A fast algorithm for the 4×4 discrete Krawtchouk transform
Recently, research effort has been paid to the fast computation of the small fixed 4×4-, 8×8-point discrete orthogonal transforms, for example (Lee & Cho 1992, Nakagaki & Mukundan 2006, Nakagaki & Mukundan 2007, Ishwar et al. 2008, Zhu et al. 2009, Bouguezel et al. 2013, Cintra et al. 2014). (Lee & Cho 1992) proposed a 4×4 DCT algorithm to serve the base case for the recursive computation of two-dimensional (2-D) DCT. Nakagaki and Mukundan derived a fast algorithm for the computation of 4×4 DTT (Nakagaki & Mukundan 2006, Nakagaki & Mukundan 2007). Inspired by the research work presented in (Lee & Cho 1992, Nakagaki & Mukundan 2006, Nakagaki & Mukundan 2007), we propose in this letter a fast 4×4 DKT algorithm which could be used as the building-block for the DKT computation.