/*****************************************************************************
** 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
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_HANNING = 2;
const int SignalFilter::FILTER_ABS_COSINE = 3;
*
* 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
+* 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_nFilterPoints = 0;
m_dBandwidth = dBandwidth;
- m_dFilterParam = dFilterParam;
+ m_dFilterParam = dFilterParam;
m_idFilter = convertFilterNameToID (szFilterName);
if (m_idFilter == FILTER_INVALID) {
m_fail = true;
m_failMessage = " less than 2";
return;
}
-
+
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_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)
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 {
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);
}
SignalFilter::convertFilterIDToName (const int filterID)
{
static const char *name = "";
-
+
if (filterID >= 0 && filterID < s_iFilterCount)
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]);
-
+
return (title);
}
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);
}
SignalFilter::convertDomainIDToName (const int domainID)
{
static const char *name = "";
-
+
if (domainID >= 0 && domainID < s_iDomainCount)
return (s_aszDomainName [domainID]);
-
+
return (name);
}
SignalFilter::convertDomainIDToTitle (const int domainID)
{
static const char *title = "";
-
+
if (domainID >= 0 && domainID < s_iDomainCount)
return (s_aszDomainTitle [domainID]);
-
+
return (title);
}
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
+double
SignalFilter::spatialResponse (int filterID, double bw, double x, double param)
{
if (haveAnalyticSpatial(filterID))
{
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
-* transform of filters's frequency
-* response
+* 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 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
+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;
-
+
if (filterID == FILTER_TRIANGLE) {
zmin = 0;
zmax = bw;
zmax = bw / 2;
}
double zinc = (zmax - zmin) / (n - 1);
-
+
double z = zmin;
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;
-
+
return (y);
}
/* NAME
-* filter_frequency_response Return filter frequency response
+* 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 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
+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 (au >= (abw / 2) + F_EPSILON)
q = au * abw * sinc (PI * abw * au, 1.);
break;
case FILTER_HANNING:
- param = 0.5;
+ param = 0.5;
// follow through to G_HAMMING
case FILTER_G_HAMMING:
if (au >= (abw / 2) + F_EPSILON)
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
+* 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 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
+double
SignalFilter::spatialResponseAnalytic (double x) const
{
return spatialResponseAnalytic (m_idFilter, m_dBandwidth, x, m_dFilterParam);
SignalFilter::haveAnalyticSpatial (int filterID)
{
bool haveAnalytic = false;
-
+
switch (filterID) {
case FILTER_BANDLIMIT:
case FILTER_TRIANGLE:
default:
break;
}
-
+
return (haveAnalytic);
}
-double
+double
SignalFilter::spatialResponseAnalytic (int filterID, double bw, double x, double param)
{
double q, temp;
double w = bw / 2;
double b = PI / bw;
double b2 = TWOPI / bw;
-
+
switch (filterID) {
case FILTER_BANDLIMIT:
q = bw * sinc(u * w, 1.0);
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
projects / ctsim.git / blobdiff