public static float[] GetAmps1D(Image volume)
{
Image VolumeFT = volume.IsComplex ? volume : volume.AsFFT(true);
Image VolumeAbs = VolumeFT.AsAmplitudes();
if (VolumeFT != volume)
{
VolumeFT.Dispose();
}
int NShells = volume.Dims.X / 2;
float[] PS1D = new float[NShells];
float[] Samples = new float[NShells];
float[] VolumeAbsData = VolumeAbs.GetHostContinuousCopy();
int3 DimsFT = VolumeAbs.DimsFT;
Parallel.For(0, 20, p =>
{
float[] ThreadPS1D = new float[NShells];
float[] ThreadSamples = new float[NShells];
for (int z = p; z < DimsFT.Z; z += 20)
{
int zz = z < DimsFT.Z / 2 + 1 ? z : z - DimsFT.Z;
zz *= zz;
for (int y = 0; y < DimsFT.Y; y++)
{
int yy = y < DimsFT.Y / 2 + 1 ? y : y - DimsFT.Y;
yy *= yy;
for (int x = 0; x < DimsFT.X; x++)
{
int xx = x;
xx *= x;
float R = (float)Math.Sqrt(zz + yy + xx);
if (R >= NShells)
{
continue;
}
int ID = (int)R;
float W1 = R - ID;
float W0 = 1f - W1;
int i = (z * DimsFT.Y + y) * DimsFT.X + x;
float Amp = VolumeAbsData[i];
ThreadPS1D[ID] += W0 * Amp;
ThreadSamples[ID] += W0;
if (ID < NShells - 1)
{
ThreadPS1D[ID + 1] += W1 * Amp;
ThreadSamples[ID + 1] += W1;
}
}
}
}
lock (PS1D)
for (int i = 0; i < PS1D.Length; i++)
{
PS1D[i] += ThreadPS1D[i];
Samples[i] += ThreadSamples[i];
}
});
float[] Result = new float[NShells];
for (int i = 0; i < Result.Length; i++)
{
Result[i] = PS1D[i] / Math.Max(1e-6f, Samples[i]);
}
return(Result);
}