Table tennis path shooting method, shooting system and storage medium

Abstract

The invention belongs to the technical field of image analysis, and particularly relates to a table tennis path shooting method and system and a storage medium, and the table tennis path shooting method comprises the steps: obtaining the proportion of the clear frame number to the fuzzy frame number in image data, so as to adjust corresponding shooting parameters; acquiring an air flight path of the table tennis and table tennis motion data; constructing a table top actual rebound model, and obtaining a table top movement track of the table tennis; combining the air flight track with the desktop motion track to form a complete motion track; the shooting parameters are adjusted to improve the proportion of the clear frame number in the image data, different athletes can be adapted, meanwhile, the table top actual rebound model is constructed to reproduce the table top rebound process of the table tennis ball, the air flight track and the table top motion track are combined to form a complete motion track, and the table tennis ball rebound effect is improved. The problem that the table tennis is difficult to capture and analyze in the rebound process on the table top is solved, and finally the accurate and complete table tennis motion path is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of graphic data reading, and specifically relates to image analysis, and in particular to a table tennis path shooting method, shooting system and storage medium. Background Art

[0002] Motion evaluation is gradually shifting towards data-based and intelligent directions, which requires cameras to capture video data and extract images from the video data to reproduce the path of the ping-pong ball.

[0003] However, the batting level of professional athletes means that even high-speed cameras cannot clearly capture the path of the ping-pong ball. At the same time, different athletes have different batting levels, and the shutter speed of the high-speed camera remains unchanged, which will cause the captured image to have problems such as blur and afterimage. In addition, the shooting angle of the high-speed camera is relatively fixed. When shooting the ping-pong ball bouncing on the table, there is not only the movement process of the ping-pong ball itself, but also the movement process of the interaction between the ping-pong ball and the table. At the same time, there are obstructions such as athletes, rackets, and table nets. Therefore, it is difficult to capture the rebound process of the ping-pong ball on the table, and it is impossible to obtain the complete movement trajectory of the ping-pong ball.

[0004] Therefore, there is an urgent need to develop a new table tennis path shooting method, table tennis path shooting system and storage medium to solve the technical problem of how to adjust shooting parameters to adapt to different users to collect high-definition image data and fully obtain the table tennis motion trajectory.

[0005] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0006] The embodiments of the present disclosure at least provide a table tennis path shooting method, a shooting system and a storage medium.

[0007] In a first aspect, an embodiment of the present disclosure provides a method for photographing a table tennis path, comprising: obtaining the ratio of clear frames to blurred frames in image data to adjust corresponding photographing parameters; reacquiring image data according to the photographing parameters, and obtaining an aerial flight trajectory and table tennis motion data of the table tennis ball from the image data; constructing an actual desktop rebound model, and bringing the table tennis motion data into the actual desktop rebound model to obtain the desktop motion trajectory of the table tennis ball; combining the aerial flight trajectory with the desktop motion trajectory to form a complete motion trajectory.

[0008] In an optional implementation, the shooting parameters include: a shutter speed of a high-speed camera; and adjusting the shutter speed until a ratio of clear frames to blurry frames is within a set ratio threshold.

[0009] In an optional implementation, a desktop theoretical rebound model is constructed; a ping-pong ball is struck according to a first set striking condition to obtain corresponding ping-pong ball motion data; the ping-pong ball motion data is brought into the desktop theoretical rebound model to obtain a theoretical pop-up linear velocity and a theoretical pop-up angular velocity of the ping-pong ball; a test ball is struck according to the first set striking condition to obtain a test pop-up linear velocity and a test pop-up angular velocity of the test ball; a first compensation value between the theoretical pop-up linear velocity and the test pop-up linear velocity and a second compensation value between the theoretical pop-up angular velocity and the test pop-up angular velocity are calculated, so as to construct a desktop actual rebound model in combination with the desktop theoretical rebound model.

[0010] In an optional embodiment, the long side of the table is X Axis, the short side of the table is Y Axis, perpendicular to the table plane and pointing upward Y Axis, build the coordinate system; build the desktop theory rebound model as: ; ; in, is the theoretical ejection linear velocity, is the incident ray velocity of the ping-pong ball, for exist X The component in the axial direction, for exist Y The component in the axial direction, for exist Z The component in the axial direction, is the elastic recovery coefficient of the table, is the sliding friction coefficient between the table tennis ball and the table, is the angle between the incident ray velocity and the normal direction of the hitting surface, ctg is the cotangent function, is the radius of the ping-pong ball, is the theoretical ejection angular velocity, is the incident angular velocity of the ping-pong ball, for exist X The component in the axial direction, for exist Y The component in the axial direction, for exist Z Component in the direction of the axis.

