Discrete Cosine Transform

DESCRIPTION:
Performs the discrete cosine transform (DCT) on a vector or a matrix.

USAGE:
dct(x, type=2, inv=F)
dct.2d(x, type=2, inv=F)

REQUIRED ARGUMENTS:
x:
a vector, or a matrix.

OPTIONAL ARGUMENTS:
type:
one of the integers 2 or 4, indicating the discrete cosine transfer type, DCT-II or DCT-IV, to use. See below for details.
inv:
logical flag: if TRUE, the inverse of the transform os computed.

VALUE:
the normalized discrete cosine transform of te input data x (or the inverse transform if inv=TRUE). This is of the same length and mode as x.

DETAILS:
See the printed help file for the definitions of DCT-II and DCT-IV and their inverses.

REFERENCES:
Rao, K. R. and Yip, P. (1990). Discrete Cosine Transform: Algorithms, Advantages, Applications. Academic Press, Inc., San Diego, CA

SEE ALSO:
cp.table , cpt , cpt.2d .