void TimeConvolutionAction::PerformFFTSincOperation(ArtifactSet &artifacts, Image2DPtr real, Image2DPtr imag) const
{
fftw_complex
*fftIn = (fftw_complex*) fftw_malloc(sizeof(fftw_complex) * real->Width()),
*fftOut = (fftw_complex*) fftw_malloc(sizeof(fftw_complex) * real->Width());
// FFTW plan routines are not thread safe, so lock.
boost::mutex::scoped_lock lock(artifacts.IOMutex());
fftw_plan
fftPlanForward = fftw_plan_dft_1d(real->Width(), fftIn, fftOut, FFTW_FORWARD, FFTW_MEASURE),
fftPlanBackward = fftw_plan_dft_1d(real->Width(), fftIn, fftOut, FFTW_BACKWARD, FFTW_MEASURE);
lock.unlock();
const size_t width = real->Width();
const BandInfo band = artifacts.MetaData()->Band();
for(unsigned y=0;y<real->Height();++y)
{
const numl_t sincScale = ActualSincScaleInSamples(artifacts, band.channels[y].frequencyHz);
const numl_t limitFrequency = (numl_t) width / sincScale;
if(y == real->Height()/2)
{
AOLogger::Debug << "Horizontal sinc scale: " << sincScale << " (filter scale: " << Angle::ToString(ActualSincScaleAsRaDecDist(artifacts, band.channels[y].frequencyHz)) << ")\n";
}
if(sincScale > 1.0)
{
for(unsigned x=0;x<width;++x)
{
fftIn[x][0] = real->Value(x, y);
fftIn[x][1] = imag->Value(x, y);
}
fftw_execute_dft(fftPlanForward, fftIn, fftOut);
size_t filterIndexSize = (limitFrequency > 1.0) ? (size_t) ceil(limitFrequency/2.0) : 1;
// Remove the high frequencies [filterIndexSize : n-filterIndexSize]
for(size_t f=filterIndexSize;f<width - filterIndexSize;++f)
{
fftOut[f][0] = 0.0;
fftOut[f][1] = 0.0;
}
fftw_execute_dft(fftPlanBackward, fftOut, fftIn);
const double n = width;
for(unsigned x=0;x<width;++x)
{
real->SetValue(x, y, fftIn[x][0] / n);
imag->SetValue(x, y, fftIn[x][1] / n);
}
}
}
fftw_free(fftIn);
fftw_free(fftOut);
}
