Comments on "Two-dimensional interpolation by generalized spline filters based on partial differential equation image models"

The generalized spline formula corresponding to the separable semicausal Partial Differential Equation (PDE) image model is given in its correct form. In addition, the correct formula for the second-order B-spline is derived. Finally, it is shown that there is no reason to consider separable PDE image models only, at least when describing the concept of generalized splines.