X-Git-Url: http://git.kpe.io/?a=blobdiff_plain;f=libctsim%2Ffilter.cpp;h=bfb55e8dc4695ee5fb451c2847c3185d5e63990a;hb=e4ffe82feebf1df2ac1dd14633818eb9a739863f;hp=30d47185e3cd08120a9c66c826d6946afb105f71;hpb=99dd1d6ed10db1f669a5fe6af71225a50fc0ddfb;p=ctsim.git diff --git a/libctsim/filter.cpp b/libctsim/filter.cpp index 30d4718..bfb55e8 100644 --- a/libctsim/filter.cpp +++ b/libctsim/filter.cpp @@ -9,7 +9,7 @@ ** This is part of the CTSim program ** Copyright (C) 1983-2000 Kevin Rosenberg ** -** $Id: filter.cpp,v 1.1 2000/06/19 02:59:34 kevin Exp $ +** $Id: filter.cpp,v 1.6 2000/07/02 18:21:39 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 @@ -29,81 +29,357 @@ /* NAME - * filter_generate Generate a filter + * SignalFilter::SignalFilter Construct a signal * * SYNOPSIS - * f = filter_generate (filt_type, bw, xmin, xmax, n, param, domain, analytic) - * double f Generated filter vector - * int filt_type Type of filter wanted - * double bw Bandwidth of filter - * double xmin, xmax Filter limits - * int n Number of points in filter - * double param General input parameter to filters - * int domain FREQ 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 + * f = SignalFilter (filt_type, bw, xmin, xmax, n, param, domain, analytic) + * double f Generated filter vector + * int filt_type Type of filter wanted + * double bw Bandwidth of filter + * double xmin, xmax Filter limits + * int n 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 */ -double * -filter_generate (const FilterType filt_type, double bw, double xmin, double xmax, int n, double param, const DomainType domain, int numint) +SignalFilter::SignalFilter (const char* filterName, const char* filterMethodName, double bw, double signalLength, int n, double param, const char* domainName, int numIntegral = 0) { - double *f = new double [n]; - double xinc = (xmax - xmin) / (n - 1); + m_vecFilter = NULL; + m_vecFourierCosTable = NULL; + m_vecFourierSinTable = NULL; + m_idFilter = convertFilterNameToID (filterName); + if (m_idFilter == FILTER_INVALID) { + m_fail = true; + m_failMessage = "Invalid Filter name "; + m_failMessage += filterName; + return; + } + m_idFilterMethod = convertFilterMethodNameToID (filterMethodName); + if (m_idFilterMethod == FILTER_METHOD_INVALID) { + m_fail = true; + m_failMessage = "Invalid filter method name "; + m_failMessage += filterMethodName; + return; + } + m_idDomain = convertDomainNameToID (domainName); + if (m_idDomain == DOMAIN_INVALID) { + m_fail = true; + m_failMessage = "Invalid domain name "; + m_failMessage += domainName; + return; + } + init (m_idFilter, m_idFilterMethod, bw, signalLength, n, param, m_idDomain, numIntegral); +} + +SignalFilter::SignalFilter (const FilterID filterID, const FilterMethodID filterMethodID, double bw, double signalLength, int n, double param, const DomainID domainID, int numIntegral = 0) +{ + init (filterID, filterMethodID, bw, signalLength, n, param, domainID, numIntegral); +} + +SignalFilter::SignalFilter (const char* filterName, const char* domainName, double bw, double param, int numIntegral = 0) +{ + m_bw = bw; + m_nPoints = 0; + m_vecFilter = NULL; + m_vecFourierCosTable = NULL; + m_vecFourierSinTable = NULL; + m_filterParam = param; + m_numIntegral = numIntegral; + m_idFilter = convertFilterNameToID (filterName); + if (m_idFilter == FILTER_INVALID) { + m_fail = true; + m_failMessage = "Invalid Filter name "; + m_failMessage += filterName; + return; + } + m_idDomain = convertDomainNameToID (domainName); + if (m_idDomain == DOMAIN_INVALID) { + m_fail = true; + m_failMessage = "Invalid domain name "; + m_failMessage += domainName; + return; + } +} + +void +SignalFilter::init (const FilterID filterID, const FilterMethodID filterMethodID, double bw, double signalLength, int n, double param, const DomainID domainID, int numint) +{ + m_bw = bw; + m_idFilter = filterID; + m_idDomain = domainID; + m_idFilterMethod = filterMethodID; + if (m_idFilter == FILTER_INVALID || m_idDomain == DOMAIN_INVALID || m_idFilterMethod == FILTER_METHOD_INVALID) { + m_fail = true; + return; + } + 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; - if (filt_type == FILTER_SHEPP) { - double a = 2 * bw; + m_signalLength = signalLength; + m_xmin = -signalLength; + m_xmax = signalLength; + m_numIntegral = numint; + m_filterParam = param; + m_vecFilter = new double[n]; + if (m_idFilterMethod == FILTER_METHOD_FOURIER) { + int nFourier = n * n + 1; + double angleIncrement = (2. * PI) / n; + 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); + } + } + + double xinc = (m_xmax - m_xmin) / (m_nPoints - 1); + + if (m_idFilter == FILTER_SHEPP) { + double a = 2 * m_bw; double c = - 4. / (a * a); - int center = (n - 1) / 2; + int center = (m_nPoints - 1) / 2; int sidelen = center; - f[center] = 4. / (a * a); - + m_vecFilter[center] = 4. / (a * a); + for (int i = 1; i <= sidelen; i++ ) - f [center + i] = f [center - i] = c / (4 * (i * i) - 1); - } else if (domain == D_FREQ) { + 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 = xmin, i = 0; i < n; x += xinc, i++) - f[i] = filter_frequency_response (filt_type, x, bw, param); - } else if (domain == D_SPATIAL) { + for (x = m_xmin, i = 0; i < m_nPoints; x += xinc, i++) + m_vecFilter[i] = frequencyResponse (x, param); + } else if (m_idDomain == DOMAIN_SPATIAL) { double x; int i; - for (x = xmin, i = 0; i < n; x += xinc, i++) + for (x = m_xmin, i = 0; i < m_nPoints; x += xinc, i++) if (numint == 0) - f[i] = filter_spatial_response_analytic (filt_type, x, bw, param); + m_vecFilter[i] = spatialResponseAnalytic (x, param); else - f[i] = filter_spatial_response_calc (filt_type, x, bw, param, numint); + m_vecFilter[i] = spatialResponseCalc (x, param, numint); } else { - sys_error (ERR_WARNING, "Illegal domain %d [filt_generate]", domain); - return (NULL); + m_failMessage = "Illegal domain name "; + m_failMessage += m_idDomain; + m_fail = true; } - - return (f); +} + +SignalFilter::~SignalFilter (void) +{ + delete m_vecFilter; + delete m_vecFourierSinTable; + delete m_vecFourierCosTable; +} + + +const SignalFilter::FilterID +SignalFilter::convertFilterNameToID (const char *filterName) +{ + FilterID filterID = FILTER_INVALID; + + if (strcasecmp (filterName, FILTER_BANDLIMIT_STR) == 0) + filterID = FILTER_BANDLIMIT; + else if (strcasecmp (filterName, FILTER_HAMMING_STR) == 0) + filterID = FILTER_G_HAMMING; + else if (strcasecmp (filterName, FILTER_SINC_STR) == 0) + filterID = FILTER_SINC; + else if (strcasecmp (filterName, FILTER_COS_STR) == 0) + filterID = FILTER_COSINE; + else if (strcasecmp (filterName, FILTER_TRIANGLE_STR) == 0) + filterID = FILTER_TRIANGLE; + else if (strcasecmp (filterName, FILTER_ABS_BANDLIMIT_STR) == 0) + filterID = FILTER_ABS_BANDLIMIT; + else if (strcasecmp (filterName, FILTER_ABS_HAMMING_STR) == 0) + filterID = FILTER_ABS_G_HAMMING; + else if (strcasecmp (filterName, FILTER_ABS_SINC_STR) == 0) + filterID = FILTER_ABS_SINC; + else if (strcasecmp (filterName, FILTER_ABS_COS_STR) == 0) + filterID = FILTER_ABS_COSINE; + else if (strcasecmp (filterName, FILTER_SHEPP_STR) == 0) + filterID = FILTER_SHEPP; + + return (filterID); +} + +const char * +SignalFilter::convertFilterIDToName (const FilterID filterID) +{ + const char *name = ""; + + if (filterID == FILTER_SHEPP) + name = FILTER_SHEPP_STR; + else if (filterID == FILTER_ABS_COSINE) + name = FILTER_ABS_COS_STR; + else if (filterID == FILTER_ABS_SINC) + name = FILTER_ABS_SINC_STR; + else if (filterID == FILTER_ABS_G_HAMMING) + name = FILTER_ABS_HAMMING_STR; + else if (filterID == FILTER_ABS_BANDLIMIT) + name = FILTER_ABS_BANDLIMIT_STR; + else if (filterID == FILTER_COSINE) + name = FILTER_COS_STR; + else if (filterID == FILTER_SINC) + name = FILTER_SINC_STR; + else if (filterID == FILTER_G_HAMMING) + name = FILTER_HAMMING_STR; + else