private static void Filter2D(Bitmap input, ref Bitmap output, FilterFunction filterFunction)
{
int[] dims = new int[2] {
input.Width, input.Height
};
kiss_fft_cpx <float>[] timeDomain = new kiss_fft_cpx <float> [input.Width * input.Height];
kiss_fft_cpx <float>[] frequencyDomain = new kiss_fft_cpx <float> [input.Width * input.Height];
for (int i = 0; i < input.Width * input.Height; ++i)
{
timeDomain[i] = new kiss_fft_cpx <float>();
frequencyDomain[i] = new kiss_fft_cpx <float>();
}
{ // FFT
for (int x = 0; x < input.Width; ++x)
{
for (int y = 0; y < input.Height; ++y)
{
timeDomain[y * input.Width + x].r = input.GetPixel(x, y).R;
timeDomain[y * input.Width + x].i = 0.0f;
}
}
KissFFTnd <float> kissFftnd = new KissFFTnd <float>(dims, 2, false, new FloatArithmetic());
kissFftnd.kiss_fftnd(new Array <kiss_fft_cpx <float> >(timeDomain), new Array <kiss_fft_cpx <float> >(frequencyDomain));
for (int i = 0; i < input.Width * input.Height; ++i)
{
frequencyDomain[i].r /= input.Width * input.Height;
frequencyDomain[i].i /= input.Width * input.Height;
}
}
{ // filter
for (int x = 0; x < input.Width; ++x)
{
for (int y = 0; y < input.Height; ++y)
{
float q = filterFunction(x, y, input.Width, input.Height);
frequencyDomain[y * input.Width + x].r *= q;
frequencyDomain[y * input.Width + x].i *= q;
}
}
}
{ // IFFT
output = new Bitmap(input.Width, input.Height);
KissFFTnd <float> kissFftnd = new KissFFTnd <float>(dims, 2, true, new FloatArithmetic());
kissFftnd.kiss_fftnd(new Array <kiss_fft_cpx <float> >(frequencyDomain), new Array <kiss_fft_cpx <float> >(timeDomain));
for (int x = 0; x < input.Width; ++x)
{
for (int y = 0; y < input.Height; ++y)
{
int intensity = (int)timeDomain[y * input.Width + x].r;
intensity = Math.Min(255, Math.Max(0, intensity));
output.SetPixel(x, y, Color.FromArgb(intensity, intensity, intensity));
}
}
}
}
private static void Filter2D(Bitmap input, ref Bitmap output, FilterFunction filterFunction)
{
int[] dims = new int[2] { input.Width, input.Height };
kiss_fft_cpx<float>[] timeDomain = new kiss_fft_cpx<float>[input.Width * input.Height];
kiss_fft_cpx<float>[] frequencyDomain = new kiss_fft_cpx<float>[input.Width * input.Height];
for (int i = 0; i < input.Width * input.Height; ++i)
{
timeDomain[i] = new kiss_fft_cpx<float>();
frequencyDomain[i] = new kiss_fft_cpx<float>();
}
{ // FFT
for (int x = 0; x < input.Width; ++x)
{
for (int y = 0; y < input.Height; ++y)
{
timeDomain[y * input.Width + x].r = input.GetPixel(x, y).R;
timeDomain[y * input.Width + x].i = 0.0f;
}
}
KissFFTnd<float> kissFftnd = new KissFFTnd<float>(dims, 2, false, new FloatArithmetic());
kissFftnd.kiss_fftnd(new Array<kiss_fft_cpx<float>>(timeDomain), new Array<kiss_fft_cpx<float>>(frequencyDomain));
for (int i = 0; i < input.Width * input.Height; ++i)
{
frequencyDomain[i].r /= input.Width * input.Height;
frequencyDomain[i].i /= input.Width * input.Height;
}
}
{ // filter
for (int x = 0; x < input.Width; ++x)
{
for (int y = 0; y < input.Height; ++y)
{
float q = filterFunction(x, y, input.Width, input.Height);
frequencyDomain[y * input.Width + x].r *= q;
frequencyDomain[y * input.Width + x].i *= q;
}
}
}
{ // IFFT
output = new Bitmap(input.Width, input.Height);
KissFFTnd<float> kissFftnd = new KissFFTnd<float>(dims, 2, true, new FloatArithmetic());
kissFftnd.kiss_fftnd(new Array<kiss_fft_cpx<float>>(frequencyDomain), new Array<kiss_fft_cpx<float>>(timeDomain));
for (int x = 0; x < input.Width; ++x)
{
for (int y = 0; y < input.Height; ++y)
{
int intensity = (int) timeDomain[y * input.Width + x].r;
intensity = Math.Min(255, Math.Max(0, intensity));
output.SetPixel(x, y, Color.FromArgb(intensity, intensity, intensity));
}
}
}
}
