X-Git-Url: http://git.kpe.io/?a=blobdiff_plain;f=libctsim%2Ffilter.cpp;h=2d315252f43012a0f8d3ea2468ba53b0b19c6ba7;hb=0dd14de503a36bb52c24625f8eac4e7163c7d068;hp=3215d6a2e27c1037ebc3a01ed385a220ccb8aa60;hpb=53c732778ed19ac5231bb17c7e5bd4d2201d9456;p=ctsim.git diff --git a/libctsim/filter.cpp b/libctsim/filter.cpp index 3215d6a..2d31525 100644 --- a/libctsim/filter.cpp +++ b/libctsim/filter.cpp @@ -1,5 +1,5 @@ /***************************************************************************** -** FILE IDENTIFICATION +** File IDENTIFICATION ** ** Name: filter.cpp ** Purpose: Routines for signal-procesing filters @@ -9,7 +9,7 @@ ** This is part of the CTSim program ** Copyright (C) 1983-2000 Kevin Rosenberg ** -** $Id: filter.cpp,v 1.7 2000/07/03 11:02:06 kevin Exp $ +** $Id: filter.cpp,v 1.11 2000/07/05 17:24:33 kevin Exp $ ** ** This program is free software; you can redistribute it and/or modify ** it under the terms of the GNU General Public License (version 2) as @@ -37,14 +37,14 @@ * int filt_type Type of filter wanted * double bw Bandwidth of filter * double filterMin, filterMax Filter limits - * int n Number of points in signal + * int nSignalPoints Number of points in signal * double param General input parameter to filters * int domain FREQUENCY or SPATIAL domain wanted * int numint Number if intervals for calculating discrete inverse fourier xform * for spatial domain filters. For ANALYTIC solutions, use numint = 0 */ -SignalFilter::SignalFilter (const char* filterName, const char* filterMethodName, double bw, double signalIncrement, int n, double param, const char* domainName, int numIntegral = 0) +SignalFilter::SignalFilter (const char* filterName, const char* filterMethodName, double bw, double signalIncrement, int nSignalPoints, double param, const char* domainName, int numIntegral = 0) { m_vecFilter = NULL; m_vecFourierCosTable = NULL; @@ -70,12 +70,12 @@ SignalFilter::SignalFilter (const char* filterName, const char* filterMethodName m_failMessage += domainName; return; } - init (m_idFilter, m_idFilterMethod, bw, signalIncrement, n, param, m_idDomain, numIntegral); + init (m_idFilter, m_idFilterMethod, bw, signalIncrement, nSignalPoints, param, m_idDomain, numIntegral); } -SignalFilter::SignalFilter (const FilterID filterID, const FilterMethodID filterMethodID, double bw, double signalIncrement, int n, double param, const DomainID domainID, int numIntegral = 0) +SignalFilter::SignalFilter (const FilterID filterID, const FilterMethodID filterMethodID, double bw, double signalIncrement, int nSignalPoints, double param, const DomainID domainID, int numIntegral = 0) { - init (filterID, filterMethodID, bw, signalIncrement, n, param, domainID, numIntegral); + init (filterID, filterMethodID, bw, signalIncrement, nSignalPoints, param, domainID, numIntegral); } SignalFilter::SignalFilter (const char* filterName, const char* domainName, double bw, double param, int numIntegral = 0) @@ -105,7 +105,7 @@ SignalFilter::SignalFilter (const char* filterName, const char* domainName, doub } void -SignalFilter::init (const FilterID filterID, const FilterMethodID filterMethodID, double bw, double signalIncrement, int n, double param, const DomainID domainID, int numint) +SignalFilter::init (const FilterID filterID, const