2.1.22.2.1.15 fft_2d_real

1 Description
2 Syntax
3 Parameters
4 Return
5 Examples
6 Remark
7 See Also
8 Header to Include
9 Reference

Description

Performs nFFTRow*nFFTCol-point discrete 2D Fourier transform or 2D inverse Fourier transform.

Syntax

int fft_2d_real( int nFFTRow, int nFFTCol, matrix<complex> & mSig, FFT_SIGN iSign = FFT_FORWARD )

Parameters

nFFTRow: [input] the number of rows to do Fourier transform.
nFFTCol: [input] the number of cols to do Fourier transform.
mSig: [modify] Input: for forward transform, it contains real signal to be transformed.; for backward transform, it contains complex signal.; Output: for forward transform, it contains the complex signal of 2D DFT.; for backward transform, it contains the real signal of 2D IDFT.
iSign: [input] FFT_FORWARD: FFT; (by default); FFT_BACKWARD: IFFT.

Return

Returns 0 for success or error codes for failure.

Examples

Prior to compilation, load fftEx_utils.c to the workspace by executing the following LabTalk command:

Run.LoadOC("Originlab\fftEx_utils.c", 16);

To retain fftEx_utils.c in the workspace for successive sessions, drag and drop the file from the Temporary folder to the System folder.

EX1

#include <fftex_utils.h>
void fft_2d_real_ex1()
{
    matrix<complex> sig(2, 2);
    for (int ii=0; ii<2; ++ii)
        for (int jj=0; jj<2; ++jj)
        {
            sig[ii][jj].m_im = (ii+jj)%2;
            sig[ii][jj].m_re = !sig[ii][jj].m_im;
        }
    for (ii=0; ii<2; ++ii)
    {
        for (int jj=0; jj<2; ++jj)
            printf ("%lf+%lfi\t", sig[ii][jj].m_re, sig[ii][jj].m_im);
        printf ("\n");
    }
    printf ("\n");
    fft_2d_real(2, 2, sig, FFT_BACKWARD);
    printf ("\n");
    for (ii=0; ii<2; ++ii)
    {
        for (int jj=0; jj<2; ++jj)
            printf ("%lf+%lfi\t", sig[ii][jj].m_re, sig[ii][jj].m_im);
        printf ("\n");
    }
}