Publication Type:Journal Article
Source:IEEE Transactions on Visualization and Computer Graphics, IEEE Computer Society, Volume 17, Issue 4, Number 4, Los Alamitos, CA, USA, p.426-439 (2011)
Keywords:Approximation theory, body-centered cubic lattice, box splines, normal reconstruction, orthogonal projection, Taylor series expansion
Schematic overview of the two-stage orthogonal projection scheme
In this paper, we present two methods for accurate gradient estimation from scalar field data sampled on regular lattices. The first method is based on the multi-dimensional Taylor series expansion of the convolution sum and allows us to specify design criteria such as compactness and approximation power. The second method is based on a Hilbert space framework and provides a minimum error solution in the form of an orthogonal projection operating between two approximation spaces. Both methods lead to discrete filters which can be combined with continuous reconstruction kernels to yield highly accurate estimators as compared to the current state of the art. We demonstrate the advantages of our methods in the context of volume rendering of data sampled on Cartesian and Body-Centered Cubic lattices. Our results show significant qualitative and quantitative improvements for both synthetic and real data, while incurring a moderate pre-processing and storage overhead.