CN113101630A

CN113101630A - Method for measuring throwing distance of track and field throwing type project and long jumping distance of long jumping type project based on image processing

Info

Publication number: CN113101630A
Application number: CN202110375052.7A
Authority: CN
Inventors: 杨清平
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-04-08
Filing date: 2021-04-08
Publication date: 2021-07-13

Abstract

The invention discloses a novel method for measuring the throwing distance of an athletic throwing type project and the long jump distance of a long jump type project. The method is characterized in that one or more cameras are erected beside a field, and a throwing distance and a long jump distance are measured by an image processing method. The hardware equipment used by the invention comprises one or more cameras, a computer or other equipment for running an image processing program, and a large screen for displaying the measurement result. The software aspect includes an image processing program running on a computer or other equipment, and may also include a program for displaying the measurement result, and the like. The invention has the following characteristics: 1. the whole distance measuring process is automatically completed by the system without manual participation; 2. the equipment and the field do not need to be modified; 3. the measurement error is within 1 cm, and the requirement of the International Union of fields is met; 4. the measurement real-time performance is high, and only less than 1 second is needed from the ground to the calculation result. 5. All hardware devices are general devices, and the cost is low.

Description

Method for measuring throwing distance of track and field throwing type project and long jumping distance of long jumping type project based on image processing

Technical Field

The invention belongs to the field of training and match judgment of sports track and field projects, and particularly relates to a method for measuring a throwing distance of a track and field throwing type project and a long jump distance of a long jump type project.

Background

In training and competition for track and field throwing type items (including javelins, hammer shots, discuss) and long jump type items (including long jump and triple jump), it is desirable to accurately measure the distance thrown and long jump distances. At present, the distance of the type is measured mainly by means of manual methods, the measurement work is more complicated, the efficiency is not high, the condition that the measurement data is inaccurate often caused, in javelins and chain ball projects, the falling point area is a dangerous area, the measurer needs to be alerted, and the accidents that the javelins and the chain ball injure people also occur occasionally.

In order to solve the above problems, new technologies have appeared in the art, such as "a javelin distance measuring device" with application No. 2016100375035, "a javelin with automatic distance measurement" with application No. 2015204297055, and "an electronic device for automatic shot-put distance measurement" with application No. 2016103370688, etc., which have common features and characteristics of being modified for instruments and/or fields, and the modifications have the following problems: 1. the approval of the field union can not be obtained; 2. the modification of the apparatus does not influence the weight and the gravity center of the apparatus, thereby influencing training and competition; 3. the cost is high for the reconstruction of the apparatus and the field, and whether the athlete is convenient to use or willing to use is the second athlete. These limitations limit the utility of these technologies and their spread and popularity.

Disclosure of Invention

The invention discloses a novel method for measuring the throwing distance of an athletic throwing type project and the long jump distance of a long jump type project. The method is characterized in that one or more cameras are erected beside a field, and a throwing distance and a long jump distance are measured by an image processing method. The hardware equipment used by the invention comprises one or more cameras, a computer or other equipment for running an image processing program, and a large screen for displaying the measurement result. The software aspect includes an image processing program running on a computer or other equipment, and may also include a program for displaying the measurement result, and the like.

The steps of measuring the throwing distance or the long jump distance of the invention are as follows:

step S1: and erecting a camera, and calibrating external parameters, internal parameters and distortion parameters of the camera.

Step S2: when throwing or jumping, capturing image data of the throwing or jumping process, transmitting the image data to an image processing program, and analyzing the image data by the image processing program to obtain coordinate information of the landing point in the image when the instrument or the human body lands on the ground.

Step S3: the physical coordinates of the landing spot on the ground are calculated according to the coordinate information of the landing spot in the image and the parameters of the camera obtained in step S1.

Step S4: and calculating the throwing distance or the long jump distance according to the physical coordinates of the landing point on the ground and the physical coordinates of the starting point on the ground.

The invention has the following characteristics: 1. the whole distance measuring process is automatically completed by the system without manual participation; 2. the equipment and the field do not need to be modified; 3. the measurement error is within 1 cm, and the requirement of the International Union of fields is met; 4. the measurement real-time performance is high, and only less than 1 second is needed from the ground to the calculation result. 5. All hardware devices are general devices, and the cost is low.

Regarding the number of cameras used in the present invention, in terms of technical principle, a single camera can complete the distance measurement, for example, in the event of shot, long jump, and triple jump, because the measurement range is small, a single camera can be used. In the projects of javelins, hammer balls and discus, a single camera can also complete the measurement, but the accuracy is reduced due to the large measurement range. If it is desired to improve the accuracy of the measurement, 2 or more cameras may be erected to ensure the accuracy of the measurement by covering a part of the measurement range with each camera. Since there is no difference in technical principle, the following description of the present specification will use one camera as an example, except for the embodiment 3 of step 2.