[0011] In an optional embodiment, the first set hitting condition includes: a first set hitting position, a first set hitting angle and a first set hitting force; the table tennis motion data includes: the incident ray velocity, the angle between the incident ray velocity and the normal direction of the hitting surface, and the incident angular velocity.

[0012] In an optional embodiment, stripes of at least two colors are sequentially painted on the surface of a table tennis ball to form a test ball, and the colors of two adjacent stripes are different; each stripe on the test ball is marked, and the change of the spatial position of each stripe in the image data is obtained to obtain the test ejection linear velocity of the test ball V 检验 and check the ejection angular velocity ω 检验 .

[0013] In an optional implementation, a table tennis ball is hit according to a first set hitting condition to obtain corresponding table tennis ball motion data, and the table tennis ball motion data is brought into a desktop theoretical rebound model to obtain corresponding theoretical pop-up linear velocity and theoretical pop-up angular velocity; a test ball is hit according to the first set hitting condition to obtain a test pop-up linear velocity and a test pop-up angular velocity of the test ball; and a first compensation value is calculated. E 1 and the second compensation value E 2.

[0014] In an optional implementation, the desktop actual rebound model is constructed as follows: V 实际 = + E 1; ω 实际 = + E 2; in, V 实际 is the actual ejection line speed, ω 实际 It is the actual ejection line speed.

[0015] In a second aspect, the disclosed embodiment also provides a table tennis path shooting system, comprising: a processor, a high-speed camera and a table tennis ball; wherein the high-speed camera acquires image data; the processor acquires the proportion of clear frames and blurred frames in the image data, and the processor controls the high-speed camera to adjust the corresponding shooting parameters; the high-speed camera reacquires the image data according to the shooting parameters, and the processor acquires the aerial flight trajectory and the table tennis motion data of the table tennis ball from the image data; the processor constructs an actual desktop rebound model, and brings the table tennis motion data into the actual desktop rebound model to acquire the desktop motion trajectory of the table tennis ball; the processor combines the aerial flight trajectory with the desktop motion trajectory to form a complete motion trajectory.

[0016] In an optional embodiment, the table tennis path shooting system also includes: a test ball; a processor constructs a desktop theoretical rebound model; the table tennis ball is hit according to a first set hitting condition, and the processor obtains corresponding table tennis motion data; the processor brings the table tennis motion data into the desktop theoretical rebound model to obtain the theoretical pop-up linear velocity and theoretical pop-up angular velocity of the table tennis ball; the test ball is hit according to the first set hitting condition, and the processor obtains the test pop-up linear velocity and test pop-up angular velocity of the test ball; the processor calculates a first compensation value between the theoretical pop-up linear velocity and the test pop-up linear velocity and a second compensation value between the theoretical pop-up angular velocity and the test pop-up angular velocity, so as to construct a desktop actual rebound model in combination with the desktop theoretical rebound model.

[0017] In a third aspect, the embodiments of the present disclosure further provide a computer-readable storage medium on which a computer program / instruction is stored, wherein the computer program / instruction, when executed by a processor, implements the steps of the above-mentioned table tennis path shooting method.

[0018] The beneficial effect of the present invention is that the present invention increases the proportion of clear frames in image data by adjusting shooting parameters, can adapt to different athletes, and at the same time reproduces the process of table tennis ball rebounding on the table by constructing an actual table rebound model, realizes the combination of the aerial flight trajectory and the table motion trajectory to form a complete motion trajectory, overcomes the problem that the table tennis ball is difficult to capture and analyze in the process of table tennis ball rebounding on the table, and finally obtains an accurate and complete table tennis ball motion path.

[0019] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A flow chart of a table tennis path shooting method provided by an embodiment of the present disclosure; Figure 2A flowchart of constructing a desktop actual rebound model provided by an embodiment of the present disclosure; Figure 3 A flowchart for obtaining test ball motion data provided by an embodiment of the present disclosure; Figure 4 A structural diagram of a test ball provided in an embodiment of the present disclosure; Figure 5 A flowchart for calculating a first compensation value and a second compensation value is provided in an embodiment of the present disclosure.

