Matrices for Generating Orthogonal Eigenvector Bases of Trigonometric Number Transforms

This paper introduces a method based on generating matrices for obtaining trigonometric number transform (TNT) eigenvectors. We show how to construct such matrices and explain how to use them to produce specific orthogonal TNT eigenbases. Such eigenbases can be employed, in turn, to define fractional versions of the referred transforms. We discuss the main aspects of the method, provide examples and preliminarily evaluate its applicability in an image encryption scheme.