Spline Approximation, Part 2: From Polynomials in the Monomial Basis to B-splines-A Derivation

In a series of three articles, spline approximation is presented from a geodetic point of view. In part 1, an introduction to spline approximation of 2D curves was given and the basic methodology of spline approximation was demonstrated using splines constructed from ordinary polynomials. In this article (part 2), the notion of B-spline is explained by means of the transition from a representation of a polynomial in the monomial basis (ordinary polynomial) to the Lagrangian form, and from it to the Bernstein form, which finally yields the B-spline representation. Moreover, the direct relation between the B-spline parameters and the parameters of a polynomial in the monomial basis is derived. The numerical stability of the spline approximation approaches discussed in part 1 and in this paper, as well as the potential of splines in deformation detection, will be investigated on numerical examples in the forthcoming part 3.

Automated summary

This article introduces spline approximation from a geodetic perspective, explaining the concept of B-spline and the direct relationship between B-spline parameters and polynomial parameters. The next step will involve investigating the numerical stability of spline approximation methods and the potential applications of splines in deformation detection through numerical examples.