[0023] In the figure: 1. Check ball; 101. Stripes. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limited. As used herein, the singular articles "one", "an" and "the" may also be intended to include plural forms, unless it is clearly indicated above that this is not the case. The terms "comprise", "include" and "have" are inclusive, and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0026] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0028] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0029] like Figures 1 to 5 At least one embodiment provides a table tennis path shooting method, which includes: obtaining the ratio of clear frames to blurred frames in image data to adjust corresponding shooting parameters; reacquiring image data according to the shooting parameters, and obtaining the aerial flight trajectory and table tennis motion data of the table tennis ball from the image data; constructing an actual desktop rebound model, bringing the table tennis motion data into the actual desktop rebound model to obtain the desktop motion trajectory of the table tennis ball; combining the aerial flight trajectory with the desktop motion trajectory to form a complete motion trajectory.

[0030] In at least one embodiment, by adjusting the shooting parameters to increase the proportion of clear frames in the image data, it can adapt to different athletes. At the same time, by constructing an actual desktop rebound model to reproduce the process of table tennis ball rebounding on the desktop, the aerial flight trajectory and the desktop motion trajectory are combined to form a complete motion trajectory, thereby overcoming the problem that the table tennis ball is difficult to capture and analyze in the process of desktop rebounding, and finally obtaining an accurate and complete table tennis ball motion path.

[0031] In at least one embodiment, the shooting parameters include: a shutter speed of a high-speed camera; and adjusting the shutter speed until the ratio of clear frames to blurry frames is within a set ratio threshold.

[0032] Specifically, the shutter speed of a high-speed camera will affect the shooting effect. A shutter speed that is too fast or too slow will lead to an increase in the proportion of blurred frames. Therefore, the shutter speed of a high-speed camera must match the movement speed of the table tennis ball. At this time, the proportion of clear frames in the image data can be increased.

[0033] Specifically, the motion data of the table tennis ball includes linear velocity and angular velocity.

[0034] Specifically, if the shutter speed is too fast relative to the moving speed of the ping-pong ball, the exposure will be reduced, the image will be too dark, the background will be blurred, the image will be shaken, the image noise will increase, and afterimages will appear in the image.

[0035] Specifically, the shutter speed is too slow relative to the moving speed of the table tennis ball, resulting in a blurred image and an overly bright image.

[0036] Specifically, the higher the proportion of clear frames in the image data, the more accurate the motion data obtained, and the more accurate the reproduced aerial flight trajectory.

[0037] In at least one embodiment, see Figure 2 , construct a desktop theoretical rebound model; hit the ping-pong ball according to the first set hitting condition to obtain corresponding ping-pong ball motion data; bring the ping-pong ball motion data into the desktop theoretical rebound model to obtain the theoretical pop-up linear velocity and theoretical pop-up angular velocity of the ping-pong ball; hit the test ball 1 according to the first set hitting condition to obtain the test pop-up linear velocity and test pop-up angular velocity of the test ball 1; calculate a first compensation value between the theoretical pop-up linear velocity and the test pop-up linear velocity and a second compensation value between the theoretical pop-up angular velocity and the test pop-up angular velocity, so as to construct a desktop actual rebound model in combination with the desktop theoretical rebound model.

[0038] First, the ping-pong ball is hit once according to the first set hitting condition to obtain the corresponding ping-pong ball motion data, and the data is brought into the table theoretical rebound model for calculation, so as to obtain the theoretical pop-up linear velocity and theoretical pop-up angular velocity of the ping-pong ball under the first set hitting condition. Then, the test ball 1 is hit according to the same hitting condition, and the test ball 1 can directly obtain the test pop-up linear velocity and test pop-up angular velocity of the test ball 1 under the first set hitting condition from the image data, and then calculate the first compensation value and the second compensation value, so as to optimize the table theoretical rebound model and then obtain the table actual rebound model, and finally realize that the ping-pong ball can be brought into the table actual rebound model each time it is hit to obtain the corresponding actual pop-up linear velocity and actual pop-up angular velocity, so as to obtain the table motion trajectory of the ping-pong ball, and combine it with the aerial flight trajectory to obtain the complete motion trajectory.

