A table tennis line analysis method and system based on a split button and vibration sensor linkage

Abstract

The application discloses a table tennis route analysis method and system based on linkage of a point button and a vibration sensor, and mainly relates to the technical field of table tennis route analysis. The method comprises the following steps: obtaining score information through a point button; collecting a landing point signal and calculating a coordinate through a vibration sensor; tracing back two consecutive landing points corresponding to the score; calculating a hitting route according to the landing point coordinate; and calculating the score proportion of each route. The application firstly associates the score event of the point button with the landing point data of the vibration sensor, solves the problem that the prior art only knows the landing point but does not know who scores, realizes automatic identification and statistical analysis of four routes, i.e., a forehand straight line, a forehand oblique line, a backhand straight line and a backhand oblique line, and has low deployment cost and accurate identification, and can provide reliable data support for technical diagnosis and training guidance of athletes.

Description

Technical Field

[0001] This invention mainly relates to the field of table tennis trajectory analysis technology, specifically to a table tennis trajectory analysis method and system based on the linkage between the paddle button and a vibration sensor. Background Technology

[0002] Technical analysis in table tennis is crucial for improving athletes' training and competitive performance. Currently, table tennis trajectory analysis mainly relies on coaches' manual observation and recording, which is inefficient and inaccurate. Existing technologies include table tennis ball landing point detection systems based on vibration sensors, such as the table tennis athlete training analysis system disclosed in patent application CN112587902A, which uses vibration sensors to obtain the landing point coordinates. However, these existing technologies can only detect the landing point location; they cannot correlate the landing point data with scoring events or ball possession information, nor can they automatically identify the shot trajectory and perform statistical analysis.

[0003] Furthermore, patent CN106492440B discloses a device and analysis system for acquiring and processing table tennis ball landing point data, but its piezoelectric sensor array is costly and complex to deploy, and it also fails to solve the core problem of "who scores". Currently, there is no technology that can automatically identify and statistically analyze the trajectory of the ball based on the scoring event information provided by the scoring button and the landing point data acquired by the vibration sensor.

[0004] Most motion capture-based shot trajectory analysis systems on the market require several high-speed cameras and extensive professional calibration, easily costing hundreds of thousands of yuan. They are also extremely delicate; changes in lighting or the presence of an obstruction can distort the data, rendering them unusable for daily training. While vibration sensors are significantly cheaper, current technology is also not without its challenges. For example, the patent disclosed in CN106492440B requires covering the entire table tennis table with piezoelectric sensors, resulting in a large number of sensors, messy wiring, and, more importantly, focusing on the landing point coordinates—where the ball hit—while coaches truly want to know who scored the point and whether the shot was effective. Landing point data is detached from scoring information and cannot be directly used to analyze shot scoring efficiency; this is the biggest blind spot of current technology. Summary of the Invention

[0005] (a) Technical problems to be solved In view of the above-mentioned problems, the present invention provides a method and system for analyzing table tennis ball trajectories based on the linkage between the scoring button and the vibration sensor, and solves the following technical problems: how to associate scoring events with landing point data to achieve automatic identification of scoring trajectories; how to calculate the type of shot based on the coordinates of two consecutive landing points; and how to count the number and percentage of points scored for each trajectories.

[0006] (II) Technical Solution To address the aforementioned technical problems, this invention provides a method for analyzing the trajectory of a ping-pong ball based on the linkage between a shot button and a vibration sensor, comprising the following steps: S1: The scoring information, losing information, and scoring time of each point are obtained through the scoring buttons located on both sides of the table; the vibration signal of the landing point of each shot is collected through multiple vibration sensors located at the bottom of the table. S2: Based on the vibration signal collected by the vibration sensor, calculate the landing point coordinates of the ball on the table for each shot using the time difference of arrival positioning principle; S3: Based on the scoring moment, backtrack to determine the landing points of the two consecutive shots corresponding to the score, where the first landing point is the landing point of the last shot by the scoring side, and the second landing point is the landing point of the last return shot by the losing side; S4: Calculate the shot trajectory based on the coordinates of two consecutive landing points; S5: Based on the scorer information, calculate the number of points for each line and the percentage of each line's score in the total score.

[0007] Further, step S4 specifically includes: S4.1: Establish a table tennis table coordinate system with one corner of the table tennis table as the origin, the width direction of the table tennis table as the X-axis, and the length direction as the Y-axis; S4.2: Calculate the X-coordinate of the intersection point of line P1P2 and the opposite endpoint line: x_end = x1 + (y_end - y1) (x2-x1) / (y2-y1) Where P1(x1,y1) is the coordinate of the first landing point, P2(x2,y2) is the coordinate of the second landing point, and y_end is the Y coordinate of the opponent's end line; S4.3: Determine the line type based on the positional relationship between the X coordinate of P1 and the center line of the table, and the positional relationship between x_end and the center line of the table.

