spm_dftmtx.m
31022b3a13e6master

spm_dftmtx.m
View Options

			function C = spm_dftmtx(N,K,a)
			% Creates basis functions for Discrete Cosine Transform.
			% FORMAT C = spm_dftmtx(N,K,a)
			%
			% N - dimension
			% K - order
			% a - number of (1/2)5Hz frequency steps (default a = 2)
			%__________________________________________________________________________
			% spm_dftmtx creates a matrix for the first few basis functions of a one
			% dimensional discrete Fourier transform.
			%
			% See: Fundamentals of Digital Image Processing (p 150-154).
			% Anil K. Jain 1989.
			%__________________________________________________________________________
			% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

			% Karl Friston
			% $Id: spm_dftmtx.m 4170 2011-01-24 18:37:42Z karl $


			% initialise
			%--------------------------------------------------------------------------
			try, a; catch, a = 2; end

			C = ones(N,1);
			x = (0:(N - 1))/N;
			for k = 1:K
			C(:,end + 1) = sin(apik*x);
			C(:,end + 1) = cos(apik*x);
			end