JP2005233800A - Apparatus for measuring falling point of ball - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus which can precisely and easily measure the falling point Pe of a golf ball G. <P>SOLUTION: The apparatus is provided with a CCD camera 2, a sound sensor 4, an arithmetic part, and a control part. The CCD camera 2 images the flying golf ball G from the upper side. The image obtained by the CCD camera 2 is recorded for each frame, and is subjected to a differential peak hold processing. According to the processing, a pixel of the golf ball G for each frame is specified. The fall of the golf ball G is detected by the sound sensor 4. The sound sensor 4 transmits a signal to the control part after the detection. The control part specifies the time of the fall, and transmits data on the time to the arithmetic part. The arithmetic part extracts frame data at the time of the fall, and specifies the pixel of the golf ball G in the frame data. The X-Y coordinates of the falling point Pe are calculated, on the basis of the pixel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus for measuring a falling point of a flying ball.

  A golf ball flies by being hit with a golf club. The golf ball eventually falls and rolls on the ground. The flight distance from the hitting point to the falling point is called carry. Carry can be calculated by grasping the falling point. If the carry is obtained, it is useful for performance evaluation of a golf ball, performance evaluation of a golf club, and diagnosis of a golfer's swing form.

  In Japanese Patent Laid-Open No. 2001-145718, the trajectory of a golf ball is measured based on image data obtained by a CCD camera behind the launch point and image data obtained by a number of CCD cameras installed on the side of the trajectory. An apparatus is disclosed. In this method, a large number of cameras are required to detect the falling point. Moreover, in this method, the falling point is determined from the image. An error is likely to occur in this determination. With this method, the carry is not accurately measured.

Japanese Patent Application Laid-Open No. 2003-42716 includes a CCD camera for photographing a flying ball from behind and a CCD camera for photographing the ball from the front, and based on an image obtained by these cameras, a difference method is used. An apparatus for calculating the coordinates of a ball is disclosed. In this method, the optical axis of the camera is set obliquely upward, so that it is difficult to photograph a golf ball near the falling point. Even when the golf ball in the vicinity of the falling point can be photographed, the falling point is grasped based on the image, so it is difficult to accurately measure the carry.
JP 2001-145718 A JP 2003-42716 A

  Because of this situation, the carry is usually measured by a measurer waiting in the vicinity of the falling point. This measurement requires manpower. The measurer may lose sight of the golf ball in flight, and in this case, the carry cannot be measured. In addition, equipment such as a protective net and a helmet must be prepared for the purpose of preventing the golf ball from colliding with the worker.

  An object of the present invention is to provide an apparatus capable of accurately and simply measuring the falling point of a flying ball.

The ball falling point measuring device according to the present invention is:
A camera for shooting the flying ball from above,
A sensor for detecting the fall of the ball,
A calculation unit that calculates a ball position at the time when the sensor detects a fall based on an image obtained by the camera.

  Preferably, a sound sensor is used for detecting the fall.

  Preferably, the calculation of the ball position by the calculation unit is achieved by a differential peak hold process.

The measuring method of the ball drop point according to the present invention is:
(1) a step in which image data obtained by a camera that photographs a flying ball from above is recorded for each frame;
(2) A step in which differential peak hold processing is performed on the image data in the order of frames to obtain frame data in which only the ball image remains;
(3) a step of detecting the fall of the ball by the sensor, and (4) a step of calculating the coordinates of the fall point based on the frame data at the time of the fall.

  In this measuring device, the fall of the ball is detected by a sensor. Therefore, the time of the fall can be accurately grasped. On the other hand, the position of the ball at the time of falling is calculated by the calculation unit based on the image obtained by the camera. This measurement does not require manual labor at the drop point. With this device, the falling point can be measured accurately and simply.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating a ball drop point measuring apparatus according to an embodiment of the present invention. This apparatus includes a CCD camera 2, a sound sensor 4, a calculation unit 6, and a control unit 8. The CCD camera 2 has a shutter function. The sound sensor 4 detects a sound in a specific frequency region or a sound whose volume is equal to or higher than a predetermined value. A typical sound sensor is a sound collecting microphone. The calculation unit 6 includes a computer and peripheral devices. The control unit 8 also includes a computer and peripheral devices. The calculation unit 6 and the control unit 8 may be configured from the same computer. The control unit 8 has a timer function. The ball drop point measuring device may include a printing unit, a display unit, and the like not shown.

  FIG. 2 is a front view showing a state in which a fall point is measured by the apparatus of FIG. In FIG. 2, a golf ball is represented by a symbol G, and a trajectory of the golf ball G is represented by a symbol T. The golf ball G flies from left to right in FIG. What is indicated by a reference symbol Ps is a launch point of the golf ball G, and what is indicated by a reference symbol Pe is a fall point of the golf ball G.

  A pole 10 is erected in the vertical direction slightly behind the launch point Ps. The CCD camera 2 is fixed above the pole 10. The optical axis of the CCD camera 2 is inclined downward with respect to the horizontal direction. A region sandwiched between the virtual line L1 and the virtual line L2 is the angle of view of the CCD camera 2. As is apparent from FIG. 2, the CCD camera 2 photographs the flying ball from above. The sound sensor 4 is disposed near the drop point Pe.

