** 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 1.8 2000/07/04 18:33:35 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
* 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;
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)
}
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;
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 = 0;
+ m_filterMax = m_nSignalPoints * m_signalInc;
+ m_filterInc = (m_filterMax - m_filterMin) / (m_nFilterPoints - 1);
+ m_vecFilter = new double [m_nFilterPoints];
+ int halfFilter = m_nFilterPoints / 2;
+ for (int i = 0; i < halfFilter; i++)
+ m_vecFilter[i] = static_cast<double>(i) / (halfFilter - 1) / (2 * m_signalInc);
+ for (int i = 0; i < halfFilter; i++)
+ m_vecFilter[m_nFilterPoints - i - 1] = static_cast<double>(i) / (halfFilter - 1) / (2 * m_signalInc);
+ if (halfFilter % 2) // odd
+ m_vecFilter[halfFilter] = 1;
+ } 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<int>(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 = 0;
+ m_filterMax = m_nSignalPoints * m_signalInc;
+ m_filterInc = (m_filterMax - m_filterMin) / (m_nFilterPoints - 1);
+ m_vecFilter = new double [m_nFilterPoints];
+ int halfFilter = m_nFilterPoints / 2;
+ for (int i = 0; i < halfFilter; i++)
+ m_vecFilter[i] = static_cast<double>(i) / (halfFilter - 1) / (2 * m_signalInc);
+ for (int i = 0; i < halfFilter; i++)
+ m_vecFilter[m_nFilterPoints - i - 1] = static_cast<double>(i) / (halfFilter - 1) / (2 * m_signalInc);
+ if (halfFilter % 2) // odd
+ m_vecFilter[halfFilter] = 1;
+
+#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;
+ }
}
}
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
}
output[i] = convolve (input, m_signalInc, i, m_nSignalPoints);
} else if (m_idFilterMethod == FILTER_METHOD_FOURIER) {
complex<double> fftSignal[m_nSignalPoints];
- complex<double> complexOutput;
- finiteFourierTransform (input, fftSignal, 1);
- // finiteFourierTransform (fftSignal, complexOutput, -1);
- // for (int i = 0; i < m_nSignalPoints; i++)
- // output[i] = complexOutput[i].hypot();
+ complex<double> complexOutput[m_nSignalPoints];
+ complex<double> 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] = abs( complexOutput[i] );
+ }
+ } 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 / m_nSignalPoints;
+ out[i].im = m_vecFilter[i] * out[i].im / m_nSignalPoints;
+ }
+ fftw_one(m_planBackward, out, in);
+ for (int i = 0; i < m_nSignalPoints; i++)
+ output[i] = sqrt (in[i].re * in[i].re + in[i].im * in[i].im);
}
}
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;
}
}
}
+
+void
+SignalFilter::finiteFourierTransform (const complex<double> input[], complex<double> 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<double> sum (0,0);
+ for (int j = 0; j < n; j++) {
+ double angle = i * j * angleIncrement * direction;
+ complex<double> exponentTerm (cos(angle), sin(angle));
+ sum += input[j] * exponentTerm;
+ }
+ if (direction < 0) {
+ sum /= n;
+ }
+ output[i] = sum;
+ }
+}
+
void
SignalFilter::finiteFourierTransform (const float input[], complex<double> output[], int direction) const
{
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<double> (sumReal, sumImag);
+ }
+}
+
+// (a+bi) * (c + di) = (ac - db) + (bc + da)i
+#if 0
+void
+SignalFilter::finiteFourierTransform (const complex<double> input[], complex<double> 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++) {
output[i] = complex<double> (sumReal, sumImag);
}
}
+#endif
+
+void
+SignalFilter::dotProduct (const double v1[], const complex<double> v2[], complex<double> output[], const int n)
+{
+ for (int i = 0; i < n; i++)
+ output[i] = v1[i] * v2[i];
+}
projects / ctsim.git / blobdiff