A tracking algorithm for extracting ridge lines in three-dimensional gray images using curvature of four-dimensional hypersurface

This paper proposes a thinning algorithm for tracking ridge lines in three-dimensional (3D) gray images. A characteristic of this algorithm is that input 3D gray images can be used directly without preprocessing such as binarization or separation of background. This algorithm obtains thin lines by tracking ridge lines, starting at points where the intensity has its local maximum. Combinations of three principal curvatures of a 4D hypersurface are used for the condition of continuation of tracking. It has been verified that lines considered to be ridge lines can be extracted when the proposed algorithm is applied to artificial images and real images. © 2001 Scripta Technica, Syst Comp Jpn, 32(12): 25–37, 2001