FilterMethodID filterMethodID, double bw, double signalIncrement, int nSignalPoints, double param, const DomainID domainID, int numint) { m_bw = bw; m_idFilter = filterID; @@ -115,57 +115,101 @@ SignalFilter::init (const FilterID filterID, const FilterMethodID filterMethodID m_fail = true; return; } + m_traceLevel = TRACE_NONE; m_nameFilter = convertFilterIDToName (m_idFilter); m_nameDomain = convertDomainIDToName (m_idDomain); m_nameFilterMethod = convertFilterMethodIDToName (m_idFilterMethod); m_fail = false; - m_nSignalPoints = n; - m_nFilterPoints = 2 * m_nSignalPoints - 1; - + m_nSignalPoints = nSignalPoints; m_signalInc = signalIncrement; - m_filterMin = -signalIncrement * (m_nSignalPoints - 1); - m_filterMax = signalIncrement * (m_nSignalPoints - 1); - m_filterInc = (m_filterMax - m_filterMin) / (m_nFilterPoints - 1); - m_numIntegral = numint; m_filterParam = param; - m_vecFilter = new double[ m_nFilterPoints ]; + if (m_idFilterMethod == FILTER_METHOD_FOURIER) { - int nFourier = n * n + 1; - double angleIncrement = (2. * PI) / n; + int nFourier = m_nSignalPoints * m_nSignalPoints + 1; + double angleIncrement = (2. * PI) / m_nSignalPoints; m_vecFourierCosTable = new double[ nFourier ]; m_vecFourierSinTable = new double[ nFourier ]; for (int i = 0; i < nFourier; i++) { m_vecFourierCosTable[i] = cos (angleIncrement * i); m_vecFourierSinTable[i] = sin (angleIncrement * i); } + m_nFilterPoints = m_nSignalPoints; + m_filterMin = -1. / (2 * m_signalInc); + m_filterMax = 1. / (2 * m_signalInc); + m_filterInc = (m_filterMax - m_filterMin) / m_nFilterPoints; + m_vecFilter = new double [m_nFilterPoints]; + int halfFilter = m_nFilterPoints / 2; + for (int i = 0; i < halfFilter; i++) + m_vecFilter[i] = static_cast(i) / (halfFilter - 1) / (2 * m_signalInc); + for (int i = 0; i < halfFilter; i++) + m_vecFilter[m_nFilterPoints - i - 1] = static_cast(i+1) / (halfFilter - 1) / (2 * m_signalInc); + if (halfFilter % 2) // odd + m_vecFilter[halfFilter] = 1 / (2 * m_signalInc); + } else if (m_idFilterMethod == FILTER_METHOD_FFT || m_idFilterMethod == FILTER_METHOD_FFT_ZEROPAD_2 || m_idFilterMethod == FILTER_METHOD_FFT_ZEROPAD_4) { + m_nFilterPoints = m_nSignalPoints; + if (m_idFilterMethod == FILTER_METHOD_FFT_ZEROPAD_2 || m_idFilterMethod == FILTER_METHOD_FFT_ZEROPAD_4) { + double logBase2 = log(m_nSignalPoints) / log(2); + int nextPowerOf2 = static_cast(floor(logBase2)) + 1; + if (m_idFilterMethod == FILTER_METHOD_FFT_ZEROPAD_4) + nextPowerOf2++; + if (logBase2 != floor(logBase2)) + nextPowerOf2++; + m_nFilterPoints = 1 << nextPowerOf2; + cout << "nFilterPoints = " << m_nFilterPoints << endl; + } + m_filterMin = -1. / (2 * m_signalInc); + m_filterMax = 1. / (2 * m_signalInc); + m_filterInc = (m_filterMax - m_filterMin) / m_nFilterPoints; + m_vecFilter = new double [m_nFilterPoints]; + int halfFilter = m_nFilterPoints / 2; + for (int i = 0; i < halfFilter; i++) + m_vecFilter[i] = static_cast(i) / (halfFilter - 1) / (2 * m_signalInc) / m_nSignalPoints; + for (int i = 0; i < halfFilter; i++) + m_vecFilter[m_nFilterPoints - i - 1] = static_cast(i+1) / (halfFilter - 1) / (2 * m_signalInc) / m_nSignalPoints; + if (halfFilter % 2) // odd + m_vecFilter[halfFilter] = 1 / (2 * m_signalInc) / m_nSignalPoints; + +#if HAVE_FFTW + m_planForward = fftw_create_plan (m_nFilterPoints, FFTW_FORWARD, FFTW_ESTIMATE); + m_planBackward = fftw_create_plan (m_nFilterPoints, FFTW_BACKWARD, FFTW_ESTIMATE); +#endif } - if (m_idFilter == FILTER_SHEPP) { - double a = 2 * m_bw; - double c = - 4. / (a * a); - int center = (m_nFilterPoints - 1) / 2; - int sidelen = center; - m_vecFilter[center] = 4. / (a * a); - - for (int i = 1; i <= sidelen; i++ ) - m_vecFilter [center + i] = m_vecFilter [center - i] = c / (4 * (i * i) - 1); - } else if (m_idDomain == DOMAIN_FREQUENCY) { - double x; - int i; - for (x = m_filterMin, i = 0; i < m_nFilterPoints; x += m_filterInc, i++) - m_vecFilter[i] = frequencyResponse (x, param); - } else if (m_idDomain == DOMAIN_SPATIAL) { - double x; - int i; - for (x = m_filterMin, i = 0; i < m_nFilterPoints; x += m_filterInc, i++) - if (numint == 0) - m_vecFilter[i] = spatialResponseAnalytic (x, param); - else - m_vecFilter[i] = spatialResponseCalc (x, param, numint); - } else { + if (m_idFilterMethod == FILTER_METHOD_CONVOLUTION) { + m_nFilterPoints = 2 * m_nSignalPoints - 1; + m_filterMin = -m_signalInc * (m_nSignalPoints - 1); + m_filterMax = m_signalInc * (m_nSignalPoints - 1); + m_filterInc = (m_filterMax - m_filterMin) / (m_nFilterPoints - 1); + m_numIntegral = numint; + m_vecFilter = new double[ m_nFilterPoints ]; + + if (m_idFilter == FILTER_SHEPP) { + double a = 2 * m_bw; + double c = - 4. / (a * a); + int center = (m_nFilterPoints - 1) / 2; + int sidelen = center; + m_vecFilter[center] = 4. / (a * a); + + for (int i = 1; i <= sidelen; i++ ) + m_vecFilter [center + i] = m_vecFilter [center - i] = c / (4 * (i * i) - 1); + } else if (m_idDomain == DOMAIN_FREQUENCY) { + double x; + int i; + for (x = m_filterMin, i = 0; i < m_nFilterPoints; x += m_filterInc, i++) + m_vecFilter[i] = frequencyResponse (x, param); + } else if (m_idDomain == DOMAIN_SPATIAL) { + double x; + int i; + for (x = m_filterMin, i = 0; i < m_nFilterPoints; x += m_filterInc, i++) + if (numint == 0) + m_vecFilter[i] = spatialResponseAnalytic (x, param); + else + m_vecFilter[i] = spatialResponseCalc (x, param, numint); + } else { m_failMessage = "Illegal domain name "; m_failMessage += m_idDomain; m_fail = true; + } } } @@ -174,6 +218,12 @@ SignalFilter::~SignalFilter (void) delete m_vecFilter; delete m_vecFourierSinTable; delete m_vecFourierCosTable; +#if HAVE_FFTW + if (m_idFilterMethod == FILTER_METHOD_FFT) { + fftw_destroy_plan(m_planForward); + fftw_destroy_plan(m_planBackward); + } +#endif } @@ -312,11 +362,30 @@ SignalFilter::filterSignal (const float input[], double output[]) const output[i] = convolve (input, m_signalInc, i, m_nSignalPoints); } else if (m_idFilterMethod == FILTER_METHOD_FOURIER) { complex fftSignal[m_nSignalPoints]; - complex complexOutput; - finiteFourierTransform (input, fftSignal, 1); - // finiteFourierTransform (fftSignal, complexOutput, -1); - // for (int i = 0; i < m_nSignalPoints; i++) - // output[i] = complexOutput[i].hypot(); + complex complexOutput[m_nSignalPoints]; + complex filteredSignal[m_nSignalPoints]; + finiteFourierTransform (input, fftSignal, m_nSignalPoints, -1); + dotProduct (m_vecFilter, fftSignal, filteredSignal, m_nSignalPoints); + finiteFourierTransform (filteredSignal, complexOutput, m_nSignalPoints, 