Non-contact automatic measurement method for golf clubs

Abstract

To allow even an unskilled worker to measure the specifications of a golf club, and quickly and accurately realize measurement with a simple device.SOLUTION: When a servo motor 20 is activated and its main axis is rotated, a movable carriage 16 moves along a rail 15 (x axis direction). A laser light irradiator 25 which radiates laser light and a digital camera 27 are arranged on the movable carriage 16. Slit light 26 from the laser light irradiator 25 is radiated from above a shaft 6 of a golf club 5. A digital camera 27 images reflection light, images the semi-ellipse thereof and calculates a center line 7 of the shaft 6 from its shape. A score line 11 is also detected, a lie angle, a loft angle, and face progression are calculated and obtained.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a non-contact automatic measurement method for golf clubs that measures loft angle, lie angle, face progression (FP), etc. without contact. More specifically, it is used in production processes and the like, and relates to a non-contact automatic measurement method for golf clubs that can measure the loft angle, lie angle, face progression (FP), etc. of a golf club and determine whether it is being produced as designed in a short time and without contact.

Background Art

[0002] For golf clubs, it is important to ensure that they maintain the designed dimensions and the like, and the loft angle, lie angle, FP, etc. greatly affect the trajectory of the ball. Also, the quality control of golf clubs during production processes and the like is important, and accurate and rapid measurement of the loft angle, lie angle, FP, etc. is required. The measurement of these specifications is subject to 100% inspection by highly skilled personnel using measuring instruments for measurement at production processes, shipping stages, etc. On the other hand, conventionally, in order to automate this measurement, a method has been proposed in which an image is taken with a CCD camera and the angle is automatically measured from the image (Patent Document 1). Also, a measuring device has been proposed in which the measurement is automated by irradiating laser light, which is slit light (Patent Document 2). This measuring device uses two digital cameras, a laser slit projector, and two lighting devices. Also, when measuring, the central axis of the shaft of the golf club needs to be installed so as to overlap with the optical axis of the digital camera in a vertical plane.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The measuring device described in Patent Document 1 above cannot accurately measure angles and the like in the image of a CCD camera. Further, the measuring device described in Patent Document 2 requires two cameras, a laser slit projector, and two lighting devices, which makes the device large. Further, since it is necessary to vertically install the shaft of the golf club during measurement, it takes skill and time to operate the measuring device and is not suitable for use in the production process. An object of the present invention is to provide a non-contact automatic measurement method for golf clubs that allows even an unskilled operator to measure the specifications of a golf club. Another object of the present invention is to provide a non-contact automatic measurement method for golf clubs that can quickly and accurately measure the specifications of a golf club with a simple device.

Means for Solving the Problems

[0005] The non-contact automatic golf club measuring device of the first aspect of the present invention gol F a laser light irradiator that irradiates a golf club with laser light that is slit light, a digital camera that captures the reflected light of the irradiated laser light as an image, and in a non-contact automatic golf club measuring device having gol F a shaft holding step of placing and holding the shaft of the club, a shaft image capturing step of capturing a shaft image from the outer shape of the shaft, a shaft center line calculation step of obtaining the shaft center line of the shaft from the shaft image, gol F a head image capturing step of capturing a head image of the head of the golf club, a score line calculation step of obtaining the score line of the golf club from the head image, a reference face plane calculation step of obtaining a reference face plane from the head image, Determine one or more selected from the lie angle, loft angle, and face progression from the shaft center line, the score line, and the reference face surface process and perform It is characterized by this.

[0006] The non-contact automatic measurement method for a golf club according to the second aspect of the present invention is the non-contact automatic measurement method for a golf club according to the first aspect of the present invention, wherein the shaft image capturing step and the head image capturing step move the laser light irradiator and the digital camera, or the golf club in the direction of the shaft center line to irradiate the slit light. It is characterized by being like that. The non-contact automatic measurement method for a golf club according to the third aspect of the present invention is the method according to the second aspect of the present invention, wherein the irradiation direction of the laser light is perpendicular to the shaft center line, and the photographing direction of the digital camera forms an angle with the irradiation direction of the laser light. It is characterized by this.

