r382: no message

[ctsim.git] / libctsim / procsignal.cpp

diff --git a/libctsim/procsignal.cpp b/libctsim/procsignal.cpp
index 71a0e67bad2121c37eb063ca893f0e70f4e7919e..4fdefe6679e9fd16346259c8566ce8ebea0f510d 100644 (file)
--- a/libctsim/procsignal.cpp
+++ b/libctsim/procsignal.cpp
@@ -9,7 +9,7 @@
 **  This is part of the CTSim program
 **  Copyright (C) 1983-2000 Kevin Rosenberg
 **
-**  $Id: procsignal.cpp,v 1.14 2001/01/02 16:02:13 kevin Exp $
+**  $Id: procsignal.cpp,v 1.17 2001/01/12 14:14:58 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
@@ -77,7 +77,10 @@ const int ProcessSignal::s_iFilterGenerationCount = sizeof(s_aszFilterGeneration
 // CLASS IDENTIFICATION
 //   ProcessSignal
 //
-ProcessSignal::ProcessSignal (const char* szFilterName, const char* szFilterMethodName, double dBandwidth, double dSignalIncrement, int nSignalPoints, double dFilterParam, const char* szDomainName, const char* szFilterGenerationName, int iZeropad, int iPreinterpolationFactor, int iTraceLevel, int iGeometry, double dFocalLength, SGP* pSGP)
+ProcessSignal::ProcessSignal (const char* szFilterName, const char* szFilterMethodName, double dBandwidth, 
+                                                         double dSignalIncrement, int nSignalPoints, double dFilterParam, const char* szDomainName, 
+                                                         const char* szFilterGenerationName, int iZeropad, int iPreinterpolationFactor, int iTraceLevel, 
+                                                         int iGeometry, double dFocalLength, SGP* pSGP)
 : m_adFourierCosTable(NULL), m_adFourierSinTable(NULL), m_adFilter(NULL), m_fail(false)
 {
   m_idFilterMethod = convertFilterMethodNameToID (szFilterMethodName);
@@ -109,12 +112,16 @@ ProcessSignal::ProcessSignal (const char* szFilterName, const char* szFilterMeth
     return;
   }
   
-  init (m_idFilter, m_idFilterMethod, dBandwidth, dSignalIncrement, nSignalPoints, dFilterParam, m_idDomain, m_idFilterGeneration, iZeropad, iPreinterpolationFactor, iTraceLevel, iGeometry, dFocalLength, pSGP);
+  init (m_idFilter, m_idFilterMethod, dBandwidth, dSignalIncrement, nSignalPoints, dFilterParam, m_idDomain, 
+         m_idFilterGeneration, iZeropad, iPreinterpolationFactor, iTraceLevel, iGeometry, dFocalLength, pSGP);
 }
 
 
 void
-ProcessSignal::init (const int idFilter, const int idFilterMethod, double dBandwidth, double dSignalIncrement, int nSignalPoints, double dFilterParam, const int idDomain, const int idFilterGeneration, const int iZeropad, const int iPreinterpolationFactor, int iTraceLevel, int iGeometry, double dFocalLength, SGP* pSGP)
+ProcessSignal::init (const int idFilter, const int idFilterMethod, double dBandwidth, double dSignalIncrement, 
+                                        int nSignalPoints, double dFilterParam, const int idDomain, const int idFilterGeneration, 
+                                        const int iZeropad, const int iPreinterpolationFactor, int iTraceLevel, int iGeometry, 
+                                        double dFocalLength, SGP* pSGP)
 {
   int i;
   m_idFilter = idFilter;
@@ -139,7 +146,8 @@ ProcessSignal::init (const int idFilter, const int idFilterMethod, double dBandw
   m_iPreinterpolationFactor = iPreinterpolationFactor;
   
   // scale signalInc/BW to signalInc/2 to adjust for imaginary detector
-  // through origin of phantom, see Kak-Slaney Fig 3.22, for Collinear
+  // through origin of phantom rather than 2 times distance to detector, 
+  // see Kak-Slaney Fig 3.22, for Collinear diagram
   if (m_idGeometry == Scanner::GEOMETRY_EQUILINEAR) {
     m_dSignalInc /= 2;
     m_dBandwidth *= 2;
@@ -272,12 +280,16 @@ ProcessSignal::init (const int idFilter, const int idFilterMethod, double dBandw
         m_dFilterMax -= m_dFilterInc;
       }
       
