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); }