public static Complex[,] ConvolveInFrequencyDomain(Complex[,] fftImage, Complex[,] fftKernel)
{
Complex[,] convolve = null;
int imageWidth = fftImage.GetLength(0);
int imageHeight = fftImage.GetLength(1);
int maskWidth = fftKernel.GetLength(0);
int maskHeight = fftKernel.GetLength(1);
if (imageWidth == maskWidth && imageHeight == maskHeight)
{
Complex[,] fftConvolved = new Complex[imageWidth, imageHeight];
for (int j = 0; j < imageHeight; j++)
{
for (int i = 0; i < imageWidth; i++)
{
fftConvolved[i, j] = fftImage[i, j] * fftKernel[i, j];
}
}
FourierTransform ftForConv = new FourierTransform();
ftForConv.InverseFFT(fftConvolved);
convolve = FourierShifter.FFTShift(ftForConv.GrayscaleImageComplex);
Rescale(convolve);
}
else
{
throw new Exception("padding needed");
}
return(convolve);
}
/*
* public void Pad(int newWidth, int newHeight)
* {
* double[,] temp = (double[,])Kernel.Clone();
* PaddedKernel = ImagePadder.Pad(temp, newWidth, newHeight);
* }*/
public void Pad(int unpaddedWidth, int unpaddedHeight, int newWidth, int newHeight)
{
cPaddedKernel = new Complex[newWidth, newHeight];
//32x32
Complex[,] unpaddedKernelFrequencyDomain = ImageDataConverter.ToComplex((double[, ])Kernel.Clone());
FourierTransform ftInverse = new FourierTransform();
ftInverse.InverseFFT(FourierShifter.RemoveFFTShift(unpaddedKernelFrequencyDomain));
//32x32
Complex[,] unpaddedKernelTimeDomain = FourierShifter.FFTShift(ftInverse.GrayscaleImageComplex);
int startPointX = (int)Math.Ceiling((double)(newWidth - unpaddedWidth) / (double)2) - 1;
int startPointY = (int)Math.Ceiling((double)(newHeight - unpaddedHeight) / (double)2) - 1;
for (int j = startPointY; j < startPointY + unpaddedHeight; j++)
{
for (int i = startPointX; i < startPointX + unpaddedWidth; i++)
{
cPaddedKernel[i, j] = unpaddedKernelTimeDomain[i - startPointX, j - startPointY];
}
}
/*
* for (int j = 0; j < newHeight; j++)
* {
* for (int i = 0; i < startPointX; i++)
* {
* unpaddedKernelTimeDomain[i, j] = 0;
* }
* for (int i = startPointX + unpaddedWidth; i < newWidth; i++)
* {
* unpaddedKernelTimeDomain[i, j] = 0;
* }
* }
*
* for (int i = startPointX; i < startPointX + unpaddedWidth; i++)
* {
* for (int j = 0; j < startPointY; j++)
* {
* unpaddedKernelTimeDomain[i, j] = 0;
* }
* for (int j = startPointY + unpaddedHeight; j < newHeight; j++)
* {
* unpaddedKernelTimeDomain[i, j] = 0;
* }
* }
**/
FourierTransform ftForward = new FourierTransform(cPaddedKernel); ftForward.ForwardFFT();
//cPaddedKernel = ftForward.FourierImageComplex;
}
private void fftButton_Click(object sender, EventArgs e)
{
Bitmap lena = inputImagePictureBox.Image as Bitmap;
FourierTransform ft = new FourierTransform(lena);
ft.ForwardFFT();
___shifted = FourierShifter.FFTShift(ft.FourierImageComplex);
Bitmap magnitudePlot = FourierPlotter.FftMagnitudePlot(___shifted);
Bitmap phasePlot = FourierPlotter.FftPhasePlot(___shifted);
fourierMagnitudePictureBox.Image = (Image)magnitudePlot;
fourierPhasePictureBox.Image = (Image)phasePlot;
}
public static Complex[,] Convolve(Complex[,] image, Complex[,] mask)
{
Complex[,] convolve = null;
int imageWidth = image.GetLength(0);
int imageHeight = image.GetLength(1);
int maskWidth = mask.GetLength(0);
int maskeHeight = mask.GetLength(1);
if (imageWidth == maskWidth && imageHeight == maskeHeight)
{
FourierTransform ftForImage = new FourierTransform(image); ftForImage.ForwardFFT();
FourierTransform ftForMask = new FourierTransform(mask); ftForMask.ForwardFFT();
Complex[,] fftImage = ftForImage.FourierImageComplex;
Complex[,] fftKernel = ftForMask.FourierImageComplex;
Complex[,] fftConvolved = new Complex[imageWidth, imageHeight];
for (int j = 0; j < imageHeight; j++)
{
for (int i = 0; i < imageWidth; i++)
{
fftConvolved[i, j] = fftImage[i, j] * fftKernel[i, j];
}
}
FourierTransform ftForConv = new FourierTransform();
ftForConv.InverseFFT(fftConvolved);
convolve = ftForConv.GrayscaleImageComplex;
Rescale(convolve);
convolve = FourierShifter.FFTShift(convolve);
}
else
{
throw new Exception("padding needed");
}
return(convolve);
}