This paper presents the cubic trigonometric interpolation curves with two parameters generated over the space {1, sint, cost, sin 2 t, sin 3 t, cos 3 t}. The new curves can not only automatically interpolate the given data points without solving equation systems, but are also C 2 and adjust their shape by altering values of the two parameters. The optimal interpolation curves can be determined by an energy optimization model. The corresponding interpolation surfaces have characteristics similar to the new curves.The rest of this paper is organized as follows. In Section 2, the cubic trigonometric interpolation basis functions with two parameters generated over the space {1, sint, cost, sin 2 t, sin 3 t, cos 3 t} are presented, and some properties of the basis functions are given. In Section 3, the interpolation curves are defined on the base of the basis functions and some properties of the curves are given. Then, determining the optimal interpolation curves is discussed. In Section 4, the corresponding interpolation surfaces are presented. A short conclusion is given in Section 5.
The CTI-Basis FunctionsThe cubic trigonometric interpolation basis functions with two parameters are defined as follows.Definition 1. For 0 ď t ď 1, α, β P R, the following four functions about t are called cubic trigonometric interpolation basis functions with parameters α and β (CTI-basis functions for short),