idct2D: Calculate an inverse DCT for an image

Description Usage Arguments Value Warning See Also

View source: R/univariateExpansions.R

Description

This function calculates an inverse (orthonormal) discrete cosine transformation for given coefficients in two dimensions using the C-library fftw3 (see http://www.fftw.org/). As many coefficients are expected to be zero, the values are given in compressed format (indices and values only of non-zero coefficients).

Usage

1
idct2D(scores, ind, dim)

Arguments

scores

A numeric vector, containing the non-zero coefficients.

ind

An integer vector, containing the indices of the non-zero coefficients.

dim

A numeric vector of length 2, giving the resulting image dimensions.

Value

A matrix of dimensions dim, which is a linear combination of cosine tensor basis functions with the given 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.