/*****************************************************************************
** File IDENTIFICATION
-**
+**
** Name: filter.cpp
** Purpose: Routines for signal-procesing filters
-** Progammer: Kevin Rosenberg
+** Progammer: Kevin Rosenberg
** Date Started: Aug 1984
**
** This is part of the CTSim program
-** Copyright (c) 1983-2000 Kevin Rosenberg
-**
-** $Id: filter.cpp,v 1.36 2001/02/11 04:56:37 kevin Exp $
+** Copyright (c) 1983-2009 Kevin Rosenberg
**
** 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 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_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 int SignalFilter::FILTER_ABS_HANNING = 2;
+const int SignalFilter::FILTER_ABS_COSINE = 3;
+const int SignalFilter::FILTER_ABS_SINC = 4;
+const int SignalFilter::FILTER_SHEPP = 5;
+const int SignalFilter::FILTER_BANDLIMIT = 6;
+const int SignalFilter::FILTER_SINC = 7;
+const int SignalFilter::FILTER_G_HAMMING = 8;
+const int SignalFilter::FILTER_HANNING = 9;
+const int SignalFilter::FILTER_COSINE = 10;
+const int SignalFilter::FILTER_TRIANGLE = 11;
+
+const int SignalFilter::s_iReconstructFilterCount = 4;
+
+const char* const SignalFilter::s_aszFilterName[] = {
+ "abs_bandlimit",
+ "abs_hamming",
+ "abs_hanning",
+ "abs_cosine",
+ "shepp",
+ "abs_sinc",
+ "bandlimit",
+ "sinc",
+ "hamming",
+ "hanning",
+ "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 char* const SignalFilter::s_aszFilterTitle[] = {
+ "Abs(w) * Bandlimit",
+ "Abs(w) * Hamming",
+ "Abs(w) * Hanning",
+ "Abs(w) * Cosine",
+ "Shepp",
+ "Abs(w) * Sinc",
+ "Bandlimit",
+ "Sinc",
+ "Hamming",
+ "Hanning",
+ "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* const SignalFilter::s_aszDomainName[] = {
+ "frequency",
+ "spatial",
};
-const char* SignalFilter::s_aszDomainTitle[] = {
- {"Frequency"},
- {"Spatial"},
+const char* const SignalFilter::s_aszDomainTitle[] = {
+ "Frequency",
+ "Spatial",
};
const int SignalFilter::s_iDomainCount = sizeof(s_aszDomainName) / sizeof(const char*);
/* NAME
- * SignalFilter::SignalFilter Construct a signal
- *
- * SYNOPSIS
- * 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
- */
+* SignalFilter::SignalFilter Construct a signal
+*
+* SYNOPSIS
+* 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
+*/
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_adFilter(NULL), m_fail(false)
{
m_idFilter = convertFilterNameToID (szFilterName);
if (m_idFilter == FILTER_INVALID) {
}
SignalFilter::SignalFilter (const int idFilter, double dFilterMinimum, double dFilterMaximum, int nFilterPoints, double dBandwidth, double dFilterParam, const int idDomain)
- : m_adFilter(NULL), m_fail(false)
+: 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_adFilter(NULL), m_fail(false)
{
m_nFilterPoints = 0;
m_dBandwidth = dBandwidth;
- m_dFilterParam = dFilterParam;
+ m_dFilterParam = dFilterParam;
m_idFilter = convertFilterNameToID (szFilterName);
if (m_idFilter == FILTER_INVALID) {
m_fail = true;
m_nameFilter = convertFilterIDToName (m_idFilter);
m_nameDomain = convertDomainIDToName (m_idDomain);
m_nFilterPoints = nFilterPoints;
- m_dFilterParam = dFilterParam;
+ m_dFilterParam = dFilterParam;
m_dBandwidth = dBandwidth;
m_dFilterMin = dFilterMinimum;
m_dFilterMax = dFilterMaximum;
m_adFilter = new double [m_nFilterPoints];
if (m_idDomain == DOMAIN_FREQUENCY)
- createFrequencyFilter (m_adFilter);
+ createFrequencyFilter (m_adFilter);
else if (m_idDomain == DOMAIN_SPATIAL)
- createSpatialFilter (m_adFilter);
+ createSpatialFilter (m_adFilter);
}
SignalFilter::~SignalFilter (void)
{
- delete [] m_adFilter;
+ delete [] m_adFilter;
}
void
int center = (m_nFilterPoints - 1) / 2;
int sidelen = center;
m_adFilter[center] = 4. / (a * a);
-
+
for (int i = 1; i <= sidelen; i++ )
m_adFilter [center + i] = m_adFilter [center - i] = c / (4 * (i * i) - 1);
