Generation of two-dimensional digital functions without non-essential singularities of the second kind

A class of two variable Hurwitz polynomials called very strict Hurwitz polynomials (VSHPs) are defined and their properties are studied. Their application in the generation of two variable functions without non-essential singularities of the second kind are indicated. Necessary and sufficient conditions on general and reactance one-variable to two-variable transformations so that they yield two variable transfer functions without singularities of the second kind are obtained.