# 3D Kinematic Analysis of Intelligent Vision Sensor Image in Football Training

Authors: Pengcheng Ni; Xi Luo
Journal: Journal of Sensors
 (2021)

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## Abstract

With its advantages of high precision, noncontact, and high intelligence, intelligent visual sensor detection technology meets the requirements for online detection of motion status and intelligent recognition of motion images during sports activities, and its applications are becoming more and more extensive. In order to deeply explore the feasibility of using intelligent vision sensor technology to analyze the three-dimensional action of football, this article uses algorithm analysis method, technology summary method, and physical assembly method, collects samples, analyzes the motion model, streamlines the algorithm, and then creates a model based on intelligent visual sensor technology that can analyze the three-dimensional movement in football training. After the experimental objects are selected, the model is established in the ADM environment. All athletes do a uniform motion, the standard input motion speed is 5 m/s, they all move in the opposite direction relative to their respective coordinate axes, and the motion time is 6 seconds. The results show that the movement curves of the athletes in the three coordinate axis directions are basically the same. When the exercise time is 6 seconds, the coordinate values of the athletes on the three coordinate axes are all 0.992 m. We set six intensities in the experiment: 5%, 15%, 25%, 35%, 45%, and 55%. It can be found that as the noise intensity increases from 5% to 45%, the estimation error gradually increases, but as a whole, it is still at a relatively small level. It shows that the algorithm in this paper still has practical significance. It is basically realized that under the guidance of intelligent vision sensor technology, a model can be designed to successfully and efficiently analyze the three-dimensional movement pattern in training.


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## Body

## 1. Introduction

Humans observe and understand the world by relying on sense such as vision, touch, hearing, and smell. Vision is the most important way to obtain information. The acquired images are the main carrier for humans to communicate with each other and understand the objective world, and they are also the most complex perception of humans. In the era of big data, the ubiquitous mass of data has begun to influence and change our way of life. The camera has been around for more than a hundred years. Among the vast array of image and video resources, human activities constitute a very important part of it. Movement is an important feature of objective existence in the real world. The world is a moving world. Stillness is relative. Everything in nature changes with time. An important purpose of vision measurement is to measure and analyze the spatial motion state of the measured moving target and select an appropriate number of vision sensors according to the measurement process. At present, this vision sensor technology is close to maturity.At the same time, we can see that football is an enduring sport and is deeply loved by the Chinese people. Up to now, the World Cup is the one with the most spectators of all sports events. According to data provided by FIFA, during the 2018 World Cup in Russia, 3.5 billion people worldwide watched the game, and there were 660 million Chinese viewers, including multimedia channels such as TV and the Internet. However, the problem that cannot be ignored at present is that the strength of Chinese football is still at a relatively low level, which is inseparable from the usual training methods. If the new technology can be used to analyze the sports of football, then this will definitely affect China. Football is a major plus. Youth football is the initial stage of development. If it is not done properly, then there is no way to talk about the development of football. It is based on such considerations that our country has increased its emphasis on the training of youth football talents. Training is the foundation of youth football talent training. How to strengthen the daily football training methods of young people has become our primary consideration. Intelligent visual sensors can be well applied to the range of movements in training and they can complete their training. In the system construction of 3D kinematics, in a word, the research of 3D human motion analysis based on sensor images has naturally become a very meaningful research direction. The results can be applied to many fields and have high practical application value.Football has always been one of the most popular sports. Therefore, the study of three-dimensional kinematics analysis in its training has always been a hot topic, and many scholars have used smart sensor images to study it. In 2018, Wenyuan stated that he was preparing for international sports events including the Tokyo Olympics. In his research, he uses multiple cameras from a single angle of view, by taking pictures of occlusion points at a high zoom magnification, and then applying OpenPose’s deep learning sensor to identify American football players with high precision and specify their positions. However, there is no analysis process [1]. In 2020, based on mobile artificial intelligence terminal technology, Ma has developed and designed a C/S mode athlete training process monitoring system. It uses GPS to obtain real-time position information of athletes and provides real-time guidance for athletes. In order to reveal the changing laws of various indicators in the training state of athletes, real-time remote monitoring of sensor images is used. Nevertheless, the image monitoring results are not accurate [2]. In 2021, Jebur aims to determine the differences in football cognitive achievement of students with different learning styles. The researchers used a combination of descriptive methods and comparative research methods to adapt to the nature of the problem and sampled students from the fourth stage of the school year in the School of Physical Education and Exercise Science at Samara University. It is found that students with different learning styles have significant differences in football cognitive achievement. Unfortunately, there is no data to support it [3]. In 2016, Fantozzi aims to develop a protocol to evaluate the three-dimensional kinematics of the upper limbs during swimming with IMMU. Eight swimmers evaluated the kinematics in a simulated dryland swimming test conducted in the laboratory. The results showed that the multiple correlation coefficient (CMC) value was very high, and the median CMC value displayed by the wrist index was always higher than 0.90. However, the experimental environment limits its development [4]. In 2017, Hyungkyoo aims to establish a kinematic reference range for the femoral tibial (FT) and patellofemoral (PF) of healthy small dogs by measuring the 3D kinematics during walking. In this study, the normal in vivo 3D FT and PF kinematics were demonstrated, and the average kinematic parameters of walking beagles were determined, but the research object is that the animal does not meet the requirements [5]. In 2016, Campbell tried to compare a new type of head impact monitoring device that is not limited to a specific helmet style with a reference acceleration sensor measurement. The original GFT is accurate when measuring the peak rotation speed of the HIII centroid (MAPE=9%). GFT seems to be a suitable impact monitoring device, but correction algorithms need to be developed for each helmet type. However, the research scope is relatively limited [6]. In 2016, Rubiopalau used customized cutting and positioning rail sensors to output virtual surgery to the operating room, improving accuracy and improving results. They showed their experience in using 3D plans to treat craniofacial deformities. 3D planning reduces surgical time and allows prediction of possible difficulties and complications. However, the sensor is not used at all during this operation [7].The innovations of this paper are as follows: (1) a method for byte feature recognition and high-precision positioning of a circular target is proposed and a multiconstrained byte recognition scheme based on morphology is adopted for byte features to identify its byte identity information. (2) A high-precision camera calibration error compensation method based on a new stereo vision beam adjustment algorithm is proposed, which improves the calibration accuracy of the three-dimensional motion vision sensor measurement. (3) A generalized correction method based on the weighted feature measurement error is proposed. The alternate iterative pose estimation method integrates the uncertainty of the target feature measurement error into the pose estimation objective function and extends it to three-dimensional vision, which improves the stability and accuracy of the pose estimation. (4) While applying the visual sensor technology analysis, it always integrates the actual scene and does not deviate from the coverage of the football stadium. Such research steps can improve the problem of the theory and practice not fitting well and contribute to the practical application of this article. Through the above work, the accuracy of the intelligent sensor image analysis of the three-dimensional kinematics in football training is ensured.


## 2. Realization Method of 3D Kinematics in Football Training Based on Intelligent Vision Sensor Image

### 2.1. Football Training Mode

Modes, which can also be called “paradigm,” understand the method of solving a certain type of problem in the book, that is, the mode, which generally refers to the method as a copy or a variant [8]. Like many other sports, the training course mode of football in our country is mainly based on the training course mode of the previous big brother and gradually forms its own characteristics in combination with its basic situation. The structure of traditional football training courses in our country is generally divided into three parts: preparation part, basic part, and end part. Figure 1 carefully introduces some basic content in football training [9].Figure 1
Football field and football training technical movements.It can be seen from Figure1 that physical training classes generally focus on physical exercise, including speed, strength, fitness, and patience. A training class can only practice a certain essence or a few essences and generally do not hold the ball [10]. The technical class is generally to practice football skills, including passing, stopping, banding, and shooting. Technical exercises generally focus on basic technical exercises, which are usually practiced in an environment with no or weak resistance. Strategy classes are generally strategy exercises. The content of strategy exercises includes basic strategy, team strategy, and set-up strategy. Strategy training is usually completed in an environment with no or weak resistance [11]. The comprehensive course is not a single physical exercise, technique, or strategy exercise content. According to the difference in practice, the comprehensive class is divided into the following: comprehensive classes of techniques and strategies, comprehensive classes of techniques and physical training, comprehensive classes of strategies and physical training and skills, and a comprehensive course of strategy and physical training.


