Become an expert in R — Interactive courses, Cheat Sheets, certificates and more!
Get Started for Free

idct2

Inverse 2-D Discrete Cosine Transform

Description

Compute the inverse two-dimensional discrete cosine transform of a matrix.

Usage

idct2(x, m = NROW(x), n = NCOL(x))

Arguments

x

2-D numeric matrix
m

Number of rows, specified as a positive integer. dct2 pads or truncates x so that it has m rows. Default: NROW(x).
n

Number of columns, specified as a positive integer. dct2 pads or truncates x so that it has n columns. Default: NCOL(x).

Details

The discrete cosine transform (DCT) is closely related to the discrete Fourier transform. It is a separable linear transformation; that is, the two-dimensional transform is equivalent to a one-dimensional DCT performed along a single dimension followed by a one-dimensional DCT in the other dimension.

Value

m-by-n numeric discrete cosine transformed matrix.

Author(s)

Paul Kienzle, pkienzle@users.sf.net.
Conversion to R by Geert van Boxtel, G.J.M.vanBoxtel@gmail.com.

See Also

Examples

A <- matrix(50 * runif(100), 10, 10)
B <- dct2(A)
B[which(B < 1)] <- 0
AA <- idct2(B)
gsignal

Signal Processing

v0.3-1
GPL-3
Authors
Geert van Boxtel [aut, cre] (Maintainer), Tom Short [aut] (Author of 'signal' package), Paul Kienzle [aut] (Majority of the original sources), Ben Abbott [ctb], Juan Aguado [ctb], Muthiah Annamalai [ctb], Leonardo Araujo [ctb], William Asquith [ctb], David Bateman [ctb], David Billinghurst [ctb], Juan Pablo Carbajal [ctb], André Carezia [ctb], Vincent Cautaerts [ctb], Eric Chassande-Mottin [ctb], Luca Citi [ctb], Dave Cogdell [ctb], Carlo de Falco [ctb], Carne Draug [ctb], Pascal Dupuis [ctb], John W. Eaton [ctb], R.G.H Eschauzier [ctb], Andrew Fitting [ctb], Alan J. Greenberger [ctb], Mike Gross [ctb], Daniel Gunyan [ctb], Kai Habel [ctb], Kurt Hornik [ctb], Jake Janovetz [ctb], Alexander Klein [ctb], Peter V. Lanspeary [ctb], Bill Lash [ctb], Friedrich Leissh [ctb], Laurent S. Mazet [ctb], Mike Miller [ctb], Petr Mikulik [ctb], Paolo Neis [ctb], Georgios Ouzounis [ctb], Sylvain Pelissier [ctb], Francesco Potortì [ctb], Charles Praplan [ctb], Lukas F. Reichlin [ctb], Tony Richardson [ctb], Asbjorn Sabo [ctb], Thomas Sailer [ctb], Rolf Schirmacher [ctb], Rolf Schirmacher [ctb], Ivan Selesnick [ctb], Julius O. Smith III [ctb], Peter L. Soendergaard [ctb], Quentin Spencer [ctb], Doug Stewart [ctb], P. Sudeepam [ctb], Stefan van der Walt [ctb], Andreas Weber [ctb], P. Sudeepam [ctb], Andreas Weingessel [ctb]
Initial release
2021-05-02

We don't support your browser anymore

Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.