Comments on "Phase-Shifting for Nonseparable 2-D Haar Wavelets

In their recent paper, (see ibid., vol.17, no.7, p.1061-8, 2008) Alnasser and Foroosh derive a wavelet-domain (in-band) method for phase-shifting of 2-D ldquononseparablerdquo Haar transform coefficients. Their approach is parametrical to the (a priori known) image translation. In this correspondence, we show that the utilized transform is in fact the separable Haar discrete wavelet transform (DWT). As such, wavelet-domain phase shifting can be performed using previously-proposed phase-shifting approaches that utilize the overcomplete DWT (ODWT), if the given image translation is mapped to the phase component and in-band position within the ODWT.