In the mathematical subfield numerical analysis, tricubic interpolation is a method for obtaining values at arbitrary points in 3D space of a function defined on a regular grid. More at Wikipedia
Cubic interpolation - In the mathematical subfield of numerical analysis a cubic Hermite spline, named in honor of Charles Hermite, is a third-degree spline with each polynomial of the spline in Hermite form.
Bicubic interpolation - In mathematics, bicubic interpolation is an extension of cubic interpolation for interpolating data points on a two dimensional regular grid.