“…Multidimensional (m-D) signal processing has a variety of applications and the modeling of multiple variables is carried out traditionally within the real-valued matrix algebra, while in recent years we have observed the successful exploitation of hypercomplex numbers in areas including colour image processing (Pei and Cheng, 1999;Pei et al, 2004;Sangwine and Ell, 2000;Parfieniuk and Petrovsky, 2010;Ell et al, 2014;Liu et al, 2014), vector-sensor array processing (Le Bihan and Mars, 2004;Miron et al, 2006;Le Bihan et al, 2007;Tao, 2013;Tao and Chang, 2014;Zhang et al, 2014;Hawes and Liu, 2015;Jiang et al, 2016a,b), and quaternion-valued wireless communications (Zetterberg and Brandstrom, 1977;Isaeva and Sarytchev, 1995;Liu, 2014). The most widely used hypercomplex numbers are quaternions, with rigorous physical interpretation for 3-D and 4-D rotational problems (Kantor et al, 1989;Ward, 1997).…”