van Nieuwenhuizen, Peter R.Kiewiet, OlafBronsvoort, Willem F.2014-10-212014-10-2119941467-8659https://doi.org/10.1111/1467-8659.1330349A method is presented to compute a vector representation of an arbitrary line in a bi-level raster image The line may have varying line width and irregular borders. Furthermore, at line crossings and branches the user is offered the opportunity to choose from the directions in which line tracking may he continued The method avoids thinning and vectorization of chain codes. Instead, a contour follower is used at both sides of the line, and median line calculation is integrated with contour following. This leads to an efficient algorithm, in particular when individual lines have to be interactively extracted from a raster image.10.1111/1467-8659.1330349349-359