/*****************************************************************************
** FILE IDENTIFICATION
**
-** Name: backprojectors.cpp Classes for backprojection
+** Name: backprojectors.cpp Classes for backprojection
** Programmer: Kevin Rosenberg
** Date Started: June 2000
**
** This is part of the CTSim program
-** Copyright (c) 1983-2001 Kevin Rosenberg
-**
-** $Id: backprojectors.cpp,v 1.31 2001/03/11 15:27:30 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
******************************************************************************/
#include "ct.h"
+#include "interpolator.h"
const int Backprojector::BPROJ_INVALID = -1;
const int Backprojector::BPROJ_TRIG = 0;
const int Backprojector::BPROJ_DIFF = 2;
const int Backprojector::BPROJ_IDIFF = 3;
-const char* const Backprojector::s_aszBackprojectName[] =
+const char* const Backprojector::s_aszBackprojectName[] =
{
- {"trig"},
- {"table"},
- {"diff"},
- {"idiff"},
+ "trig",
+ "table",
+ "diff",
+ "idiff",
};
-const char* const Backprojector::s_aszBackprojectTitle[] =
+const char* const Backprojector::s_aszBackprojectTitle[] =
{
- {"Direct Trigometric"},
- {"Trigometric Table"},
- {"Difference Iteration"},
- {"Integer Difference Iteration"},
+ "Direct Trigometric",
+ "Trigometric Table",
+ "Difference Iteration",
+ "Integer Difference Iteration",
};
const int Backprojector::s_iBackprojectCount = sizeof(s_aszBackprojectName) / sizeof(const char*);
const int Backprojector::INTERP_3BSPLINE = 7;
#endif
-const char* const Backprojector::s_aszInterpName[] =
+const char* const Backprojector::s_aszInterpName[] =
{
- {"nearest"},
- {"linear"},
- {"cubic"},
+ "nearest",
+ "linear",
+ "cubic",
#if HAVE_FREQ_PREINTERP
- {"freq_preinterpolationj"},
+ "freq_preinterpolationj",
#endif
#if HAVE_BSPLINE_INTERP
- {"bspline"},
- {"1bspline"},
- {"2bspline"},
- {"3bspline"},
+ "bspline",
+ "1bspline",
+ "2bspline",
+ "3bspline",
#endif
};
-const char* const Backprojector::s_aszInterpTitle[] =
+const char* const Backprojector::s_aszInterpTitle[] =
{
- {"Nearest"},
- {"Linear"},
- {"Cubic"},
+ "Nearest",
+ "Linear",
+ "Cubic",
#if HAVE_FREQ_PREINTERP
- {"Frequency Preinterpolation"},
+ "Frequency Preinterpolation",
#endif
#if HAVE_BSPLINE_INTERP
- {"B-Spline"},
- {"B-Spline 1st Order"},
- {"B-Spline 2nd Order"},
- {"B-Spline 3rd Order"},
+ "B-Spline",
+ "B-Spline 1st Order",
+ "B-Spline 2nd Order",
+ "B-Spline 3rd Order",
#endif
};
-Backprojector::Backprojector (const Projections& proj, ImageFile& im, const char* const backprojName,
+Backprojector::Backprojector (const Projections& proj, ImageFile& im, const char* const backprojName,
const char* const interpName, const int interpFactor, const ReconstructionROI* pROI)
{
m_fail = false;
m_pBackprojectImplem = NULL;
-
+
initBackprojector (proj, im, backprojName, interpName, interpFactor, pROI);
}
-void
+void
Backprojector::BackprojectView (const double* const viewData, const double viewAngle)
{
if (m_pBackprojectImplem != NULL)
m_pBackprojectImplem->BackprojectView (viewData, viewAngle);
}
-void
+void
Backprojector::PostProcessing()
{
if (m_pBackprojectImplem != NULL)
// Backproject* projector = selectBackprojector (...)
