| Type: | Package |
| Title: | Discrete Trigonometric Transforms |
| Version: | 0.1-2.1 |
| License: | GPL-2 | GPL-3 [expanded from: GPL (≥ 2)] |
| URL: | https://www.r-project.org, https://www.komsta.net/ |
| Description: | Provides functions for 1D and 2D Discrete Cosine Transform (DCT), Discrete Sine Transform (DST) and Discrete Hartley Transform (DHT). |
| Packaged: | 2025-06-17 10:37:11 UTC; hornik |
| Repository: | CRAN |
| Date/Publication: | 2025-06-17 10:53:30 UTC |
| NeedsCompilation: | no |
| Author: | Lukasz Komsta [aut, cre] |
| Maintainer: | Lukasz Komsta <lukasz.komsta@umlub.pl> |
Discrete Trigonometric Transforms
Description
This package provides functions for 1D and 2D Discrete Cosine Transform (DCT), Discrete Sine Transform (DST) and Discrete Hartley Transform (DHT).
Details
| Package: | dtt |
| Type: | Package |
| Version: | 0.1-1 |
| Date: | 2007-02-25 |
| License: | GPL version 2 or newer. |
Author(s)
Maintainer: Lukasz Komsta <luke@novum.am.lublin.pl>
Discrete Trigonometric Transforms
Description
Performs univariate discrete sine, cosine or Hartley transform.
Usage
dtt(x, type = c("dct", "dst", "dht"), variant = 2, inverted = FALSE)
dct(x, variant = 2, inverted = FALSE)
dst(x, variant = 2, inverted = FALSE)
dht(x, inverted = FALSE)
Arguments
x |
a vector or matrix to be transformed |
type |
type of transform. Default "dct" is discrete cosine, "dst" is discrete sine and "dht" is discrete Hartley |
variant |
a transformation variant - 1...4 for DCT-I...DCT-IV or DST-I...DST-IV. Default is DCT-II or DST-II. Ignored when type = "dht" |
inverted |
if the inverted transform should be performed? |
Details
This function transforms a vector of real numbers into a vector of its DCT, DST or DHT components, of the same length.
If the x is a matrix, the transform goes by rows (each row of a result is a transform of corresponding row in x).
The dct, dst and dht functions are simple wrappers for choosing the type by function name.
Value
A transformed vector.
Author(s)
Lukasz Komsta
References
1. N. Ahmed, T. Natarajan, and K. R. Rao, "Discrete Cosine Transform", IEEE Trans. Computers, 90-93, Jan 1974. 2. S. A. Martucci, "Symmetric convolution and the discrete sine and cosine transforms", IEEE Trans. Sig. Processing SP-42, 1038-1051 (1994). 3. R. V. L. Hartley, "A more symmetrical Fourier analysis applied to transmission problems," Proc. IRE 30, 144-150 (1942).
See Also
Examples
x=seq(0,20,length=200)
y=x*sin(x)+cos(x)+5*cos(10*x)+rnorm(200,sd=0.1)
plot(y)
z=dct(y); z[151:200]=0; lines(dct(z,inverted=TRUE),col=2);
z=dct(y); z[21:200]=0; lines(dct(z,inverted=TRUE),col=4);
2D Discrete Trigonometric Transforms
Description
Performs multivariate (2D) discrete sine, cosine or Hartley transform.
Usage
mvdtt(x, type = c("dct", "dst", "dht"), variant = 2, inverted = FALSE)
mvdct(x, variant = 2, inverted = FALSE)
mvdst(x, variant = 2, inverted = FALSE)
mvdht(x, inverted = FALSE)
Arguments
x |
a matrix to be transformed |
type |
type of transform. Default "dct" is discrete cosine, "dst" is discrete sine and "dht" is discrete Hartley |
variant |
a transformation variant - 1...4 for DCT-I...DCT-IV or DST-I...DST-IV. Default is DCT-II or DST-II. Ignored when type = "dht" |
inverted |
if the inverted transform should be performed? |
Details
This function transforms a matrix of real numbers into a matrix of its DCT, DST or DHT components, of the same dimensions. It is done by so-called row-matrix algorithm.
The mvdct, mvdst and mvdht functions are simple wrappers for choosing the type by function name.
Value
A transformed matrix.
Author(s)
Lukasz Komsta
References
1. N. Ahmed, T. Natarajan, and K. R. Rao, "Discrete Cosine Transform", IEEE Trans. Computers, 90-93, Jan 1974. 2. S. A. Martucci, "Symmetric convolution and the discrete sine and cosine transforms", IEEE Trans. Sig. Processing SP-42, 1038-1051 (1994). 3. R. V. L. Hartley, "A more symmetrical Fourier analysis applied to transmission problems," Proc. IRE 30, 144-150 (1942).
See Also
Examples
x = rnorm(100);
dim(x) = c(10,10);
x
mvdct(x)
mvdct(mvdct(x),inverted=TRUE)