The Properties of Orthogonal Nonseparable Four-Dimensional Wavelet Packets
In this article, the notion of orthogonal nonseparable four-dimensional wavelet packets, which is the generalization of orthogonal univariate wavelet packets, is introduced. A new approach for constructing them is presented by iteration method. The orthogonality properties of four-dimensional wavelet packets are discussed. Three orthogonality formulas concerning these wavelet packets are estabished.
Y. J. Liu "The Properties of Orthogonal Nonseparable Four-Dimensional Wavelet Packets ", Key Engineering Materials, Vols. 439-440, pp. 944-949, 2010