An effective detection method of rotational and divergent structures in still images based on Helmholtz decomposition

This paper proposes a novel detection method of rotational and divergent structures in still images based on Helmholtz decomposition. These structures are mathematical features in vector analysis. Traditionally, some detection methods of these structures in image sequences have been proposed. By using the Helmholtz decomposition, which can decompose flows into rotational and divergent components, the traditional methods can detect these structures in image sequences. However, the rotational and divergent structures in still images cannot be detected with the traditional methods. Therefore, the proposed method introduces a new criterion into the traditional schemes in order to realize the detection of the rotational and divergent structures in still images. This criterion is derived from two properties based on relation between still images and the flows, which are composed of the rotational and divergent components. Consequently, the detection of the rotational and divergent structures in still images can be achieved.