-      SignalFilter filter (m_idFilter, m_dFilterMin, m_dFilterMax, m_nFilterPoints, m_dBandwidth, m_dFilterParam, SignalFilter::DOMAIN_FREQUENCY);
+      SignalFilter filter (m_idFilter, m_dFilterMin, m_dFilterMax, m_nFilterPoints, m_dBandwidth, 
+                 m_dFilterParam, SignalFilter::DOMAIN_FREQUENCY);
       m_adFilter = new double [m_nFilterPoints];
       filter.copyFilterData (m_adFilter, 0, m_nFilterPoints);
       
       // This doesn't work!
       // Need to add filtering for divergent geometries & Frequency/Direct filtering
+         // Jan 2001: Direct seems to work for equilinear and equiangular
+         // however, inverse_fourier doesn't work for equiangular on all versions of CTSim tested
+
       if (m_idGeometry == Scanner::GEOMETRY_EQUILINEAR) {
         for (i = 0; i < m_nFilterPoints; i++)
           m_adFilter[i] *= 0.5;
@@ -336,7 +348,8 @@ ProcessSignal::init (const int idFilter, const int idFilterMethod, double dBandw
         std::cout << "nFilterPoints = " << m_nFilterPoints << endl;
 #endif
       double* adSpatialFilter = new double [m_nFilterPoints];
-      SignalFilter filter (m_idFilter, m_dFilterMin, m_dFilterMax, nSpatialPoints, m_dBandwidth, m_dFilterParam, SignalFilter::DOMAIN_SPATIAL);
+      SignalFilter filter (m_idFilter, m_dFilterMin, m_dFilterMax, nSpatialPoints, m_dBandwidth, 
+                 m_dFilterParam, SignalFilter::DOMAIN_SPATIAL);
       filter.copyFilterData (adSpatialFilter, 0, nSpatialPoints);
 #ifdef HAVE_SGP
       EZPlot* pEZPlot = NULL;
@@ -350,6 +363,9 @@ ProcessSignal::init (const int idFilter, const int idFilterMethod, double dBandw
         delete pEZPlot;
       }
 #endif
+
+// #define PRE_JAN_2001 1
+#ifdef PRE_JAN_2001
       if (m_idGeometry == Scanner::GEOMETRY_EQUILINEAR) {
         for (i = 0; i < m_nFilterPoints; i++)
           adSpatialFilter[i] *= 0.5;
@@ -375,6 +391,35 @@ ProcessSignal::init (const int idFilter, const int idFilterMethod, double dBandw
       for (i = 0; i < m_nFilterPoints; i++)
         m_adFilter[i] = std::abs (acInverseFilter[i]) * m_dSignalInc;
       delete acInverseFilter;
+#else
+      for (i = nSpatialPoints; i < m_nFilterPoints; i++)
+        adSpatialFilter[i] = 0;
+      
+      std::complex<double>* acInverseFilter = new std::complex<double> [m_nFilterPoints];
+      finiteFourierTransform (adSpatialFilter, acInverseFilter, m_nFilterPoints, FORWARD);
+      delete adSpatialFilter;
+      m_adFilter = new double [m_nFilterPoints];
+      for (i = 0; i < m_nFilterPoints; i++)
+                 m_adFilter[i] = std::abs(acInverseFilter[i]);
+      delete acInverseFilter;
+
+      if (m_idGeometry == Scanner::GEOMETRY_EQUILINEAR) {
+        for (i = 0; i < m_nFilterPoints; i++)
+          m_adFilter[i] *= 0.5;
+      } else if (m_idGeometry == Scanner::GEOMETRY_EQUIANGULAR) {
+        for (i = 0; i < m_nFilterPoints; i++) {
+          int iDetFromZero = i - ((m_nFilterPoints - 1) / 2);
+          double sinScale = sin (iDetFromZero * m_dSignalInc);
+          if (fabs(sinScale) < 1E-7)
+            sinScale = 1;
+          else
+            sinScale = (iDetFromZero * m_dSignalInc) / sinScale;
+          double dScale = 0.5 * sinScale * sinScale;
+          m_adFilter[i] *= dScale;
+        }
+      }
+#endif
+
 #ifdef HAVE_SGP
       if (pEZPlot && m_traceLevel >= Trace::TRACE_PLOT) {
         pEZPlot->ezset ("title Spatial Filter: Inverse");