//
// PURPOSE
-// Selects a backprojector based on BackprojType
+// Selects a backprojector based on BackprojType
// and initializes the backprojector
bool
-Backprojector::initBackprojector (const Projections& proj, ImageFile& im, const char* const backprojName,
+Backprojector::initBackprojector (const Projections& proj, ImageFile& im, const char* const backprojName,
const char* const interpName, const int interpFactor, const ReconstructionROI* pROI)
{
m_nameBackproject = backprojName;
m_failMessage = "Invalid interpolation name ";
m_failMessage += interpName;
}
-
+
if (m_fail || m_idBackproject == BPROJ_INVALID || m_idInterpolation == INTERP_INVALID) {
m_fail = true;
return false;
}
-
+
if (proj.geometry() == Scanner::GEOMETRY_EQUILINEAR)
m_pBackprojectImplem = static_cast<Backproject*>(new BackprojectEquilinear(proj, im, m_idInterpolation, interpFactor, pROI));
- else if (proj.geometry() == Scanner::GEOMETRY_EQUIANGULAR)
+ else if (proj.geometry() == Scanner::GEOMETRY_EQUIANGULAR)
m_pBackprojectImplem = static_cast<Backproject*>(new BackprojectEquiangular(proj, im, m_idInterpolation, interpFactor, pROI));
else if (proj.geometry() == Scanner::GEOMETRY_PARALLEL) {
if (m_idBackproject == BPROJ_TRIG)
m_failMessage = "Unable to select a backprojection method [Backprojector::initBackprojector]";
return false;
}
-
+
return true;
}
Backprojector::convertBackprojectNameToID (const char* const backprojName)
{
int backprojID = BPROJ_INVALID;
-
- for (int i = 0; i < s_iBackprojectCount; i++)
+
+ for (int i = 0; i < s_iBackprojectCount; i++) {
if (strcasecmp (backprojName, s_aszBackprojectName[i]) == 0) {
backprojID = i;
break;
}
-
- return (backprojID);
+ }
+ return (backprojID);
}
const char*
Backprojector::convertBackprojectIDToName (int bprojID)
{
static const char *bprojName = "";
-
+
if (bprojID >= 0 && bprojID < s_iBackprojectCount)
return (s_aszBackprojectName[bprojID]);
-
+
return (bprojName);
}
Backprojector::convertBackprojectIDToTitle (const int bprojID)
{
static const char *bprojTitle = "";
-
+
if (bprojID >= 0 && bprojID < s_iBackprojectCount)
return (s_aszBackprojectTitle[bprojID]);
-
+
return (bprojTitle);
}
Backprojector::convertInterpNameToID (const char* const interpName)
{
int interpID = INTERP_INVALID;
-
- for (int i = 0; i < s_iInterpCount; i++)
+
+ for (int i = 0; i < s_iInterpCount; i++) {
if (strcasecmp (interpName, s_aszInterpName[i]) == 0) {
interpID = i;
break;
}
-
- return (interpID);
+ }
+ return (interpID);
}
const char*
Backprojector::convertInterpIDToName (const int interpID)
{
static const char *interpName = "";
-
+
if (interpID >= 0 && interpID < s_iInterpCount)
return (s_aszInterpName[interpID]);
-
+
return (interpName);
}
Backprojector::convertInterpIDToTitle (const int interpID)
{
static const char *interpTitle = "";
-
+
if (interpID >= 0 && interpID < s_iInterpCount)
return (s_aszInterpTitle[interpID]);
-
+
return (interpTitle);
}
// PURPOSE
// Pure virtual base class for all backprojectors.
