Patent ID: 11857855
Assignee: HEAD TECHNOLOGY GMBH
Field: Furniture, games (Other fields)
Classification: CPC A  G | IPC A  G

Claim 7:
8. A method for characterizing a racket head (1) of a ball game racket frame comprising the steps of:
(a) providing data of a ball game racket frame that describe the contour of the racket head of the ball game racket frame;
(b) automatically determining one or more of the following parameters characterizing the racket head shape on the basis of the contour data: measure of the length-width asymmetry of the racket head, measure of the deviation of the racket head shape from a circular shape, evolute of the racket head contour;
(c) outputting and/or graphically representing the determined parameter or parameters;
wherein step (a) comprises:
(i) creating an image of the racket head of the ball game racket frame with a viewing axis perpendicular to a string bed plane; and
(ii) automatically determining the contour of the racket head from the image by (1) converting the image of the racket head into a binary pixel image, wherein a threshold value is selected such that a first value is assigned to each of the pixels of the frame and a second value is assigned to each of all other pixels; and (2) identifying the frame pixels and determining the racket head contour;
wherein in step (b) the evolute of the racket head contour is determined by:
(i) identifying the normal vectors (9) to a plurality of points along the racket head contour, wherein the end point (10) of each normal vector (9) corresponds to the center of the associated circle of curvature; and
(ii) connecting the end points (10) to form a curve.