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 fc3c95882dd768458613be752749c10e759978a9..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 1.28 2001/02/23 02:06:01 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
@@ -289,6 +289,7 @@ Backproject::Backproject (const Projections& proj, ImageFile& im, int interpType
   yInc = (yMax - yMin) / ny;
   
   m_dFocalLength = proj.focalLength();
+  m_dSourceDetectorLength = proj.sourceDetectorLength();
 }
 
 Backproject::~Backproject ()
@@ -664,10 +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) {