### 2.2. Smart Vision Sensor

Vision sensors, also called smart cameras, are the fastest growing new technology in the field of machine vision in recent years. Vision sensors are the direct source of information for the entire machine vision system. It is mainly composed of one or two graphic sensors, sometimes with auxiliary equipment such as light projectors. The main function of the vision sensor is to obtain enough original images for processing by the machine vision system. The vision sensor is a small machine vision system with image acquisition, image processing, information transmission functions, and unit control. It is an embedded machine vision system [12]. After describing the visual sensor, we should also know what a sensor is. A sensor is a device or device that can sense a specified measurement value and convert it into a usable output signal according to certain rules. The visual sensor system constitution is shown as in Figure 2.Figure 2
Visual sensor system configuration diagram.It can be seen from Figure2 that the biggest feature of the visual sensor is high integration and modular function and conforms to industrial characteristics [13]. It integrates light source, camera, image processor, standard control and communication interface, etc., and it can easily realize communication with PC, PLC, and other equipment [14]. Sensor technology is an important part of realizing testing and automatic control. In the test system, as an instrument for positioning, its main feature is that it can accurately transmit and detect a certain form of information and convert it into another form of information. In order to realize that the vision sensor has the functions of image acquisition, image processing, information transmission, and unit control, the hardware structure block diagram of the designed vision sensor is shown in Figure 3 [15].Figure 3
Block diagram of the vision sensor.It can be seen from Figure3 that the system can be divided into core modules and expansion modules in terms of function. The core modules of the system can be divided into acquisition modules, processing modules, and communication modules. Expansion modules include storage expansion modules, unit modules, display modules (with touch screen), and power modules [16]. The whole system can start acquisition and detection commands through communication interface, internal cycle trigger, touch screen, and external trigger of unit interface, complete image acquisition through acquisition module and complete image processing in DSP, and then transmit it to PC or other through communication interface [17]. Control the equipment and display the image processing results on the display module at the same time [18]. Sensing technology can be roughly divided into 3 generations. The first generation is a structural sensor. It uses structural parameter changes to sense and transform signals, for example, resistance strain sensor, which uses the change of resistance when the metal material undergoes elastic deformation to transform electrical signals. The second-generation sensor is a solid sensor developed in the 1970s. This sensor is composed of solid components such as semiconductors, dielectrics, and magnetic materials. It is made using certain characteristics of materials. For example, the use of pyroelectric effect, Hall effect, and photosensitive effect, respectively, made into thermocouple sensor, Hall sensor, photosensitive sensor, and so on. The third-generation sensor is a smart sensor that has just been developed in the 1980s. The so-called smart sensor means that it has certain detection, self-diagnosis, data processing, and self-adaptive capabilities for external information and is a product of the combination of microcomputer technology and detection technology.


### 2.3. Three-Dimensional Kinematics and Algorithm Description

The content of kinematics research includes two parts: forward and inverse position solutions, velocity, and acceleration analysis. Knowing the position parameters of the driving link of the parallel mechanism, solving all possible positions and attitudes of the moving platform of the mechanism is called forward kinematics solution. The tracker is set in the key part of the moving object, and the position of the tracker is captured by the motion capture system. After computer processing, the data of three-dimensional space coordinates is obtained. After the data is recognized by the computer, it can be used for animation production, gait analysis, and biomechanics, ergonomics, and other fields. If the position and attitude parameters of the moving platform are known, solving the position parameters of the driving link of the mechanism is called kinematics. Learn the inverse solution or the inverse kinematics solution. The most common applications of machine vision include target detection, recognition, positioning, and tracking in natural scenes. Detection is mainly to judge whether there is a target in the scene; recognition is mainly to judge what the target is in the scene; positioning is mainly to calculate the specific position of the target in the scene; tracking is mainly to track the moving target in the scene [19]. The use of motion capture technology in animation production can greatly improve the level of animation production, greatly improve the efficiency of animation production, reduce costs, and make the animation production process more intuitive and vivid. For the three-dimensional human body motion analysis in this article, it can be divided into three major aspects as shown in Figure 4.Figure 4
Vision-based 3D human motion analysis process.From Figure4, we can see that after the human motion analysis system inputs images or video clips, after a period of processing, the output of the system, including whether there is a person in the image, where the person is, what posture and parameter configuration are all clear to see. There are even some outputs rich in high-level semantics, such as what the person in the image is doing and what objects are they carrying [20]. To solve this series of problems, the research content involved includes three aspects: (1) human detection (2) human pose estimation and tracking, and (3) human behavior recognition. The system formed by motion capture technology includes mechanical linkages, magnetic sensors, light sensors, acoustic sensors, and inertial sensors. Each technology has its own advantages, but no matter which technology is adopted, users will be subject to certain restrictions.With the rapid development of integrated circuits, breakthroughs have been made in computer technology and sensor chip manufacturing technology, and computer vision motion measurement technology has also developed rapidly [21]. More and more people need advanced visual motion measurement systems for production and life and advanced foreign scientific research. Institutions and companies have successively developed visual motion measurement systems suitable for different occasions, as shown in Figure 5,Figure 5
The VICON motion capture system.It can be seen from Figure5 that these measurement systems have reached a very high level in terms of performance and measurement accuracy and have obtained good application effects in many fields, such as modern industrial measurement fields, bionics and animation production fields, modern Medical recovery field, and virtual reality field. Among them, focus on the OT system, which is a set of motion capture system developed by NPl companies and successfully applied to UVA football training in a college, as shown in Figure 6 [22].Figure 6
The OT motion capture system.It can be seen from Figure6 that the real-time positioning accuracy of the OT system is effectively controlled within 0.45 mm, up to 0.05 mm in an excellent capture environment, and it has leading 3D reconstruction and rigid body resolution accuracy. Using the high-precision OT three-dimensional motion capture system to capture the special marking points fixed on the athletes at a shooting rate of hundreds of frames per second, it can accurately construct the three-dimensional space position information of the marking points in real time and realize the position and posture information of the football players. The capture is an advanced assisting device for athletes in the running process. The first half of our part focuses on drawing the framework diagram and concept diagram, and in the experiment, we focus on the description of pictures and texts. This deliberately can improve the reader’s reading experience, and it will also help to sort out the layout logic of this article.This paper proposes a multifaceted sparse byte algorithm. By introducing multifaceted learning, it can not only solve the “dimension disaster” problem of human motion data but also deal with the nonlinear characteristics of human motion data. Among them, the highest level kernel function is obtained through the linear collocation of different types of kernel functions in the kernel function pool, which effectively solves the difficulty of selecting kernel functions and their parameters [23].