[0008] Furthermore, the rule for determining the line type is as follows: If x1 is greater than the center line of the table and x_end is less than the center line of the table, it is determined to be a forehand straight shot. If x1 is greater than the center line of the table and x_end is greater than the center line of the table, it is determined to be a forehand cross-court shot; If x1 is less than the center line of the table and x_end is greater than the center line of the table, it is determined to be a backhand straight shot; If x1 is less than the center line of the table and x_end is less than the center line of the table, it is determined to be a backhand cross-court shot.

[0009] Furthermore, the method for calculating the landing point coordinates using the time difference of arrival (TDOA) positioning principle in step S2 is as follows: Let the coordinates of the three vibration sensors in a time-difference combination on the table surface be (x_s1, y_s1), (x_s2, y_s2), and (x_s3, y_s3), respectively, and the coordinates of the collision point P_d between the ping-pong ball and the table be (x_d, y_d). Then the following conditions must be met: [(x_d-x_s2) 2 +(y_d-y_s2) 2 ]- [(x_d-x_s1) 2 +(y_d-y_s1) 2 ]=v·(t2-t1) [(x_d-x_s3) 2 +(y_d-y_s3) 2 ]- [(x_d-x_s1) 2 +(y_d-y_s1) 2 ]=v·(t3-t1) Where v is the speed at which the vibration signal propagates, and t1, t2, and t3 are the times when the signal arrives at each sensor.

[0010] Furthermore, it also includes a step of counting the number of times each line is used throughout the entire game.

[0011] A table tennis ball trajectory analysis system based on the linkage between the score button and a vibration sensor includes: Score button module: used to obtain information about the scorer, the loser, and the time of each score; Vibration sensor module: includes multiple vibration sensors installed at the bottom of the table tennis table to collect vibration signals at the landing point of each shot; Data processing module: connected to the scoring button module and vibration sensor module, used to execute the above-mentioned table tennis ball trajectory analysis method based on the linkage of the scoring button and vibration sensor; Output module: Used to output statistical analysis results.

[0012] The advantages of this invention compared to existing technologies are: 1. Innovative data association: For the first time, the scoring event information of the scoring button is associated with the landing point data of the vibration sensor, realizing the automatic identification of "scoring lines" and solving the defect of existing technologies that "only know the landing point but not who scored"; 2. Accurate line identification: Using a calculation method based on the coordinates of the intersection of the straight line and the end line, it can accurately distinguish four line types: forehand / backhand, straight / diagonal; 3. Low deployment cost: Only a small number of vibration sensors need to be placed on the bottom of the table to achieve full-table landing point positioning, without the need for complex vision equipment; 4. High practicality: It can generate a score distribution report for each line, providing technical diagnosis and training guidance for athletes. 5. Easy to operate and highly adaptable: The scoring button is linked to the vibration sensor. Users only need to press the button at the end of each point, and the system can automatically align the scoring event with the landing point data without the need for manual post-marking or correction. This reduces the professional requirements for operators and makes it easy to promote and use in grassroots training units and amateur clubs. 6. Data is traceable and supports targeted review: The system saves the line judgment results and corresponding landing point coordinates for each point. Coaches and athletes can filter and view relevant scoring rounds by line type after the game, which can quickly locate technical weaknesses (such as a low backhand straight scoring rate) and thus formulate more targeted training plans. Detailed Implementation

[0013] The present invention will be further described below with reference to specific embodiments. The invention is explained through illustrative embodiments and descriptions, but is not intended to limit the invention.

[0014] Example 1: A method for analyzing the trajectory of a ping-pong ball based on the linkage between the score button and a vibration sensor, comprising the following steps: Data collection steps S1: The scoring information, losing information, and scoring time of each point are obtained through the scoring buttons located on both sides of the table; the vibration signal of the landing point of each shot is collected through multiple vibration sensors located at the bottom of the table. Landing point positioning steps S2: Based on the vibration signal collected by the vibration sensor, calculate the landing point coordinates of the ball on the table for each shot using the time difference of arrival positioning principle; Score backtracking steps S3: Based on the scoring moment, backtrack to determine the landing points of the two consecutive shots corresponding to the score, where the first landing point is the landing point of the last shot by the scoring side, and the second landing point is the landing point of the last return shot by the losing side; Line calculation steps S4: Calculate the shot trajectory based on the coordinates of two consecutive landing points P1(x1,y1) and P2(x2,y2); Step S4 specifically includes: S4.1: Establish a table tennis table coordinate system with one corner of the table tennis table as the origin, the width direction of the table tennis table as the X-axis, and the length direction as the Y-axis; S4.2: Calculate the X-coordinate of the intersection point of line P1P2 and the opposite endpoint line: x_end = x1 + (y_end - y1) (x2-x1) / (y2-y1) Where P1(x1,y1) is the coordinate of the first landing point, P2(x2,y2) is the coordinate of the second landing point, and y_end is the Y coordinate of the opponent's end line; S4.3: Determine the line type based on the positional relationship between the X coordinate of P1 and the center line of the table, and the positional relationship between x_end and the center line of the table.

