/// <summary>
/// Constructor for Inverse FFT
/// </summary>
/// <param name="Input"></param>
public FFT(ComplexNumber[,] Input)
{
nx = Width = Input.GetLength(0);
ny = Height = Input.GetLength(1);
Fourier = Input;
}
/**
* Perform a 2D FFT inplace given a complex 2D array
* The direction dir, 1 for forward, -1 for reverse
* The size of the array (nx,ny)
* Return false if there are memory problems or
* the dimensions are not powers of 2
*/
public ComplexNumber[,] fft2d(ComplexNumber[,] c, int nx, int ny, int dir)
{
int i,j;
int m;//Power of 2 for current number of points
double []real;
double []imag;
ComplexNumber [,] output;//=new COMPLEX [nx,ny];
output = c; // Copying Array
// Transform the Rows
real = new double[nx] ;
imag = new double[nx];
for (j=0;j<ny;j++)
{
for (i=0;i<nx;i++)
{
real[i] = c[i,j].real;
imag[i] = c[i,j].imag;
}
// Calling 1D FFT Function for Rows
m = (int)System.Math.Log((double)nx, 2);//Finding power of 2 for current number of points e.g. for nx=512 m=9
FFT1D(dir,m,ref real,ref imag);
for (i=0;i<nx;i++)
{
output[i, j].real = real[i];
output[i, j].imag = imag[i];
}
}
// Transform the columns
real = new double[ny];
imag = new double[ny];
for (i=0;i<nx;i++)
{
for (j=0;j<ny;j++)
{
real[j] = output[i, j].real;
imag[j] = output[i, j].imag;
}
// Calling 1D FFT Function for Columns
m = (int)System.Math.Log((double)ny, 2);//Finding power of 2 for current number of points e.g. for nx=512 m=9
FFT1D(dir,m,ref real,ref imag);
for (j=0;j<ny;j++)
{
output[i, j].real = real[j];
output[i, j].imag = imag[j];
}
}
return(output);
}