/*****************************************************************************
-** FILE IDENTIFICATION
+** File IDENTIFICATION
**
** Name: filter.cpp
** Purpose: Routines for signal-procesing filters
** Date Started: Aug 1984
**
** This is part of the CTSim program
-** Copyright (C) 1983-2000 Kevin Rosenberg
+** Copyright (c) 1983-2000 Kevin Rosenberg
**
-** $Id: filter.cpp,v 1.1 2000/06/19 02:59:34 kevin Exp $
+** $Id: filter.cpp,v 1.36 2001/02/11 04:56:37 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
#include "ct.h"
+int SignalFilter::N_INTEGRAL=500; //static member
+
+const int SignalFilter::FILTER_INVALID = -1 ;
+const int SignalFilter::FILTER_ABS_BANDLIMIT = 0; // filter times |x|
+const int SignalFilter::FILTER_ABS_G_HAMMING = 1;
+const int SignalFilter::FILTER_ABS_COSINE = 2;
+const int SignalFilter::FILTER_ABS_SINC = 3;
+const int SignalFilter::FILTER_SHEPP = 4;
+const int SignalFilter::FILTER_BANDLIMIT = 5;
+const int SignalFilter::FILTER_SINC = 6;
+const int SignalFilter::FILTER_G_HAMMING = 7;
+const int SignalFilter::FILTER_COSINE = 8;
+const int SignalFilter::FILTER_TRIANGLE = 9;
+
+const int SignalFilter::s_iReconstructFilterCount = 5;
+
+const char* SignalFilter::s_aszFilterName[] = {
+ {"abs_bandlimit"},
+ {"abs_hamming"},
+ {"abs_cosine"},
+ {"abs_sinc"},
+ {"shepp"},
+ {"bandlimit"},
+ {"sinc"},
+ {"hamming"},
+ {"cosine"},
+ {"triangle"},
+};
+
+const char* SignalFilter::s_aszFilterTitle[] = {
+ {"Abs(w) * Bandlimit"},
+ {"Abs(w) * Hamming"},
+ {"Abs(w) * Cosine"},
+ {"Abs(w) * Sinc"},
+ {"Shepp"},
+ {"Bandlimit"},
+ {"Sinc"},
+ {"Hamming"},
+ {"Cosine"},
+ {"Triangle"},
+};
+
+const int SignalFilter::s_iFilterCount = sizeof(s_aszFilterName) / sizeof(const char*);
+
+
+const int SignalFilter::DOMAIN_INVALID = -1;
+const int SignalFilter::DOMAIN_FREQUENCY = 0;
+const int SignalFilter::DOMAIN_SPATIAL = 1;
+
+const char* SignalFilter::s_aszDomainName[] = {
+ {"frequency"},
+ {"spatial"},
+};
+
+const char* SignalFilter::s_aszDomainTitle[] = {
+ {"Frequency"},
+ {"Spatial"},
+};
+
+const int SignalFilter::s_iDomainCount = sizeof(s_aszDomainName) / sizeof(const char*);
+
/* 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, filterMin, filterMax, n, param, domain, analytic)
+ * double f Generated filter vector
+ * int filt_type Type of filter wanted
+ * double bw Bandwidth of filter
+ * double filterMin, filterMax Filter limits
+ * int nFilterPoints Number of points in signal
+ * double param General input parameter to filters
+ * int domain FREQUENCY or SPATIAL domain wanted
*/
-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* szFilterName, double dFilterMinimum, double dFilterMaximum, int nFilterPoints, double dBandwidth, double dFilterParam, const char* szDomainName)
+ : m_adFilter(NULL), m_fail(false)
+{
+ m_idFilter = convertFilterNameToID (szFilterName);
+ if (m_idFilter == FILTER_INVALID) {
+ m_fail = true;
+ m_failMessage = "Invalid Filter name ";
+ m_failMessage += szFilterName;
+ return;
+ }
+ m_idDomain = convertDomainNameToID (szDomainName);
+ if (m_idDomain == DOMAIN_INVALID) {
+ m_fail = true;
+ m_failMessage = "Invalid domain name ";
+ m_failMessage += szDomainName;
+ return;
+ }
+ init (m_idFilter, dFilterMinimum, dFilterMaximum, nFilterPoints, dBandwidth, dFilterParam, m_idDomain);
