This function calculates the (orthonormal) discrete cosine
transformation for a 3D image and returns thresholded DCT coefficients
using the C-library fftw3
(see http://www.fftw.org/).
dct3D(image, qThresh)
An integer vector, containing the indices of non-thresholded (hence non-zero) coefficients.
A numeric vector, giving the values of the corresponding coefficients.
A 3D image (a 3D array with real values).
A numeric with value in \([0,1]\), giving the quantile
for thresholding the coefficients. See dctBasis3D
for
details.
If the C-library fftw3
is not available when
the package MFPCA
is installed, this function is disabled an
will throw an error. For full functionality install the C-library
fftw3
from http://www.fftw.org/ and reinstall
MFPCA
. This function has not been tested with
ATLAS/MKL/OpenBLAS.
dctBasis3D