if (filterID == FILTER_BANDLIMIT) + name = FILTER_BANDLIMIT_STR; + else if (filterID == FILTER_TRIANGLE) + name = FILTER_TRIANGLE_STR; + + return (name); +} + +const SignalFilter::FilterMethodID +SignalFilter::convertFilterMethodNameToID (const char* const filterMethodName) +{ + FilterMethodID fmID = FILTER_METHOD_INVALID; + + if (strcasecmp (filterMethodName, FILTER_METHOD_CONVOLUTION_STR) == 0) + fmID = FILTER_METHOD_CONVOLUTION; + else if (strcasecmp (filterMethodName, FILTER_METHOD_FOURIER_STR) == 0) + fmID = FILTER_METHOD_FOURIER; + else if (strcasecmp (filterMethodName, FILTER_METHOD_FFT_STR) == 0) + fmID = FILTER_METHOD_FFT; + else if (strcasecmp (filterMethodName, FILTER_METHOD_FFT_ZEROPAD_2_STR) == 0) + fmID = FILTER_METHOD_FFT_ZEROPAD_2; + else if (strcasecmp (filterMethodName, FILTER_METHOD_FFT_ZEROPAD_4_STR) == 0) + fmID = FILTER_METHOD_FFT_ZEROPAD_4; + else if (strcasecmp (filterMethodName, FILTER_METHOD_FFT_ZEROPAD_6_STR) == 0) + fmID = FILTER_METHOD_FFT_ZEROPAD_6; + + return (fmID); +} + +const char * +SignalFilter::convertFilterMethodIDToName (const FilterMethodID fmID) +{ + const char *name = ""; + + if (fmID == FILTER_METHOD_CONVOLUTION) + return (FILTER_METHOD_CONVOLUTION_STR); + else if (fmID == FILTER_METHOD_FOURIER) + return (FILTER_METHOD_FOURIER_STR); + else if (fmID == FILTER_METHOD_FFT) + return (FILTER_METHOD_FFT_STR); + else if (fmID == FILTER_METHOD_FFT_ZEROPAD_2) + return (FILTER_METHOD_FFT_ZEROPAD_2_STR); + else if (fmID == FILTER_METHOD_FFT_ZEROPAD_4) + return (FILTER_METHOD_FFT_ZEROPAD_4_STR); + else if (fmID == FILTER_METHOD_FFT_ZEROPAD_6) + return (FILTER_METHOD_FFT_ZEROPAD_6_STR); + + return (name); +} + +const SignalFilter::DomainID +SignalFilter::convertDomainNameToID (const char* const domainName) +{ + DomainID dID = DOMAIN_INVALID; + + if (strcasecmp (domainName, DOMAIN_SPATIAL_STR) == 0) + dID = DOMAIN_SPATIAL; + else if (strcasecmp (domainName, DOMAIN_FREQUENCY_STR) == 0) + dID = DOMAIN_FREQUENCY; + + return (dID); +} + +const char * +SignalFilter::convertDomainIDToName (const DomainID domain) +{ + const char *name = ""; + + if (domain == DOMAIN_SPATIAL) + return (DOMAIN_SPATIAL_STR); + else if (domain == DOMAIN_FREQUENCY) + return (DOMAIN_FREQUENCY_STR); + + return (name); +} + + +void +SignalFilter::filterSignal (const double input[], double output[], double dx, const int n) const +{ + if (m_idFilterMethod == FILTER_METHOD_CONVOLUTION) { + for (int i = 0; i < n; i++) + output[i] = convolve (input, dx, i, n); + } else if (m_idFilterMethod == FILTER_METHOD_FOURIER) { + complex fftSignal[n]; + complex complexOutput; + finiteFourierTransform (input, fftSignal, 1); + finiteFourierTransform (fftSignal, complexOutput, -1); + for (int i = 0; i < n; i++) + output[i] = complexOutput[i].mag(); + } +} + +void +SignalFilter::filterSignal (const float input[], double output[], double dx, const int n) const +{ + if (m_idFilterMethod == FILTER_METHOD_CONVOLUTION) { + for (int i = 0; i < n; i++) + output[i] = convolve (input, dx, i, n); + } +} + + +double +SignalFilter::response (double x) +{ + double response = 0; + + if (m_idDomain == DOMAIN_SPATIAL) + response = spatialResponse (m_idFilter, m_bw, x, m_filterParam, m_numIntegral); + else if (m_idDomain == DOMAIN_FREQUENCY) + response = frequencyResponse (m_idFilter, m_bw, x, m_filterParam); + + return (response); } +double +SignalFilter::spatialResponse (FilterID filterID, double bw, double x, double param, int nIntegral = 0) +{ + if (nIntegral == 0) + return spatialResponseAnalytic (filterID, bw, x, param); + else + return spatialResponseCalc (filterID, bw, x, param, nIntegral); +} + /* NAME * filter_spatial_response_calc Calculate filter by discrete inverse fourier * transform of filters's frequency * response * * SYNOPSIS - * y = filter_spatial_response_calc (filt_type, x, bw, param, n) + * y = filter_spatial_response_calc (filt_type, x, m_bw, param, n) * double y Filter's response in spatial domain * int filt_type Type of filter (definitions in ct.h) * double x Spatial position to evaluate filter - * double bw Bandwidth of window + * double m_bw Bandwidth of window * double param General parameter for various filters * int n Number of points to calculate integrations */ double -filter_spatial_response_calc (int filt_type, double x, double bw, double param, int n) +SignalFilter::spatialResponseCalc (double x, double param, int nIntegral) const +{ + return (spatialResponseCalc (m_idFilter, m_bw, x, param, nIntegral)); +} + +double +SignalFilter::spatialResponseCalc (FilterID filterID, double bw, double x, double param, int n) { double zmin, zmax; - if (filt_type == FILTER_TRIANGLE) { + if (filterID == FILTER_TRIANGLE) { zmin = 0; zmax = bw; } else { @@ -115,7 +391,7 @@ filter_spatial_response_calc (int filt_type, double x, double bw, double param, double z = zmin; double q [n]; for (int i = 0; i < n; i++, z += zinc) - q[i] = filter_frequency_response (filt_type, z, bw, param) * cos (TWOPI * z * x); + q[i] = frequencyResponse (filterID, bw, z, param) * cos (TWOPI * z * x); double y = 2 * integrateSimpson (zmin, zmax, q, n); @@ -127,21 +403,28 @@ filter_spatial_response_calc (int filt_type, double x, double bw, double param, * filter_frequency_response Return filter frequency response * * SYNOPSIS - * h = filter_frequency_response (filt_type, u, bw, param) + * h = filter_frequency_response (filt_type, u, m_bw, param) * double h Filters frequency response at u * int filt_type Type of filter * double u Frequency to evaluate filter at - * double bw Bandwidth of filter + * double m_bw Bandwidth of filter * double param General input parameter for various filters */ double -filter_frequency_response (int filt_type, double u, double bw, double param) +SignalFilter::frequencyResponse (double u, double param) const +{ + return frequencyResponse (m_idFilter, m_bw, u, param); +} + + +double +SignalFilter::frequencyResponse (FilterID filterID, double bw, double u, double param) { double q; double au = fabs (u); - switch (filt_type) { + switch (filterID) { case FILTER_BANDLIMIT: if (au >= bw / 2) q = 0.; @@ -192,9 +475,7 @@ filter_frequency_response (int filt_type, double u, double bw, double param) break; default: q = 0; - sys_error (ERR_WARNING, - "Frequency response for filter %d not implemented [filter_frequency_response]", - filt_type); + sys_error (ERR_WARNING, "Frequency response for filter %d not implemented [filter_frequency_response]", filterID); break; } return (q); @@ -208,16 +489,22 @@ filter_frequency_response (int filt_type, double u, double bw, double param) * response * * SYNOPSIS - * y = filter_spatial_response_analytic (filt_type, x, bw, param) + * y = filter_spatial_response_analytic (filt_type, x, m_bw, param) * double y Filter's response in spatial domain * int filt_type Type of filter (definitions in ct.h) * double x Spatial position to evaluate filter - * double bw Bandwidth of window + * double m_bw Bandwidth of window * double param General parameter for various filters */ double -filter_spatial_response_analytic (int filt_type, double x, double bw, double param) +SignalFilter::spatialResponseAnalytic (double x, double param) const +{ + return spatialResponseAnalytic (m_idFilter, m_bw, x, param); +} + +double +SignalFilter::spatialResponseAnalytic (FilterID filterID, double bw, double x, double param) { double q, temp; double u = TWOPI * x; @@ -225,7 +512,7 @@ filter_spatial_response_analytic (int filt_type, double x, double bw, double par double b = PI / bw; double b2 = TWOPI / bw; - switch (filt_type) { + switch (filterID) { case FILTER_BANDLIMIT: q = bw * sinc(u * w, 1.0); break; @@ -237,8 +524,7 @@ filter_spatial_response_analytic (int filt_type, double x, double bw, double par q = sinc(b-u,w) + sinc(b+u,w); break; case FILTER_G_HAMMING: - q = 2 * param * sin(u*w)/u + (1-param) * - (sinc(b2-u, w) + sinc(b2+u, w)); + q = 2 * param * sin(u*w)/u + (1-param) * (sinc(b2-u, w) + sinc(b2+u, w)); break; case FILTER_ABS_BANDLIMIT: q = 2 * integral_abscos (u, w); @@ -264,9 +550,7 @@ filter_spatial_response_analytic (int filt_type, double x, double bw, double par break; case FILTER_ABS_SINC: default: - sys_error (ERR_WARNING, - "Analytic filter type %d not implemented [filter_spatial_response_analytic]", - filt_type); + sys_error (ERR_WARNING, "Analytic filter type %d not implemented [filter_spatial_response_analytic]", filterID); q = 0; break; } @@ -287,12 +571,6 @@ filter_spatial_response_analytic (int filt_type, double x, double bw, double par * v = sin(x * mult) / x; */ -double -sinc (double x, double mult) -{ - return (fabs(x) > F_EPSILON ? (sin (x * mult) / x) : 1.0); -} - /* NAME * integral_abscos Returns integral of u*cos(u) @@ -308,12 +586,126 @@ sinc (double x, double mult) */ double -integral_abscos (double u, double w) +SignalFilter::integral_abscos (double u, double w) { - if (fabs (u) > F_EPSILON) - return (cos(u * w) - 1) / (u * u) + w / u * sin (u * w); - else - return (w * w / 2); + return (fabs (u) > F_EPSILON + ? (cos(u * w) - 1) / (u * u) + w / u * sin (u * w) + : (w * w / 2)); +} + + +/* NAME + * convolve Discrete convolution of two functions + * + * SYNOPSIS + * r = convolve (f1, f2, dx, n, np, func_type) + * double r Convolved result + * double f1[], f2[] Functions to be convolved + * double dx Difference between successive x values + * int n Array index to center convolution about + * int np Number of points in f1 array + * int func_type EVEN or ODD or EVEN_AND_ODD function f2 + * + * NOTES + * f1 is the projection data, its indices range from 0 to np - 1. + * The index for f2, the filter, ranges from -(np-1) to (np-1). + * There are 3 ways to handle the negative vertices of f2: + * 1. If we know f2 is an EVEN function, then f2[-n] = f2[n]. + * All filters used in reconstruction are even. + * 2. If we know f2 is an ODD function, then f2[-n] = -f2[n] + * 3. If f2 is both ODD AND EVEN, then we must store the value of f2 + * for negative indices. Since f2 must range from -(np-1) to (np-1), + * if we add (np - 1) to f2's array index, then f2's index will + * range from 0 to 2 * (np - 1), and the origin, x = 0, will be + * stored at f2[np-1]. + */ + +double +SignalFilter::convolve (const double func[], const double dx, const int n, const int np) const +{ + double sum = 0.0; + +#if UNOPTIMIZED_CONVOLUTION + for (int i = 0; i < np; i++) + sum += func[i] * m_vecFilter[n - i + (np - 1)]; +#else + double* f2 = m_vecFilter + n + (np - 1); + for (int i = 0; i < np; i++) + sum += *func++ * *f2--; +#endif + + return (sum * dx); +} + + +double +SignalFilter::convolve (const float func[], const double dx, const int n, const int np) const +{ + double sum = 0.0; + +#if UNOPTIMIZED_CONVOLUTION +for (int i = 0; i < np; i++) + sum += func[i] * m_vecFilter[n - i + (np - 1)]; +#else +double* f2 = m_vecFilter + n + (np - 1); +for (int i = 0; i < np; i++) + sum += *func++ * *f2--; +#endif + + return (sum * dx); } +void +SignalFilter::finiteFourierTransform (const double 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++) { + double sumReal = 0; + 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); + } + if (direction > 0) { + sumReal /= n; + sumImag /= n; + } + output[i] = complex (sumReal, sumImag); + } +} + +void +SignalFilter::finiteFourierTransform (const double input[], complex output[], int direction) const +{ + if (direction < 0) + direction = -1; + else + direction = 1; + + double angleIncrement = 2 * PI / m_nPoints; + for (int i = 0; i < m_nPoints; i++) { + double sumReal = 0, sumImag = 0; + for (int j = 0; j < m_nPoints; 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_nPoints; + sumImag /= m_nPoints; + } + output[i] = complex (sumReal, sumImag); + } +}