Effect of the Invention

[0010] The non-contact automatic measurement method for a golf club of the present invention has the advantages that even an unskilled operator can measure the specifications of a golf club, and the specifications of a golf club can be measured quickly and accurately with a simple device.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

[0012] [First Embodiment] Hereinafter, a non-contact automatic golf club measuring device 1 according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing an outline of the measurement principle of the non-contact automatic golf club measuring device 1. On the measuring device main body 2 of the non-contact automatic golf club measuring device 1, two mounting blocks 3 are fixed at intervals, and a V block 4 is fixed on the mounting block 3. The V block 4 is a general one, and in this example, it is a rectangular parallelepiped base made of steel having a V groove with an angle of 90 degrees. The two V blocks 4 are arranged and fixed such that the V grooves are in the same plane linearly. The shaft 6 of the cylindrical golf club 5 is placed on the two V blocks 4, and the shaft 6 is positioned and supported by the V grooves. Since the shaft 6 is placed on the V grooves, the shaft center line 7 does not move and is always positioned at a predetermined position in the width direction of the V grooves.

[0013] Further, since the V-block 4 is attached via the mounting block 3 fixed on the measuring device main body 2, when the shaft 6 is placed on this V-block 4, the shaft 6 is placed in a substantially horizontal direction with a gap D. Note that when the shaft 6 has a taper rather than being a cylinder, it may not be placed horizontally. Therefore, the horizontal in the present invention is a concept including a substantially horizontal direction. Since the club head 8 at the tip of the shaft 6 is heavier than other parts, it swings about the shaft center line 7 due to its own weight and is always positioned below the placement position of the shaft 6. The face surface 9 of the club head 8 is held at a predetermined angle in a stable state without moving or swinging. As a result, specular reflection of the slit light 26, which is the laser light irradiated on the club head 8, hardly occurs, and specular reflection that obstructs measurement can be prevented.

[0014] On the measuring device main body 2, at the upper positions of the two V-blocks 4, a rail 15 is arranged and fixed in parallel with the shaft center line 7. On the rail 15, a box-shaped moving table 16 is mounted movably by a linear bearing (not shown). At the end of the rail 15, a servo motor 20 is arranged. A feed screw 21, which is a ball screw, is connected to the output shaft of the servo motor 20. The feed screw 21 is a screw for converting rotational motion into linear motion to drive the moving table 16. A ball nut 22 that engages with the feed screw 21 is fixedly arranged on the moving table 16. Therefore, when the servo motor 20 is activated and its main shaft is rotated, the moving table 16 moves along the rail 15 (in the x-axis direction). A laser light irradiator 25 that irradiates laser light is arranged on the moving table 16. This laser light irradiator 25 outputs a linear laser light for measurement called slit light 26 in the Y-axis direction. The slit light 26 is irradiated from above the shaft 6 in a direction substantially perpendicular to the shaft center line 7. Note that this substantially perpendicular direction does not necessarily form an exact 90-degree angle and can be corrected by calculation. Therefore, the substantially perpendicular in the present invention is a concept including angles before and after the perpendicular direction.

[0015] Since the slit light 26 is irradiated from above in a direction perpendicular to the shaft center line 7 of the cylindrical shaft 6, its shape is a linear semi-circle and appears on the surface of the shaft 6. The moving table 16 is equipped with a digital camera 27 that photographs this semi-circle. The center line 28, which is the optical axis of the lens of the digital camera 27, is installed at an angular position that forms an angle θ (acute angle) with the slit light 26. The center line of the slit light 26 of the laser light irradiator 25 and the center line 28 of the lens of the digital camera 27 are along the shaft center line 7 7. This movement is carried out by activating and rotating the servo motor 20, and moving the laser light irradiator 25 and the digital camera 27 mounted on the moving table 16 together along the shaft center line 7. The slit light 26 emitted from the laser light irradiator 25 is irradiated onto the shaft 6, and the slit light 26 forms a linear semi-circle and appears on the surface of the shaft 6. Since this semi-circular irradiation light is photographed by the digital camera 27 and photographed from the direction of the angle θ with the slit light 26, its shape can be captured as a semi-ellipse (accurately, an arc of an ellipse) (see Fig. 2(a)). Based on this semi-ellipse, the position of the shaft center line 7 is obtained by the calculation method described later.

[0016] [Specifications of the golf club head 8] Fig. 8 is an explanatory diagram of the specifications of the club head. Fig. 8(a) is a front view, and Fig. 8(b) is a left side view. The lie angle β is the angle formed by the shaft center line 7 and the score line 11. The loft angle α is the angle formed by the face surface 9, which is a substantially flat surface of the club head 8, and the plane containing the shaft center line 7 (which is also a plane parallel to the score line 11). Since the face surface 9 on which the score line 11 is formed is not necessarily a flat surface over the entire surface, the face surface 9 referred to in this embodiment is the surface measured and calculated by the method described later. As shown in Fig. 8, the face progression (FP) refers to the distance (interval) between the plane containing the shaft center line 7 (which is also a plane parallel to the score line 11) and the plane parallel to this plane and containing the leading edge side (the foremost side of the face surface 9) of the leading edge 14.

