Discrete Cosine Transform of Type II
c = dct_ii(x)
signal of dyadic length
discrete cosine transform, type II, of x
The form c = dct_ii(x) computes c defined by c_m = sqrt(2/N) * sum_n x(n) k_m cos( pi * m (2n+1) / 2N ) where 0 <= m,n <= N-1, N = length(x) = length(c) and k_m = [ 1 if 1 <= m <= N-1 [ 1/sqrt(2) if m = 0
The dct_ii is inverted by the dct_iii.