AForge.Imaging.ComplexImage.ForwardFourierTransform C# (CSharp) Method

        public void ForwardFourierTransform( )
        {
            if ( !fourierTransformed )
            {
                for ( int y = 0; y < height; y++ )
                {
                    for ( int x = 0; x < width; x++ )
                    {
                        if ( ( ( x + y ) & 0x1 ) != 0 )
                        {
                            data[y, x].Re *= -1;
                            data[y, x].Im *= -1;
                        }
                    }
                }

                FourierTransform.FFT2( data, FourierTransform.Direction.Forward );
                fourierTransformed = true;
            }
        }

        private void SpectraWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            if (input.Width != input.Height)
            {
                throw new System.ApplicationException(
                          "The image height and width must be the same.");
            }

            SpectraWorker.ReportProgress(0, "Computing spectra");

            // The AForge FFT requires an 8 bits per pixel input format.
            Bitmap gray_8bpp
                = AForge.Imaging.Filters.Grayscale.CommonAlgorithms.Y.Apply(input);

            AForge.Imaging.ComplexImage fft
                = ComplexImage.FromBitmap(gray_8bpp);
            fft.ForwardFourierTransform();

            SpectraWorker.ReportProgress(100, "Fourier Spectra Calculated.");
            fourier = fft.ToBitmap();
        }