[0039] In at least one embodiment, the long side of the table is X Axis, the short side of the table is Y Axis, perpendicular to the table plane and pointing upward Z Axis, build the coordinate system; build the desktop theory rebound model as: ; ; in, is the theoretical ejection linear velocity, is the incident ray velocity of the ping-pong ball, for exist X The component in the axial direction, for exist Y The component in the axial direction, for exist Z The component in the axial direction, is the elastic recovery coefficient of the table, is the sliding friction coefficient between the table tennis ball and the table, is the angle between the incident ray velocity and the normal direction of the hitting surface, ctg is the cotangent function, is the radius of the ping-pong ball, is the theoretical ejection angular velocity, is the incident angular velocity of the ping-pong ball, for exist X The component in the axial direction, for exist Y The component in the axial direction, for exist Z Component in the direction of the axis.

[0040] Specifically, when relative sliding occurs between the table tennis ball and the table, assuming that the landing point of the table tennis ball on the table is M , the center position of the table tennis ball in the coordinate system is O , then the table has a vertical upward support force on the ping-pong ball N and the friction in the horizontal direction f , and the sliding friction coefficient between the table tennis ball and the table is ,but f The size meets f = N , which is in the opposite direction to the velocity component of point M in the tangent direction of the hitting surface, and the mass of the ping-pong ball is m The impulse on the ping-pong ball is P , the moment of inertia of the ping-pong ball is ,but , The motion of the table tennis ball in the normal direction of the hitting surface is decoupled. The table tennis ball is only affected by the supporting force in the normal direction of the hitting surface. Therefore, the change of its motion speed in the normal direction of the hitting surface is only related to N The elastic recovery coefficient of the table is ,but , according to the impulse theorem, ,in S is the action period of the collision between the ping-pong ball and the table.

[0041] Specifically, the impulse received by the table tennis ball in the direction parallel to the hitting surface is , then according to f = N and the impulse theorem, , Direction and M The speed of the point in the tangent direction of the table The direction is the same, while the friction f Direction and Direction room, and The impulses in the X-axis and Y-axis directions are , ,but .

[0042] Specifically, .

[0043] Specifically, .

[0044] Specifically, the angle between the incident velocity of the table tennis ball and the normal direction of the hitting surface is , that is, the angle of incidence is ,but , and finally get ; .

[0045] Specifically, the theoretical ejection linear velocity is given by X The component in the axial direction, Y The component in the axial direction, Z Component composition in the axial direction.

[0046] Specifically, the theoretical ejection angular velocity is given by X The component in the axial direction, Y The component in the axial direction, Z Component composition in the axial direction.

[0047] Specifically, the obtained theoretical rebound linear velocity and theoretical rebound angular velocity have a motion direction, and together constitute the rotation speed and rotation direction of the table tennis ball during the rebound process.

[0048] Specifically, by constructing a theoretical table rebound model, we can obtain the theoretical linear velocity and theoretical angular velocity of the ping-pong ball, and then obtain the actual linear velocity and actual angular velocity, and reproduce the rebound process of the ping-pong ball on the table each time, that is, obtain the table motion trajectory.

[0049] In at least one embodiment, the first set hitting condition includes: a first set hitting position, a first set hitting angle and a first set hitting force; the table tennis motion data includes: the incident ray velocity, the angle between the incident ray velocity and the normal direction of the hitting surface, and the incident angular velocity.

[0050] Specifically, the incident ray velocity, the angle between the incident ray velocity and the normal direction of the hitting surface, and the incident angular velocity can all be directly obtained from the image data.

[0051] In at least one embodiment, see Figure 3 to Figure 4, at least two colors of stripes 101 are painted on the surface of the table tennis ball in sequence to form a test ball 1, and the colors of two adjacent stripes 101 are different; mark each stripe 101 on the test ball 1, and obtain the change of the spatial position of each stripe 101 in the image data to obtain the test ejection linear velocity of the test ball 1 V 检验 and check the ejection angular velocity ω 检验 .

[0052] Specifically, since the stripes 101 are arranged at intervals on the test ball 1, by extracting the changes in the spatial positions of the stripes 101 from the image data, all the motion data of the test ball 1 can be obtained, that is, the test ejection linear velocity of the test ball 1 can be obtained. V 检验 and check the ejection angular velocity ω 检验 .

[0053] In at least one embodiment, see Figure 5 , hit the table tennis ball according to the first set hitting condition to obtain the corresponding table tennis motion data, and bring the table tennis motion data into the desktop theoretical rebound model to obtain the corresponding theoretical pop-up linear velocity and theoretical pop-up angular velocity; hit the test ball 1 according to the first set hitting condition to obtain the test pop-up linear velocity and test pop-up angular velocity of the test ball 1; calculate the first compensation value E 1 and the second compensation value E 2.