#### 2.3.1. Establish the Objective Function

Assuming there ism training sample pairs, under the multifaceted learning framework, the initial value is mapped to the high-dimensional space H with the multifaceted function, and then the kernel function of the training sample pair τu,τk can be expressed as
(1)gστu,τk=σρτus∗σρτke=∑k=1iρk2giτu,τk.When the initial features are mapped to the space, the sample pairau,bu is replaced by σρau,σρbu, and the image node wl∈eo∗g and human motion node wq∈ee∗g are replaced by σρwl and σρwq, respectively. Finally, the target value of sparse bytes in many aspects can be expressed as the following formula:
(2)maxx,y,d,pσa−σρaxdl2+β2σg−σρbydl2+σd.In formula (2), the first two items are the reconstruction error of the image feature vector and the posture mark vector, respectively; β1, β2, and β3 are the number of weights, and g represents the posture parameter matrix with the minimum geodesic distance to the corresponding image feature. Substitute σd into equation (2) to obtain the following equation:
(3)maxx,y,d,ρσa−σρaxdl2+β1d1+β2σg−σρbydl2+β3∑u,k=1ndu−dkl2tuke.


#### 2.3.2. Human Body Posture Space Conversion

The human motion nodewq∈ee∗g contains the relevant segment angle data πuu=1i∈−120,120, which makes the posture unable to be measured repeatedly with i2 [24]. Therefore, in order to use the i2 norm to measure the attitude reconstruction error, this paper uses a special mapping to convert σu∈wq to a unit of e2e:
(4)σuˇ=1esinσu,tanσu,u=1,⋯,h.In formula (4), sinσu=sinσu1,⋯,sinσue, and cosσu=cosσu1,⋯,cosσue, the mapping makes the image characteristics and the posture parameters in the same space in the process, so that the data on the posture features in the target is effective [25].


#### 2.3.3. Optimize the Objective Function

After the objective function is established, the objective function needs to be iteratively optimized to solve three types of parameters: the span parameter matricesx and y and the multifaceted function weight coefficient ρ.In order to update the sparse byte vectordu independently, now, the target value is changed into a vector form, which is denoted as
(5)maxa,y,dk,ρ∑u=1nσau−σρaxdul2=β1+β2+β3.Assuming that all vectors exceptdu, including dkk≠u,x,y and ρ, are known, formula (5) can be further rewritten as
(6)maxdkσau−σρaxdul2=β1+β2+β3−dk.In formula (6), duk represents the absolute number of the k-th coefficient in the sparse vector du.Starting from the zero coefficient indu, the coefficient index k is selected by the following formula:
(7)xehmink∇uklpykdu=xehminkμσau−σρaxdul2μun.Among them,xehmink is the basic data. When duk locally improves the objective function, the activation coefficient is divided into a positive sign and a negative sign.Get a specific value analysis solution by solving a free mm problem:(8)maxdmdu^=σau−σρa^∗x^du^l2+β1ls^d^.Expand the formula (8) and find the derivative of du^, let μmdu^/μdu^=0, and get the optimal solution under the activation set:
(9)d^uold=xs^gρa^,a^x^+ys^gρb,b^y^y^+β1+β2+β3.In formula (9), u represents an identity matrix.In order to update the excess numberx, it is necessary to determine the sparse byte d, the excess parameter matrix y, and the multifaceted weight ρ, delete the lonely quantity in the target value, and obtain the following formula:
(10)maxxσa−σρaxdl2,t∗s∗xu2≤z,u=1,⋯,g.In Equation (10), σa is a constant [26]. The high-level dual function of formula (10) is expressed as the following formula:
(11)hμ=uolwliwl,μ=∑u=1gμuxu2−z.Assuming thatω is a diagonal matrix of g×g, and ωuu=μu, and then iwl,μ can be expressed as
(12)iwl,μ=σa−σρaxdl2−zseω.Among them,iwl,μ represents the average value. For formula (12), let μiwl,μ/μx=0 obtain the optimal solution x′, namely,
(13)μiwl,μ/μx=−2gρa,ads+∏k=1nAk=0,(14)x′=gρa,ads∗dsgρa,ad+gρa,aω−1.In the formula,x′ represents the target. Substituting formula (14) into formula (12), the dual function of advanced algorithms is called
(15)kω=segρa,a−segρa,adsdds+ωd−zseω.kω is the transformed result, and the optimal solution ω∗ is calculated by solving the following Lagrangian dual problem:
(16)maxωsegρa,a∗dsdds+ω−1d+zseω,t∗s∗μu≥0,u=1,⋯,g.For formula (16), Newton’s method or gradient descent method can be directly used to calculate the highest point ω∗, and the learning weight ρ is to construct the optimal core from the kernel function pool to process multiple types of inputs, thereby improving generalization performance [27]. Now, given the sparse byte d and the extra parameter matrices x and y, delete the irrelevant terms of the objective function and get the following formula:
(17)max¨∑u=1nσau−σρaxdul2+β2∑u=1nσgu−μρbˇydul2.After the value ofσgu is reduced, Equation (17) can be regarded as a problem about the imprisonment of the average value ρ, namely,
(18)∑i=1iρk2fl+β2∑i=1iρi2fq,t∗s∗∑i=1iρi=1,ρi≥0.In the formula,ρi≥0 is the standard to be followed. In formula (18), fl and fq can be expressed as
(19)fl=segka,a−2segua,axd+sedsxsgua,axd,(20)fq=segkg,g−2segug,b^yd+sedsysgub^,b^yd.fl and fq are the different solution sets of the algorithm, respectively. In addition, s and e are the constant distributions of the formula, g and a are the medians, and yd and xd are a range of values that change over time; so, this formula can well summarize the entire process range. Substitute Equation (20) into Equation (19) to solve a standard problem to update the weight ρ. In order to improve the efficiency of the algorithm, this paper uses a dual action set algorithm to search for analytical solutions in the feasible region to achieve the optimization of this problem.


## 2.1. Football Training Mode

Modes, which can also be called “paradigm,” understand the method of solving a certain type of problem in the book, that is, the mode, which generally refers to the method as a copy or a variant [8]. Like many other sports, the training course mode of football in our country is mainly based on the training course mode of the previous big brother and gradually forms its own characteristics in combination with its basic situation. The structure of traditional football training courses in our country is generally divided into three parts: preparation part, basic part, and end part. Figure 1 carefully introduces some basic content in football training [9].Figure 1
Football field and football training technical movements.It can be seen from Figure1 that physical training classes generally focus on physical exercise, including speed, strength, fitness, and patience. A training class can only practice a certain essence or a few essences and generally do not hold the ball [10]. The technical class is generally to practice football skills, including passing, stopping, banding, and shooting. Technical exercises generally focus on basic technical exercises, which are usually practiced in an environment with no or weak resistance. Strategy classes are generally strategy exercises. The content of strategy exercises includes basic strategy, team strategy, and set-up strategy. Strategy training is usually completed in an environment with no or weak resistance [11]. The comprehensive course is not a single physical exercise, technique, or strategy exercise content. According to the difference in practice, the comprehensive class is divided into the following: comprehensive classes of techniques and strategies, comprehensive classes of techniques and physical training, comprehensive classes of strategies and physical training and skills, and a comprehensive course of strategy and physical training.