[0017] [Measurement of the shaft center line 7] The principle of shape measurement, image processing, and calculation processing by the above-described non-contact automatic golf club measuring device 1 will be described below. FIGS. 2(a) to 2(c) are explanatory diagrams for explaining the principle when determining the position of the shaft center line 7 from the circle of the shaft 6. FIG. 2(a) is an example of a captured image of the slit light of the shaft, FIG. 2(b) is a diagram in which the shaft center line is calculated from the captured image of the shaft, and FIG. 2(c) is an example of a captured image showing an example of imaging at regular intervals in the axial direction of the shaft. The slit light 26 irradiated from the laser light irradiator 25 is irradiated from above in a direction perpendicular to the shaft center line 7 of the cylindrical shaft 6. Therefore, theoretically, its shape appears as a linear semi-circle. The irradiated light of the slit light 26 does not appear in the lower half of the cylindrical shaft 6 as it is a blind spot.

[0018] Since the digital camera 27 captures this from the position at an angle θ (see FIG. 1), as shown in FIG. 2(a), the captured image screen to be captured is semi-elliptical. This semi-elliptical arc, which is two-dimensional data (pixels), is converted into three-dimensional data (space of the x, y, and z axes) (in mm units). This data conversion is based on the previously calibrated data. This calibration geometrically associates the three-dimensional position (space of the x, y, and z axes) of the outer diameter of the shaft 6 with the semi-elliptical arc data of the two-dimensional data of the imaging screen. A circle is obtained from this three-dimensionally converted semi-arc by the least squares method, and the center of this circle is set as the center 7 of the shaft 6. This calculation is performed multiple times in the set length direction of the shaft 6 (see FIG. 2(c)), and the circular center points are calculated. Then, a straight line (three-dimensional) is obtained from the center points by the least squares method, and this is set as the shaft center line 7. Thus, the vector and position of the shaft center line 7, which is the center of the shaft 6 of the golf club 5, are determined.

[0019] [Measurement of the score line 11] The score line 11 formed on the face surface 9 is variously specified by the R&A etc. as the "groove specifications". According to the specifications, the edge of the groove must have a substantially circular cross-sectional shape, and the dimension of its effective radius is also specified. Fig. 3 is an explanatory diagram when irradiating the score line with slit light, and is a cross-sectional view of the score line. Fig. 3(a) is an enlarged cross-sectional view, and Fig. 3(b) is a cross-sectional view for explaining the position of the score line. As shown in Fig. 3(a), the score line 11 of the face surface 9 placed at an angle γ with the slit light 26 is continuously irradiated with the slit light 26. At this time, each position (3D spatial position) as each measurement point is specified from the reflected light of the reflected slit light 26.

[0020] As shown in Fig. 3(a), the measurement points (black dots in the figure) on the face surface 9 at this time are close to the immediately preceding measurement points and are continuously specified. However, the side wall 12 of the score line 11 becomes a blind spot and does not reflect from this side wall 12 but reflects from the groove bottom 13. That is, the slit light 26 is irradiated while being moved in the x-axis direction (Fig. 3), and the reflected light is measured at regular intervals. When the slit light 26 reaches the position of the score line 11, it does not reflect from the side wall 12 but reflects from the groove bottom 13. At this time, the measured value has a step difference (in the y-axis direction) numerically in the y-axis direction, so this measurement position (black dot in the figure) is determined as the position of the groove bottom 13 of the score line 11 (Fig. 3(b)). This measurement is performed on the entire surface of the face surface 9. The criterion for determining that the measurement position is the step position of the score line 11 is determined by its magnitude (in the y-axis direction). This magnitude is set numerically from the dimensions and tolerances set in the design, and is determined by differential values, threshold values, measurement data of actual production products, etc.

[0021] According to the above-described method for detecting the score line 11, FIG. 4 is a diagram in which the face surface is measured and determined to be at the score line position. FIG. 4(a) shows the determined position (black dots) drawn on the face surface, and FIG. 4(b) is an explanatory diagram based on the long score line. Each point (black dot) in FIG. 4(a) is the identified score line 11 by the above-described algorithm. The score line 11 is formed as a plurality of parallel grooves and is detected as shown by the dot drawing in FIG. 4(a). A straight line is obtained from each of these measurement points (black dots) by the least squares method, and this straight line is taken as the score line 11. At this time, only the long straight line is adopted as the score line 11 from among the straight lines. Note that, unlike the design value, the measured length of the score line 11 is not necessarily the same. Therefore, here, the average value of the vectors of the plurality of score lines 11 is taken as the inclination of the score line 11. Also, the coordinates (positions on the x, y, and z axes) of both ends of the straight line calculated to be the longest among the score lines 11 are taken as both ends of the score line 11.

