r591: Added Center-Detector length to scanning and reconstruction

[ctsim.git] / libctsim / backprojectors.cpp

diff --git a/libctsim/backprojectors.cpp b/libctsim/backprojectors.cpp
index ebfe2a4358326b16aafafb2b30ef8fe84b3240f9..bab1dc7b18fc75e349cc961c43165f884545ed87 100644 (file)
--- a/libctsim/backprojectors.cpp
+++ b/libctsim/backprojectors.cpp
@@ -8,7 +8,7 @@
 **  This is part of the CTSim program
 **  Copyright (c) 1983-2001 Kevin Rosenberg
 **
-**  $Id: backprojectors.cpp,v 1.27 2001/02/22 18:22:40 kevin Exp $
+**  $Id: backprojectors.cpp,v 1.29 2001/03/01 07:30:49 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
@@ -113,6 +113,13 @@ Backprojector::BackprojectView (const double* const viewData, const double viewA
     m_pBackprojectImplem->BackprojectView (viewData, viewAngle);
 }
 
+void 
+Backprojector::PostProcessing()
+{
+  if (m_pBackprojectImplem != NULL)
+    m_pBackprojectImplem->PostProcessing();
+}
+
 Backprojector::~Backprojector ()
 {
   delete m_pBackprojectImplem;
@@ -254,7 +261,7 @@ Backprojector::convertInterpIDToTitle (const int interpID)
 //   Pure virtual base class for all backprojectors.
 
 Backproject::Backproject (const Projections& proj, ImageFile& im, int interpType, const int interpFactor)
-: proj(proj), im(im), interpType(interpType), m_interpFactor(interpFactor)
+: proj(proj), im(im), interpType(interpType), m_interpFactor(interpFactor), m_bPostProcessingDone(false)
 {
   detInc = proj.detInc();
   nDet = proj.nDet();
@@ -282,11 +289,18 @@ Backproject::Backproject (const Projections& proj, ImageFile& im, int interpType
   yInc = (yMax - yMin) / ny;
   
   m_dFocalLength = proj.focalLength();
+  m_dSourceDetectorLength = proj.sourceDetectorLength();
 }
 
 Backproject::~Backproject ()
 {}
 
+void
+Backproject::PostProcessing()
+{
+  m_bPostProcessingDone = true;
+}
+
 void
 Backproject::ScaleImageByRotIncrement ()
 {
@@ -389,7 +403,15 @@ BackprojectTable::BackprojectTable (const Projections& proj, ImageFile& im, int
 
 BackprojectTable::~BackprojectTable ()
 {
-  ScaleImageByRotIncrement();
+}
+
+void
+BackprojectTable::PostProcessing()
+{
+  if (! m_bPostProcessingDone) {
+    ScaleImageByRotIncrement();
+    m_bPostProcessingDone = true;
+  }
 }
 
 void
@@ -451,11 +473,18 @@ BackprojectDiff::BackprojectDiff (const Projections& proj, ImageFile& im, int in
   im.arrayDataClear();
 }
 
-BackprojectDiff::~BackprojectDiff()
+BackprojectDiff::~BackprojectDiff ()
 {
-  ScaleImageByRotIncrement();
 }
 
+void
+BackprojectDiff::PostProcessing()
+{
+  if (! m_bPostProcessingDone) {
+    ScaleImageByRotIncrement();
+    m_bPostProcessingDone = true;
+  }
+}
 
 void
 BackprojectDiff::BackprojectView (const double* const filteredProj, const double view_angle)
@@ -636,10 +665,8 @@ BackprojectEquilinear::BackprojectView (const double* const filteredProj, const
       
       double dU = (m_dFocalLength + rsin_t) / m_dFocalLength;
       double dDetPos =  rcos_t / dU;
-      // double to scale for imaginary detector that passes through origin
-      // of phantom, see Kak-Slaney Figure 3.22. This assumes that the detector is also
-      // located focal-length away from the origin.
-      dDetPos *= 2; 
+      // Scale for imaginary detector that passes through origin of phantom, see Kak-Slaney Figure 3.22. 
+      dDetPos *= m_dSourceDetectorLength / m_dFocalLength; 
       double dPos = dDetPos / detInc;  // position along detector array 
 
       if (interpType == Backprojector::INTERP_NEAREST) {