} else {
double x = m_dFilterMin;
for (int i = 0; i < m_nFilterPoints; i++, x += m_dFilterInc) {
if (haveAnalyticSpatial(m_idFilter))
- m_adFilter[i] = spatialResponseAnalytic (x);
+ m_adFilter[i] = spatialResponseAnalytic (x);
else
- m_adFilter[i] = spatialResponseCalc (x);
+ m_adFilter[i] = spatialResponseCalc (x);
}
}
}
{
int filterID = FILTER_INVALID;
- for (int i = 0; i < s_iFilterCount; i++)
+ for (int i = 0; i < s_iFilterCount; i++) {
if (strcasecmp (filterName, s_aszFilterName[i]) == 0) {
filterID = i;
break;
}
+ }
- return (filterID);
+ return (filterID);
}
const char *
SignalFilter::convertFilterIDToName (const int filterID)
{
static const char *name = "";
-
+
if (filterID >= 0 && filterID < s_iFilterCount)
- return (s_aszFilterName [filterID]);
+ return (s_aszFilterName [filterID]);
return (name);
}
SignalFilter::convertFilterIDToTitle (const int filterID)
{
static const char *title = "";
-
- if (filterID >= 0 && filterID < s_iFilterCount)
- return (s_aszFilterTitle [filterID]);
+ 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) {
+ for (int i = 0; i < s_iDomainCount; i++) {
+ if (strcasecmp (domainName, s_aszDomainName[i]) == 0) {
dID = i;
break;
}
-
+ }
return (dID);
}
static const char *name = "";
if (domainID >= 0 && domainID < s_iDomainCount)
- return (s_aszDomainName [domainID]);
+ return (s_aszDomainName [domainID]);
return (name);
}
static const char *title = "";
if (domainID >= 0 && domainID < s_iDomainCount)
- return (s_aszDomainTitle [domainID]);
+ return (s_aszDomainTitle [domainID]);
return (title);
}
}
-double
+double
SignalFilter::spatialResponse (int filterID, double bw, double x, double param)
{
if (haveAnalyticSpatial(filterID))
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);
+ 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];
+ for (int i = iFirst; i <= iLast; i++)
+ pdFilter[i - iFirst] = m_adFilter[i];
}
/* 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, 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 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 Calculate filter by discrete inverse fourier
+* transform of filters's frequency
+* response
+*
+* SYNOPSIS
+* 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 m_bw Bandwidth of window
+* double param General parameter for various filters
+* int n Number of points to calculate integrations
+*/
+
+double
SignalFilter::spatialResponseCalc (double x) const
{
return (spatialResponseCalc (m_idFilter, m_dBandwidth, x, m_dFilterParam, N_INTEGRAL));
}
-double
+double
SignalFilter::spatialResponseCalc (int filterID, double bw, double x, double param, int n)
{
double zmin, zmax;
double* q = new double [n];
for (int i = 0; i < n; i++, z += zinc)
q[i] = frequencyResponse (filterID, bw, z, param) * cos (TWOPI * z * x);
-
+
double y = 2 * integrateSimpson (zmin, zmax, q, n);
delete q;
/* NAME
- * filter_frequency_response Return filter frequency response
- *
- * SYNOPSIS
- * 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 m_bw Bandwidth of filter
- * double param General input parameter for various filters
- */
-
-double
+* filter_frequency_response Return filter frequency response
+*
+* SYNOPSIS
+* 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 m_bw Bandwidth of filter
+* double param General input parameter for various filters
+*/
+
+double
SignalFilter::frequencyResponse (double u) const
{
return frequencyResponse (m_idFilter, m_dBandwidth, u, m_dFilterParam);
}
-double
+double
SignalFilter::frequencyResponse (int filterID, double bw, double u, double param)
{
double q;
double au = fabs (u);
+ double abw = fabs (bw);
switch (filterID) {
case FILTER_BANDLIMIT:
- if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
+ if (au >= (abw / 2) + F_EPSILON)
q = 0.;
else
q = 1;
break;
case FILTER_ABS_BANDLIMIT:
