A new method for extracting and representing object contours in real images

This paper introduces a new operator for the calculation of the brightness gradient (derived from the Compass gradient) and a new methodology based on a fuzzy algorithm for extraction of the contour points of objects in a real image. A bidimensional geometrical representation of the contours thus extracted is then given in the form of arcs and segments in order to exploit this simplified description as an index for a search in a database of 3-D primitives. The procedure described gives good results, even in the presence of juxtaposed surfaces of the same nature and color, or with contours which do not contrast very well.