## 2.2. Smart Vision Sensor

Vision sensors, also called smart cameras, are the fastest growing new technology in the field of machine vision in recent years. Vision sensors are the direct source of information for the entire machine vision system. It is mainly composed of one or two graphic sensors, sometimes with auxiliary equipment such as light projectors. The main function of the vision sensor is to obtain enough original images for processing by the machine vision system. The vision sensor is a small machine vision system with image acquisition, image processing, information transmission functions, and unit control. It is an embedded machine vision system [12]. After describing the visual sensor, we should also know what a sensor is. A sensor is a device or device that can sense a specified measurement value and convert it into a usable output signal according to certain rules. The visual sensor system constitution is shown as in Figure 2.Figure 2
Visual sensor system configuration diagram.It can be seen from Figure2 that the biggest feature of the visual sensor is high integration and modular function and conforms to industrial characteristics [13]. It integrates light source, camera, image processor, standard control and communication interface, etc., and it can easily realize communication with PC, PLC, and other equipment [14]. Sensor technology is an important part of realizing testing and automatic control. In the test system, as an instrument for positioning, its main feature is that it can accurately transmit and detect a certain form of information and convert it into another form of information. In order to realize that the vision sensor has the functions of image acquisition, image processing, information transmission, and unit control, the hardware structure block diagram of the designed vision sensor is shown in Figure 3 [15].Figure 3
Block diagram of the vision sensor.It can be seen from Figure3 that the system can be divided into core modules and expansion modules in terms of function. The core modules of the system can be divided into acquisition modules, processing modules, and communication modules. Expansion modules include storage expansion modules, unit modules, display modules (with touch screen), and power modules [16]. The whole system can start acquisition and detection commands through communication interface, internal cycle trigger, touch screen, and external trigger of unit interface, complete image acquisition through acquisition module and complete image processing in DSP, and then transmit it to PC or other through communication interface [17]. Control the equipment and display the image processing results on the display module at the same time [18]. Sensing technology can be roughly divided into 3 generations. The first generation is a structural sensor. It uses structural parameter changes to sense and transform signals, for example, resistance strain sensor, which uses the change of resistance when the metal material undergoes elastic deformation to transform electrical signals. The second-generation sensor is a solid sensor developed in the 1970s. This sensor is composed of solid components such as semiconductors, dielectrics, and magnetic materials. It is made using certain characteristics of materials. For example, the use of pyroelectric effect, Hall effect, and photosensitive effect, respectively, made into thermocouple sensor, Hall sensor, photosensitive sensor, and so on. The third-generation sensor is a smart sensor that has just been developed in the 1980s. The so-called smart sensor means that it has certain detection, self-diagnosis, data processing, and self-adaptive capabilities for external information and is a product of the combination of microcomputer technology and detection technology.


## 2.3. Three-Dimensional Kinematics and Algorithm Description

The content of kinematics research includes two parts: forward and inverse position solutions, velocity, and acceleration analysis. Knowing the position parameters of the driving link of the parallel mechanism, solving all possible positions and attitudes of the moving platform of the mechanism is called forward kinematics solution. The tracker is set in the key part of the moving object, and the position of the tracker is captured by the motion capture system. After computer processing, the data of three-dimensional space coordinates is obtained. After the data is recognized by the computer, it can be used for animation production, gait analysis, and biomechanics, ergonomics, and other fields. If the position and attitude parameters of the moving platform are known, solving the position parameters of the driving link of the mechanism is called kinematics. Learn the inverse solution or the inverse kinematics solution. The most common applications of machine vision include target detection, recognition, positioning, and tracking in natural scenes. Detection is mainly to judge whether there is a target in the scene; recognition is mainly to judge what the target is in the scene; positioning is mainly to calculate the specific position of the target in the scene; tracking is mainly to track the moving target in the scene [19]. The use of motion capture technology in animation production can greatly improve the level of animation production, greatly improve the efficiency of animation production, reduce costs, and make the animation production process more intuitive and vivid. For the three-dimensional human body motion analysis in this article, it can be divided into three major aspects as shown in Figure 4.Figure 4
Vision-based 3D human motion analysis process.From Figure4, we can see that after the human motion analysis system inputs images or video clips, after a period of processing, the output of the system, including whether there is a person in the image, where the person is, what posture and parameter configuration are all clear to see. There are even some outputs rich in high-level semantics, such as what the person in the image is doing and what objects are they carrying [20]. To solve this series of problems, the research content involved includes three aspects: (1) human detection (2) human pose estimation and tracking, and (3) human behavior recognition. The system formed by motion capture technology includes mechanical linkages, magnetic sensors, light sensors, acoustic sensors, and inertial sensors. Each technology has its own advantages, but no matter which technology is adopted, users will be subject to certain restrictions.With the rapid development of integrated circuits, breakthroughs have been made in computer technology and sensor chip manufacturing technology, and computer vision motion measurement technology has also developed rapidly [21]. More and more people need advanced visual motion measurement systems for production and life and advanced foreign scientific research. Institutions and companies have successively developed visual motion measurement systems suitable for different occasions, as shown in Figure 5,Figure 5
The VICON motion capture system.It can be seen from Figure5 that these measurement systems have reached a very high level in terms of performance and measurement accuracy and have obtained good application effects in many fields, such as modern industrial measurement fields, bionics and animation production fields, modern Medical recovery field, and virtual reality field. Among them, focus on the OT system, which is a set of motion capture system developed by NPl companies and successfully applied to UVA football training in a college, as shown in Figure 6 [22].Figure 6
The OT motion capture system.It can be seen from Figure6 that the real-time positioning accuracy of the OT system is effectively controlled within 0.45 mm, up to 0.05 mm in an excellent capture environment, and it has leading 3D reconstruction and rigid body resolution accuracy. Using the high-precision OT three-dimensional motion capture system to capture the special marking points fixed on the athletes at a shooting rate of hundreds of frames per second, it can accurately construct the three-dimensional space position information of the marking points in real time and realize the position and posture information of the football players. The capture is an advanced assisting device for athletes in the running process. The first half of our part focuses on drawing the framework diagram and concept diagram, and in the experiment, we focus on the description of pictures and texts. This deliberately can improve the reader’s reading experience, and it will also help to sort out the layout logic of this article.This paper proposes a multifaceted sparse byte algorithm. By introducing multifaceted learning, it can not only solve the “dimension disaster” problem of human motion data but also deal with the nonlinear characteristics of human motion data. Among them, the highest level kernel function is obtained through the linear collocation of different types of kernel functions in the kernel function pool, which effectively solves the difficulty of selecting kernel functions and their parameters [23].


### 2.3.1. Establish the Objective Function

Assuming there ism training sample pairs, under the multifaceted learning framework, the initial value is mapped to the high-dimensional space H with the multifaceted function, and then the kernel function of the training sample pair τu,τk can be expressed as
(1)gστu,τk=σρτus∗σρτke=∑k=1iρk2giτu,τk.When the initial features are mapped to the space, the sample pairau,bu is replaced by σρau,σρbu, and the image node wl∈eo∗g and human motion node wq∈ee∗g are replaced by σρwl and σρwq, respectively. Finally, the target value of sparse bytes in many aspects can be expressed as the following formula:
(2)maxx,y,d,pσa−σρaxdl2+β2σg−σρbydl2+σd.In formula (2), the first two items are the reconstruction error of the image feature vector and the posture mark vector, respectively; β1, β2, and β3 are the number of weights, and g represents the posture parameter matrix with the minimum geodesic distance to the corresponding image feature. Substitute σd into equation (2) to obtain the following equation:
(3)maxx,y,d,ρσa−σρaxdl2+β1d1+β2σg−σρbydl2+β3∑u,k=1ndu−dkl2tuke.


### 2.3.2. Human Body Posture Space Conversion

The human motion nodewq∈ee∗g contains the relevant segment angle data πuu=1i∈−120,120, which makes the posture unable to be measured repeatedly with i2 [24]. Therefore, in order to use the i2 norm to measure the attitude reconstruction error, this paper uses a special mapping to convert σu∈wq to a unit of e2e:
(4)σuˇ=1esinσu,tanσu,u=1,⋯,h.In formula (4), sinσu=sinσu1,⋯,sinσue, and cosσu=cosσu1,⋯,cosσue, the mapping makes the image characteristics and the posture parameters in the same space in the process, so that the data on the posture features in the target is effective [25].