-Backproject::Backproject (const Projections& proj, ImageFile& im, int interpType, const int interpFactor,
+Backproject::Backproject (const Projections& proj, ImageFile& im, int interpType, const int interpFactor,
const ReconstructionROI* pROI)
: proj(proj), im(im), interpType(interpType), m_interpFactor(interpFactor), m_bPostProcessingDone(false)
{
detInc = proj.detInc();
nDet = proj.nDet();
- iDetCenter = (nDet - 1) / 2; // index refering to L=0 projection
- rotScale = proj.rotInc();
-
+ iDetCenter = (nDet - 1) / 2; // index refering to L=0 projection
+
if (proj.geometry() == Scanner::GEOMETRY_PARALLEL)
- rotScale /= (proj.nView() * proj.rotInc() / PI); // scale by number of PI rotations
+ rotScale = PI / proj.nView(); // scale by number of PI rotations
else if (proj.geometry() == Scanner::GEOMETRY_EQUIANGULAR || proj.geometry() == Scanner::GEOMETRY_EQUILINEAR)
- rotScale /= (proj.nView() * proj.rotInc() / (2 * PI)); // scale by number of 2PI rotations
+ rotScale = (2 * PI) / proj.nView(); // scale by number of 2PI rotations
else
sys_error (ERR_SEVERE, "Invalid geometry type %d [Backproject::Backproject]", proj.geometry());
-
+
v = im.getArray();
nx = im.nx();
ny = im.ny();
im.arrayDataClear();
-
+
xMin = -proj.phmLen() / 2; // Retangular coords of phantom
xMax = xMin + proj.phmLen();
yMin = -proj.phmLen() / 2;
yMax = yMin + proj.phmLen();
-
+
if (pROI) {
if (pROI->m_dXMin > xMin)
xMin = pROI->m_dXMin;
}
}
- xInc = (xMax - xMin) / nx; // size of cells
+ xInc = (xMax - xMin) / nx; // size of cells
yInc = (yMax - yMin) / ny;
-
+
+ im.setAxisIncrement (xInc, yInc);
+ im.setAxisExtent (xMin, xMax, yMin, yMax);
+
m_dFocalLength = proj.focalLength();
m_dSourceDetectorLength = proj.sourceDetectorLength();
}
os << "xMin=" << xMin << ", xMax=" << xMax << ", xInc=" << xInc << "\n";
os << "yMin=" << yMin << ", yMax=" << yMax << ", yInc=" << yInc << "\n";
os << "iDetPos index outside bounds: " << iDetPos << " [backprojector]";;
-
+
sys_error (ERR_WARNING, os.str().c_str());
#endif
}
BackprojectTrig::BackprojectView (const double* const filteredProj, const double view_angle)
{
double theta = view_angle;
-
+
CubicPolyInterpolator* pCubicInterp = NULL;
if (interpType == Backprojector::INTERP_CUBIC)
pCubicInterp = new CubicPolyInterpolator (filteredProj, nDet);
-
- double x = xMin + xInc / 2; // Rectang coords of center of pixel
- for (int ix = 0; ix < nx; x += xInc, ix++) {
+
+ double xstart = xMin + xInc / 2; // Rectang coords of center of pixel
+#if HAVE_OPENMP
+ #pragma omp parallel for
+#endif
+ for (int ix = 0; ix < nx; ix++) {
+ double x = xstart + (ix * xInc);
+
double y = yMin + yInc / 2;
for (int iy = 0; iy < ny; y += yInc, iy++) {
double r = sqrt (x * x + y * y); // distance of cell from center
double phi = atan2 (y, x); // angle of cell from center
double L = r * cos (theta - phi); // position on detector
-
+
if (interpType == Backprojector::INTERP_NEAREST) {
int iDetPos = iDetCenter + nearest<int> (L / detInc); // calc'd index in the filter raysum array
-
+
if (iDetPos >= 0 && iDetPos < nDet)
v[ix][iy] += rotScale * filteredProj[iDetPos];
} else if (interpType == Backprojector::INTERP_LINEAR) {
- double p = L / detInc; // position along detector
+ double p = L / detInc; // position along detector
double pFloor = floor (p);
int iDetPos = iDetCenter + static_cast<int>(pFloor);
- double frac = p - pFloor; // fraction distance from det
+ double frac = p - pFloor; // fraction distance from det
if (iDetPos >= 0 && iDetPos < nDet - 1)
v[ix][iy] += rotScale * ((1-frac) * filteredProj[iDetPos] + frac * filteredProj[iDetPos+1]);
} else if (interpType == Backprojector::INTERP_CUBIC) {
- double p = iDetCenter + (L / detInc); // position along detector
+ double p = iDetCenter + (L / detInc); // position along detector
if (p >= 0 && p < nDet)
v[ix][iy] += rotScale * pCubicInterp->interpolate (p);
}
if (interpType == Backprojector::INTERP_CUBIC)
delete pCubicInterp;
-}
+}
// CLASS IDENTICATION
// PURPOSE
// Precalculates trigometric function value for each point in image for backprojection.
