# US 12,008,770 B2 · Method, system, and non-transitory computer-readable recording medium for measuring ball spin

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- Number: US 12,008,770 B2
- Document ID: US12008770B2
- Status: Granted
- Kind: B2
- Application number: 17/204,310
- Filed: 2021-03-17
- Published: 2021-07-22
- Granted: 2024-06-11
- Earliest claimed: 2020-01-16
- Assignees: Creatz Inc.
- Applicants: Creatz Inc.
- Inventors: Yong Ho Suk; Jey Ho Suk; Hyeon Seok Choi
- Web page: https://patentgrep.com/patent/US12008770B2

## CPC

- G06T 7/246: using feature-based methods, e.g. the tracking of corners or segments
- A63B 24/0006: {Computerised comparison for qualitative assessment of motion sequences or the course of a movement}
- G06F 18/2113: by ranking or filtering the set of features, e.g. using a measure of variance or of feature cross-correlation
- G06V 10/242: {by image rotation, e.g. by 90 degrees}
- G06V 10/751: {Comparing pixel values or logical combinations thereof, or feature values having positional relevance, e.g. template matching}
- G06V 20/00: Scenes; Scene-specific elements (control of digital cameras H04N23/60)
- G09B 19/0038: {Sports}
- A63B 69/36: for golf
- A63B 69/3655: {Balls, ball substitutes, or attachments on balls therefor}
- A63B 71/022: {Backstops, cages, enclosures or the like, e.g. for spectator protection, for arresting balls}
- A63B 2024/0028: {Tracking the path of an object, e.g. a ball inside a soccer pitch}
- A63B 2071/0638: {Displaying moving images of recorded environment, e.g. virtual environment}
- A63B 2220/806: Video cameras
- A63B 2220/807: Photo cameras
- A63B 2225/74: with powered illuminating means, e.g. lights
- G06T 2207/10016: Video; Image sequence
- G06T 2207/30224: Ball; Puck
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G09B: EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS (devices for psychotechnics or for testing reaction times A61B5/16; games, sports, amusements A63; projectors, projector screens G03B)

## Abstract

According to one aspect of the present invention, there is provided a method for measuring ball spin, the method comprising the steps of: detecting a plurality of dimples in each of a plurality of images of a ball for which physical quantities are to be measured; and measuring physical quantities related to spin of the ball with reference to a relationship between properties of the plurality of dimples detected in a first image among the plurality of images and properties of the plurality of dimples detected in a second image among the plurality of images.

## Claims

### Claim 1

A method for measuring ball spin, the method comprising the steps of:
detecting a plurality of dimples in each of a plurality of images of a ball for which physical quantities are to be measured; and
measuring physical quantities related to spin of the ball with reference to a relationship between properties of the plurality of dimples detected in a first image among the plurality of images and properties of the plurality of dimples detected in a second image among the plurality of images,
wherein the detecting step comprises the steps of:
detecting a position of a center of each of bright areas in each of the plurality of images;
detecting a position of each of the plurality of dimples on the basis of the position of the center of each of the bright areas in each of the plurality of images; and
correcting the position of each of the plurality of dimples with reference to a direction in which light is applied to the ball in each of the plurality of images.

### Claim 2 (depends on 1)

The method of claim 1, wherein in the detecting step, preprocessing for improving discrimination of the plurality of dimples is performed by applying at least one filter having a window of a size equal to or similar to a size of the dimple of the ball to each of the plurality of images.

### Claim 3 (depends on 1)

The method of claim 1, wherein in the detecting step, preprocessing for increasing contrast of the plurality of images is performed by applying a filter obtained by increasing a size of a central part of a Gaussian filter at a predetermined level and offsetting the Gaussian filter such that an average of distribution is maintained at a predetermined level.

### Claim 4 (depends on 1)

The method of claim 1, wherein the measuring step comprises the steps of:
comparing properties of at least one dimple pair among the plurality of dimples detected in the first image and properties of at least one dimple pair among the plurality of dimples detected in the second image to determine at least one associated dimple pair on the basis of an extent of matching between the properties; and
measuring the physical quantities related to spin of the ball with reference to rotation information of the at least one associated dimple pair.

### Claim 5 (depends on 1)

The method of claim 1, wherein the measuring step comprises the steps of:
comparing properties of at least one dimple pair among the plurality of dimples detected in the first image and properties of at least one dimple pair among the plurality of dimples detected in the second image to determine at least one first associated dimple pair on the basis of an extent of matching between the properties;
determining at least one second associated dimple pair among the at least one first associated dimple pair on the basis of an extent of matching between the plurality of dimples in the first and second images, which is calculated on the basis of rotation information of the at least one first associated dimple pair; and
measuring the physical quantities related to spin of the ball with reference to rotation information of the at least one second associated dimple pair.

### Claim 6 (depends on 1)

A non-transitory computer-readable recording medium having stored thereon a computer program for executing the method of claim 1.

### Claim 7

A system for measuring ball spin, the system comprising:
a dimple detection management unit configured to detect a plurality of dimples in each of a plurality of images of a ball for which physical quantities are to be measured; and
a physical quantity measurement unit configured to measure physical quantities related to spin of the ball with reference to a relationship between properties of the plurality of dimples detected in a first image among the plurality of images and properties of the plurality of dimples detected in a second image among the plurality of images,
wherein the dimple detection management unit is configured to:
detect a position of a center of each of bright areas in each of the plurality of images;
detect a position of each of the plurality of dimples on the basis of the position of the center of each of the bright areas in each of the plurality of images; and
correct the position of each of the plurality of dimples with reference to a direction in which light is applied to the ball in each of the plurality of images.

### Claim 8 (depends on 7)

The system of claim 7, wherein the dimple detection management unit is configured to perform preprocessing for improving discrimination of the plurality of dimples by applying at least one filter having a window of a size equal to or similar to a size of the dimple of the ball to each of the plurality of images.

### Claim 9 (depends on 7)

The system of claim 7, wherein the dimple detection management unit is configured to perform preprocessing for increasing contrast of the plurality of images by applying a filter obtained by increasing a size of a central part of a Gaussian filter at a predetermined level and offsetting the Gaussian filter such that an average of distribution is maintained at a predetermined level.

### Claim 10 (depends on 7)

The system of claim 7, wherein the physical quantity measurement unit is configured to:
compare properties of at least one dimple pair among the plurality of dimples detected in the first image and properties of at least one dimple pair among the plurality of dimples detected in the second image to determine at least one associated dimple pair on the basis of an extent of matching between the properties; and
measure the physical quantities related to spin of the ball with reference to rotation information of the at least one associated dimple pair.

### Claim 11 (depends on 7)

The system of claim 7, wherein the physical quantity measurement unit is configured to:
compare properties of at least one dimple pair among the plurality of dimples detected in the first image and properties of at least one dimple pair among the plurality of dimples detected in the second image to determine at least one first associated dimple pair on the basis of an extent of matching between the properties;
determine at least one second associated dimple pair among the at least one first associated dimple pair on the basis of an extent of matching between the plurality of dimples in the first and second images, which is calculated on the basis of rotation information of the at least one first associated dimple pair; and
measure the physical quantities related to spin of the ball with reference to rotation information of the at least one second associated dimple pair.