=ADD= =reftype= 14 =number= 04-11 =url= ftp://ftp.risc.uni-linz.ac.at/pub/techreports/2004/04-11.ps.gz =year= 2004 =month= 04 =author= Juettler; Bert + Schicho; Josef + Shalaby; Mohamed =title= Spline Implicitization of Planar Curves =abstract= We present a new method for constructing a low degree implicit spline representation of a given parametric planar curve. To ensure the low degree condition, quadratic B-splines are used to approximate the given curve via orthogonal projection in Sobolev spaces. Adaptive knot removal, which is based on spline wavelets, is used to reduce the number of segments. The B-spline segments are implicitized, and the resulting bivariate functions are joined along suitable transversal lines, yielding a globally continuous bivariate function. As shown by analyzing the asymptotic behavior of these transversal lines for step size $h\to0$, the given curve can be implicitized with any desired accuracy. =note= conference paper =howpublished= In T. Lyche, M.L. Mazure, L. Schumaker (eds.), Curve and Surface Design: St. Malo 2002 , Nashboro Press, Brentwood 2003, 225-234 =sponsor= FWF project SFB01315 =keywords= implicitization, B-spline, approximation, knot removal