[0054] Specifically, the same first setting striking condition is set, when the theoretical ejection linear velocity and the test ejection linear velocity have a first compensation value E 1, then the desktop theoretical rebound model is supplemented; set the same first set hitting condition, when the theoretical pop-up angular velocity and the test pop-up angular velocity have a second compensation value E 2, then complement the desktop theory rebound model.

[0055] In at least one embodiment, the actual desktop rebound model is constructed as follows: V 实际 = + E 1; ω 实际 = + E 2; in, V 实际 is the actual ejection line speed, ω 实际 It is the actual ejection line speed.

[0056] Specifically, by obtaining the actual ejection linear velocity and the actual ejection angular velocity through the actual desktop rebound model, the desktop motion trajectory of the table tennis ball during the rebound process on the desktop can be obtained, and then the complete motion trajectory can be obtained.

[0057] Specifically, the rebound process of the table tennis ball on the table refers to the sliding process of the table tennis ball on the table, that is, the table motion trajectory.

[0058] Based on the same technical concept, at least one embodiment also provides a table tennis path shooting system, which includes: a processor, a high-speed camera and a table tennis ball; wherein the high-speed camera acquires image data; the processor acquires the proportion of clear frames and blurred frames in the image data, and the processor controls the high-speed camera to adjust the corresponding shooting parameters; the high-speed camera reacquires the image data according to the shooting parameters, and the processor acquires the aerial flight trajectory and table tennis motion data of the table tennis ball from the image data; the processor constructs an actual desktop rebound model, and brings the table tennis motion data into the actual desktop rebound model to obtain the desktop motion trajectory of the table tennis ball; the processor combines the aerial flight trajectory with the desktop motion trajectory to form a complete motion trajectory.

[0059] In an optional embodiment, the table tennis path shooting system also includes: a test ball 1; a processor constructs a desktop theoretical rebound model; the table tennis ball is hit according to a first set hitting condition, and the processor obtains corresponding table tennis motion data; the processor brings the table tennis motion data into the desktop theoretical rebound model to obtain the theoretical pop-up linear velocity and theoretical pop-up angular velocity of the table tennis ball; the test ball 1 is hit according to the first set hitting condition, and the processor obtains the test pop-up linear velocity and test pop-up angular velocity of the test ball 1; the processor calculates a first compensation value between the theoretical pop-up linear velocity and the test pop-up linear velocity and a second compensation value between the theoretical pop-up angular velocity and the test pop-up angular velocity, so as to construct a desktop actual rebound model in combination with the desktop theoretical rebound model.

[0060] Based on the same technical concept, at least one embodiment further provides a computer-readable storage medium on which a computer program / instruction is stored, characterized in that when the computer program / instruction is executed by a processor, the steps of the above-mentioned table tennis path shooting method are implemented.

[0061] In summary, the present invention increases the proportion of clear frames in image data by adjusting shooting parameters, and can adapt to different athletes. At the same time, by constructing an actual desktop rebound model to reproduce the process of table tennis ball rebounding on the desktop, the aerial flight trajectory is combined with the desktop motion trajectory to form a complete motion trajectory, thereby overcoming the problem that the table tennis ball is difficult to capture and analyze in the process of desktop rebounding, and finally obtaining an accurate and complete table tennis ball motion path.

[0062] The disclosure and other solutions, examples, embodiments, modules and functional operations described in this document can be implemented in digital electronic circuits, or computer software, firmware or hardware, including the structures disclosed in this document and their structural equivalents, or a combination of one or more thereof. The disclosure and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a tangible and non-volatile computer-readable medium for execution by a data processing device or to control the operation of the data processing device. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a storage device, a material composition that affects a machine-readable propagation signal, or a combination of one or more thereof. The term "data processing unit" or "data processing device" includes all devices, equipment and machines for processing data, including, for example, a programmable processor, a computer or a multiprocessor or a computer group. In addition to hardware, the device may also include code that creates an execution environment for a computer program, for example, code constituting processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more thereof. A propagated signal is an artificially generated signal, for example, a machine-generated electrical, optical or electromagnetic signal, which is generated to encode information for transmission to a suitable receiver device.