### 2.3.3. Optimize the Objective Function

After the objective function is established, the objective function needs to be iteratively optimized to solve three types of parameters: the span parameter matricesx and y and the multifaceted function weight coefficient ρ.In order to update the sparse byte vectordu independently, now, the target value is changed into a vector form, which is denoted as
(5)maxa,y,dk,ρ∑u=1nσau−σρaxdul2=β1+β2+β3.Assuming that all vectors exceptdu, including dkk≠u,x,y and ρ, are known, formula (5) can be further rewritten as
(6)maxdkσau−σρaxdul2=β1+β2+β3−dk.In formula (6), duk represents the absolute number of the k-th coefficient in the sparse vector du.Starting from the zero coefficient indu, the coefficient index k is selected by the following formula:
(7)xehmink∇uklpykdu=xehminkμσau−σρaxdul2μun.Among them,xehmink is the basic data. When duk locally improves the objective function, the activation coefficient is divided into a positive sign and a negative sign.Get a specific value analysis solution by solving a free mm problem:(8)maxdmdu^=σau−σρa^∗x^du^l2+β1ls^d^.Expand the formula (8) and find the derivative of du^, let μmdu^/μdu^=0, and get the optimal solution under the activation set:
(9)d^uold=xs^gρa^,a^x^+ys^gρb,b^y^y^+β1+β2+β3.In formula (9), u represents an identity matrix.In order to update the excess numberx, it is necessary to determine the sparse byte d, the excess parameter matrix y, and the multifaceted weight ρ, delete the lonely quantity in the target value, and obtain the following formula:
(10)maxxσa−σρaxdl2,t∗s∗xu2≤z,u=1,⋯,g.In Equation (10), σa is a constant [26]. The high-level dual function of formula (10) is expressed as the following formula:
(11)hμ=uolwliwl,μ=∑u=1gμuxu2−z.Assuming thatω is a diagonal matrix of g×g, and ωuu=μu, and then iwl,μ can be expressed as
(12)iwl,μ=σa−σρaxdl2−zseω.Among them,iwl,μ represents the average value. For formula (12), let μiwl,μ/μx=0 obtain the optimal solution x′, namely,
(13)μiwl,μ/μx=−2gρa,ads+∏k=1nAk=0,(14)x′=gρa,ads∗dsgρa,ad+gρa,aω−1.In the formula,x′ represents the target. Substituting formula (14) into formula (12), the dual function of advanced algorithms is called
(15)kω=segρa,a−segρa,adsdds+ωd−zseω.kω is the transformed result, and the optimal solution ω∗ is calculated by solving the following Lagrangian dual problem:
(16)maxωsegρa,a∗dsdds+ω−1d+zseω,t∗s∗μu≥0,u=1,⋯,g.For formula (16), Newton’s method or gradient descent method can be directly used to calculate the highest point ω∗, and the learning weight ρ is to construct the optimal core from the kernel function pool to process multiple types of inputs, thereby improving generalization performance [27]. Now, given the sparse byte d and the extra parameter matrices x and y, delete the irrelevant terms of the objective function and get the following formula:
(17)max¨∑u=1nσau−σρaxdul2+β2∑u=1nσgu−μρbˇydul2.After the value ofσgu is reduced, Equation (17) can be regarded as a problem about the imprisonment of the average value ρ, namely,
(18)∑i=1iρk2fl+β2∑i=1iρi2fq,t∗s∗∑i=1iρi=1,ρi≥0.In the formula,ρi≥0 is the standard to be followed. In formula (18), fl and fq can be expressed as
(19)fl=segka,a−2segua,axd+sedsxsgua,axd,(20)fq=segkg,g−2segug,b^yd+sedsysgub^,b^yd.fl and fq are the different solution sets of the algorithm, respectively. In addition, s and e are the constant distributions of the formula, g and a are the medians, and yd and xd are a range of values that change over time; so, this formula can well summarize the entire process range. Substitute Equation (20) into Equation (19) to solve a standard problem to update the weight ρ. In order to improve the efficiency of the algorithm, this paper uses a dual action set algorithm to search for analytical solutions in the feasible region to achieve the optimization of this problem.


## 2.3.1. Establish the Objective Function

Assuming there ism training sample pairs, under the multifaceted learning framework, the initial value is mapped to the high-dimensional space H with the multifaceted function, and then the kernel function of the training sample pair τu,τk can be expressed as
(1)gστu,τk=σρτus∗σρτke=∑k=1iρk2giτu,τk.When the initial features are mapped to the space, the sample pairau,bu is replaced by σρau,σρbu, and the image node wl∈eo∗g and human motion node wq∈ee∗g are replaced by σρwl and σρwq, respectively. Finally, the target value of sparse bytes in many aspects can be expressed as the following formula:
(2)maxx,y,d,pσa−σρaxdl2+β2σg−σρbydl2+σd.In formula (2), the first two items are the reconstruction error of the image feature vector and the posture mark vector, respectively; β1, β2, and β3 are the number of weights, and g represents the posture parameter matrix with the minimum geodesic distance to the corresponding image feature. Substitute σd into equation (2) to obtain the following equation:
(3)maxx,y,d,ρσa−σρaxdl2+β1d1+β2σg−σρbydl2+β3∑u,k=1ndu−dkl2tuke.


## 2.3.2. Human Body Posture Space Conversion

The human motion nodewq∈ee∗g contains the relevant segment angle data πuu=1i∈−120,120, which makes the posture unable to be measured repeatedly with i2 [24]. Therefore, in order to use the i2 norm to measure the attitude reconstruction error, this paper uses a special mapping to convert σu∈wq to a unit of e2e:
(4)σuˇ=1esinσu,tanσu,u=1,⋯,h.In formula (4), sinσu=sinσu1,⋯,sinσue, and cosσu=cosσu1,⋯,cosσue, the mapping makes the image characteristics and the posture parameters in the same space in the process, so that the data on the posture features in the target is effective [25].


## 2.3.3. Optimize the Objective Function

After the objective function is established, the objective function needs to be iteratively optimized to solve three types of parameters: the span parameter matricesx and y and the multifaceted function weight coefficient ρ.In order to update the sparse byte vectordu independently, now, the target value is changed into a vector form, which is denoted as
(5)maxa,y,dk,ρ∑u=1nσau−σρaxdul2=β1+β2+β3.Assuming that all vectors exceptdu, including dkk≠u,x,y and ρ, are known, formula (5) can be further rewritten as
(6)maxdkσau−σρaxdul2=β1+β2+β3−dk.In formula (6), duk represents the absolute number of the k-th coefficient in the sparse vector du.Starting from the zero coefficient indu, the coefficient index k is selected by the following formula:
(7)xehmink∇uklpykdu=xehminkμσau−σρaxdul2μun.Among them,xehmink is the basic data. When duk locally improves the objective function, the activation coefficient is divided into a positive sign and a negative sign.Get a specific value analysis solution by solving a free mm problem:(8)maxdmdu^=σau−σρa^∗x^du^l2+β1ls^d^.Expand the formula (8) and find the derivative of du^, let μmdu^/μdu^=0, and get the optimal solution under the activation set:
(9)d^uold=xs^gρa^,a^x^+ys^gρb,b^y^y^+β1+β2+β3.In formula (9), u represents an identity matrix.In order to update the excess numberx, it is necessary to determine the sparse byte d, the excess parameter matrix y, and the multifaceted weight ρ, delete the lonely quantity in the target value, and obtain the following formula:
(10)maxxσa−σρaxdl2,t∗s∗xu2≤z,u=1,⋯,g.In Equation (10), σa is a constant [26]. The high-level dual function of formula (10) is expressed as the following formula:
(11)hμ=uolwliwl,μ=∑u=1gμuxu2−z.Assuming thatω is a diagonal matrix of g×g, and ωuu=μu, and then iwl,μ can be expressed as
(12)iwl,μ=σa−σρaxdl2−zseω.Among them,iwl,μ represents the average value. For formula (12), let μiwl,μ/μx=0 obtain the optimal solution x′, namely,
(13)μiwl,μ/μx=−2gρa,ads+∏k=1nAk=0,(14)x′=gρa,ads∗dsgρa,ad+gρa,aω−1.In the formula,x′ represents the target. Substituting formula (14) into formula (12), the dual function of advanced algorithms is called
(15)kω=segρa,a−segρa,adsdds+ωd−zseω.kω is the transformed result, and the optimal solution ω∗ is calculated by solving the following Lagrangian dual problem:
(16)maxωsegρa,a∗dsdds+ω−1d+zseω,t∗s∗μu≥0,u=1,⋯,g.For formula (16), Newton’s method or gradient descent method can be directly used to calculate the highest point ω∗, and the learning weight ρ is to construct the optimal core from the kernel function pool to process multiple types of inputs, thereby improving generalization performance [27]. Now, given the sparse byte d and the extra parameter matrices x and y, delete the irrelevant terms of the objective function and get the following formula:
(17)max¨∑u=1nσau−σρaxdul2+β2∑u=1nσgu−μρbˇydul2.After the value ofσgu is reduced, Equation (17) can be regarded as a problem about the imprisonment of the average value ρ, namely,
(18)∑i=1iρk2fl+β2∑i=1iρi2fq,t∗s∗∑i=1iρi=1,ρi≥0.In the formula,ρi≥0 is the standard to be followed. In formula (18), fl and fq can be expressed as
(19)fl=segka,a−2segua,axd+sedsxsgua,axd,(20)fq=segkg,g−2segug,b^yd+sedsysgub^,b^yd.fl and fq are the different solution sets of the algorithm, respectively. In addition, s and e are the constant distributions of the formula, g and a are the medians, and yd and xd are a range of values that change over time; so, this formula can well summarize the entire process range. Substitute Equation (20) into Equation (19) to solve a standard problem to update the weight ρ. In order to improve the efficiency of the algorithm, this paper uses a dual action set algorithm to search for analytical solutions in the feasible region to achieve the optimization of this problem.


