 Notwithstanding this, blob descriptors have also been demonstrated to be useful when relating object models to temporal imagery.In terms of concepts, there is also a close relationship between the notion of interest points and ridge detectors, which are often used to signal the presence of "elongated objects".Moreover, with regard to features that extend along one-dimensional curves in image space, there is the related notion of edge detectors which satisfy similar requirements in terms of operational definitions, well-defined extent, locally high information contents and repeatability.