JP4028771B2 - Method for measuring impact state of golf swing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring an impact state of a golf swing, that is, a moment when a club head swung down by a golfer hits a ball.
[0002]
[Prior art]
In order to obtain data based on actual hits in measuring golf ball flight characteristics and spin characteristics, and selecting golf clubs suitable for golfers with different skill levels, the outer surface has been conventionally used. A golf ball with a mark is set at a predetermined position such as on a tee, and a shot immediately after a hit by a golf club with a predetermined club and a shot after a predetermined time have elapsed using a plurality of (for example, two) cameras. The way is 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. Also, by comparing multiple shot images, measuring the movement of the mark on the ball from the image, and the relationship between the shutter interval (time) of both cameras, the rotation speed (spin) of the ball in the vertical direction and Calculate the horizontal rotation speed. Further, the relative positional relationship between the two images in the vertical direction is measured, and the elevation angle of the hit ball is calculated. Then, using these data, a flying ball trajectory, a flight distance, and the like are calculated. In addition, in the above measurement, the club head speed is measured using an optical sensor or an acoustic sensor just before or at the time of hitting the ball.
[0004]
[Problems to be solved by the invention]
However, it is not clear what impact state is obtained by the club head, and the measurement value related to the ball obtained by the conventional measurement method described above is difficult to evaluate the measurement value sufficiently and correctly. . That is, in the conventional measuring method, it was unclear which part of the club head face the ball hit at the time of impact, whether the face surface orientation and posture at the time of impact were normal, or the like. Also, if the flight distance is smaller than expected, is the cause of the problem in the club itself, whether it is out of the sweet spot on the face surface, or because the orientation of the face surface is not appropriate, or is there a cause for the golfer? Etc. were unclear only from the measurement values relating to the balls obtained by the conventional measurement 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 the state of a club head at the time of impact and 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 measurement method shown in the following (1) to ( 6 ).
[0007]
(1) When measuring the impact state of a golf swing, a predetermined height is 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 flying line direction. A method of photographing an impact state by a golfer using a measurement system including a camera and a control analysis unit set at a position of the position, and analyzing the impact state from the photographed image. The x, y, and z axes with the center of the golf ball being used as the origin and their reference lengths are input to the control analysis unit, and a plurality of vertical and horizontal intervals are provided on the face surface of the club head. The x, y, and z axes are determined from the positional relationship of the marks on the face surface on the photographed image. Impact state measuring method of a golf swing, characterized in that to measure the position of the face based on the length of the beauty those criteria.
[0008]
(2) Regarding the distance between the center of the ball and the center of the lens of the camera, the distance in the flying ball horizontal direction (x direction) is m3, and in the direction (y direction) orthogonal to the flying ball horizontal direction in the horizontal plane. When the distance is w and the distance (height) in the vertical direction (z direction) is h, at least one unit is in the area where m3 is 1 to 700 mm, w is 100 to 600 mm, and h is 20 to 700 mm. The golf swing according to (1), wherein a high-speed shutter camera is disposed, and at least one of a state immediately before an impact by a club head on a ball, a state at the time of impact, and a state immediately after an impact is photographed by the high-speed shutter camera. Impact state measurement method.
[0010]
( 3 ) Using a reference device indicating the extension in the x, y, and z-axis directions with the center of the set golf ball as the origin, the origin of the reference device is set in advance to a position corresponding to the center of the golf ball. (1) A golf swing impact state measurement method according to (1) or (2) , wherein the posture of the face surface is measured with reference to a photographed image.
[0011]
( 4 ) The center position of the ball is calculated by measuring the outer periphery of the part of the golf ball that is far from the club face surface and not substantially deformed from the image of the shot golf ball, and the club face surface closest to the ball center position The golf swing impact state measuring method according to any one of (1) to ( 3 ), wherein an upper position is detected to analyze an impact position of the club face surface.
[0012]
( 5 ) The golf according to any one of (1) to ( 4 ), wherein a plurality of cameras are used to photograph two or more states of a state immediately before, during and immediately after an impact by a club head on a ball. Swing impact state measurement method.
