Efficient computation of the 2-D discrete pseudo-Wigner distribution by the fast Hartley transform

Wigner distribution (WD) is useful in analyzing and processing nonstationary signals. In this paper the fast Hartley transform (FHT) approach for computing the one-dimensional discrete pseudo-Wigner distribution (1D DPWD) is extended to compute the two-dimensional (2-D) DPWD and a new fast algorithm is presented for computing the 2-D DPWD by the 2-D FHT entirely in the real domain. First, the original 2-D real signal is converted into its complex analytic version. A fast algorithm is proposed to compute the 2-D discrete Hilbert transform using the 2-D FHT instead of the 2-D complex FFT with a reduced number of real operations. Then, the algorithm formulae are derived for computing the 2-D DPWD of the analytic signal by the 2-D FHT. Compared with the conventional FFT approach, the proposed algorithm is performed entirely in the real domain, and the computational complexity is greatly reduced from 3 2-D complex FFT´s to 3 2-D real FHT´s