-BackprojectTable::BackprojectTable (const Projections& proj, ImageFile& im, int interpType,
+BackprojectTable::BackprojectTable (const Projections& proj, ImageFile& im, int interpType,
const int interpFactor, const ReconstructionROI* pROI)
: Backproject (proj, im, interpType, interpFactor, pROI)
{
arrayPhi.initSetSize (im.nx(), im.ny());
r = arrayR.getArray();
phi = arrayPhi.getArray();
-
- double x, y; // Rectang coords of center of pixel
- int ix, iy;
- for (x = xMin + xInc / 2, ix = 0; ix < nx; x += xInc, ix++)
- for (y = yMin + yInc / 2, iy = 0; iy < ny; y += yInc, iy++) {
+
+ double xstart = xMin + xInc / 2;
+
+#if HAVE_OPENMP
+ #pragma omp parallel for
+#endif
+ for (int ix = 0; ix < nx; ix++) {
+ double x = xstart + (ix * xInc);
+ double y = yMin + yInc / 2;
+ for (int iy = 0; iy < ny; iy++, y += yInc) {
r[ix][iy] = sqrt (x * x + y * y);
phi[ix][iy] = atan2 (y, x);
}
+ }
}
BackprojectTable::~BackprojectTable ()
BackprojectTable::BackprojectView (const double* const filteredProj, const double view_angle)
{
double theta = view_angle;
-
+
CubicPolyInterpolator* pCubicInterp = NULL;
if (interpType == Backprojector::INTERP_CUBIC)
pCubicInterp = new CubicPolyInterpolator (filteredProj, nDet);
-
+
+#if HAVE_OPENMP
+ #pragma omp parallel for
+#endif
for (int ix = 0; ix < nx; ix++) {
ImageFileColumn pImCol = v[ix];
-
+
for (int iy = 0; iy < ny; iy++) {
double L = r[ix][iy] * cos (theta - phi[ix][iy]);
-
+
if (interpType == Backprojector::INTERP_NEAREST) {
- int iDetPos = iDetCenter + nearest<int>(L / detInc); // calc index in the filtered raysum vector
-
- if (iDetPos >= 0 && iDetPos < nDet)
+ int iDetPos = iDetCenter + nearest<int>(L / detInc); // calc index in the filtered raysum vector
+
+ if (iDetPos >= 0 && iDetPos < nDet) {
pImCol[iy] += filteredProj[iDetPos];
+ }
} else if (interpType == Backprojector::INTERP_LINEAR) {
- double dPos = L / detInc; // position along detector
+ double dPos = L / detInc; // position along detector
double dPosFloor = floor (dPos);
int iDetPos = iDetCenter + static_cast<int>(dPosFloor);
- double frac = dPos - dPosFloor; // fraction distance from det
- if (iDetPos >= 0 && iDetPos < nDet - 1)
+ double frac = dPos - dPosFloor; // fraction distance from det
+ if (iDetPos >= 0 && iDetPos < nDet - 1) {
pImCol[iy] += ((1-frac) * filteredProj[iDetPos] + frac * filteredProj[iDetPos+1]);
+ }
} else if (interpType == Backprojector::INTERP_CUBIC) {
- double p = iDetCenter + (L / detInc); // position along detector
- if (p >= 0 && p < nDet)
+ double p = iDetCenter + (L / detInc); // position along detector
+ if (p >= 0 && p < nDet) {
pImCol[iy] += pCubicInterp->interpolate (p);
+ }
}
- } // end for y
- } // end for x
+ } // end for y
+ } // end for x
if (interpType == Backprojector::INTERP_CUBIC)
delete pCubicInterp;
// Backprojects by precalculating the change in L position for each x & y step in the image.
