system is recorded as a two-dimensional coordinate (u b ,v b ); Preferably, in step c, a conversion matrix from the image coordinate system to the camera coordinate system is obtained based on the intrinsic parameter matrix K of the image acquisition device; a conversion matrix from the camera coordinate system to the course coordinate system is obtained based on the posture data obtained in step b, denoted as R, and the direction vector from the optical center of the image acquisition device to the golf ball in the course coordinate system is The standard equation for the ray from the optical center of the image acquisition device to the golf ball is Where δ is the ray length.

3. A method for golf guidance according to any one of claims 1-2, characterized in that: In step d, the steps of calculating the position of the golf ball by ray method are as follows:

1. Obtain the course terrain function z = h(x, y) from the course information database, where x, y, and z are the three-axis coordinates of a point on the course, and h(·) represents the height function; 2. Combine the terrain function z = h(x, y) and the ray equation Solve the equation about δ and get the intersection of the ray and the ground, which is the position P of the golf ball. b .

4. A method for golf guidance according to any one of claims 1-2, characterized in that: In step d, the step of calculating the position of the golf ball by depth estimation method is as follows: I. Use the depth estimation model to generate the depth map Depth(u,v) of the image; II. Extract target coordinates (u b ,v b ) at a depth value d = Depth(u b ,v b ); III. Substitute the depth value d into the standard equation of the ray to calculate the three-dimensional coordinates P of the golf ball in the course coordinate system b .

5. A method for golf guidance according to any one of claims 1 to 4, characterized in that: The target detection method is a target detection algorithm based on traditional computer vision or a target detection method based on deep learning; further preferably, the target detection method based on deep learning is a CNN model or a Transformer-based deep learning model, and further preferably, the CNN model is a YOLO series model; Preferably, the initial motion conditions in step S2 include initial velocity, launch angle, azimuth angle and rotational angular velocity; further preferably, in step S3, the processor converts the reference motion trajectory into a camera coordinate system, superimposes it on the real course and presents it on the AR terminal display, and the AR terminal display also displays the initial motion conditions of the golf ball; preferably, the AR terminal display also displays information such as the distance to the target hole, course information, the actual motion trajectory of the golf ball, shot history information, and the current best score on the course.

6. An AR device for golf guidance, characterized in that: Including AR terminal display, position sensor, attitude sensor, image acquisition device, processor, and stadium information database; The AR terminal display is used to present sports guidance information to the golfer; The course information database collects the topography of the golf course; The processor is used to receive data acquired by the position sensor, attitude sensor, and image acquisition device, retrieve information from a golf course information database, and further calculate information required by a user; the image acquisition device and the position sensor have a relatively fixed positional relationship, and the image acquisition device and the attitude sensor have a relatively fixed spatial relationship; the position sensor acquires position information of the image acquisition device, the attitude sensor acquires attitude information of the image acquisition device, and the image acquisition device acquires real-time image information. The processor processes the acquired information to obtain the position of the golf ball, then establishes a golf ball dynamics model, constructs a numerical optimization problem with the initial motion conditions of the golf ball as independent variables and minimizing the distance deviation between the golf ball's motion trajectory and the target hole as the objective function, solves the problem, and obtains the initial motion conditions that make the golf ball's motion trajectory pass through the target point, and generates a reference motion trajectory.

7. The AR device for golf guidance according to claim 6, characterized in that: The topography of the golf course includes the height information of the golf course, the location of the holes, the location and shape of the obstacles and greens. The height information is represented by the function z=h(x,y) 表示 .

8. An AR device for golf guidance according to any one of claims 6-7, characterized in that: The course information database also includes golfers' shot history data.

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