In color imaging, the two-dimension discrete Fourier transform (2-D DFT) is used to process separately color channels and in the quaternion space the processing of the image with 2-D quaternion Fourier transforms do consider interactions between the color channels. The color image can be also considered in different models with transformation to the octonion space with following processing in the 8-D frequency domain. In this work, we describe the algorithm for the 2-D two-side octonion DFT (ODFT), by using two-side 2-D quaternion DFTs.
Artyom M. Grigoryan, Sos S. Agaian, "2-D Octonion Discrete Fourier Transform: Fast Algorithms" in Proc. IS&T Int’l. Symp. on Electronic Imaging: Image Processing: Algorithms and Systems XV, 2017, pp 21 - 26, https://doi.org/10.2352/ISSN.2470-1173.2017.13.IPAS-200