Method and device for determining a contour and a center of an object

US8331642B2 · kind B2 · utility

Assignee

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE

Inventors

• Thorsten Zerfass · Nuremberg, DE
• Tobias Bergen · Erlangen, DE
• Dirk Steckhan · Munich, DE

Key dates

• Filing date: Dec 29, 2010
• Grant date: Dec 11, 2012
• Expiry date: Jul 28, 2031

Classification

• Technology area (CPC G): Physics
• CPC primary: G06T2207/30024
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A method for determining a contour of an object in a digital image includes determining a preliminary object center and determining contour candidate image points. The contour candidate image points are determined as image points on a plurality of paths leading away from a preliminary object center by detecting a change from a first section to a second section on a feature space based on the image point value range of the digital image or by detecting the exceeding of a predetermined strength of a feature change in the feature space, wherein the contour candidate image points have a distance to the preliminary or to an improved object center and are ordered according to a polar angle. Further, the method includes determining zones of neighboring contour candidate image points within which a change of the distance of the contour candidate image points lies above a threshold value and an elimination of contour candidate image points which lie between the zones of neighboring contour candidate image points. Finally, a determination of the contour is executed on the basis of the remaining contour candidate image points.