Method of image processing of paint dots on golf balls

• US 6,390,934 B1
• Filed: 03/29/2001
• Issued: 05/21/2002
• Est. Priority Date: 03/29/2001
• Status: Expired due to Term

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Winfield, Douglas C., Gobush, William, Pelletier, Diane
• Primary Examiner(s): Cheng, Joe H.
• Assistant Examiner(s): Nguyen, Kim T.
• Application Number:
  US09/821,629
• Time in Patent Office: 418 Days
• Field of Search: 473/125, 473/131, 473/156, 473/140, 473/141, 473/198-200, 473/220-226, 473/351, 473/152, 473/409, 382/106, 382/169-172, 382/295
• US Class Current: 473/351
• CPC Class Codes: A63B 2024/0031 at the starting point
• CPC Class Codes: A63B 2024/0034 during flight
• CPC Class Codes: A63B 2220/05 Image processing for measuring physical parameters
• CPC Class Codes: A63B 2220/30 Speed
• CPC Class Codes: A63B 2220/35 Spin
• CPC Class Codes: A63B 2220/806 Video cameras
• CPC Class Codes: A63B 2220/807 Photo cameras
• CPC Class Codes: A63B 2220/808 Microphones
• CPC Class Codes: A63B 24/0021 Tracking a path or terminating locations
• CPC Class Codes: A63B 43/008 with means for improving visibility, e.g. special markings or colours illuminating or reflecting means A63B43/06
• CPC Class Codes: A63B 69/3658 Means associated with the ball for indicating or measuring, e.g. speed, direction

Abstract

A method of automatically calculating the spatial relationship of a plurality of diffuse dots on a ball, comprising the automated steps of obtaining at least two ball images of the ball at two or more discrete times; calculating a first gray level of the image; smoothing and binarizing the image; locating and determining the number of ball images in the image; locating and determining the number of diffuse dots on each ball image; confirming that the calculated number of dots equals a predetermined number of dots on each ball image; and calculating movement characteristics of the ball.

Claims

1. A method of automatically calculating the spatial relationship of a plurality of diffuse dots on a ball, comprising the automated steps of:

(a) obtaining at least two ball images of the ball at two or more discrete times;

(b) calculating a first gray level of the image;

(c) smoothing and binarizing the image;

(d) locating and determining the number of ball images in the image;

(e) locating and calculating the number of diffuse dots on each ball image;

(f) confirming that the calculated number of dots equals a predetermined number of dots on each ball image; and

(g) calculating movement characteristics of the ball.

2. The method of claim 1, wherein the first gray level is calculated using an iterative selection algorithm.

3. The method of claim 1, wherein the step of locating and determining the number of ball images in the image further comprises:

(a) determining a boundary of the ball images in the image; and

(b) calculating a region of interest around each boundary.

4. The method of claim 3, wherein the step of determining the boundary of the ball images in the image further comprises a contour following or a boundary chain algorithm.

5. The method of claim 3, wherein the region of interest is rectangular.

6. The method of claim 1, wherein the step of locating and determining the number of diffuse dots on each ball image further comprises the steps of:

(a) isolating a region of interest;

(b) inverting the image; and

(c) calculating a second gray level to provide a threshold value.

7. The method of claim 1, wherein the step of determining the number of diffuse dots on each ball image further comprises the steps of:

(a) identifying at least one discrete object within the image using a contour tracing or a boundary chain algorithm;

(b) calculating an area, a centroid, and an aspect ratio for each discrete object in a region of interest; and

(c) filtering the objects based on the area and aspect ratio.

8. The method of claim 1, wherein the step of confirming that the calculated number of dots equals the predetermined number of dots on each ball image further comprises using a Golden Mean algorithm.

9. The method of claim 1, wherein the characteristics of the ball comprise magnitude of velocity, direction of velocity, magnitude of spin, direction of spin.

10. The method of claim 9, wherein the direction of velocity is defined as angles relative to an orthogonal gravity oriented coordinate system.

11. The method of claim 9, wherein the direction of spin is defined as components of spin about an orthogonal axis.

12. The method of claim 1, wherein the dots have a thickness of less than about 0.001 inches.

13. The method of claim 1, where in the diffuse dots are pad printed or inkjet printed on the ball.