228 research outputs found
Curve network interpolation by quadratic B-spline surfaces
In this paper we investigate the problem of interpolating a B-spline curve
network, in order to create a surface satisfying such a constraint and defined
by blending functions spanning the space of bivariate quadratic splines
on criss-cross triangulations. We prove the existence and uniqueness of the
surface, providing a constructive algorithm for its generation. We also present
numerical and graphical results and comparisons with other methods.Comment: With respect to the previous version, this version of the paper is
improved. The results have been reorganized and it is more general since it
deals with non uniform knot partitions. Accepted for publication in Computer
Aided Geometric Design, October 201
Near-best quartic spline quasi-interpolants on type-6 tetrahedral partitions of bounded domains
In this paper, we present new quasi-interpolating spline schemes defined on
3D bounded domains, based on trivariate quartic box splines on type-6
tetrahedral partitions and with approximation order four. Such methods can be
used for the reconstruction of gridded volume data. More precisely, we propose
near-best quasi-interpolants, i.e. with coefficient functionals obtained by
imposing the exactness of the quasi-interpolants on the space of polynomials of
total degree three and minimizing an upper bound for their infinity norm. In
case of bounded domains the main problem consists in the construction of the
coefficient functionals associated with boundary generators (i.e. generators
with supports not completely inside the domain), so that the functionals
involve data points inside or on the boundary of the domain.
We give norm and error estimates and we present some numerical tests,
illustrating the approximation properties of the proposed quasi-interpolants,
and comparisons with other known spline methods. Some applications with real
world volume data are also provided.Comment: In the new version of the paper, we have done some minor revisions
with respect to the previous version, CALCOLO, Published online: 10 October
201
On unequally smooth bivariate quadratic spline spaces
International audienceIn this paper we consider spaces of unequally smooth local bivariate quadratic splines, defined on criss-cross triangulations of a rectangular domain. For such spaces we present some results on the dimension and on a local basis. Finally an application to B-spline surface generation is provided
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