+}
+
+SignalFilter::SignalFilter (const int idFilter, double dFilterMinimum, double dFilterMaximum, int nFilterPoints, double dBandwidth, double dFilterParam, const int idDomain)
+ : m_adFilter(NULL), m_fail(false)
+{
+ init (idFilter, dFilterMinimum, dFilterMaximum, nFilterPoints, dBandwidth, dFilterParam, idDomain);
+}
+
+SignalFilter::SignalFilter (const char* szFilterName, const char* szDomainName, double dBandwidth, double dFilterParam)
+ : m_adFilter(NULL), m_fail(false)
+{
+ m_nFilterPoints = 0;
+ m_dBandwidth = dBandwidth;
+ m_dFilterParam = dFilterParam;
+ m_idFilter = convertFilterNameToID (szFilterName);
+ if (m_idFilter == FILTER_INVALID) {
+ m_fail = true;
+ m_failMessage = "Invalid Filter name ";
+ m_failMessage += szFilterName;
+ return;
+ }
+ m_idDomain = convertDomainNameToID (szDomainName);
+ if (m_idDomain == DOMAIN_INVALID) {
+ m_fail = true;
+ m_failMessage = "Invalid domain name ";
+ m_failMessage += szDomainName;
+ return;
+ }
+}
+
+void
+SignalFilter::init (const int idFilter, double dFilterMinimum, double dFilterMaximum, int nFilterPoints, double dBandwidth, double dFilterParam, const int idDomain)
+{
+ m_idFilter = idFilter;
+ m_idDomain = idDomain;
+ if (m_idFilter == FILTER_INVALID || m_idDomain == DOMAIN_INVALID) {
+ m_fail = true;
+ return;
+ }
+ if (nFilterPoints < 2) {
+ m_fail = true;
+ m_failMessage = "Number of filter points ";
+ m_failMessage += nFilterPoints;
+ m_failMessage = " less than 2";
+ return;
+ }
+
+ m_nameFilter = convertFilterIDToName (m_idFilter);
+ m_nameDomain = convertDomainIDToName (m_idDomain);
+ m_nFilterPoints = nFilterPoints;
+ m_dFilterParam = dFilterParam;
+ m_dBandwidth = dBandwidth;
+ m_dFilterMin = dFilterMinimum;
+ m_dFilterMax = dFilterMaximum;
+
+ m_dFilterInc = (m_dFilterMax - m_dFilterMin) / (m_nFilterPoints - 1);
+ m_adFilter = new double [m_nFilterPoints];
+
+ if (m_idDomain == DOMAIN_FREQUENCY)
+ createFrequencyFilter (m_adFilter);
+ else if (m_idDomain == DOMAIN_SPATIAL)
+ createSpatialFilter (m_adFilter);
+}
+
+
+SignalFilter::~SignalFilter (void)
+{
+ delete [] m_adFilter;
+}
+
+void
+SignalFilter::createFrequencyFilter (double* adFilter) const
{
- double *f = new double [n];
- double xinc = (xmax - xmin) / (n - 1);
+ double x;
+ int i;
+ for (x = m_dFilterMin, i = 0; i < m_nFilterPoints; x += m_dFilterInc, i++)
+ adFilter[i] = frequencyResponse (x);
+}
- if (filt_type == FILTER_SHEPP) {
- double a = 2 * bw;
+
+void
+SignalFilter::createSpatialFilter (double* adFilter) const
+{
+ if (m_idFilter == FILTER_SHEPP) {
+ double a = 2 * m_dBandwidth;
double c = - 4. / (a * a);
- int center = (n - 1) / 2;
+ int center = (m_nFilterPoints - 1) / 2;
int sidelen = center;
- f[center] = 4. / (a * a);
-
+ m_adFilter[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) {
- 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) {
- double x;
- int i;
- for (x = xmin, i = 0; i < n; x += xinc, i++)
- if (numint == 0)
- f[i] = filter_spatial_response_analytic (filt_type, x, bw, param);
- else
- f[i] = filter_spatial_response_calc (filt_type, x, bw, param, numint);
+ m_adFilter [center + i] = m_adFilter [center - i] = c / (4 * (i * i) - 1);
} else {
- sys_error (ERR_WARNING, "Illegal domain %d [filt_generate]", domain);