[0013]
( 6 ) Using a golf ball with a mark on the surface, set the first and second ball measurement cameras sideways at a predetermined distance from the set ball position, and send a shutter signal at different times. Thus, when the ball comes to the front of each of the ball measuring cameras, 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 (1). ( 5 ) The impact state measurement method of the golf swing of ( 5 ).
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram relating to 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 the arrangement interval of each device, and FIG. 3 is a diagram showing the position of the camera in more detail.
[0015]
The measurement system of the example shown in the figure is a ball setting means for setting a golf ball 12, specifically, a tee 14 on which the golf ball 12 is placed, and a ball setting means 14 located behind the flying line and swings to hit the ball. Sensor means 18 for detecting the passage of the lowered club head 16 and one impact camera 22 are provided.
[0016]
The sensor means 18 is set with a first sensor 18A and a second sensor 18B composed of an optical light emitting part and a light receiving part 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 around 40 mm.
[0017]
The impact camera 22 has a distance w (y direction) away from the position where the golfer stands to give an impact to the golf ball 12 with respect to the center of the golf ball 12 on the opposite side in the horizontal plane including the center 20 of the ball. In order to measure the impact state of the ball at a position of a distance m3 ahead of the flying ball direction (x direction) from the set position and at a predetermined height h (z direction), the ball is set toward the ball set position. . The impact camera 22 is preferably a CCD camera having a shutter speed of 1/10000 to 1/20000 seconds, and the impact camera 22 is preferably provided with a strobe 22S.
[0018]
The distance m3 in the x direction is preferably 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 preferably 20 to 700 mm. Further, in order to continuously shoot a plurality of images immediately before impact, at the time of impact, and immediately after impact, a plurality of impact cameras may be installed. In this case, the distances m3, w and h of each camera are It is appropriate to be within the numerical range described above.
[0019]
When it is desired to photograph a hit ball after impact, for example, two cameras, that is, a first ball measurement camera 26 and a second ball measurement are located at a predetermined distance along the flight line (flight trajectory) 24 of the hit ball. Set the camera 28 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 lateral first ball measurement camera 26 is set in the 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 the range of 100 to 250 mm. can do.
[0021]
The sensor means 18, the impact camera 22 and the strobe 22S, the two ball measurement cameras 26 and 28, and the strobes 26S and 28S are connected to a control analysis unit 32 having a display monitor 30 (connection relationship is not shown).
[0022]
The control analysis unit 32 includes the following.
(1) Control box section The following items are included.
a) Frame memory for camera image recording 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) Impact image recording frame memory (2) Software section Software for calculating and displaying the following is incorporated.
a) Face angle calculation and display b) Hit point (up and down, left and right) position calculation and display c) Ball position display and position correction d) Face surface mark input and display e) Reference axis input and camera direction angle calculation f) Impact shooting Timing (delay time) setting g) Head speed value, initial speed, launch angle (upward with respect to the horizontal line, lateral direction with respect to the reference line), backspin amount, side spin amount measurement calculation and numerical display h) trajectory, flight distance Calculation i) Screen display / divided screen as follows (2 shots shot screen + measured value screen)
-Launch angle distribution screen-Carry and / or total distance distribution screen-Ballistic trajectory screen j) Accumulation of data values (3) Monitor, printer [0023]
FIG. 4 shows an outline of an impact image taken by the impact camera, and FIG. 5 shows a front view of the face surface of the club head (driver) used at that time. The club head 42 shown in FIGS. 4 and 5 includes a face surface 44 and is painted with a dark color (dark blue) as a whole, and a score line 46 is represented by a white line thereon. On the line 46, a plurality of black marks 48 of opposite colors are provided. The distance a in the horizontal direction of the mark 48 is about 10 mm, and the distance b in the vertical direction is also about 10 mm. In the figure, 50 indicates a toe portion of the club head 42, 52 indicates a crown portion, and 54 indicates a sole portion. On 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 movement of the ball from the image taken by the ball measuring camera (described later).
[0024]
FIG. 6 is a perspective view showing an example of an xyz reference device used for measuring the impact state. The x part 64, the y part 66, and the z part 68 of the reference device 62 are formed of metal corresponding to the x, y, and z directions shown in FIG. The position 70 (origin) where the points gather corresponds to the ball center (FIG. 3). A portion extending downward from the portion is a leg portion 72 for fixing to the tee 14.