[0022] [Calculation of the loft angle α] As shown in FIG. 5, the central position in the length direction of the averaged score line 11 is obtained, and the face surface 9 is partitioned by two partition surfaces 30, which are planes orthogonal to the score line 11 and having a constant width interval, with this central position as the center (see FIG. 5(a)). In other words, the score line 11 can also be said to be the surface normal of the partition surface 30. Then, a band-shaped reference face surface 31 is determined by the method described later (see FIG. 5(b)). Only a point group whose shape change amount is determined to be less than a preset threshold value by a differential value or the like is extracted from the band-shaped face surface 9 partitioned by the two partition surfaces 30. Thereby, the upper and lower curved surfaces of the face surface 9, the unevenness within the score line 11, etc. can be excluded. A plane is calculated from this extracted point group by the least squares method and taken as the reference face surface 31. When the reference face surface 31 is determined, the loft angle α formed with the above-described shaft center line 12 can be calculated and thus is determined.

[0023] [Measurement of face progression (FP)] As described with reference to FIG. 8(b), face progression (FP) is a numerical value (interval) indicating how far the leading edge 14 of the club head 8 is from the shaft center line 7. FIG. 6 is an explanatory diagram for explaining the principle of FP measurement. A shaft center line plane 32 including the shaft center line 7 is defined in a plane parallel to the score line 11 described above. The normal distance of each measurement point 33 of the measured leading edge 14 from the shaft center line plane 32 is calculated. The measurement point at the farthest normal distance from each measurement point 33 is defined as the FP point, and this is defined as the face progression (FP) (see FIG. 8).

[0024] [Control device 40 of golf club non-contact automatic measuring device] FIG. 7 is a block diagram showing an overview of a control system 40 for controlling the golf club non-contact automatic measuring device 1. The control device 41 of the control system 40 is a known sequence control means including a CPU (Central Processing Unit), RAM, ROM, auxiliary storage device, display means, input means, various output means, etc. A position signal is sent from the position detection sensor 43 to the control device 41 via the interface (I / F) 42. The position detection sensor 43 is for detecting the position of the moving table 16 in the x-axis direction. Specifically, it is a rotary encoder for detecting the rotation of the servo motor 20. Further, the servo motor 20, laser light irradiator 25, and digital camera 27 are connected to the control device 41 via the interface (I / F) 42, and their ON, OFF, etc. are controlled. The above-described image processing and calculation processing are performed by software stored in the control device 41 in the CPU (Central Processing Unit), RAM, ROM, auxiliary storage device, etc. These specific processes are known techniques and will not be described herein.

[0025] [Second Embodiment] The golf club non-contact automatic measurement device 1 of the first embodiment described above mounts the laser light irradiator 25 and the digital camera 27 on the moving table 16 and moves them on the guide rail 15 by screw drive. However, a method of fixing the laser light irradiator 25 and the digital camera 27 and moving the golf club 5 may also be used. FIG. 9 is an external view showing the appearance of the golf club non-contact automatic measurement device 50 of the second embodiment of the present invention. The golf club non-contact automatic measurement device 50 is an example of a structure of a type that moves the golf club 5. The measurement device main body 51, which is a housing, is in the shape of a rectangular box with a hollow interior and has an open front surface. For this reason, during measurement, it prevents external light, dust, etc. that would interfere with the measurement, and it is easy to place and remove the golf club 5 from the front. On the bottom plate of the measurement device main body 51, an automatic stage mechanism 52, which is a unit for moving the golf club 5, is arranged. The unitized automatic stage mechanism 52 is known and commercially available including its movement control device. A rail (not shown) is arranged and fixed on this stage 53. On this rail, a moving table 56 is mounted movably by a linear bearing (not shown).

