Method for automatically digitizing the contours of line graphics, e.g. characters

摘要

An automatic digitization of line graphics, letters, etc., which hardly requires more human effort than scanning, but gives far better results than this, which are practically equivalent to those available with hand digitization, enables a multi-stage process, after the 1st after scanning from the template, for example of a letter and digitally stored image information with fixed programs stored in microprocessors and memories 2. are converted into vector data one after the other, this vector image 3. is subjected to a design recognition program and is divided into the image elements straight, sharp and round corner, narrow, normal and flat Curve and turning and tangent points is broken down. 4. The curvy picture elements are subjected to a spline fit, whereby mathematical curves are laid out by the point groups of the picture elements according to the method of least squares. These curve pieces are modified so that they have the same xy value pairs and the same gradients and curvatures at the connection points, so that they can be put together to form complete curves describing the outline of letters. 5. From the total curve obtained, as many coordinate pairs are calculated as are necessary to adequately describe the outline according to the rules of the IKARUS concept, with which the outline is digitized. 6. It is advantageous to use the outline representation to calculate, in particular, special points, such as turning points, extremes of the x, y values of curves and any intersection points of straight lines and / or curves with one another.