1); + for (int i = 0; i < m_nSignalPoints; i++) + output[i] = complexOutput[i].real(); + } else if (m_idFilterMethod == FILTER_METHOD_FFT || FILTER_METHOD_FFT_ZEROPAD_2 || FILTER_METHOD_FFT_ZEROPAD_4) { + fftw_complex in[m_nFilterPoints], out[m_nFilterPoints]; + for (int i = 0; i < m_nSignalPoints; i++) { + in[i].re = input[i]; + in[i].im = 0; + } + for (int i = m_nSignalPoints; i < m_nFilterPoints; i++) { + in[i].re = in[i].im = 0; // ZeroPad + } + fftw_one(m_planForward, in, out); + for (int i = 0; i < m_nFilterPoints; i++) { + out[i].re = m_vecFilter[i] * out[i].re; + out[i].im = m_vecFilter[i] * out[i].im; + } + fftw_one(m_planBackward, out, in); + for (int i = 0; i < m_nSignalPoints; i++) + output[i] = in[i].re; } } @@ -660,10 +729,10 @@ SignalFilter::finiteFourierTransform (const float input[], complex outpu double sumImag = 0; for (int j = 0; j < n; j++) { double angle = i * j * angleIncrement * direction; - sumReal += input[i] * cos(angle); - sumImag += input[i] * sin(angle); + sumReal += input[j] * cos(angle); + sumImag += input[j] * sin(angle); } - if (direction > 0) { + if (direction < 0) { sumReal /= n; sumImag /= n; } @@ -671,6 +740,30 @@ SignalFilter::finiteFourierTransform (const float input[], complex outpu } } + +void +SignalFilter::finiteFourierTransform (const complex input[], complex output[], const int n, int direction) +{ + if (direction < 0) + direction = -1; + else + direction = 1; + + double angleIncrement = 2 * PI / n; + for (int i = 0; i < n; i++) { + complex sum (0,0); + for (int j = 0; j < n; j++) { + double angle = i * j * angleIncrement * direction; + complex exponentTerm (cos(angle), sin(angle)); + sum += input[j] * exponentTerm; + } + if (direction < 0) { + sum /= n; + } + output[i] = sum; + } +} + void SignalFilter::finiteFourierTransform (const float input[], complex output[], int direction) const { @@ -679,7 +772,36 @@ SignalFilter::finiteFourierTransform (const float input[], complex outpu else direction = 1; - double angleIncrement = 2 * PI / m_nSignalPoints; + for (int i = 0; i < m_nSignalPoints; i++) { + double sumReal = 0, sumImag = 0; + for (int j = 0; j < m_nSignalPoints; j++) { + int tableIndex = i * j; + if (direction > 0) { + sumReal += input[i] * m_vecFourierCosTable[tableIndex]; + sumImag += input[i] * m_vecFourierSinTable[tableIndex]; + } else { + sumReal += input[i] * m_vecFourierCosTable[tableIndex]; + sumImag -= input[i] * m_vecFourierSinTable[tableIndex]; + } + } + if (direction < 0) { + sumReal /= m_nSignalPoints; + sumImag /= m_nSignalPoints; + } + output[i] = complex (sumReal, sumImag); + } +} + +// (a+bi) * (c + di) = (ac - db) + (bc + da)i +#if 0 +void +SignalFilter::finiteFourierTransform (const complex input[], complex output[], int direction) const +{ + if (direction < 0) + direction = -1; + else + direction = 1; + for (int i = 0; i < m_nSignalPoints; i++) { double sumReal = 0, sumImag = 0; for (int j = 0; j < m_nSignalPoints; j++) { @@ -699,3 +821,11 @@ SignalFilter::finiteFourierTransform (const float input[], complex outpu output[i] = complex (sumReal, sumImag); } } +#endif + +void +SignalFilter::dotProduct (const double v1[], const complex v2[], complex output[], const int n) +{ + for (int i = 0; i < n; i++) + output[i] = v1[i] * v2[i]; +}