// Iterates in x & y direction by adding difference in L position
-BackprojectDiff::BackprojectDiff (const Projections& proj, ImageFile& im, int interpType,
+BackprojectDiff::BackprojectDiff (const Projections& proj, ImageFile& im, int interpType,
const int interpFactor, const ReconstructionROI* pROI)
: Backproject (proj, im, interpType, interpFactor, pROI)
{
- // calculate center of first pixel v[0][0]
+ // calculate center of first pixel v[0][0]
double x = xMin + xInc / 2;
double y = yMin + yInc / 2;
start_r = sqrt (x * x + y * y);
start_phi = atan2 (y, x);
-
+
im.arrayDataClear();
}
BackprojectDiff::BackprojectView (const double* const filteredProj, const double view_angle)
{
double theta = view_angle;
-
- // Distance between detectors for an angle given in units of detectors
+
+ // Distance between detectors for an angle given in units of detectors
double det_dx = xInc * cos (theta) / detInc;
double det_dy = yInc * sin (theta) / detInc;
-
- // calculate detPosition for first point in image (ix=0, iy=0)
- double detPosColStart = start_r * cos (theta - start_phi) / detInc;
-
+
+ // calculate detPosition for first point in image (ix=0, iy=0)
+ double detPosColBase = iDetCenter + start_r * cos (theta - start_phi) / detInc;
+
CubicPolyInterpolator* pCubicInterp = NULL;
- if (interpType == Backprojector::INTERP_CUBIC)
+ double* deltaFilteredProj = NULL;
+ if (interpType == Backprojector::INTERP_LINEAR) {
+ // precalculate scaled difference for linear interpolation
+ deltaFilteredProj = new double [nDet];
+ for (int i = 0; i < nDet - 1; i++)
+ deltaFilteredProj[i] = filteredProj[i+1] - filteredProj[i];
+ deltaFilteredProj[nDet - 1] = 0; // last detector
+ } else if (interpType == Backprojector::INTERP_CUBIC) {
pCubicInterp = new CubicPolyInterpolator (filteredProj, nDet);
-
- for (int ix = 0; ix < nx; ix++, detPosColStart += det_dx) {
- double curDetPos = detPosColStart;
+ }
+
+ int iLastDet = nDet - 1;
+
+#if HAVE_OPENMP
+ #pragma omp parallel for
+#endif
+ for (int ix = 0; ix < nx; ix++) {
+ double detPos = detPosColBase + (ix * det_dx);
ImageFileColumn pImCol = v[ix];
-
- for (int iy = 0; iy < ny; iy++, curDetPos += det_dy) {
+
+ for (int iy = 0; iy < ny; iy++, detPos += det_dy) {
if (interpType == Backprojector::INTERP_NEAREST) {
- int iDetPos = iDetCenter + nearest<int> (curDetPos); // calc index in the filtered raysum vector
-
- if (iDetPos >= 0 && iDetPos < nDet)
+ int iDetPos = nearest<int> (detPos); // calc index in the filtered raysum vector
+ if (iDetPos >= 0 && iDetPos < nDet) {
*pImCol++ += filteredProj[iDetPos];
+ }
} else if (interpType == Backprojector::INTERP_LINEAR) {
- double detPosFloor = floor (curDetPos);
- int iDetPos = iDetCenter + static_cast<int>(detPosFloor);
- double frac = curDetPos - detPosFloor; // fraction distance from det
- if (iDetPos > 0 && iDetPos < nDet - 1)
- *pImCol++ += filteredProj[iDetPos] + (frac * (filteredProj[iDetPos+1] - filteredProj[iDetPos]));
+ double detPosFloor = floor (detPos);
