dct {tidynorm} | R Documentation |
Discrete Cosine Transform
Description
Discrete Cosine Transform
Usage
dct(x)
## S3 method for class 'numeric'
dct(x)
## S3 method for class 'matrix'
dct(x)
Arguments
x |
A vector or matrix to which the discrete cosine transform is applied |
Details
The DCT definitions here are based on the python scipy.fft.dct
definitions.
Specifically this use:
# python code scipy.fft.dct(x, norm = "forward", orthogonalize = True)
y_k = \frac{1}{zN} \sum_{j=0}^{N-1}x_j\cos\left(\frac{\pi k(2j+1)}{2N}\right)
z = \begin{cases}
\sqrt{2}& \text{for }k=0\\
1 & \text{for }k>0
\end{cases}
For the Inverse Discrete Cosine Transform, see idct.
Value
Returned value depends on x
.
When passed a numeric vector, returns a numeric
vector the same size as x
with the DCT Coefficients.
When passed a matrix, returns a matrix
the same size as x
with the DCT Coefficients.
Examples
x <- seq(0, 1, length = 10)
y <- 5 + x + (2 * (x^2)) + (-2 * (x^4))
dct_coefs <- dct(y)
[Package tidynorm version 0.3.0 Index]