[0025]
Prior to the measurement 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. Further, it is convenient to record the value of the diameter of the golf ball in the same memory as the reference dimension of the ball (the reference length described above).
[0026]
Next, the impact state measurement method of this example will be described with reference to the arrangement of the 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 passing time t1 is measured, and the head speed is determined from the relationship between the distance (m1) between the two sensors 18A and 18B. Is measured. Next, in response to the 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, a plurality of head speeds to be applied are measured in advance, for example, 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 shoot multiple images immediately before impact, during impact, and immediately after impact, set the delay time and the shutter interval between the installed cameras according to the position of those cameras .
[0027]
Images taken by each camera are displayed on the monitor 30 of the control analysis unit 32. FIG. 4 shows an outline of an image at the time of impact on the monitor. The obtained video is labeled and stored in the frame memory.
[0028]
Next, from the image on the monitor (FIG. 4), the mark 48 (position) appearing on the face surface 44 of the club head is measured from the image using an appropriate means (for example, a mouse). From this measurement result, the extension of the face surface can be calculated based on the reference length described above. 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 a predetermined means. As a result, it is possible to know the vertical and horizontal tilts of the face surface in the x, y, and z directions by the reference device 62 previously captured 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). Based on the result, a position corresponding to the center of the ball that is not substantially deformed is calculated based on the reference length, and a vertical line (from the ball center to the face surface) is calculated from the position on the calculated face surface. The impact position in the face surface with respect to the ball can be known from the position on the face surface where the vertical line is lowered.
[0030]
In addition, if a plurality of impact cameras are installed and images immediately before impact and / or immediately after impact can be obtained continuously in addition to the images at the time of impact, 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 and down blow, and to know the causal relationship with the movement of the golf ball by image analysis taken with the ball measurement camera described below.
[0031]
A method for analyzing the motion of the golf ball described above will be described. The initial velocity of the golf ball is measured from the relationship between the time when the hit ball has passed between the both ball measurement cameras 26 and 28 and the distance between the both ball measurement cameras 26 and 28.
[0032]
The measurement of the golf ball launch angle (upward with respect to the horizontal line), backspin amount, side spin amount, and flight distance is as follows. FIG. 8 shows the display of the hit ball projected on the monitor 30. The monitor screen 80 is divided into four, and the first ball 80A shows the hit ball caught from the side by the first ball measurement camera 26, and the second screen 80B shows the hit ball caught from the side by the second ball measurement camera 28, respectively. Then, the measurement value is displayed on the third screen 80C. In this system, the shape of the mark M marked on the surface of the golf ball 12 is an isosceles triangle. In addition, the color of the mark M is black or a dark color similar to it in order to stand out from the color of the ball surface.
[0033]
In this system, with respect to the images displayed on the first and second screens 80A and 80B, the outer shape of the golf ball 12 that is a white portion is extracted from the background of the black area by a binarization method (white / black) from the screen. To 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 further, a vertical search is performed from the main axis to obtain a change point at which black changes to white. The search for change points from black to white by this vertical search is performed along the main axis, and as a result, straight lines passing through the point sequence of these change points, that is, two oblique sides are 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 base is obtained by searching from this to the block side. When obtaining the hypotenuse and the base, it is preferable to obtain the curve by approximating the curvature due to the spherical surface. Since the mark M is an isosceles triangle, the main axis of the mark M is a straight line including a perpendicular passing through the midpoint of the base.
[0035]
When the triangle, that is, the mark M is specified by the image processing, three vertices are obtained from the three sides, and the three vertices 90x, 90y, and 90z are determined. Then, from the images displayed on the first screen 80A and the second screen 80B, a three-dimensional vector of three vertices 90x, 90y, 90z when the ball is a unit sphere of radius 1 is obtained, and the second screen is obtained from the first screen 80A. A rotation axis vector of the ball is obtained from the movement to the screen 80B, and a vector calculation is performed on the rotation axis vector and the position vector of each point to obtain the rotation amount of the ball. When the rotation axis vector and the rotation amount are obtained, the back spin amount and side spin amount of the ball can be obtained. Further, by measuring the positional relationship of the ball 12 in the vertical direction on the first screen 80A and the second screen 80B, from the relationship with the distance m5 (horizontal distance) between the two ball measuring cameras 26, 28, A launch angle can be obtained. Further, the flight distance can be calculated from the obtained initial velocity, launch angle, back spin amount, and side spin amount.