+ int iDetPos = static_cast<int>(detPosFloor);
+ double frac = detPos - detPosFloor; // fraction distance from det
+ if (iDetPos >= 0 && iDetPos <= iLastDet) {
+ *pImCol++ += filteredProj[iDetPos] + (frac * deltaFilteredProj[iDetPos]);
+ }
} else if (interpType == Backprojector::INTERP_CUBIC) {
- double p = iDetCenter + curDetPos; // position along detector
- if (p >= 0 && p < nDet)
+ double p = detPos; // position along detector
+ if (p >= 0 && p < nDet) {
*pImCol++ += pCubicInterp->interpolate (p);
+ }
}
- } // end for y
- } // end for x
+ } // end for y
+ } // end for x
- if (interpType == Backprojector::INTERP_CUBIC)
+ if (interpType == Backprojector::INTERP_LINEAR)
+ delete deltaFilteredProj;
+ else if (interpType == Backprojector::INTERP_CUBIC)
delete pCubicInterp;
}
BackprojectIntDiff::BackprojectView (const double* const filteredProj, const double view_angle)
{
double theta = view_angle; // add half PI to view angle to get perpendicular theta angle
+#if SIZEOF_LONG == 4
static const int scaleShift = 16;
- static const kint32 scale = (1 << scaleShift);
- static const kint32 scaleBitmask = scale - 1;
- static const kint32 halfScale = scale / 2;
+#elif SIZEOF_LONG == 8
+ static const int scaleShift = 32;
+#endif
+ static const long scale = (1L << scaleShift);
+ static const long scaleBitmask = scale - 1;
+ static const long halfScale = scale / 2;
static const double dInvScale = 1. / scale;
-
- const kint32 det_dx = nearest<kint32> (xInc * cos (theta) / detInc * scale);
- const kint32 det_dy = nearest<kint32> (yInc * sin (theta) / detInc * scale);
-
- // calculate L for first point in image (0, 0)
- kint32 detPosColStart = nearest<kint32> ((start_r * cos (theta - start_phi) / detInc + iDetCenter) * scale);
-
- double* deltaFilteredProj = NULL;
+
+ const long det_dx = nearest<long> (xInc * cos (theta) / detInc * scale);
+ const long det_dy = nearest<long> (yInc * sin (theta) / detInc * scale);
+
+ // calculate L for first point in image (0, 0)
+ long detPosColBase = nearest<long> ((start_r * cos (theta - start_phi) / detInc + iDetCenter) * scale);
+
+ double* deltaFilteredProj = NULL;
CubicPolyInterpolator* pCubicInterp = NULL;
if (interpType == Backprojector::INTERP_LINEAR) {
// precalculate scaled difference for linear interpolation
} else if (interpType == Backprojector::INTERP_CUBIC) {
pCubicInterp = new CubicPolyInterpolator (filteredProj, nDet);
}
-
+
int iLastDet = nDet - 1;
- for (int ix = 0; ix < nx; ix++, detPosColStart += det_dx) {
- kint32 curDetPos = detPosColStart;
+#if HAVE_OPENMP
+ #pragma omp parallel for
+#endif
+ for (int ix = 0; ix < nx; ix++) {
+ long detPos = detPosColBase + (ix * det_dx);
ImageFileColumn pImCol = v[ix];
-
- if (interpType == Backprojector::INTERP_NEAREST) {
- for (int iy = 0; iy < ny; iy++, curDetPos += det_dy) {
- const int iDetPos = (curDetPos + halfScale) >> 16;
- if (iDetPos >= 0 && iDetPos <= iLastDet)
+
+ for (int iy = 0; iy < ny; iy++, detPos += det_dy) {
