1 /*****************************************************************************
5 ** Purpose: Signal filter header file
6 ** Programmer: Kevin Rosenberg
7 ** Date Started: June 2000
9 ** This is part of the CTSim program
10 ** Copyright (C) 1983-2000 Kevin Rosenberg
12 ** $Id: filter.h,v 1.6 2000/07/02 18:21:39 kevin Exp $
14 ** This program is free software; you can redistribute it and/or modify
15 ** it under the terms of the GNU General Public License (version 2) as
16 ** published by the Free Software Foundation.
18 ** This program is distributed in the hope that it will be useful,
19 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
20 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 ** GNU General Public License for more details.
23 ** You should have received a copy of the GNU General Public License
24 ** along with this program; if not, write to the Free Software
25 ** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
26 ******************************************************************************/
41 FILTER_ABS_BANDLIMIT, // filter times |x|
49 FILTER_METHOD_INVALID,
50 FILTER_METHOD_CONVOLUTION,
51 FILTER_METHOD_FOURIER,
53 FILTER_METHOD_FFT_ZEROPAD_2,
54 FILTER_METHOD_FFT_ZEROPAD_4,
55 FILTER_METHOD_FFT_ZEROPAD_6
64 static const char FILTER_ABS_BANDLIMIT_STR[]= "abs_bandlimit";
65 static const char FILTER_ABS_SINC_STR[]= "abs_sinc";
66 static const char FILTER_ABS_COS_STR[]= "abs_cos";
67 static const char FILTER_ABS_HAMMING_STR[]= "abs_hamming";
68 static const char FILTER_SHEPP_STR[]= "shepp";
69 static const char FILTER_BANDLIMIT_STR[]= "bandlimit";
70 static const char FILTER_SINC_STR[]= "sinc";
71 static const char FILTER_COS_STR[]= "cos";
72 static const char FILTER_HAMMING_STR[]= "hamming";
73 static const char FILTER_TRIANGLE_STR[]= "triangle";
75 static const char FILTER_METHOD_CONVOLUTION_STR[]= "convolution";
76 static const char FILTER_METHOD_FOURIER_STR[]= "fourier";
77 static const char FILTER_METHOD_FFT_STR[]= "fft";
78 static const char FILTER_METHOD_FFT_ZEROPAD_2_STR[]="fft_zeropad2";
79 static const char FILTER_METHOD_FFT_ZEROPAD_4_STR[]="fft_zeropad4";
80 static const char FILTER_METHOD_FFT_ZEROPAD_6_STR[]="fft_zeropad6";
82 static const char DOMAIN_FREQUENCY_STR[]= "frequency";
83 static const char DOMAIN_SPATIAL_STR[]= "spatial";
86 SignalFilter (const char* filterName, const char* filterMethodName,double bw, double signalLength, int n, double param, const char* domainName, const int numIntegral = 0);
88 SignalFilter (const FilterID filt_type, FilterMethodID filterMethodID, double bw, double signalLength, int n, double param, const DomainID domain, const int numIntegral = 0);
90 SignalFilter (const char* filterName, const char* domainName, double bw, double param, int numIntegral = 0);
94 double* getFilter (void) const
95 { return m_vecFilter; }
97 int getNFilterPoints (void) const
98 { return m_nFilterPoints; }
100 double convolve (const double f[], const double dx, const int n, const int np) const;
102 double convolve (const float f[], const double dx, const int n, const int np) const;
104 void filterSignal (const double input[], double output[], double dx, const int n) const;
105 void filterSignal (const float input[], double output[], double dx, const int n) const;
107 static void finiteFourierTransform (const double input[], complex<double> output[], const int n, const int direction);
109 void finiteFourierTransform (const double input[], complex<double> output[], const int direction) const;
111 bool fail(void) const {return m_fail;}
112 const string& failMessage(void) const {return m_failMessage;}
114 const string& nameFilter(void) const { return m_nameFilter;}
115 const string& nameDomain(void) const { return m_nameDomain;}
116 const FilterID idFilter(void) const { return m_idFilter;}
117 const DomainID idDomain(void) const { return m_idDomain;}
119 double response (double x);
121 static double spatialResponse (FilterID fType, double bw, double x, double param, int nIntegral = 0);
123 static double frequencyResponse (FilterID fType, double bw, double u, double param);
125 static double spatialResponseCalc (FilterID fType, double bw, double x, double param, int n);
127 static double spatialResponseAnalytic (FilterID fType, double bw, double x, double param);
133 double m_signalLength;
137 double* m_vecFourierCosTable;
138 double* m_vecFourierSinTable;
141 string m_failMessage;
143 string m_nameFilterMethod;
146 FilterMethodID m_idFilterMethod;
148 double m_filterParam;
151 static const FilterID convertFilterNameToID (const char* filterName);
152 static const char* convertFilterIDToName (const FilterID filterID);
153 static const FilterMethodID convertFilterMethodNameToID (const char* filterMethodName);
154 static const char* convertFilterMethodIDToName (const FilterMethodID filterMethodID);
155 static const DomainID convertDomainNameToID (const char* domainName);
156 static const char* convertDomainIDToName (const DomainID domainID);
158 void init (const FilterID filt_type, const FilterMethodID filterMethod, double bw, double xmin, double xmax, int n, double param, const DomainID domain, const int numInt);
160 double spatialResponseCalc (double x, double param, int n) const;
162 double spatialResponseAnalytic (double x, double param) const;
164 double frequencyResponse (double u, double param) const;
166 static double sinc (double x, double mult)
167 { return (fabs(x) > F_EPSILON ? (sin (x * mult) / x) : 1.0); }
169 static double integral_abscos (double u, double w);