[0063] A computer program (also referred to as a program, software, software application, script, or code) may be written in any form of programming language (including compiled or interpreted languages) and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program may be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program, or in multiple coordinated files (e.g., files that store one or more modules, subroutines, or portions of code). A computer program may be deployed for execution on one or more computers that are located at one site or distributed across multiple sites and interconnected by a communications network.

[0064] The processes and logic flows described in this document may be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by, and apparatus may also be implemented as, special purpose logic circuits, e.g., FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit).

[0065] For example, processors suitable for executing a computer program include general and special purpose microprocessors, and any one or more of any type of digital computer. Typically, the processor will receive instructions and data from a read-only memory or a random access memory, or both. The basic components of a computer are a processor that executes instructions and one or more storage devices that store instructions and data. Typically, a computer will also include one or more mass storage devices for storing data, such as magnetic, magneto-optical or optical disks, or operatively coupled to receive data from a mass storage device or transfer data to a mass storage device, or both. However, a computer need not necessarily have such a device. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including, for example, semiconductor memory devices, such as erasable programmable read-only memories (EPROMs). EPROM ), Electrically Erasable Programmable Read-Only Memory (EEPROM) EEPROM ) and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and compact disk read-only memory ( CD ROM ) and digital versatile disc read-only memory ( DVD - ROM The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0066] Although this patent document contains many details, they should not be construed as limitations on the scope of any invention or the claims, but rather as descriptions of features of particular embodiments of particular inventions. Certain features described in this patent document in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various functions described in the context of a single embodiment may also be implemented separately in multiple embodiments, or in any suitable subcombination. In addition, although the above-mentioned features may be described as working in certain combinations, or even initially claimed to be so, in some cases, one or more features in the claim combination may be removed from the combination, and the claim combination may be directed to subcombinations or variations of subcombinations.

[0067] Likewise, although operations are described in a particular order in the drawings, this should not be understood as requiring that such operations be performed in the particular order or order shown, or that all illustrated operations be performed, in order to achieve the desired results. In addition, the separation of various system components in the embodiments of this patent document should not be understood as requiring such separation in all embodiments.

[0068] Only a few implementations and examples are described, and other implementations, enhancements, and variations can be made based on what is described and illustrated in this patent document.

[0069] A first component is directly coupled to a second component when there are no intermediate components other than a line, trace, or another medium between the first component and the second component. A first component is indirectly coupled to a second component when there are intermediate components other than a line, trace, or another medium between the first component and the second component. The term "coupled" and its variations include direct coupling and indirect coupling. Unless otherwise specified, the use of the term "about" is meant to include a range of 10% above and below the value.

[0070] Although several embodiments are provided in the present disclosure, it should be understood that the disclosed systems and methods may be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are considered to be illustrative rather than restrictive and are not limited to the details given. For example, various elements or components may be combined or integrated in another system, or certain features may be omitted or not implemented.

[0071] In several embodiments provided herein, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0072] In addition, without departing from the scope of the present disclosure, the discrete or separate techniques, systems, subsystems, and methods described and illustrated in the various embodiments may be combined or integrated with other systems, modules, techniques, or methods. Other items shown or discussed as coupled may be directly connected, or may be indirectly coupled or communicated electrically, mechanically, or otherwise through some interface, device, or intermediate component. Other examples of changes, substitutions, and alterations may be determined by those skilled in the art without departing from the spirit and scope disclosed herein.

Claims

1. A table tennis path shooting method, characterized in that: include: Obtain the ratio of clear frames to blurry frames in the image data to adjust the corresponding shooting parameters; Reacquire image data according to the shooting parameters, and obtain the aerial flight trajectory of the table tennis ball and the table tennis ball motion data from the image data; Constructing a desktop actual rebound model, and bringing table tennis motion data into the desktop actual rebound model to obtain the table tennis motion trajectory; Combine the aerial flight trajectory with the desktop motion trajectory to form a complete motion trajectory.

2. The table tennis path shooting method according to claim 1, characterized in that: The shooting parameters include: shutter speed of the high-speed camera; Adjust the shutter speed until the ratio of clear frames to blurry frames is within the set ratio threshold.

3. The table tennis path shooting method according to claim 1, characterized in that: Construct a desktop theory rebound model; hitting the table tennis ball according to the first set hitting condition to obtain corresponding table tennis motion data; Bringing the table tennis ball motion data into the table theoretical rebound model to obtain the theoretical rebound linear velocity and theoretical rebound angular velocity of the table tennis ball; Hitting the test ball according to the first set hitting condition to obtain the test ejection linear velocity and the test ejection angular velocity of the test ball; A first compensation value between a theoretical ejection linear velocity and a tested ejection linear velocity and a second compensation value between a theoretical ejection angular velocity and a tested ejection angular velocity are calculated to construct an actual desktop rebound model in combination with the desktop theoretical rebound model.

4. The table tennis path shooting method as claimed in claim 3, characterized in that: The long side of the table is X Axis, the short side of the table is Y Axis, perpendicular to the table plane and pointing upward Y Axis, build coordinate system; The desktop theory rebound model is constructed as follows: ； ； in, is the theoretical ejection linear velocity, is the incident ray velocity of the ping-pong ball, for exist X The component in the axial direction, for exist Y The component in the axial direction, for exist Z The component in the axial direction, is the elastic recovery coefficient of the table, is the sliding friction coefficient between the table tennis ball and the table, is the angle between the incident ray velocity and the normal direction of the hitting surface, ctg is the cotangent function, is the radius of the ping-pong ball, is the theoretical ejection angular velocity, is the incident angular velocity of the ping-pong ball, for exist X The component in the axial direction, for exist Y The component in the axial direction, for exist Z Component in the direction of the axis.

5. The table tennis path shooting method as claimed in claim 4, characterized in that: The first set striking condition includes: a first set striking position, a first set striking angle, and a first set striking force; Table tennis motion data include: incident ray velocity, the angle between the incident ray velocity and the normal direction of the hitting surface, and the incident angular velocity.

6. The table tennis path shooting method according to claim 4, characterized in that: At least two colors of stripes are painted on the surface of the table tennis ball in sequence to form a test ball, and the colors of two adjacent stripes are different; Mark each stripe on the test ball and obtain the change of the spatial position of each stripe in the image data to obtain the test ejection linear velocity of the test ball V 检验 and check the ejection angular velocity ω 检验 .

7. The table tennis path shooting method according to claim 6, characterized in that: Hitting the table tennis ball according to the first set hitting condition to obtain corresponding table tennis ball motion data, and bringing the table tennis ball motion data into the tabletop theoretical rebound model to obtain corresponding theoretical ejection linear velocity and theoretical ejection angular velocity; Hitting the test ball according to the first set hitting condition to obtain the test ejection linear velocity and the test ejection angular velocity of the test ball; Calculate the first compensation value E 1 and the second compensation value E 2.

8. The table tennis path shooting method according to claim 7, characterized in that: The actual desktop rebound model is constructed as follows: V 实际 = + E 1； ω 实际 = + E 2； in, V 实际 is the actual ejection line speed, ω 实际 It is the actual ejection line speed.

9. A table tennis path shooting system, characterized in that: include: processors, high-speed cameras, and ping-pong balls; in A high-speed camera acquires image data; The processor obtains the ratio of clear frames to blurry frames in the image data, and the processor controls the high-speed camera to adjust corresponding shooting parameters; The high-speed camera reacquires image data according to the shooting parameters, and the processor acquires the aerial flight trajectory of the table tennis ball and the table tennis ball motion data from the image data; The processor constructs a desktop actual rebound model, and brings the table tennis ball motion data into the desktop actual rebound model to obtain the desktop motion trajectory of the table tennis ball; The processor combines the aerial flight trajectory with the desktop motion trajectory to form a complete motion trajectory.

10. The table tennis path shooting system as claimed in claim 9, characterized in that: Also includes: Test ball; The processor builds a desktop theoretical rebound model; The table tennis ball is hit according to the first set hitting condition, and the processor obtains corresponding table tennis motion data; The processor brings the table tennis ball motion data into the table theoretical rebound model to obtain the theoretical bounce linear velocity and theoretical bounce angular velocity of the table tennis ball; The test ball is hit according to the first set hitting condition, and the processor obtains the test ejection linear velocity and the test ejection angular velocity of the test ball; The processor is configured to calculate a first compensation value between a theoretical ejection linear velocity and a tested ejection linear velocity and a second compensation value between a theoretical ejection angular velocity and a tested ejection angular velocity, so as to construct an actual desktop rebound model in combination with the desktop theoretical rebound model.

11. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instruction is executed by a processor, the steps of the table tennis path shooting method described in any one of claims 1-8 are implemented.

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