[0015] The rules for determining the line type are as follows: If x1 is greater than the center line of the table and x_end is less than the center line of the table, it is determined to be a forehand straight shot. If x1 is greater than the center line of the table and x_end is greater than the center line of the table, it is determined to be a forehand cross-court shot; If x1 is less than the center line of the table and x_end is greater than the center line of the table, it is determined to be a backhand straight shot; If x1 is less than the center line of the table and x_end is less than the center line of the table, it is determined to be a backhand cross-court shot.

[0016] Statistical analysis steps S5: Based on the scorer information, calculate the number of points for each line and the percentage of each line's score in the total score.

[0017] The method for calculating the landing point coordinates using the time difference of arrival (TDOA) positioning principle in step S2 is as follows: Let the coordinates of the three vibration sensors in a time-difference combination on the table surface be (x_s1, y_s1), (x_s2, y_s2), and (x_s3, y_s3), respectively, and the coordinates of the collision point P_d between the ping-pong ball and the table be (x_d, y_d). Then the following conditions must be met: [(x_d-x_s2) 2 +(y_d-y_s2) 2 ]- [(x_d-x_s1) 2 +(y_d-y_s1) 2 ]=v·(t2-t1) [(x_d-x_s3) 2 +(y_d-y_s3) 2 ]- [(x_d-x_s1) 2 +(y_d-y_s1)2 ]=v·(t3-t1) Where v is the speed at which the vibration signal propagates, and t1, t2, and t3 are the times when the signal arrives at each sensor.

[0018] The center line coordinate of the table is equal to half the width of the table, and the Y coordinate of the opponent's end line is equal to the length of the table.

[0019] It also includes a step to count the number of times each line is used throughout the game.

[0020] Example 2: A table tennis ball trajectory analysis system based on the linkage between the score button and a vibration sensor, comprising: Score button module: used to obtain information about the scorer, the loser, and the time of each score; Vibration sensor module: includes multiple vibration sensors installed at the bottom of the table tennis table to collect vibration signals at the landing point of each shot; Data processing module: connected to the scoring button module and vibration sensor module, used to execute a table tennis ball trajectory analysis method based on the linkage between the scoring button and the vibration sensor; Output module: Used to output statistical analysis results.

[0021] Implementation details: System hardware deployment This embodiment provides a table tennis ball trajectory analysis system based on the linkage between the scoring button and a vibration sensor, including: Score buttons: 2, installed on both sides of the table tennis table and connected to the data acquisition module; Vibration sensors: 8 in total, 4 of which are installed near the four corners of the bottom of each half of the table. The sensors are microphone sensors with metal shielding boxes and are installed close to the bottom of the table. Data processing module: connected to the scoring button and vibration sensor, used to synchronously collect scoring events and vibration signals, and run the core algorithm of the method of this invention; Output module: Used to display and print analysis reports.

[0022] Landing point positioning method This embodiment details the specific process of landing point positioning using the TDOA principle. Referring to the TDOA positioning method-5 disclosed in patent CN112587902A, and combining it with the sensor arrangement of this invention, when the ping-pong ball lands at a certain point on the table, the vibration signal arrives at different sensors at different times. The data processing module records the signal arrival times of the eight sensors, iterates through all non-collinear combinations of three sensors, solves for the landing point coordinates based on the time difference equations, and finally determines the final landing point position using the majority rule.

[0023] Line Calculation and Statistics This example uses a game as an example to illustrate the line calculation and statistics process. Assume the table width is 152.5cm, the length is 274cm, the center line X=76.25cm, and the opponent's end line Y=274cm.

[0024] Let player A score a point. Retrace the coordinates of the last two landing points: P1 (Player A's last shot landing point): (90, 150) P2 (Player B's last return shot landing point): (30, 210) Calculate the X-coordinate of the intersection point of line P1P2 and the opposite endpoint line: x_end=90+(274-150)×(30-90) / (210-150)=90+124×(-60) / 60=90-124=-34 Since x_end < 0, the actual out-of-bounds point is to the left of the end line, and it is judged to be a backhand position.

