METHOD OF MEASURING ROTATIONAL MOTION OF A GOLF BALL

• US 20020022531A1
• Filed: 06/14/1999
• Published: 02/21/2002
• Est. Priority Date: 06/30/1998
• Status: Active Grant

• Current Assignee: Bridgestone Sports Co Limited (Bridgestone Corporation)
• Original Assignee: Bridgestone Sports Co Limited (Bridgestone Corporation)
• Inventors: KATAYAMA, SHU
• Granted Patent: US 6,458,035 B1
• Time in Patent Office: Days
• US Class Current: 473/151
• CPC Class Codes: A63B 2024/0031 at the starting point
• CPC Class Codes: A63B 2024/0034 during flight
• CPC Class Codes: A63B 2220/35 Spin
• CPC Class Codes: A63B 24/0021 Tracking a path or terminating locations
• CPC Class Codes: A63B 69/3658 Means associated with the ball for indicating or measuring, e.g. speed, direction

Abstract

A method of measuring rotational motion of a golf ball. A hit golf ball is photographed by use of two cameras disposed along the traveling direction of the golf ball with a predetermined distance therebetween, and rotational motion of the golf ball is measured based on the photographed images of the golf ball. There is used a golf ball that has a no-depression polygonal mark in black or a dark color close to black printed on the surface of the golf ball. The hit golf ball is photographed by use of two cameras, and the position of an angular point of the no-depression polygonal mark is detected from photographed images, by means of image processing. The rotational motion of the hit golf ball is calculated based on change in position of the angular point in images photographed by the two cameras.

Claims

1. A method of measuring rotational motion of a golf ball in which a hit golf ball is photographed by use of two cameras disposed along the traveling direction of the golf ball with a predetermined distance therebetween, and the rotational motion of the golf ball is measured based on the photographed images of the golf ball, said method comprising the steps of:

providing a golf ball having a no-depression polygonal mark in black or a dark color close to black printed on the surface of the golf ball;

hitting a golf ball;

photographing the hit golf ball by use of two cameras;

detecting the position of an angular point of the no-depression polygonal mark from photographed images, by means of image processing; and

calculating the rotational motion of the hit golf ball based on change in position of the angular point in images photographed by the two cameras.

2. A method of measuring rotational motion of a golf ball according to claim 1, wherein said no-depression polygonal mark is an isosceles triangle mark.

3. A method according to claim 2, wherein the ratio between the length of the base and the altitude of the isosceles triangle is within the range of 1:

1 to 1;

3.

4. A method according to claim 2, wherein the length of the base of the isosceles triangle is 6-15 mm.