- if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
+ if (au >= (abw / 2) + F_EPSILON)
q = 0.;
else
q = au;
break;
case FILTER_TRIANGLE:
- if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
+ if (au >= (abw / 2) + F_EPSILON)
q = 0;
else
- q = 1 - au / bw;
+ q = 1 - au / abw;
break;
case FILTER_COSINE:
- if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
+ if (au >= (abw / 2) + F_EPSILON)
q = 0;
else
- q = cos(PI * u / bw);
+ q = cos(PI * au / abw);
break;
case FILTER_ABS_COSINE:
- if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
+ if (au >= (abw / 2) + F_EPSILON)
q = 0;
else
- q = au * cos(PI * u / bw);
+ q = au * cos(PI * au / abw);
break;
case FILTER_SINC:
- q = bw * sinc (PI * bw * u, 1.);
+ q = abw * sinc (PI * abw * au, 1.);
break;
case FILTER_ABS_SINC:
- q = au * bw * sinc (PI * bw * u, 1.);
+ if (au >= (abw / 2) + F_EPSILON)
+ q = 0;
+ else
+ q = au * abw * sinc (PI * abw * au, 1.);
break;
+ case FILTER_HANNING:
+ param = 0.5;
+ // follow through to G_HAMMING
case FILTER_G_HAMMING:
- if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
+ if (au >= (abw / 2) + F_EPSILON)
q = 0;
else
- q = param + (1 - param) * cos (TWOPI * u / bw);
+ q = param + (1 - param) * cos (TWOPI * au / abw);
break;
+ case FILTER_ABS_HANNING:
+ param = 0.5;
+ // follow through to ABS_G_HAMMING
case FILTER_ABS_G_HAMMING:
- if (fabs(au) >= fabs(bw / 2) + F_EPSILON)
+ if (au >= (abw / 2) + F_EPSILON)
q = 0;
else
- q = au * (param + (1 - param) * cos(TWOPI * u / bw));
+ q = au * (param + (1 - param) * cos(TWOPI * au / abw));
break;
default:
q = 0;
sys_error (ERR_WARNING, "Frequency response for filter %d not implemented [filter_frequency_response]", filterID);
break;
}
+
return (q);
}
/* NAME
- * filter_spatial_response_analytic Calculate filter by analytic inverse fourier
- * transform of filters's frequency
- * response
- *
- * SYNOPSIS
- * 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 m_bw Bandwidth of window
- * double param General parameter for various filters
- */
-
-double
+* filter_spatial_response_analytic Calculate filter by analytic inverse fourier
+* transform of filters's frequency
+* response
+*
+* SYNOPSIS
+* 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 m_bw Bandwidth of window
+* double param General parameter for various filters
+*/
+
+double
SignalFilter::spatialResponseAnalytic (double x) const
{
return spatialResponseAnalytic (m_idFilter, m_dBandwidth, x, m_dFilterParam);
case FILTER_TRIANGLE:
case FILTER_COSINE:
case FILTER_G_HAMMING:
+ case FILTER_HANNING:
case FILTER_ABS_BANDLIMIT:
case FILTER_ABS_COSINE:
case FILTER_ABS_G_HAMMING:
+ case FILTER_ABS_HANNING:
case FILTER_SHEPP:
case FILTER_SINC:
haveAnalytic = true;
return (haveAnalytic);
}
-double
+double
SignalFilter::spatialResponseAnalytic (int filterID, double bw, double x, double param)
{
double q, temp;
case FILTER_COSINE:
q = sinc(b-u,w) + sinc(b+u,w);
break;
+ case FILTER_HANNING:
+ param = 0.5;
+ // follow through to G_HAMMING
case FILTER_G_HAMMING:
q = 2 * param * sin(u*w)/u + (1-param) * (sinc(b2-u, w) + sinc(b2+u, w));
break;
case FILTER_ABS_COSINE:
q = integral_abscos(b-u,w) + integral_abscos(b+u,w);
break;
+ case FILTER_ABS_HANNING:
+ param = 0.5;
+ // follow through to ABS_G_HAMMING
case FILTER_ABS_G_HAMMING:
q = 2 * param * integral_abscos(u,w) +
(1-param)*(integral_abscos(u-b2,w)+integral_abscos(u+b2,w));
q = 0;
break;
}
-
+
return (q);
}
// Functions that are inline in filter.h
-// sinc Return sin(x)/x function
+// sinc Return sin(x)/x function
// v = sinc (x, mult)
// Calculates sin(x * mult) / x;
-// integral_abscos Returns integral of u*cos(u)
+// 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
+// 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
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