[0025] The X coordinate of P1 is 90 > 76.25, which is the player's forehand position. The x_end is < 76.25, which is the opponent's backhand position. According to the judgment rules, this line is a "forehand straight line".

[0026] The system adds this score to the "forehand straight shot" score counter. After the match, the system outputs the scores and percentages for each shot.

[0027] Any aspects not covered in this invention are applicable to existing technologies.

Claims

1. A method for analyzing the trajectory of a ping-pong ball based on the linkage between a shot button and a vibration sensor, characterized in that, Includes the following steps: S1: The scoring information, losing information, and scoring time of each point are obtained through the scoring buttons located on both sides of the table; the vibration signal of the landing point of each shot is collected through multiple vibration sensors located at the bottom of the table. S2: Based on the vibration signal collected by the vibration sensor, calculate the landing point coordinates of the ball on the table for each shot using the time difference of arrival positioning principle; S3: Based on the scoring moment, backtrack to determine the landing points of the two consecutive shots corresponding to the score, where the first landing point is the landing point of the last shot by the scoring side, and the second landing point is the landing point of the last return shot by the losing side; S4: Calculate the shot trajectory based on the coordinates of two consecutive landing points; S5: Based on the scorer information, calculate the number of points for each line and the percentage of each line's score in the total score.

2. The method for analyzing the trajectory of a ping-pong ball based on the linkage between a shot button and a vibration sensor, as described in claim 1, is characterized in that... Step S4 specifically includes: S4.1: Establish a table tennis table coordinate system with one corner of the table tennis table as the origin, the width direction of the table tennis table as the X-axis, and the length direction as the Y-axis; S4.2: Calculate the X-coordinate of the intersection point of line P1P2 and the opposite endpoint line: x_end=x1+(y_end-y1) (x2-x1) / (y2-y1) Where P1(x1,y1) is the coordinate of the first landing point, P2(x2,y2) is the coordinate of the second landing point, and y_end is the Y coordinate of the opponent's end line; S4.3: Determine the line type based on the positional relationship between the X coordinate of P1 and the center line of the table, and the positional relationship between x_end and the center line of the table.

3. The method for analyzing the trajectory of a ping-pong ball based on the linkage between a shot button and a vibration sensor, as described in claim 2, is characterized in that... The rule for determining the line type is as follows: If x1 is greater than the center line of the table and x_end is less than the center line of the table, it is determined to be a forehand straight shot. If x1 is greater than the center line of the table and x_end is greater than the center line of the table, it is determined to be a forehand cross-court shot; If x1 is less than the center line of the table and x_end is greater than the center line of the table, it is determined to be a backhand straight shot; If x1 is less than the center line of the table and x_end is less than the center line of the table, it is determined to be a backhand cross-court shot.

4. The method for analyzing the trajectory of a ping-pong ball based on the linkage between a shot button and a vibration sensor, as described in claim 1, is characterized in that... The method for calculating the landing point coordinates using the time difference of arrival (TDOA) positioning principle in step S2 is as follows: Let the coordinates of the three vibration sensors in a time-difference combination on the table surface be (x_s1, y_s1), (x_s2, y_s2), and (x_s3, y_s3), respectively, and the coordinates of the collision point P_d between the ping-pong ball and the table be (x_d, y_d). Then the following conditions are met: [(x_d-x_s2) 2 +(y_d-y_s2) 2 ]- [(x_d-x_s1) 2 +(y_d-y_s1) 2 ]=v·(t2-t1) [(x_d-x_s3) 2 +(y_d-y_s3) 2 ]- [(x_d-x_s1) 2 +(y_d-y_s1) 2 ]=v·(t3-t1) Where v is the propagation speed of the vibration signal, and t1, t2, and t3 are the times when the signal arrives at each sensor.

5. The method for analyzing the trajectory of a ping-pong ball based on the linkage between a shot button and a vibration sensor, as described in claim 1, is characterized in that... It also includes a step to count the number of times each line is used throughout the game.

6. A table tennis ball trajectory analysis system based on the linkage between a shot button and a vibration sensor, characterized in that, include: Score button module: used to obtain information about the scorer, the loser, and the time of each score; Vibration sensor module: includes multiple vibration sensors installed at the bottom of the table tennis table to collect vibration signals at the landing point of each shot; Data processing module: connected to the scoring button module and vibration sensor module, used to execute the table tennis ball trajectory analysis method based on the linkage between the scoring button and the vibration sensor as described in any one of claims 1 to 5; Output module: Used to output statistical analysis results.

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