DCTIV Discrete Consine Transform type IV Usage: c=dctiv(f); DCTIV(f) computes the discrete cosine transform of type IV of the input signal f. If f is multi-dimensional, the transformation is applied along the first non-singleton dimension. DCTIV(f,L) zero-pads or truncates f to length L before doing the transformation. DCTIV(f,[],dim) or DCTIV(f,L,dim) applies the transformation along dimension dim. The transform is real (output is real if input is real) and orthonormal. It is its own inverse. Let f be a signal of length L and let c=DCTIV(f). Then L-1 c(n+1) = sqrt(2/L) * sum f(m+1)*cos(pi*(n+.5)*(m+.5)/L) m=0 Examples: --------- The following figures show the first 4 basis functions of the DCTIV of length 20: % The dctiv is its own adjoint. F=dctiv(eye(20)); for ii=1:4 subplot(4,1,ii); stem(F(:,ii)); end; References: K. Rao and P. Yip. Discrete Cosine Transform, Algorithms, Advantages, Applications. Academic Press, 1990. M. V. Wickerhauser. Adapted wavelet analysis from theory to software. Wellesley-Cambridge Press, Wellesley, MA, 1994.
Url: http://ltfat.github.io/doc/fourier/dctiv.html
See also: dctii, dctiii, dstii.
Package: ltfat