A Set of Invariants Within the Power Spectrum of Unitary Transformations
Wendling, Gagneux, Stamon · IEEE Transactions on Computers · 1978
This correspondence presents a device for designing unitary transformations based on the Hadamard transform process. The notion of "invariants" within the power spectrum of one-dimensional transformations is developed and the specific case of some widespread transformations is considered. The results are extended to two-dimensional transformations and a character recognition experiment using the invariants thus obtained is presented.