## 3. Experiments and Conclusions of the Design and Realization Method of Three-Dimensional Kinematics in Football Training Based on Intelligent Vision Sensor Images

### 3.1. Vision Sensor Prototype Construction Plan

With the rapid development of electronic technology, the integration of chips continues to increase, and the volume and weight of the new generation of vision sensor products are getting smaller and smaller. At present, the competition of electronic products has entered an era of all-round competition. An excellent product must not only have good performance but also have a friendly appearance and small structure size. Small and exquisite product design can always give consumers more attractiveness. For this reason, product designers are paying more and more attention to product appearance and structural size design. In the design of the vision sensor, the factor that has the greatest influence on its structural size comes from the design of the core circuit board. Although a highly integrated digital chip and a compact component package are used, how to arrange the components reasonably is also crucial. In this system, the circuit of the vision sensor is divided into three PCB board designs: DSP main board, liquid crystal display board, and CMOS image acquisition board. The DSP main board and the liquid crystal display board are connected by FPC flexible cable, and the important signals are protected by ground wire to prevent interference; the CMOS image acquisition board and the DSP main board are connected by 90°pins, and important signals are connected at the same time.


### 3.2. System Anti-Interference Measures and Signal Integrity

Measures to improve system anti-interference:(1)
When wiring, the power wire and ground wire should be as thick as possible. In addition to reducing the pressure drop, it is more important to reduce the coupling noise(2)
For the idle I/O ports of some chips, do not float and connect to ground or power. For the idle pins of the IC, they should be grounded or connected to the power supply without changing the system logic(3)
The clock signal line should be as short as possible, and the ground wire should be used as escort on the training field(4)
The area enclosed by the signal output line and the return line should be as small as possible to reduce the antenna effect; for single and double panels, additional ground wires can be added to achieve thisThe image transmission design method to ensure signal integrity can be seen in Table1.Table 1
Image transmission design method to ensure signal integrity.
MethodAccuracyReliabilityMethod to realizeSynchronous switching output93.6%100%PCD65221Minimize trace length95.2%99.8%JXH5244Shorten signal routing91.8%99.3%KDSJ485Terminal match90.6%96.4%AIJK364Reduce inductive coupling96.3%98.8%JUWSS47In the intelligent vision inspection system, it is an indispensable step to transfer the collected image data to the PC. Even in the design of the vision sensor system separated from the PC, there are many loops in the system installation, debugging, information storage, etc. It must be required to realize the data communication between the sensor and the PC.Universal Serial Bus (USB) is a new interface standard jointly launched by 7 world-renowned computer and communication companies, including Intel, Com, Dig, IBM, Microsoft, NEC, and NT. It is based on universal connection technology and realizes the simple and fast connection of peripherals, achieving the purpose of facilitating users, reducing costs, and expanding the interface range of PC peripherals. At the same time, it can provide power for peripherals, unlike ordinary serial and parallel devices that require a separate power supply system. The characteristics of the USB interface are shown in Table2.Table 2
USB interface characteristics.
CharacteristicsDataData sourceReliabilityEasy to install and configure1 for 1Internet86.9%High speed1.5MbpsIBM79.9%Easy to extend125-33 mDig86.7%Able to use bus power4.5 V, 450 mACom91.7%Flexible to use4 patternsNT91.4%After consideration, this article selects the built-in USB module of TMS, which is a slave USB module that conforms to the USB1.1 protocol. The features are as follows:(1)
Compatible with USB2.0(2)
With 15 endpointsTI provides an onchip support library USB CSL for the USB modules of the 5611 and 5711 series DSPs. This CSL has the advantages described in Table3:Table 3
CSL advantages and pin description of TMS built-in USB module.
AdvantageBytePinIllustrateComplete hardware abstraction521 bytesDPTransmit positive differential data (+458)A function call499 bytesDNNTransmit negative differential data (-624)Single API365 bytesPTU3.3 VSupport single data and multiple data buffers400 bytesCT4.6 VProcessing routine association647 bytesXU5.2 V


### 3.3. Brief Introduction of Image Software

ADM is a mechanical system dynamic simulation software developed by American Mechanical Power Corporation. It is the most authoritative and widely used mechanical system dynamic analysis software in the world. It uses an interactive graphic environment and parts library, constraint library, and force library, and its solver uses the Lagrangian equation method in multirigid body system dynamic theory to establish system dynamics equations and perform statics and motion on virtual mechanical systems scientific and dynamic analysis, output displacement, velocity, acceleration and reaction force curves, etc. The simulation of ADM software can be used to predict the performance of the mechanical motion system, the range of motion, collision detection, peak load, and calculation of finite element input load. This article uses the most basic simulation function of ADM to perform entity modeling and sports simulation for football training players.


### 3.4. Kinematic Simulation

This research takes 10 football training camps or clubs in a certain state as the research object. It mainly conducts actual investigations on the football coaches (25 people), young football players (480 people), and school football managers (10 people) in the training camps. Table4 is a statistical table about the state’s youth football training survey data.Table 4
Survey data statistics of youth football training camps or clubs.
Training campClubSchoolFootball coachSoccer playerThe city (%)3 (60%)3 (60%)0 (0%)10 (40%)240 (50%)Other counties (%)2 (40%)2 (40%)0 (0%)15 (60%)240 (50%)Total (%)5 (100%)5 (100%)0 (0%)25 (100%)480 (100%)Establish the model in the ADM environment, and the selected parameters are consistent with the previous ones. All athletes perform uniform motion, the standard input motion speed is 5 m/s, they all move in the opposite direction relative to their respective coordinate axes, and the motion time is 6 seconds. The displacement curves of the athletes in the directions of the three coordinate axes are shown in Figure7.Figure 7
Athlete’s displacement curve with time.It can be seen from Figure7 that the movement curves of the athletes in the three coordinate axis directions are basically the same. There is a one-to-one correspondence between the movement of the athlete in the directions of the three coordinate axes and the angle of rotation input. The final simulation result is that when the exercise time is 6 seconds, the coordinates of the athletes on the three coordinate axes are all 0.992 m. Then, the calculation is carried out by the algorithm, and the simulation result is completely consistent with the theoretical calculation.The curve of the corresponding athlete’s speed in the three coordinate axis directions with time is shown in Figure8.Figure 8
Movement speed vs. time curve.According to Figure8, the speed curves in the three coordinate axis directions are basically the same in the training state. The slope of the histogram has a small change and is approximately the same, which is consistent with the actual situation. In the final simulation result, when the exercise time is 6 seconds, the speed of the athletes on the three coordinate axes is 0.158 m/s, which is completely consistent with the calculation results after the parameter values are substituted into the formula. And the moving speed has a one-to-one correspondence with the input rotation angle, which is consistent with the theoretical deduction result.