+ if (interpType == Backprojector::INTERP_NEAREST) {
+ const int iDetPos = (detPos + halfScale) >> scaleShift;
+ if (iDetPos >= 0 && iDetPos <= iLastDet) {
*pImCol++ += filteredProj[iDetPos];
- } // end for iy
- } else if (interpType == Backprojector::INTERP_FREQ_PREINTERPOLATION) {
- for (int iy = 0; iy < ny; iy++, curDetPos += det_dy) {
- const int iDetPos = ((curDetPos + halfScale) >> 16) * m_interpFactor;
- if (iDetPos >= 0 && iDetPos <= iLastDet)
+ } else
+ pImCol++;
+ } else if (interpType == Backprojector::INTERP_FREQ_PREINTERPOLATION) {
+ const int iDetPos = ((detPos + halfScale) >> scaleShift) * m_interpFactor;
+ if (iDetPos >= 0 && iDetPos <= iLastDet) {
*pImCol++ += filteredProj[iDetPos];
- } // end for iy
- } else if (interpType == Backprojector::INTERP_LINEAR) {
- for (int iy = 0; iy < ny; iy++, curDetPos += det_dy) {
- const kint32 iDetPos = curDetPos >> scaleShift;
- const kint32 detRemainder = curDetPos & scaleBitmask;
- if (iDetPos >= 0 && iDetPos <= iLastDet)
+ } else
+ pImCol++;
+ } else if (interpType == Backprojector::INTERP_LINEAR) {
+ const long iDetPos = detPos >> scaleShift;
+ if (iDetPos >= 0 && iDetPos <= iLastDet) {
+ const long detRemainder = detPos & scaleBitmask;
*pImCol++ += filteredProj[iDetPos] + (detRemainder * deltaFilteredProj[iDetPos]);
- } // end for iy
- } else if (interpType == Backprojector::INTERP_CUBIC) {
- for (int iy = 0; iy < ny; iy++, curDetPos += det_dy) {
- *pImCol++ += pCubicInterp->interpolate (static_cast<double>(curDetPos) / 65536);
- }
- } // end Cubic
+ } else
+ pImCol++;
+ } else if (interpType == Backprojector::INTERP_CUBIC) {
+ *pImCol++ += pCubicInterp->interpolate (static_cast<double>(detPos) / scale);
+ } // end Cubic
+ } // end for iy
} // end for ix
-
+
if (interpType == Backprojector::INTERP_LINEAR)
delete deltaFilteredProj;
else if (interpType == Backprojector::INTERP_CUBIC)
BackprojectEquiangular::BackprojectView (const double* const filteredProj, const double view_angle)
{
double beta = view_angle;
-
+
CubicPolyInterpolator* pCubicInterp = NULL;
if (interpType == Backprojector::INTERP_CUBIC)
pCubicInterp = new CubicPolyInterpolator (filteredProj, nDet);
-
+
+#if HAVE_OPENMP
+ #pragma omp parallel for
+#endif
for (int ix = 0; ix < nx; ix++) {
ImageFileColumn pImCol = v[ix];
-
- for (int iy = 0; iy < ny; iy++) {
+
+ for (int iy = 0; iy < ny; iy++) {
double dAngleDiff = beta - phi[ix][iy];
double rcos_t = r[ix][iy] * cos (dAngleDiff);
double rsin_t = r[ix][iy] * sin (dAngleDiff);
double gamma = atan (rcos_t / dFLPlusSin);
double dPos = gamma / detInc; // position along detector
double dL2 = dFLPlusSin * dFLPlusSin + (rcos_t * rcos_t);
-
+
if (interpType == Backprojector::INTERP_NEAREST) {
- int iDetPos = iDetCenter + nearest<int>(dPos); // calc index in the filtered raysum vector
+ int iDetPos = iDetCenter + nearest<int>(dPos); // calc index in the filtered raysum vector
if (iDetPos >= 0 && iDetPos < nDet)
pImCol[iy] += filteredProj[iDetPos] / dL2;