[0026] Two V-blocks 55 are mounted and fixed on the moving table 56. A servo motor 54 is arranged at the end of the rail. A feed screw (not shown), which is a ball screw, is connected to the output shaft of the servo motor 54. The feed screw is a screw for converting rotational motion into linear motion to drive the moving table 56. A ball nut (not shown) that engages with the feed screw is fixedly arranged on the moving table 56. Therefore, when the servo motor 54 is activated and its main shaft is rotated, the moving table 56 moves along the rail (in the x-axis direction). On the measurement device main body 51 above the automatic stage mechanism 52, a laser light irradiator 58 for irradiating laser light and a digital camera 59 are fixedly arranged. The laser light irradiator 58 and the digital camera 59 are the laser light irradiations of the first embodiment deviceIt has the same structure and functions as the digital camera 27, and its description is omitted. In the measuring device main body 51, an automatic stage mechanism 52, a laser light irradiator 58, and a control device 57 for controlling the digital camera 59 are arranged. The golf club non-contact automatic measuring device 50 of the second embodiment is preferably used for measuring the golf club 5 having a long shaft. Although there was one feed screw for feeding the moving table 56, it is also possible to mount another moving table on the moving table 56, provide a feed screw on this other moving table, and adopt a structure of a two-stage moving table.

[0027] [Other Embodiments] The score line 11 described above, more precisely the reference face 31, was determined at the position of the groove bottom 13. As another determination method, as shown in FIG. 3(a), the position of one corner 11b of the score line 11 may be determined as the score line. According to this determination, since it is detected in pairs with the other corner 11a across the groove bottom 13, there is an advantage that the detection can be performed accurately. That is, since it can be judged based on the measured value of the score line 11 by the differential value in the Y-axis direction of the corner 11a and the differential value of the side wall 12 of the corner 11b, there is an advantage that it is accurate. The reference face 31 described above was in a band shape, but it may be a circular reference face 31 so as to include the sweet spot 34 (see FIG. 5(b)). Also, as described above, the lie angle β is the angle formed by the ground contact surface of the shaft center line 7 when the score line 11 is placed parallel to the ground contact surface and the plane including the shaft center line 7 is arranged vertically. Therefore, since the positions of the shaft center line 7 and the score line 11 could be measured, the lie angle β could also be measured.

[0028] The shooting direction of the digital camera 27 described above forms an angle θ with the irradiation direction of the slit light 26. This angle θ can be any angle as long as specular reflection or the like does not occur. Similarly, the slit light 26 irradiated by the laser light irradiator 25 is irradiated from the direction perpendicular to the shaft center line 7. It is not limited to this perpendicular direction, and the irradiation direction can be any angle as long as specular reflection or the like does not occur. Note that the golf club non-contact automatic measurement device 1 described above has been mainly described assuming measurement in the production process of golf clubs, but it may also be used for golf clubs that are in use or on sale at golf courses, golf driving ranges, golf equipment stores, etc.

Explanation of Signs

[0029] 1,50… Golf club non-contact automatic measurement device 2,51… Measurement device main body 3… Mounting block 4,55… V-block 5… Golf club 6… Shaft 7… Shaft center line 8… Club head 9… Face surface 11… Score line (face line) 12… Side wall 13… Groove bottom 14… Leading edge 15… Rail 16,56… Moving table 20,54… Servo motor 21… Feed screw 22… Ball nut 25,58… Laser light irradiator 26… Slit light 27,59… Digital camera 30… Area screen 31… Reference face surface 32… Shaft center line plane 33… Measurement point (leading edge) 34… Sweet spot 52… Automatic stage mechanism θ... Angle between the slit light and the center line of the optical axis of the digital camera α... Loft angle β... Lie angle γ... Angle between the slit light and the face plane

Claims

1. A laser light irradiator that irradiates a golf club with laser light that is slit light, and a digital camera that captures the reflected light of the irradiated laser light as an image In a non-contact automatic measurement device for a golf club having, A shaft holding step of placing and holding the shaft of the golf club, A shaft image capturing step of capturing a shaft image from the outer shape of the shaft, A shaft center line calculation step of obtaining the shaft center line of the shaft from the shaft image, A head image capturing step of capturing a head image of the head of the golf club, A score line calculation step of obtaining the score line of the golf club from the head image, A reference face plane calculation step of obtaining a reference face plane from the head image, Performing a step of obtaining one or more selected from a lie angle, a loft angle, and a face progression from the shaft center line, the score line, and the reference face plane A non-contact automatic measurement method for a golf club, characterized in that.

2. In the non-contact automatic measurement method for a golf club according to Claim 1, In the shaft image capturing step and the head image capturing step, the laser light irradiator and the digital camera, or the golf club are moved in the direction of the shaft center line to irradiate the slit light A non-contact automatic measurement method for a golf club, characterized in that.

3. In the non-contact automatic measurement method for a golf club according to Claim 2, The irradiation direction of the laser light is a direction perpendicular to the shaft center line, The photographing direction of the digital camera forms an angle with the irradiation direction of the laser light A non-contact automatic measurement method for a golf club, characterized in that.

Images