### 3.5. Algorithm Analysis

In order to test the practicability of the algorithm, this paragraph was experimented on the Born and HE databases of a certain university. The data is collected by four grayscale cameras K1 ~ K4 and three color cameras Z1 ~ Z3.Three visual field angles Z1 ~ Z3 of he-I, four visual field angles K1 ~ K4 of born, and four visual field angles Z1 ~ Z4 of he-ii were selected in the experiment. 10 and 15 hand and foot models were used, respectively, including head to foot, with hip bone and limb ends added behind. The experimental requirements of this section are as follows: the CPU is TMS, 4G running memory, and the experimental research is carried out by MATLAB.Table5 lists the closing angle errors of the algorithm in this paper and the other three algorithms based on HA-SIFT, SIFT, and SILH on the database of running, passing, dribbling, and receiving, respectively.Table 5
Joint angle errors on the running, passing, dribbling, and catching data sets.
AlgorithmRunningPassDribbleCatch the ballMKSC3.5842.8522.5882.248KSC4.9863.6843.9643.854LSC6.9856.5144.8954.578BSC8.8846.8746.9875.558Figure9 shows the experimental results of the four algorithms based on the three types of features on the T3_Jogging data set of HE-I, which expresses the relative angle error of the set angle variable.Figure 9
The four algorithms are based on the relative joint angle errors of the three types of features on S3_Jogging.
(a)
Relative error(b)
Relative error(c)
Relative error(d)
Relative errorAs shown in Figure9, the results show that the algorithm in this paper has a strong generalization ability for multiple types of input when the set angle is within [0,...,20], and HA-SI features perform in gesture recognition. The best, with an average of 0.225, is the smallest among the three characteristics. In the experiment, we set six kinds of noise intensity: 5%, 15%, 25%, 35%, 45%, and 55%. Figure 10 shows the walking posture error for the first 250 frames under six noise densities.Figure 10
MKSC’s antinoise performance measurement: the estimation error of walking posture under the action of six noise densities.From the results shown in Figure10, it can be found that as the noise intensity increases from 5% to 45%, the error gradually increases, but as a whole, it is still not very high. When the noise intensity increases to 55%, the estimation error rises rapidly, indicating that the algorithm is basically invalid. It can be seen that the algorithm in this paper has strong robustness only within a certain range of noise intensity.


## 3.1. Vision Sensor Prototype Construction Plan

With the rapid development of electronic technology, the integration of chips continues to increase, and the volume and weight of the new generation of vision sensor products are getting smaller and smaller. At present, the competition of electronic products has entered an era of all-round competition. An excellent product must not only have good performance but also have a friendly appearance and small structure size. Small and exquisite product design can always give consumers more attractiveness. For this reason, product designers are paying more and more attention to product appearance and structural size design. In the design of the vision sensor, the factor that has the greatest influence on its structural size comes from the design of the core circuit board. Although a highly integrated digital chip and a compact component package are used, how to arrange the components reasonably is also crucial. In this system, the circuit of the vision sensor is divided into three PCB board designs: DSP main board, liquid crystal display board, and CMOS image acquisition board. The DSP main board and the liquid crystal display board are connected by FPC flexible cable, and the important signals are protected by ground wire to prevent interference; the CMOS image acquisition board and the DSP main board are connected by 90°pins, and important signals are connected at the same time.


## 3.2. System Anti-Interference Measures and Signal Integrity

Measures to improve system anti-interference:(1)
When wiring, the power wire and ground wire should be as thick as possible. In addition to reducing the pressure drop, it is more important to reduce the coupling noise(2)
For the idle I/O ports of some chips, do not float and connect to ground or power. For the idle pins of the IC, they should be grounded or connected to the power supply without changing the system logic(3)
The clock signal line should be as short as possible, and the ground wire should be used as escort on the training field(4)
The area enclosed by the signal output line and the return line should be as small as possible to reduce the antenna effect; for single and double panels, additional ground wires can be added to achieve thisThe image transmission design method to ensure signal integrity can be seen in Table1.Table 1
Image transmission design method to ensure signal integrity.
MethodAccuracyReliabilityMethod to realizeSynchronous switching output93.6%100%PCD65221Minimize trace length95.2%99.8%JXH5244Shorten signal routing91.8%99.3%KDSJ485Terminal match90.6%96.4%AIJK364Reduce inductive coupling96.3%98.8%JUWSS47In the intelligent vision inspection system, it is an indispensable step to transfer the collected image data to the PC. Even in the design of the vision sensor system separated from the PC, there are many loops in the system installation, debugging, information storage, etc. It must be required to realize the data communication between the sensor and the PC.Universal Serial Bus (USB) is a new interface standard jointly launched by 7 world-renowned computer and communication companies, including Intel, Com, Dig, IBM, Microsoft, NEC, and NT. It is based on universal connection technology and realizes the simple and fast connection of peripherals, achieving the purpose of facilitating users, reducing costs, and expanding the interface range of PC peripherals. At the same time, it can provide power for peripherals, unlike ordinary serial and parallel devices that require a separate power supply system. The characteristics of the USB interface are shown in Table2.Table 2
USB interface characteristics.
CharacteristicsDataData sourceReliabilityEasy to install and configure1 for 1Internet86.9%High speed1.5MbpsIBM79.9%Easy to extend125-33 mDig86.7%Able to use bus power4.5 V, 450 mACom91.7%Flexible to use4 patternsNT91.4%After consideration, this article selects the built-in USB module of TMS, which is a slave USB module that conforms to the USB1.1 protocol. The features are as follows:(1)
Compatible with USB2.0(2)
With 15 endpointsTI provides an onchip support library USB CSL for the USB modules of the 5611 and 5711 series DSPs. This CSL has the advantages described in Table3:Table 3
CSL advantages and pin description of TMS built-in USB module.
AdvantageBytePinIllustrateComplete hardware abstraction521 bytesDPTransmit positive differential data (+458)A function call499 bytesDNNTransmit negative differential data (-624)Single API365 bytesPTU3.3 VSupport single data and multiple data buffers400 bytesCT4.6 VProcessing routine association647 bytesXU5.2 V


## 3.3. Brief Introduction of Image Software

ADM is a mechanical system dynamic simulation software developed by American Mechanical Power Corporation. It is the most authoritative and widely used mechanical system dynamic analysis software in the world. It uses an interactive graphic environment and parts library, constraint library, and force library, and its solver uses the Lagrangian equation method in multirigid body system dynamic theory to establish system dynamics equations and perform statics and motion on virtual mechanical systems scientific and dynamic analysis, output displacement, velocity, acceleration and reaction force curves, etc. The simulation of ADM software can be used to predict the performance of the mechanical motion system, the range of motion, collision detection, peak load, and calculation of finite element input load. This article uses the most basic simulation function of ADM to perform entity modeling and sports simulation for football training players.