[0036]
In this system, the launch angle, the back spin amount, and the side spin amount are obtained using the isosceles triangle mark M marked on the surface of the golf ball 12, but other shapes displayed on the golf ball surface are obtained. The launch angle, back spin amount, and side spin amount may be obtained by the same 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 therefore the golfer's swing can be more appropriately evaluated.
[Brief description of the drawings]
FIG. 1 is a schematic diagram regarding the arrangement of apparatuses in an example of a system used in an impact state measurement method according to the present invention.
FIG. 2 is a diagram illustrating arrangement intervals of devices in the system of FIG.
FIG. 3 is a diagram showing the position of the camera in the system of FIG. 1 in more detail.
FIG. 4 is a diagram showing an outline of an impact image 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 reference device used for measuring an impact state.
7 is an operation explanatory diagram of the system of FIG. 1. FIG.
8 is a diagram of a monitor screen of the system of FIG.
[Explanation of symbols]
12 golf ball 14 tee 16 club head 18 sensor means 20 center of ball 22 impact camera 24 hit line of flight 26 first ball measurement camera 28 second ball measurement camera 30 display monitor 32 control analysis unit 42 club head 44 face surface 46 score Line 48 Mark 62 Reference device

Claims (6)

When measuring the impact state of a golf swing, it is a position opposite to the position where the golfer stands when viewed from the ball set position, and is positioned at a predetermined height ahead in the flying line direction from the ball set position. A method of photographing an impact state by a golfer using a measurement system including a set camera and a control analysis unit, and analyzing the impact state from a photographed image , and the golf set when measuring the impact state The x, y, and z axes with the center of the ball as the origin and their reference lengths are input to the control analysis unit, and a plurality of marks are placed on the face surface of the club head at predetermined vertical and horizontal intervals. Based on the positional relationship of the marks on the face surface on the captured image, the x, y, z axes and Impact state measuring method of a golf swing, characterized in that to measure the position of the face based on the length of the al reference.   Regarding the distance between the center of the ball and the center of the lens of the camera, the distance in the flying ball horizontal direction (x direction) is m3, and the distance in the direction (y direction) perpendicular to the flying ball horizontal direction in the horizontal plane is At least one high-speed shutter camera in an area where m3 is 1 to 700 mm, w is 100 to 600 mm, and h is 20 to 700 mm, where h is the distance (height) in the vertical direction (z direction). 2. The golf swing impact according to claim 1, wherein at least one of a state immediately before the impact by the club head on the ball, a state at the time of impact, and a state immediately after the impact is photographed by the high-speed shutter camera. State measurement method. An image taken in advance using a reference device indicating the x, y, and z-axis extension with the center of the set golf ball as the origin and the origin of the reference device aligned 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 1 or 2 , wherein the posture of the face surface is measured with reference to. The center position of the ball is calculated by measuring the outer periphery of the part of the golf ball that is far from the club face surface and not substantially deformed from the image of the shot golf ball, and the position on the club face surface that is closest to the ball center position impact state measuring method of a golf swing according to any one of claims 1 to 3, detected and characterized by analyzing the impact location of the club face surface. Using a plurality of cameras, according to any one of claims 1 to 4, characterized in that shoot impact of the club head immediately before, more than two states of the impact time and the impact of the state immediately after to the ball Method for measuring the impact state of a golf swing. By using a golf ball with a mark on the surface, the first and second ball measurement cameras are set sideways at a predetermined distance from the set ball position, and the shutter signal is sent by shifting the time. shooting the ball when the ball came to the front of each ball measuring camera, according to claim 1 to 5, characterized in that analyzing the motion of the ball based on the motion of the marks in between both by comparing their video image The golf swing impact state measuring method according to any one of the preceding claims.

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