Global feature extraction using efficient Hough transform

Novel Hough transform schemes are presented to provide two kinds of function expected of a global feature extractor. While the Hough transform was originally no more than a line segment detector, more complicated pattern features can be extracted by more intensive investigation of the Hough parameter space and/or more hierarchical usage of the Hough transform. As a typical example, a method to extract convex hulls and other related features from the transform space is introduced. In order to reduce the computing cost, a few efficient algorithms are introduced. A family of the functions applicable to the Houghlike feature extractor, the extended Hough transform, is proposed. As an example of hierarchical usage, the Hough transform is applied to the feature points of the Hough space