  FIG. 3 is a plan view showing the state of measurement in FIG. In FIG. 3, the direction from left to right is the X direction, and the direction from bottom to top is the Y direction. The X coordinate of the fall point Pe is a flight distance from the launch point Ps. The Y coordinate of the falling point Pe is a deviation from the target direction of the falling point Pe.

  In FIG. 3, in the vicinity of the falling point Pe, a rectangle ABCD and a number of partition lines 12 extending vertically and horizontally to partition the rectangle ABCD are drawn. The rectangle ABCD and the partition line 12 are virtual, and the rectangle ABCD and the partition line 12 are not drawn near the actual falling point Pe. The XY coordinates of point A, point B, point C, and point D are known in advance by the measurer.

  FIG. 4 is a schematic diagram showing an image obtained by the CCD camera 2. As is apparent from FIG. 4, the angle of view of the CCD camera 2 includes a rectangle ABCD. Since the CCD camera 2 is located away from the rectangle ABCD, the rectangle ABCD is photographed as a shape close to a trapezoid in FIG.

  In the image shown in FIG. 4, each of point A, point B, point C, and point D corresponds to one pixel. Since the XY coordinates of the points A, B, C, and D are known in advance as described above, the trapezoid ABCD is based on the correspondence between the points A, B, C, and D and each pixel. XY coordinates of all the pixels included in can be calculated. In other words, the pixel and the XY coordinate can be associated with each other.

  In order to measure the coordinates of the falling point Pe with this device, the golf ball G is first launched. This launch is detected by a sensor (not shown) (for example, a laser beam sensor). This sensor emits a trigger signal. This trigger signal is detected by the control unit 8. After detection, the control unit 8 starts a timer. Further, the control unit 8 transmits a signal to the CCD camera 2. An image is taken by the CCD camera 2 receiving this signal.

  The control unit 8 also transmits a signal to the calculation unit 6 so as to start recording image data. Receiving the signal, the calculation unit 6 records the image data obtained by the CCD camera 2 for each frame. For recording, a time plus VTR, a digital disk recorder, a moving picture board, or the like can be used. The obtained data is subjected to image processing. In image processing, differential peak hold processing is performed on image data in the order of frames. Specifically, a memory of a pixel having a large change from the previous frame among pixels of a certain frame is held. Since the image of the golf ball G is whiter than the background and becomes the whitest portion in the density determination, the background is erased by this image processing, and frame data in which only the image of the golf ball G remains is obtained.

  The golf ball G will eventually fall. When falling, the golf ball G and the ground collide. A collision sound is generated by this collision. This collision sound is detected by the sound sensor 4. The sound sensor 4 that has detected the collision sound transmits a signal toward the control unit 8. The control part 8 which received the signal specifies the time of fall by a timer. The data at this time is sent to the calculation unit 6.

  Receiving the data, the calculation unit 6 extracts frame data corresponding to the time. The image of the golf ball G recorded in the frame data is that at the time of dropping. The calculation unit 6 specifies the pixel at the center of the image of the golf ball G. As described above, since the correspondence between the points A, B, C, and D and each pixel is known in advance, the calculation unit 6 can calculate the XY coordinates of the falling point Pe. Based on the coordinates of the fall point Pe and the coordinates of the launch point Ps, the calculation unit 6 calculates the carry (flying distance) and deviation of the golf ball G.

  With this measurement method, the falling point Pe of the golf ball G can be measured. In this measurement method, since the falling point Pe is automatically measured, there is no need for the measurer to stand by in the vicinity of the falling point Pe. This measurement method is simple. This method does not cause measurement errors due to human error. By this method, the falling point can be accurately measured.

  The golf ball G may be shot with two or more cameras. The golf ball G may be photographed from the front or side in the flight direction. The fall may be detected by two or more sensors.

  The measuring device according to the present invention can be applied to the measurement of the falling points of various balls such as tennis balls and baseballs.

FIG. 1 is a schematic configuration diagram illustrating a ball drop point measuring apparatus according to an embodiment of the present invention. FIG. 2 is a front view showing how the trajectory of the golf ball is measured by the apparatus of FIG. FIG. 3 is a plan view showing how the trajectory of a golf ball is measured by the apparatus of FIG. FIG. 4 is a schematic diagram showing an image obtained by a CCD camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... CCD camera 4 ... Sound sensor 6 ... Calculation part 8 ... Control part 10 ... Pole 12 ... Dividing line G ... Golf ball T ... Ballistic path Ps ... Launch point Pe ... Fall point

Claims (4)

A camera for shooting the flying ball from above,
A sensor for detecting the fall of the ball,
An apparatus for measuring a ball drop point, comprising: an arithmetic unit that calculates a ball position at the time when a drop is detected by a sensor based on an image obtained by a camera.   The measuring apparatus according to claim 1, wherein the sensor is a sound sensor.   The measuring apparatus according to claim 1, wherein the calculation of the ball position by the arithmetic unit is achieved by a differential peak hold process. Image data obtained by a camera that shoots a flying ball from above is recorded for each frame;
A step in which differential peak hold processing is performed on the image data in the order of frames to obtain frame data in which only the ball image remains;
A step in which the fall of the ball is detected by a sensor;
A method of measuring a ball drop point including a step of calculating coordinates of the drop point based on frame data at the time of drop.

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