Detailed Description

In step S1, in order to calibrate the external parameters, the internal parameters, and the distortion parameters of the camera, a number of calibration points need to be approximately uniformly arranged in the floor area of the field while the camera is erected, the number of the calibration points has no hard requirement, and in practice, about 10 calibration points of a single camera can obtain good calibration accuracy. The material of the index point is not limited, so that the physical position of the index point can be accurately measured and the position of the index point can be accurately identified in the photo. During the calibration process, a coordinate system needs to be determined, then the physical coordinates of the calibration points in the coordinate system are measured, and their positions in the photograph are measured. As for the calibration method of the camera, there are many specific calibration methods, such as a general Tsai two-step calibration method, "a camera calibration method" with application number 2020104937894, and the like.

There may be two embodiments of this step, as follows.

Example 1: the index points are fixed in the field and do not move throughout the use as well as multiple uses. The advantage of this embodiment is that they can be used repeatedly after measuring their physical position once, and there is no need to re-measure when the camera position changes, and since measuring the physical position of the calibration point is a delicate task, this embodiment can reduce much of the calibration workload, and can even be done by software fully automatically. The disadvantage is that the site is modified and if the calibration point is damaged, the calibration work is affected or even impossible.

Example 2: the calibration points are temporarily placed in the field and removed after the calibration work is finished. The method is opposite to the advantage and the disadvantage of the embodiment 1, namely, the method has the advantages that no modification site is needed, the disadvantage that the physical position of the calibration point needs to be measured every time of calibration, and the calibration workload is large.

Step S2 of the present invention requires processing the captured image to obtain the location of the landing spot in the image. There may be 3 examples of this step, as follows.

Example 1: assuming that the position of the apparatus or the human body is not changed after the apparatus or the human body falls on the ground, for example, the position of the gun head is not changed after the apparatus or the human body falls on the ground; the landing point is not changed after the human body falls to the ground. In this case, in the javelin project, we capture a picture of no instrument in the field of view, then capture a picture of an instrument in each field of view, through comparison, can find the position of the instrument in the picture, and can know whether the position of the instrument in the picture has changed, if the position of the instrument in the picture has changed, it indicates that the instrument is still in flight, and its position data needs to be discarded. If the position of the instrument in the picture does not change any more, the instrument is landed, and the specific landing position of the instrument needs to be judged as a result of the step. For long jump and triple jump projects, only the jumping pit needs to be judged whether to change or not, and the most backward point of the changed part is obtained. The embodiment does not need a camera with a high frame rate, so that the cost of the camera is low, and the algorithm of the processing program is simple.

Example 2: it is assumed that the position of the implement will change after landing, for example, a shot will continue to roll forward after landing. In this case, it is necessary to compare the frames by frames during the flight of the instrument, which follows an approximately parabolic trajectory that is not followed once the instrument has landed. Since the embodiment needs to accurately determine the moment when the instrument deviates from the trajectory and use the point as the landing point, a camera with a high frame rate is needed, so that the cost of the camera is higher than that of embodiment 1, and the algorithm of the processing procedure is complex.

Example 3: in the case of embodiment 2, that is, in the case of assuming that the position of the apparatus changes after landing, this embodiment uses two cameras to capture the trajectory of the movement of the apparatus in the air, and then calculates the landing point of the trajectory, and the specific method can refer to "a method for determining the flight trajectory of an air-borne object subjected to air resistance" of application No. 2020101423827. Because the embodiment needs two cameras to work cooperatively, the hardware cost is high, the calculation is complex, and the measurement accuracy is not high, so the embodiment is not a preferred method in practice.

Step S3 of the present invention requires calculating the actual physical coordinates of the floor point according to the position of the instrument or the human body floor point in the image obtained in step S2, using the external parameters, the internal parameters, and the distortion parameters of the camera obtained in step S1, and the specific method of this step can refer to "a monocular camera measuring target position data, shooting angle, and camera view angle method" with application No. 2019109833367.

Step S4 of the present invention requires calculating the throwing distance according to the physical coordinates of the instrument or human body landing point obtained in step S3. Since the mark points used in step S1 need to determine a coordinate system when measuring their physical coordinates, the physical coordinates of the instrument or human body landing point obtained in step S3 are also in this coordinate system, and the throwing or jumping start point is also in this coordinate system, so that the final throwing or jumping distance can be easily calculated from the physical coordinates of the landing point and the physical coordinates of the start point.

Claims

1. A method for measuring the throwing distance of a track and field throwing type project and the long jump distance of a long jump type project based on image processing is characterized in that a camera is used for capturing images when throwing or jumping far, the physical position of an instrument or a human body place is calculated through an image processing program, and the throwing distance or the long jump distance is calculated according to the physical position.

2. The image processing based method for measuring the throwing distance of an athletic throwing type project and the long jump distance of a long jump type project according to claim 1, wherein the data acquisition and calculation can be completed by using a single camera. In practice, in order to improve the accuracy, a plurality of cameras may be used, and the accuracy may be improved by covering a part of the detection range with each camera. It is within the scope of the present invention to use two cameras to calculate the flight trajectory of the instrument and thus the landing point of the instrument as described in embodiment 3 of step S2.

3. The image processing-based method for measuring the throwing distance of an athletic throwing type project and the long jump distance of a long jump type project according to claim 1, comprising: