JP2004024488A - Measuring method for impact state of golf swing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring method for an impact state of golf swing, by which the state of a golf club head at impact is measured to evaluate a golfer's swing more properly. <P>SOLUTION: The method uses a measurement system including an impact camera 22, which is set at a position opposite to a standing position of the golfer viewed from a set position 14 of a ball 12 and at a predetermined height forward from the ball set position along a direction of a target line 24, and a control analysis portion 32 including a monitor 30. The impact state of the golfer, i.e. a moment of hitting a ball by the club head 16 swung down by the golfer, is taken by the impact camera 22 to analyze the impact state from the taken images. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of measuring an impact state of a golf swing, that is, a moment at which a golf club swings down a club head and hits a ball.
[0002]
[Prior art]
Conventionally, to obtain data based on actual hitting when measuring various characteristics and spin characteristics related to the flight of a golf ball and selecting golf clubs suitable for golfers with various technical levels, conventionally, it is necessary to use an outer surface. Is set at a predetermined position on a tee or the like, and a plurality of (for example, two) cameras are used to photograph a golfer's hit ball immediately after a hit by a predetermined club and a hit ball after a predetermined time has elapsed. The way has been done.
[0003]
In the method described above, the initial velocity of the ball is calculated from the distance between the two cameras and the shutter interval (time) between the two cameras. In addition, a plurality of captured images are compared, the movement of the mark on the ball is measured from the image, and the rotation speed (spin) in the vertical direction of the ball and the rotation speed (spin) in the vertical direction of the ball are determined in relation to the shutter interval (time) of both cameras. Calculate the horizontal rotation speed. Further, the relative positional relationship between the two images in the vertical direction is measured, and the elevation angle and the like of the hit ball are calculated. Then, the flight trajectory and the flight distance are calculated using these data. In the above measurement, the head speed of the club immediately before or at the time of hitting the ball is measured using an optical sensor or an acoustic sensor.
[0004]
[Problems to be solved by the invention]
However, it is unclear what kind of impact the ball head obtained by the conventional measuring method described above was obtained by the impact state of the club head, and it was difficult to evaluate the above measured values sufficiently and correctly. . That is, in the conventional measuring method, it is unknown which part of the face of the club head the impacted ball hits at the time of impact, and whether or not the orientation and posture of the face at the time of impact were normal. Also, if the flight distance is shorter than expected, is the cause due to the club itself, being out of the sweet spot on the face surface, improper orientation of the face surface, or a golfer's cause? It was not clear only from the measured values of the ball obtained by the conventional measuring method.
[0005]
The present invention has been made in view of the above-described problems, and provides a golf swing impact state measuring method capable of measuring a state of a club head at the time of impact and capable of more appropriately evaluating a golfer's swing. The purpose is to provide.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present inventors provide a golf swing impact state measuring method shown in the following (1) to (7).
[0007]
(1) In measuring the impact state of the golf swing, a predetermined height in a position opposite to the position where the golfer stands when viewed from the ball set position and in front of the ball set position along the flight line direction. A golf swing impact state measuring method characterized in that an impact state by a golfer is photographed by using a measurement system including a camera set at a position and a control analysis unit, and the impact state is analyzed from the photographed video.
[0008]
(2) Regarding the distance between the center of the ball and the center of the lens of the camera, the distance in the horizontal direction (x direction) of the ball is m3, and the distance in the horizontal plane (y direction) orthogonal to the horizontal direction of the ball. Assuming that the distance is w and the distance (height) in the vertical direction (z direction) is h, at least one unit in an area where m3 is 1 to 700 mm, w is 100 to 600 mm, and h is 20 to 700 mm. (1) The golf swing of (1) wherein a high-speed shutter camera is disposed, and at least one of the states immediately before, at the time of impact, and immediately after the impact of the club head on the ball is photographed by the high-speed shutter camera. Impact state measurement method.
[0009]
(3) In measuring the impact state, the x, y, and z axes having the origin at the center of the golf ball to be set and their reference lengths are input to the control analysis unit and the club head of the club head is measured. A plurality of marks are provided on the face surface at predetermined vertical and horizontal intervals, and the x, y, z axes and their reference lengths are determined based on the positional relationship of the marks on the face surface in a captured image. And (2) measuring the impact state of the golf swing.
[0010]
(4) Using a reference device that extends in the x, y, and z-axis directions with the origin of the center of the golf ball to be set as the origin, adjust the origin of the reference device to a position corresponding to the center of the golf ball in advance. The method for measuring the impact state of a golf swing according to (3), wherein the posture of the face surface is measured based on the photographed video.
[0011]
(5) The center position of the ball is calculated by measuring the outer periphery of the substantially undeformed portion of the ball far from the club face surface from the photographed image of the golf ball, and the club face surface closest to the ball center position is calculated. (1) The golf swing impact state measuring method according to any one of (1) to (4), wherein an upper position is detected to analyze an impact position on the club face surface.
[0012]
(6) The golf according to (1) to (5), wherein a plurality of cameras are used to photograph two or more states of the state immediately before, at the time of, and immediately after the impact of the club head on the ball. How to measure the impact state of the swing.
[0013]
(7) Using a golf ball with a mark on its surface, the first and second ball measuring cameras are set sideways at a predetermined distance from each other and spaced apart from the set ball position, and a shutter signal is sent with a time lag. In this case, when the ball comes in front of each of the ball measuring cameras, the ball is photographed, the images are compared, and the motion of the ball is analyzed based on the movement of the mark between the two images (1). (6) The golf swing impact state measuring method.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the arrangement of devices in a system used in the impact state measuring method according to the present invention, FIG. 2 is a diagram showing arrangement intervals of each device, and FIG. 3 is a diagram showing the position of a camera in more detail.
[0015]
The measurement system in the illustrated example includes a ball setting means for setting the golf ball 12, specifically, a tee 14 on which the golf ball 12 is to be placed, and a ball set means 14 which is positioned behind the flying line of the ball setting means 14 and swings to hit the ball. It includes a sensor means 18 for detecting the passage of the lowered club head 16 and one impact camera 22.
[0016]
The sensor means 18 has a first sensor 18A and a second sensor 18B, each of which is composed of an optical light emitting unit and a light receiving unit, set at a distance m1 (about 70 mm) from each other. The distance m2 between the second sensor 18B and the tee 14 as the ball setting means is about 40 mm.
[0017]
The impact camera 22 is separated from the golf ball 12 by a distance w (y-direction) on the opposite side of a horizontal plane including the center 20 of the ball from the center of the golf ball 12 on the basis of the center of the golf ball 12. The ball is set toward the ball set position to measure the impact state of the ball at a position at a distance m3 ahead of the set ball position in the flight line direction (x direction) and at a predetermined height h (z direction). . The impact camera 22 is preferably a CCD camera having a shutter speed of 1/10000 to 1/200000 seconds, and the impact camera 22 is preferably provided with a strobe 22S.
[0018]
Here, it is preferable that the distance m3 in the x direction is 1 to 700 mm, the distance w in the y direction is 100 to 600 mm, and the distance h (height) in the z direction is 20 to 700 mm. In addition, a plurality of impact cameras may be installed in order to continuously capture a plurality of images immediately before, at the time of impact, immediately after impact, and the like. In this case, the distances m3, w, and h of each camera are also set to be equal. It is appropriate to be within the above numerical range.
[0019]
When it is desired to photograph the hit ball after impact together, for example, two cameras, that is, a first ball measuring camera 26 and a second ball measuring device, are positioned at a predetermined distance along the flight line (flight trajectory) 24 of the hit ball. The camera 28 is set sideways. The ball measuring cameras 26 and 28 are preferably CCD cameras having a shutter speed of 1/10000 to 1/200000 seconds, and the ball measuring cameras 26 and 28 are preferably provided with strobes 26S and 28S, respectively.
[0020]
Here, the distance m4 from the tee 14 to the first ball measurement camera 26 in the horizontal direction is set in a range of 50 to 300 mm, and the distance m5 between the first ball measurement camera 26 and the second ball measurement camera 28 is set in a range of 100 to 250 mm. can do.
[0021]
The sensor means 18, the impact camera 22, and the strobe 22S, the two ball measuring cameras 26, 28, and the strobes 26S, 28S are connected to a control analyzer 32 having a display monitor 30 (the connection relationship is not shown).
[0022]
The control analysis unit 32 includes the following.
(1) Control box section Includes the following.
a) Camera image recording frame memory b) Image analysis unit c) Timing control unit Sensor control, shutter control, I / O
d) CPU unit e) FDD (flexible disk drive), HDD (hard disk drive) or flash memory f) Frame memory for impact image recording (2) Software section Software for calculating and displaying the following is built in.
a) Calculation and display of face angle b) Calculation and display of hit point (up and down, left and right) position c) Display and correction of ball position d) Input and display of mark on face e) Input of reference axis and calculation of camera direction angle f) Impact shooting Timing (delay time) setting g) Head speed value, initial speed, launch angle (upward with respect to the horizontal line, leftward and rightward with respect to the reference line), back spin amount, side spin amount measurement calculation and numerical display h) trajectory, flight distance Calculation i) Screen display / split screen as follows (two video screens of hit ball + measured value screen)
• Launch angle distribution screen • Carry and / or total distance distribution screen • Trajectory trajectory screen j) Data value accumulation (3) Monitor, printer [0023]
FIG. 4 shows an outline of an image captured at the time of impact taken by the impact camera. FIG. 5 shows a front view of a face surface of a club head (driver) used at that time. The club head 42 shown in FIGS. 4 and 5 includes a face surface 44, which is entirely coated with a dark color (dark blue), and a score line 46 is indicated by a white line thereon. On the line 46, a plurality of black marks 48 of the opposite color are provided. The interval a in the horizontal direction of the mark 48 is about 10 mm, and the interval b in the vertical direction is also about 10 mm. In the figure, reference numeral 50 denotes a toe portion of the club head 42, 52 denotes a crown portion, and 54 denotes a sole portion. In the image shown in FIG. 4, a plurality of marks 48 are shown on the face surface 44 near the toe portion 50. The triangular mark M on the ball 12 is used when analyzing the motion of the ball from an image taken by the ball measuring camera (described later).
[0024]
FIG. 6 is a perspective view showing an example of the xyz standard used for measuring the impact state. The x part 64, the y part 66, and the z part 68 of the reference unit 62 are formed by metal as shown in the drawing so as to correspond to the x, y, and z directions shown in FIG. The position 70 (origin) where the points gather corresponds to the center of the ball (FIG. 3). A portion extending downward from that portion is a leg 72 for fixing to the tee 14.
[0025]
Prior to the measurement to be described later, the reference device 62 is set on the tee 14 corresponding to the positional relationship between the ball 12 and the impact camera 22 shown in FIG. 3 (FIG. 6), and the reference device 62 is photographed by the impact camera 22 and controlled. It is recorded in the frame memory of the control box section of the analysis section 32. It is also convenient to record the value of the diameter of the golf ball in the same memory as the reference size of the ball (the reference length described above).
[0026]
Next, the impact state measuring method of the present example will be described with reference to the arrangement of sensors and cameras shown in FIGS. First, when the first sensor 18A and the second sensor 18B detect the passage of the club head 16 swung by the golfer, the passage time t1 is measured, and the head speed is determined based on the relationship (m1) between the two sensors 18A and 18B. Is measured. Next, upon receiving a detection signal from the second sensor 18B, the trigger output ST acts on the impact camera 22, the first ball measurement camera 26, the second ball measurement camera 28, and the strobes 22S, 26S, 28S for these cameras. . For the trigger output, for example, a plurality of head speeds to be applied are measured in advance, and a delay time t2 and an interval t3 corresponding to these head speeds and a shutter interval t4 of the ball camera are set. When using multiple impact cameras to capture multiple images in the state immediately before, during and immediately after impact, set the delay time and the shutter interval between the installed cameras according to the position of those cameras. .
[0027]
The video captured by each camera is displayed on the monitor 30 of the control analysis unit 32. FIG. 4 schematically shows an image on the monitor at the time of impact. The obtained video is labeled, saved and stored in a frame memory.
[0028]
Next, from the image on the monitor (FIG. 4), the position of the mark 48 appearing on the face surface 44 of the club head is measured from the image using an appropriate means (for example, a mouse). Then, from this measurement result, the extension of the face surface can be calculated based on the above-described reference length. Here, the extension of the face surface refers to the spread of the face surface including an area hidden behind the golf ball. Although eight marks appear on FIG. 4, if at least three marks can be measured, the extension of the face surface can be known using predetermined means. As a result, it is possible to know the inclination of the face surface in the vertical and horizontal directions by illuminating the x-, y-, and z-directions of the reference unit 62 previously photographed and recorded.
[0029]
Further, the outer periphery of the region where the ball is not deformed at the time of impact and an appropriate position on the outer periphery are measured from the image using appropriate means (for example, a mouse). Then, from the result, a position corresponding to the center of the ball that is not substantially deformed is calculated based on the above-described reference length, and a vertical line (from the center of the ball to the face The shortest distance to the ball can be lowered, and the impact position on the face surface with respect to the ball can be known from the position on the face surface along the vertical line.
[0030]
In addition, if a plurality of impact cameras are installed, and the images immediately before and / or immediately after the impact can be continuously obtained in addition to the images at the time of the impact, the transition of the head face surface, that is, outside-in, inside-out, It is possible to know the movement of the club head such as upper blow, down blow, etc., and to know the causal relationship with the movement of the golf ball by analyzing the image taken by the ball measuring camera described below.
[0031]
A method of analyzing the motion of the golf ball described above will be described. The initial speed of the golf ball is measured from the relationship between the time the ball hits between the two ball measuring cameras 26 and 28 and the distance between the two ball measuring cameras 26 and 28.
[0032]
The measurement of the launch angle of the golf ball (upward with respect to the horizontal line), the backspin amount, the sidespin amount, and the flight distance are as follows. FIG. 8 shows a display of the hit ball projected on the monitor 30. The monitor screen 80 is divided into four parts, the hit ball captured from the side by the first ball measuring camera 26 is displayed on the first screen 80A, and the hit ball captured from the side by the second ball measuring camera 28 is displayed on the second screen 80B. Then, the measured value is displayed on the third screen 80C. In the present system, the shape of the mark M to be marked on the surface of the golf ball 12 is an isosceles triangle. The color of the mark M is black or a similar dark color to make it stand out from the color of the ball surface.
[0033]
In the present system, with respect to the images projected on the first and second screens 80A and 80B, the outline of the golf ball 12, which is a white portion, is extracted from the background of the black area by a binarization method (white / black) from within the screens. I do. Next, the mark M within the extracted outer shape of the golf ball 12 is extracted by the same binarization method.
[0034]
After the above processing is completed, the main axis (a straight line including the height) of the mark M is obtained, and a search is made vertically from the main axis to obtain a change point at which black changes to white. The search for the transition point from black to white by the vertical search is performed along the main axis, and as a result, a straight line passing through the point sequence of these transition points, that is, two hypotenuses is obtained. Next, a base line perpendicular to the middle line of the two oblique sides is set outside the black block (black mark), and the block side is searched therefrom to find the base. When obtaining the hypotenuse or the base, it is preferable to obtain the hypotenuse or the base by curve approximation in consideration of the curvature due to the spherical surface.
[0035]
When the triangle, that is, the mark M is specified by the above image processing, three vertices are obtained from three sides, and three vertices 90x, 90y, and 90z are determined. Then, from the images projected on the first screen 80A and the second screen 80B, three-dimensional vectors of three vertices 90x, 90y, and 90z when the ball is a unit sphere having a radius of 1 are obtained, and the second screen is obtained from the first screen 80A. The rotation axis vector of the ball is obtained from the movement to the screen 80B, and the vector rotation of this rotation axis vector and the vector of the position of each point is performed to obtain the rotation amount of the ball. When the rotation axis vector and the rotation amount are obtained, the back spin amount and the side spin amount of the ball can be obtained. Also, by measuring the vertical positional relationship of the ball 12 on the first screen 80A and the second screen 80B, the distance between the ball measuring cameras 26 and 28 and the distance m5 (horizontal distance) between the two cameras is increased. A launch angle can be obtained. Further, the flying distance can be calculated from the obtained initial speed, launch angle, back spin amount, and side spin amount.
[0036]
In the present system, the launch angle, the backspin amount, and the side spin amount are obtained using an isosceles triangle mark M written on the surface of the golf ball 12, but other shapes displayed on the surface of the golf ball are used. The launch angle, the back spin amount, and the side spin amount may be obtained by a similar method using marks and characters.
[0037]
【The invention's effect】
As described above, according to the present invention, the state of the club head at the time of impact can be measured, and thus it is possible to more appropriately evaluate the golfer's swing.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an arrangement of devices in an example of a system used in an impact state measuring method according to the present invention.
FIG. 2 is a diagram showing an arrangement interval of each device in the system of FIG. 1;
FIG. 3 is a diagram showing the position of a camera in the system of FIG. 1 in more detail;
FIG. 4 is a diagram showing an outline of a video at the time of impact taken by an impact camera.
FIG. 5 is a front view showing an example of a club head used for measuring an impact state.
FIG. 6 is a perspective view showing an example of an xyz standard used for measuring an impact state.
FIG. 7 is an operation explanatory view of the system of FIG. 1;
FIG. 8 is a diagram of a monitor screen of the system of FIG. 1;
[Explanation of symbols]
Reference Signs List 12 golf ball 14 tee 16 club head 18 sensor means 20 center of ball 22 impact camera 24 flight line 26 of hit ball 26 first ball measuring camera 28 second ball measuring camera 30 display monitor 32 control analyzer 42 club head 44 face surface 46 score Line 48 Mark 62 Standard

Claims (7)

In measuring the impact state of the golf swing, at the position opposite to the position where the golfer stands when viewed from the ball set position, and at a position at a predetermined height in front of the ball set position along the flight line direction A golf swing impact state measuring method, wherein an impact state by a golfer is photographed using a measurement system including a set camera and a control analysis unit, and the impact state is analyzed from the photographed video. With respect to the distance between the center of the ball and the center of the lens of the camera, the distance in the horizontal direction (x direction) of the flying ball is m3, and the distance in the horizontal plane (y direction) orthogonal to the horizontal direction of the flying ball. w, when the distance (height) in the vertical direction (z direction) is h, at least one high-speed shutter camera within an area where m3 is 1 to 700 mm, w is 100 to 600 mm, and h is 20 to 700 mm. 2. A golf swing impact according to claim 1, wherein the high-speed shutter camera captures at least one of states immediately before, at the time of impact, and immediately after the impact of the club head on the ball. State measurement method. In measuring the impact state, the x, y, and z axes having the origin at the center of the golf ball to be set and their reference lengths are input to the control analysis unit, and the values are recorded on the face of the club head. A plurality of marks are provided at predetermined intervals in the vertical and horizontal directions, and based on the x, y, z axes and their reference lengths based on the positional relationship of the marks on the face surface in the captured video. The method of measuring an impact state of a golf swing according to claim 1, wherein the posture of the face surface is measured by using the method. An image photographed in advance by using a reference device that extends in the x, y, and z-axis directions with the center of the golf ball set as the origin, and aligning the origin of the reference device with a position corresponding to the center of the golf ball. The method of measuring an impact state of a golf swing according to claim 3, wherein the posture of the face surface is measured based on the following. The center position of the ball is calculated by measuring the outer periphery of the portion of the ball that is substantially undeformed far from the club face from the image of the golf ball taken, and the position on the club face closest to the ball center is calculated. The golf swing impact state measuring method according to any one of claims 1 to 4, wherein an impact position on the club face surface is analyzed by detecting the impact position. 6. The camera according to claim 1, wherein a plurality of cameras are used to photograph two or more states of the state immediately before, at the time of, and immediately after the impact of the club head on the ball. Golf swing impact state measurement method. Using a golf ball with a mark on its surface, setting the first and second ball measuring cameras sideways at a predetermined distance from the set ball position and spaced apart from each other, and sending a shutter signal with a time lag, 7. The method according to claim 1, wherein when the ball comes in front of each ball measuring camera, the ball is photographed, the images are compared, and the movement of the ball is analyzed based on the movement of the mark between the two images. The method for measuring the impact state of a golf swing according to claim 1.

Images