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) 1983-2001 Kevin Rosenberg
12 ** $Id: filter.h,v 1.25 2001/02/11 04:56:37 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 // CLASS IDENTIFICATION
42 // SignalFilter A filter used to process signals
47 // Can create either a time/spatial waveform or a frequency signal
48 // Waveforms can be created either by direct calculation or by inverse fourier transform
52 static const int FILTER_INVALID;
53 static const int FILTER_ABS_BANDLIMIT; // filter times |x|
54 static const int FILTER_ABS_SINC;
55 static const int FILTER_ABS_G_HAMMING;
56 static const int FILTER_ABS_COSINE;
57 static const int FILTER_SHEPP;
58 static const int FILTER_BANDLIMIT;
59 static const int FILTER_SINC;
60 static const int FILTER_G_HAMMING;
61 static const int FILTER_COSINE;
62 static const int FILTER_TRIANGLE;
64 static const int DOMAIN_INVALID;
65 static const int DOMAIN_FREQUENCY;
66 static const int DOMAIN_SPATIAL;
68 SignalFilter (const char* szFilterName, double dFilterMinimum, double dFilterMaximum, int nFilterPoints, double dBandwidth, double dFilterParam, const char* szDomainName);
70 SignalFilter (const int idFilter, double dFilterMinimum, double dFilterMaximum, int nFilterPoints, double dBandwidth, double dFilterParam, const int idDomain);
72 SignalFilter (const char* szFilterName, const char* szDomainName, double dBandwidth, double dFilterParam);
76 double* getFilter (void) const
77 { return m_adFilter; }
79 bool fail(void) const {return m_fail;}
80 const std::string& failMessage(void) const {return m_failMessage;}
82 const std::string& nameFilter(void) const { return m_nameFilter;}
83 const std::string& nameDomain(void) const { return m_nameDomain;}
84 const int idFilter(void) const { return m_idFilter;}
85 const int idDomain(void) const { return m_idDomain;}
87 int getNFilterPoints (void) const { return m_nFilterPoints; }
88 const double getFilterMin(void) const {return m_dFilterMin;}
89 const double getFilterMax(void) const {return m_dFilterMax;}
90 const double getFilterIncrement(void) const {return m_dFilterInc;}
91 void copyFilterData(double *pdFilter, const int iStart, const int nPoints) const;
93 double response (double x);
95 static double spatialResponse (int fType, double bw, double x, double param);
97 static double frequencyResponse (int fType, double bw, double u, double param);
99 static double spatialResponseAnalytic (int fType, double bw, double x, double param);
101 static double spatialResponseCalc (int fType, double bw, double x, double param, int nIntegral);
103 static void setNumIntegral(int nIntegral) {N_INTEGRAL = nIntegral;}
105 static const int getFilterCount() {return s_iFilterCount;}
106 static const int getReconstructFilterCount() { return s_iReconstructFilterCount; }
108 static const char** getFilterNameArray() {return s_aszFilterName;}
109 static const char** getFilterTitleArray() {return s_aszFilterTitle;}
110 static int convertFilterNameToID (const char* const filterName);
111 static const char* convertFilterIDToName (const int idFilter);
112 static const char* convertFilterIDToTitle (const int idFilter);
114 static const int getDomainCount() {return s_iDomainCount;}
115 static const char** getDomainNameArray() {return s_aszDomainName;}
116 static const char** getDomainTitleArray() {return s_aszDomainTitle;}
117 static int convertDomainNameToID (const char* const domainName);
118 static const char* convertDomainIDToName (const int idDomain);
119 static const char* convertDomainIDToTitle (const int idDomain);
121 static double sinc (double x)
122 { return (fabs(x) > F_EPSILON ? (sin (x) / x) : 1.0); }
124 static double sinc (double x, double mult)
125 { return (fabs(x) > F_EPSILON ? (sin (x * mult) / x) : 1.0); }
130 double m_dFilterParam;
136 std::string m_nameFilter;
137 std::string m_nameDomain;
142 std::string m_failMessage;
144 static const char* s_aszFilterName[];
145 static const char* s_aszFilterTitle[];
146 static const int s_iFilterCount;
147 static const int s_iReconstructFilterCount;
148 static const char* s_aszDomainName[];
149 static const char* s_aszDomainTitle[];
150 static const int s_iDomainCount;
151 static int N_INTEGRAL;
153 static const bool haveAnalyticSpatial (const int filterID);
155 void init (const int idFilter, double dFilterMin, double dFilterMax, int nFilterPoints, double dBandwidth, double dFilterParam, const int idDomain);
157 void createFrequencyFilter (double* x) const;
158 void createSpatialFilter (double* x) const;
160 double spatialResponseCalc (double x) const;
161 double spatialResponseAnalytic (double x) const;
162 double frequencyResponse (double u) const;
164 static double integral_abscos (double u, double w)
165 { return (fabs (u) > F_EPSILON ? (cos (u * w) - 1) / (u * u) + w / u * sin (u * w) : (w * w / 2)); }