- return (NULL);
+ double x = m_dFilterMin;
+ for (int i = 0; i < m_nFilterPoints; i++, x += m_dFilterInc) {
+ if (haveAnalyticSpatial(m_idFilter))
+ m_adFilter[i] = spatialResponseAnalytic (x);
+ else
+ m_adFilter[i] = spatialResponseCalc (x);
+ }
}
-
- return (f);
}
+int
+SignalFilter::convertFilterNameToID (const char *filterName)
+{
+ int filterID = FILTER_INVALID;
+
+ for (int i = 0; i < s_iFilterCount; i++)
+ if (strcasecmp (filterName, s_aszFilterName[i]) == 0) {
+ filterID = i;
+ break;
+ }
+
+ return (filterID);
+}
+
+const char *
+SignalFilter::convertFilterIDToName (const int filterID)
+{
+ static const char *name = "";
+
+ if (filterID >= 0 && filterID < s_iFilterCount)
+ return (s_aszFilterName [filterID]);
+
+ return (name);
+}
+
+const char *
+SignalFilter::convertFilterIDToTitle (const int filterID)
+{
+ static const char *title = "";
+
+ if (filterID >= 0 && filterID < s_iFilterCount)
+ return (s_aszFilterTitle [filterID]);
+
+ return (title);
+}
+
+int
+SignalFilter::convertDomainNameToID (const char* const domainName)
+{
+ int dID = DOMAIN_INVALID;
+
+ for (int i = 0; i < s_iDomainCount; i++)
+ if (strcasecmp (domainName, s_aszDomainName[i]) == 0) {
+ dID = i;
+ break;
+ }
+
+ return (dID);
+}
+
+const char *
+SignalFilter::convertDomainIDToName (const int domainID)
+{
+ static const char *name = "";
+
+ if (domainID >= 0 && domainID < s_iDomainCount)
+ return (s_aszDomainName [domainID]);
+
+ return (name);
+}
+
+const char *
+SignalFilter::convertDomainIDToTitle (const int domainID)
+{
+ static const char *title = "";
+
+ if (domainID >= 0 && domainID < s_iDomainCount)
+ return (s_aszDomainTitle [domainID]);
+
+ return (title);
+}
+
+
+double
+SignalFilter::response (double x)
+{
+ double response = 0;
+
+ if (m_idDomain == DOMAIN_SPATIAL)
+ response = spatialResponse (m_idFilter, m_dBandwidth, x, m_dFilterParam);
+ else if (m_idDomain == DOMAIN_FREQUENCY)
+ response = frequencyResponse (m_idFilter, m_dBandwidth, x, m_dFilterParam);
+
+ return (response);
+}
+
+
+double
+SignalFilter::spatialResponse (int filterID, double bw, double x, double param)
+{
+ if (haveAnalyticSpatial(filterID))
+ return spatialResponseAnalytic (filterID, bw, x, param);
+ else
+ return spatialResponseCalc (filterID, bw, x, param, N_INTEGRAL);
+}
+
+void
+SignalFilter::copyFilterData (double* pdFilter, const int iStart, const int nPoints) const
+{
+ int iFirst = clamp (iStart, 0, m_nFilterPoints - 1);
+ int iLast = clamp (iFirst + nPoints - 1, 0, m_nFilterPoints - 1);
+
+ for (int i = iFirst; i <= iLast; i++)
+ pdFilter[i - iFirst] = m_adFilter[i];
+}
/* NAME
* filter_spatial_response_calc Calculate filter by discrete inverse fourier
* 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) const
+{
+ return (spatialResponseCalc (m_idFilter, m_dBandwidth, x, m_dFilterParam, N_INTEGRAL));
+}
+
+double
+SignalFilter::spatialResponseCalc (int 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 {
double zinc = (zmax - zmin) / (n - 1);
double z = zmin;
- double q [n];
+ double* q = new double [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);
-
+ delete q;
+
return (y);
}
* 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) const
+{
+ return frequencyResponse (m_idFilter, m_dBandwidth, u, m_dFilterParam);
