Method and apparatus for sensing moving ball

Patent metadata

Field	Value
Publication number	US-2018367764-A1
Application number	US-201816112750-A
Country	US
Kind code	A1
Filing date	Aug 26, 2018
Priority date	Jan 8, 2013
Publication date	Dec 20, 2018
Grant date	—

Abstract

Provided are an apparatus and method for sensing a moving ball, which extract a feature portion such as a trademark, a logo, etc. indicated on a ball from consecutive images of a moving ball, acquired by an image acquisition unit embodied by a predetermined camera device, and calculate a spin axis and spin amount of rotation the moving ball based on the feature portion and thus spin of the ball is simply, rapidly, and accurately calculated with low computational load, thereby achieving rapid and stable calculation of the ball in a relatively low performance system. The sensing apparatus includes an image acquisition unit for acquiring consecutive images, an image processing unit for extracting a feature portion from the acquired image, and a spin calculation unit for calculating spin using the extracted feature portion.

First claim

What is claimed is:

1 . An apparatus for sensing a moving ball, for acquiring and analyzing an image of the moving ball to calculate spin of the moving ball, the apparatus comprising:
a camera for acquiring consecutive images according to movement of a ball with a surface having a predetermined feature portion indicated thereon, wherein the feature portion is an unspecified indication including a ball's trademark or a logo and a scratch on the ball; an image processor including a ball image extraction part and a ball feature extraction part, wherein the ball image extraction part, with respect to a first image and a second image consecutively acquired by the camera, is configured to find a ball portion on the first image and extract the ball portion having a predetermined size from the first image as a first ball image, and to find a ball portion on the second image and extract the ball portion having the predetermined size from the second image as a second ball image, and the ball feature extraction part is configured to extract the feature portion of the ball from the first ball image to prepare a first feature portion image and extract the feature portion of the ball from the second ball image to prepare a second feature portion image; and a spin calculator including a spin applying part and a spin determination part, wherein the spin applying part is configured to convert position information of each pixel on the first feature portion image into 3D position information, apply a trial spin axis and a trial spin amount to the converted 3D position information, and re-convert the 3D position information to which the trial spin axis and the trial spin amount have been applied into 2D position information, wherein the spin applying part prepares the re-converted 2D position information as a trial spin feature portion, and the spin determination part is configured to compare information of the trial spin feature portion with information of the second feature portion image to calculate a similarity, and determine the trial spin axis and the trial spin amount corresponding to the trial spin feature portion as a final spin axis and spin amount according to the similarity between information of the trial spin feature portion and information of the second feature portion image.

2 . The apparatus according to claim 1 , wherein the camera is embodied as a 3D camera or a stereo camera configured by a plurality of cameras installed at different positions with respect to the same ball.

3 . The apparatus according to claim 1 , wherein the spin calculation unit further comprises a position correction part for calculating position correction information for correcting a position and direction of a camera as if respective balls on consecutively acquired images are viewed at the same position and direction with respect to the camera and applies the position correction information to position information of each pixel constituting a feature portion on each feature portion image.

4 . The apparatus according to claim 1 , wherein the spin applying part selects and applies a trial spin axis and a trial spin amount in consideration of characteristics of ball movement and a frame rate of the camera according to a preset limitation condition.

5 . A method of sensing a moving ball, for acquiring and analyzing an image of the moving ball to calculate spin of the moving ball, the method comprising:
acquiring consecutive images by an image acquisition unit according to movement of a ball with a surface having a predetermined feature portion indicated thereon, wherein the feature portion is an unspecified indication including a ball's trademark or a logo and a scratch on the ball; preparing a first image and a second image consecutively acquired by the image acquisition unit; finding a ball portion on the first image and extracting the ball portion having a predetermined size from the first image as a first ball image; finding a ball portion on the second image and extracting the ball portion having the predetermined size from the second image as a second ball image; extracting the feature portion of the ball from the first ball image to prepare a first feature portion image; extracting the feature portion of the ball from the second ball image to prepare a second feature portion image; converting position information of each pixel on the first feature portion image into 3D position information, applying a trial spin axis and a trial spin amount to the converted 3D position information, and re-converting the 3D position information to which the trial spin axis and the trial spin amount have been applied into 2D position information, wherein the re-converted 2D position information is prepared as a trial spin feature portion; and comparing information of the trial spin feature portion with information of the second feature portion image to calculate a similarity, and determining the trial spin axis and the trial spin amount corresponding to the trial spin feature portion as a final spin axis and spin amount according to the similarity between information of the trial spin feature portion and information of the second feature portion image.

6 . The method according to claim 5 , further comprising:
calculating position correction information for correcting a position and direction of a camera as if respective balls on consecutively acquired images are viewed at the same position and direction with respect to the camera, wherein the position correction information is applied to the converted three-dimensional position information to apply the trial spin information and to calculate spin information.

7 . A method of sensing a moving ball, for acquiring and analyzing an image of the moving ball to calculate spin of the moving ball, the method comprising:
acquiring consecutive images by an image acquisition unit according to movement of a ball with a surface having a predetermined feature portion indicated thereon, wherein the feature portion is an unspecified indication including a ball's trademark or a logo and a scratch on the ball; preparing a first image and a second image consecutively acquired by the image acquisition unit; finding a ball portion on the first image and extracting the ball portion having a predetermined size from the first image as a first ball image; finding a ball portion on the second image and extracting the ball portion having the predetermined size from the second image as a second ball image; extracting the feature portion of the ball from the first ball image to prepare a first feature portion image; extracting the feature portion of the ball from the second ball image to prepare a second feature portion image; searching for a trial axis and a trial spin amount in 3D space, for allowing the first feature portion image into the second feature portion image; converting position information of each pixel on the first feature portion image into 3D position information, applying the searched trial spin axis and the searched trial spin amount to the converted 3D position information, and re-converting the 3D position information to which the trial spin axis and the trial spin amount have been applied into 2D position information, wherein the re-converted 2D position information is prepared as a trial spin feature portion; and comparing information of the trial spin feature portion with information of the second feature portion image to calculate the number of corresponding pixels between information of the trial spin feature portion and information of the second feature portion image ; and determining the trial spin axis and the trial spin amount corresponding to the trial spin feature portion as a final spin axis and spin amount information according to t

Assignees

• Golfzon Co Ltd

Inventors

• Kim Se Hwan

Classifications

• H04N7/181 Primary

  for receiving images from a plurality of remote sources · CPC title

• H04N13/239 Primary

  using two two-dimensional [2D] image sensors having a relative position equal to or related to the interocular distance (H04N13/243 takes precedence) · CPC title

• G06F18/22

  Matching criteria, e.g. proximity measures · CPC title

• G03B35/08

  by simultaneous recording · CPC title

• G06T7/73

  using feature-based methods · CPC title