dct2D: Calculate and threshold DCT for an image

Description Usage Arguments Value Warning See Also

View source: R/univDecomp.R

Description

This function calculates the (orthonormal) discrete cosine transformation for an image and returns thresholded DCT coefficients using the C-library fftw3 (see http://www.fftw.org/).

Usage

1
dct2D(image, qThresh)

Arguments

image

An image (a 2D matrix with real values).

qThresh

A numeric with value in [0,1], giving the quantile for thresholding the coefficients. See dctBasis2D for details.

Value

ind

An integer vector, containing the indices of non-thresholded (hence non-zero) coefficients.

val

A numeric vector, giving the values of the corresponding coefficients.

Warning

If the C-library fftw3 is not available when the package MFPCA is installed, this function is disabled an will throw an error. For full functionality install the C-library fftw3 from http://www.fftw.org/ and reinstall MFPCA. This function has not been tested with ATLAS/MKL/OpenBLAS.

See Also

dctBasis2D


MFPCA documentation built on May 2, 2019, 2:49 p.m.