} else if (interpType == Backprojector::INTERP_LINEAR) {
double dPosFloor = floor (dPos);
int iDetPos = iDetCenter + static_cast<int>(dPosFloor);
- double frac = dPos - dPosFloor; // fraction distance from det
+ double frac = dPos - dPosFloor; // fraction distance from det
if (iDetPos >= 0 && iDetPos < nDet - 1)
pImCol[iy] += (filteredProj[iDetPos] + frac * (filteredProj[iDetPos+1] - filteredProj[iDetPos])) / dL2;
} else if (interpType == Backprojector::INTERP_CUBIC) {
- double d = iDetCenter + dPos; // position along detector
+ double d = iDetCenter + dPos; // position along detector
if (d >= 0 && d < nDet)
pImCol[iy] += pCubicInterp->interpolate (d) / dL2;
}
- } // end for y
- } // end for x
+ } // end for y
+ } // end for x
if (interpType == Backprojector::INTERP_CUBIC)
delete pCubicInterp;
BackprojectEquilinear::BackprojectView (const double* const filteredProj, const double view_angle)
{
double beta = view_angle;
-
+
CubicPolyInterpolator* pCubicInterp = NULL;
if (interpType == Backprojector::INTERP_CUBIC)
pCubicInterp = new CubicPolyInterpolator (filteredProj, nDet);
-
+
+#if HAVE_OPENMP
+ #pragma omp parallel for
+#endif
for (int ix = 0; ix < nx; ix++) {
ImageFileColumn pImCol = v[ix];
-
+
for (int iy = 0; iy < ny; iy++) {
double dAngleDiff = beta - phi[ix][iy];
double rcos_t = r[ix][iy] * cos (dAngleDiff);
double rsin_t = r[ix][iy] * sin (dAngleDiff);
-
+
double dU = (m_dFocalLength + rsin_t) / m_dFocalLength;
+ double dU2 = dU * dU;
+
double dDetPos = rcos_t / dU;
- // 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
+ // 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) {
- int iDetPos = iDetCenter + nearest<int>(dPos); // calc index in the filtered raysum vector
- if (iDetPos >= 0 && iDetPos < nDet)
- pImCol[iy] += (filteredProj[iDetPos] / (dU * dU));
+ int iDetPos = iDetCenter + nearest<int>(dPos); // calc index in the filtered raysum vector
+ if (iDetPos >= 0 && iDetPos < nDet)
+ pImCol[iy] += filteredProj[iDetPos] / dU2;
} else if (interpType == Backprojector::INTERP_LINEAR) {
double dPosFloor = floor (dPos);
int iDetPos = iDetCenter + static_cast<int>(dPosFloor);
- double frac = dPos - dPosFloor; // fraction distance from det
+ double frac = dPos - dPosFloor; // fraction distance from det
if (iDetPos >= 0 && iDetPos < nDet - 1)
- pImCol[iy] += (filteredProj[iDetPos] + frac * (filteredProj[iDetPos+1] - filteredProj[iDetPos]))
- / (dU * dU);
+ pImCol[iy] += (filteredProj[iDetPos] + frac * (filteredProj[iDetPos+1] - filteredProj[iDetPos])) / dU2;
} else if (interpType == Backprojector::INTERP_CUBIC) {
- double d = iDetCenter + dPos; // position along detector
+ double d = iDetCenter + dPos; // position along detector
if (d >= 0 && d < nDet)
- pImCol[iy] += pCubicInterp->interpolate (d) / (dU * dU);
+ pImCol[iy] += pCubicInterp->interpolate (d) / dU2;
}
- } // end for y
- } // end for x
+ } // end for y
+ } // end for x
if (interpType == Backprojector::INTERP_CUBIC)
delete pCubicInterp;
projects / ctsim.git / blobdiff