## 3.4. Kinematic Simulation

This research takes 10 football training camps or clubs in a certain state as the research object. It mainly conducts actual investigations on the football coaches (25 people), young football players (480 people), and school football managers (10 people) in the training camps. Table4 is a statistical table about the state’s youth football training survey data.Table 4
Survey data statistics of youth football training camps or clubs.
Training campClubSchoolFootball coachSoccer playerThe city (%)3 (60%)3 (60%)0 (0%)10 (40%)240 (50%)Other counties (%)2 (40%)2 (40%)0 (0%)15 (60%)240 (50%)Total (%)5 (100%)5 (100%)0 (0%)25 (100%)480 (100%)Establish the model in the ADM environment, and the selected parameters are consistent with the previous ones. All athletes perform uniform motion, the standard input motion speed is 5 m/s, they all move in the opposite direction relative to their respective coordinate axes, and the motion time is 6 seconds. The displacement curves of the athletes in the directions of the three coordinate axes are shown in Figure7.Figure 7
Athlete’s displacement curve with time.It can be seen from Figure7 that the movement curves of the athletes in the three coordinate axis directions are basically the same. There is a one-to-one correspondence between the movement of the athlete in the directions of the three coordinate axes and the angle of rotation input. The final simulation result is that when the exercise time is 6 seconds, the coordinates of the athletes on the three coordinate axes are all 0.992 m. Then, the calculation is carried out by the algorithm, and the simulation result is completely consistent with the theoretical calculation.The curve of the corresponding athlete’s speed in the three coordinate axis directions with time is shown in Figure8.Figure 8
Movement speed vs. time curve.According to Figure8, the speed curves in the three coordinate axis directions are basically the same in the training state. The slope of the histogram has a small change and is approximately the same, which is consistent with the actual situation. In the final simulation result, when the exercise time is 6 seconds, the speed of the athletes on the three coordinate axes is 0.158 m/s, which is completely consistent with the calculation results after the parameter values are substituted into the formula. And the moving speed has a one-to-one correspondence with the input rotation angle, which is consistent with the theoretical deduction result.


## 3.5. Algorithm Analysis

In order to test the practicability of the algorithm, this paragraph was experimented on the Born and HE databases of a certain university. The data is collected by four grayscale cameras K1 ~ K4 and three color cameras Z1 ~ Z3.Three visual field angles Z1 ~ Z3 of he-I, four visual field angles K1 ~ K4 of born, and four visual field angles Z1 ~ Z4 of he-ii were selected in the experiment. 10 and 15 hand and foot models were used, respectively, including head to foot, with hip bone and limb ends added behind. The experimental requirements of this section are as follows: the CPU is TMS, 4G running memory, and the experimental research is carried out by MATLAB.Table5 lists the closing angle errors of the algorithm in this paper and the other three algorithms based on HA-SIFT, SIFT, and SILH on the database of running, passing, dribbling, and receiving, respectively.Table 5
Joint angle errors on the running, passing, dribbling, and catching data sets.
AlgorithmRunningPassDribbleCatch the ballMKSC3.5842.8522.5882.248KSC4.9863.6843.9643.854LSC6.9856.5144.8954.578BSC8.8846.8746.9875.558Figure9 shows the experimental results of the four algorithms based on the three types of features on the T3_Jogging data set of HE-I, which expresses the relative angle error of the set angle variable.Figure 9
The four algorithms are based on the relative joint angle errors of the three types of features on S3_Jogging.
(a)
Relative error(b)
Relative error(c)
Relative error(d)
Relative errorAs shown in Figure9, the results show that the algorithm in this paper has a strong generalization ability for multiple types of input when the set angle is within [0,...,20], and HA-SI features perform in gesture recognition. The best, with an average of 0.225, is the smallest among the three characteristics. In the experiment, we set six kinds of noise intensity: 5%, 15%, 25%, 35%, 45%, and 55%. Figure 10 shows the walking posture error for the first 250 frames under six noise densities.Figure 10
MKSC’s antinoise performance measurement: the estimation error of walking posture under the action of six noise densities.From the results shown in Figure10, it can be found that as the noise intensity increases from 5% to 45%, the error gradually increases, but as a whole, it is still not very high. When the noise intensity increases to 55%, the estimation error rises rapidly, indicating that the algorithm is basically invalid. It can be seen that the algorithm in this paper has strong robustness only within a certain range of noise intensity.


## 4. Discussion

In order to accurately and effectively reconstruct the multiangle three-dimensional human body motion, this paper proposes a human body motion algorithm based on many sparse bytes. The algorithm first combines the Harris interest unit and the SIFT node to generate a new HA-SI and uses it to express the input image, breaking the previous pattern of byte-only single-loop representation. In addition, due to the interference of various problems, directly constructing the nearest neighbor graph in the initial environment cannot reliably reflect the inherent manifold of the data. In this article, the kernel function is used to implicitly map the original data to the advanced algorithm space, so that the nearest neighbor graph constructed in this space can accurately reflect the basic meaning of the data. Compared with the latest algorithm, this algorithm has higher estimation accuracy. However, since the rigid chain model of the human body is still in use, the effect is not ideal when estimating complex movements. In the next research, we will use the point cloud matching method to replace the energy analysis method in this paper and use the point cloud data to build the athletes, hoping to further improve the accuracy of the algorithm.This article mainly completes the processing and analysis of the collected images and discusses the algorithm flow of football training image processing and analysis. It mainly discusses image preprocessing algorithms such as image filtering and grayscale enhancement; image threshold segmentation, edge detection, and target marking algorithms; and target area, perimeter, and circularity measurement algorithms. Finally, the Hough transform algorithm for fast circle detection with known circle parameters is discussed.From the perspective of the overall system, this paper analyzes the software design plan of the vision sensor system, gives the software design block diagram of each subsystem, and realizes the connection and joint debugging of each software module. Finally, some experimental data and performance evaluation of system debugging are given.


## 5. Conclusions

Vision-based 3D human motion analysis is a hot research topic in the field of computer vision and pattern recognition. The complexity of human body structure and movement and the diversity of human appearance have brought unprecedented difficulties and challenges to the research in this field. The purpose of this article is to use the vision sensor technology to study the three-dimensional movement in football training, using the algorithm comparison method, the image and text merging method, and the parameter introduction method and simplify the algorithm. Create a system model that can achieve the goal. Of course, we have conducted many experiments. We collected a lot of data and integrated these data by first identifying the research object and then studying the system model and integrated the final available results. These parameters are as follows. Among them, the motion speed of the system is determined to be 5 m/s, and the motion duration is set to 6 seconds. We can find that the trajectories of the athletes in the three directions are basically the same. And you can see that when the coordinate axis is positioned at 6 seconds, the coordinate values on the three coordinate axes are the same, all being 0.992 m. Then, study the performance of the algorithm in this paper. Six kinds of noise density: 5%, 15%, 25%, 35%, 45%, and 55% are to verify its performance level. It is found that as the noise gradually increases, the error increases, but the maximum error does not exceed the set value. Indirectly, it shows that the model in this article is also practical. The shortcomings of this article are as follows: first, up to now, most domestic, and foreign researches in this field still remain in some static simple scenes, and the reconstruction of 3D human motion in dynamic complex scenes is still an inherently open problem; secondly, at present, most human motion analysis methods are still limited to a single human body in a simple scene and cannot cope with multiple types of human motion in real scenes and human body motion in contact with foreign objects. So, this is the next goal of this article. After all, realizing the recognition of large-scale targets in football training is a difficult problem that this article must overcome. For this reason, I will strengthen the performance of this article’s hardware and software equipment so that it can carry multiple people online at the same time, maintain the stability of the machine in the motion state, and strive to be applied on the green field as soon as possible.



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*Source: 3307902-2021-11-10.xml*