dct(x, type=2, inv=F) dct.2d(x, type=2, inv=F)
2
or
4
, indicating the discrete cosine
transfer type, DCT-II or DCT-IV, to use. See below for details.
TRUE
, the inverse of the transform os computed.
x
(or the inverse transform if
inv=TRUE
).
This is of the same length and mode as
x
.
Rao, K. R. and Yip, P. (1990). Discrete Cosine Transform: Algorithms, Advantages, Applications. Academic Press, Inc., San Diego, CA