+}
+
+
+double
+SignalFilter::frequencyResponse (int 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)
+ if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
q = 0.;
else
q = 1;
break;
case FILTER_ABS_BANDLIMIT:
- if (au >= bw / 2)
+ if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
q = 0.;
else
q = au;
break;
case FILTER_TRIANGLE:
- if (au >= bw)
+ if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
q = 0;
else
q = 1 - au / bw;
break;
case FILTER_COSINE:
- if (au >= bw / 2)
+ if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
q = 0;
else
q = cos(PI * u / bw);
break;
case FILTER_ABS_COSINE:
- if (au >= bw / 2)
+ if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
q = 0;
else
q = au * cos(PI * u / bw);
q = au * bw * sinc (PI * bw * u, 1.);
break;
case FILTER_G_HAMMING:
- if (au >= bw / 2)
+ if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
q = 0;
else
q = param + (1 - param) * cos (TWOPI * u / bw);
break;
case FILTER_ABS_G_HAMMING:
- if (au >= bw / 2)
+ if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
q = 0;
else
q = au * (param + (1 - param) * cos(TWOPI * u / bw));
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);
* 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) const
+{
+ return spatialResponseAnalytic (m_idFilter, m_dBandwidth, x, m_dFilterParam);
+}
+
+const bool
+SignalFilter::haveAnalyticSpatial (int filterID)
+{
+ bool haveAnalytic = false;
+
+ switch (filterID) {
+ case FILTER_BANDLIMIT:
+ case FILTER_TRIANGLE:
+ case FILTER_COSINE:
+ case FILTER_G_HAMMING:
+ case FILTER_ABS_BANDLIMIT:
+ case FILTER_ABS_COSINE:
+ case FILTER_ABS_G_HAMMING:
+ case FILTER_SHEPP:
+ case FILTER_SINC:
+ haveAnalytic = true;
+ break;
+ default:
+ break;
+ }
+
+ return (haveAnalytic);
+}
+
+double
+SignalFilter::spatialResponseAnalytic (int filterID, double bw, double x, double param)
{
double q, temp;
double u = TWOPI * x;
double b = PI / bw;
double b2 = TWOPI / bw;
- switch (filt_type) {
+ switch (filterID) {
case FILTER_BANDLIMIT:
q = bw * sinc(u * w, 1.0);
break;
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);
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;
}
}
-/* NAME
- * sinc Return sin(x)/x function
- *
- * SYNOPSIS
- * v = sinc (x, mult)
- * double v sinc value
- * double x, mult
- *
- * DESCRIPTION
- * v = sin(x * mult) / x;
- */
-double
-sinc (double x, double mult)
-{
- return (fabs(x) > F_EPSILON ? (sin (x * mult) / x) : 1.0);
-}
+// Functions that are inline in filter.h
-/* NAME
- * integral_abscos Returns integral of u*cos(u)
- *
- * SYNOPSIS
- * q = integral_abscos (u, w)
- * double q Integral value
- * double u Integration variable
- * double w Upper integration boundary
- *
- * DESCRIPTION
- * Returns the value of integral of u*cos(u)*dV for V = 0 to w
- */
+// sinc Return sin(x)/x function
+// v = sinc (x, mult)
+// Calculates sin(x * mult) / x;
+
+// integral_abscos Returns integral of u*cos(u)
+//
+// q = integral_abscos (u, w)
+// double q Integral value
+// double u Integration variable
+// double w Upper integration boundary
+// Returns the value of integral of u*cos(u)*dV for V = 0 to w
-double
-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);
-}
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