** Programmer: Kevin Rosenberg
** Date Started: June 2000
**
** This is part of the CTSim program
** Programmer: Kevin Rosenberg
** Date Started: June 2000
**
** This is part of the CTSim program
**
** 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
**
** 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
-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;
const char* const interpName, const int interpFactor, const ReconstructionROI* pROI)
{
m_fail = false;
m_pBackprojectImplem = NULL;
initBackprojector (proj, im, backprojName, interpName, interpFactor, pROI);
}
initBackprojector (proj, im, backprojName, interpName, interpFactor, pROI);
}
Backprojector::BackprojectView (const double* const viewData, const double viewAngle)
{
if (m_pBackprojectImplem != NULL)
m_pBackprojectImplem->BackprojectView (viewData, viewAngle);
}
Backprojector::BackprojectView (const double* const viewData, const double viewAngle)
{
if (m_pBackprojectImplem != NULL)
m_pBackprojectImplem->BackprojectView (viewData, viewAngle);
}
-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;
const char* const interpName, const int interpFactor, const ReconstructionROI* pROI)
{
m_nameBackproject = backprojName;
if (proj.geometry() == Scanner::GEOMETRY_EQUILINEAR)
m_pBackprojectImplem = static_cast<Backproject*>(new BackprojectEquilinear(proj, im, m_idInterpolation, interpFactor, pROI));
if (proj.geometry() == Scanner::GEOMETRY_EQUILINEAR)
m_pBackprojectImplem = static_cast<Backproject*>(new BackprojectEquilinear(proj, im, m_idInterpolation, interpFactor, pROI));
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_pBackprojectImplem = static_cast<Backproject*>(new BackprojectEquiangular(proj, im, m_idInterpolation, interpFactor, pROI));
else if (proj.geometry() == Scanner::GEOMETRY_PARALLEL) {
if (m_idBackproject == BPROJ_TRIG)
Backprojector::convertBackprojectNameToID (const char* const backprojName)
{
int backprojID = BPROJ_INVALID;
Backprojector::convertBackprojectNameToID (const char* const backprojName)
{
int backprojID = BPROJ_INVALID;
-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();
const ReconstructionROI* pROI)
: proj(proj), im(im), interpType(interpType), m_interpFactor(interpFactor), m_bPostProcessingDone(false)
{
detInc = proj.detInc();
nDet = proj.nDet();
if (proj.geometry() == Scanner::GEOMETRY_PARALLEL)
rotScale = PI / proj.nView(); // scale by number of PI rotations
else if (proj.geometry() == Scanner::GEOMETRY_EQUIANGULAR || proj.geometry() == Scanner::GEOMETRY_EQUILINEAR)
rotScale = (2 * PI) / proj.nView(); // scale by number of 2PI rotations
else
sys_error (ERR_SEVERE, "Invalid geometry type %d [Backproject::Backproject]", proj.geometry());
if (proj.geometry() == Scanner::GEOMETRY_PARALLEL)
rotScale = PI / proj.nView(); // scale by number of PI rotations
else if (proj.geometry() == Scanner::GEOMETRY_EQUIANGULAR || proj.geometry() == Scanner::GEOMETRY_EQUILINEAR)
rotScale = (2 * PI) / proj.nView(); // scale by number of 2PI rotations
else
sys_error (ERR_SEVERE, "Invalid geometry type %d [Backproject::Backproject]", proj.geometry());
xMin = -proj.phmLen() / 2; // Retangular coords of phantom
xMax = xMin + proj.phmLen();
yMin = -proj.phmLen() / 2;
yMax = yMin + proj.phmLen();
xMin = -proj.phmLen() / 2; // Retangular coords of phantom
xMax = xMin + proj.phmLen();
yMin = -proj.phmLen() / 2;
yMax = yMin + proj.phmLen();
im.setAxisIncrement (xInc, yInc);
im.setAxisExtent (xMin, xMax, yMin, yMax);
im.setAxisIncrement (xInc, yInc);
im.setAxisExtent (xMin, xMax, yMin, yMax);
os << "xMin=" << xMin << ", xMax=" << xMax << ", xInc=" << xInc << "\n";
os << "yMin=" << yMin << ", yMax=" << yMax << ", yInc=" << yInc << "\n";
os << "iDetPos index outside bounds: " << iDetPos << " [backprojector]";;
os << "xMin=" << xMin << ", xMax=" << xMax << ", xInc=" << xInc << "\n";
os << "yMin=" << yMin << ", yMax=" << yMax << ", yInc=" << yInc << "\n";
os << "iDetPos index outside bounds: " << iDetPos << " [backprojector]";;
BackprojectTrig::BackprojectView (const double* const filteredProj, const double view_angle)
{
double theta = view_angle;
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);
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
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 (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) {
if (iDetPos >= 0 && iDetPos < nDet)
v[ix][iy] += rotScale * filteredProj[iDetPos];
} else if (interpType == Backprojector::INTERP_LINEAR) {
if (iDetPos >= 0 && iDetPos < nDet - 1)
v[ix][iy] += rotScale * ((1-frac) * filteredProj[iDetPos] + frac * filteredProj[iDetPos+1]);
} else if (interpType == Backprojector::INTERP_CUBIC) {
if (iDetPos >= 0 && iDetPos < nDet - 1)
v[ix][iy] += rotScale * ((1-frac) * filteredProj[iDetPos] + frac * filteredProj[iDetPos+1]);
} else if (interpType == Backprojector::INTERP_CUBIC) {
-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)
{
const int interpFactor, const ReconstructionROI* pROI)
: Backproject (proj, im, interpType, interpFactor, pROI)
{
arrayPhi.initSetSize (im.nx(), im.ny());
r = arrayR.getArray();
phi = arrayPhi.getArray();
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);
}
r[ix][iy] = sqrt (x * x + y * y);
phi[ix][iy] = atan2 (y, x);
}
BackprojectTable::BackprojectView (const double* const filteredProj, const double view_angle)
{
double theta = view_angle;
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);
CubicPolyInterpolator* pCubicInterp = NULL;
if (interpType == Backprojector::INTERP_CUBIC)
pCubicInterp = new CubicPolyInterpolator (filteredProj, nDet);
- 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) {
- 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) {
// 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
// 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)
{
const int interpFactor, const ReconstructionROI* pROI)
: Backproject (proj, im, interpType, interpFactor, pROI)
{
double x = xMin + xInc / 2;
double y = yMin + yInc / 2;
start_r = sqrt (x * x + y * y);
start_phi = atan2 (y, x);
double x = xMin + xInc / 2;
double y = yMin + yInc / 2;
start_r = sqrt (x * x + y * y);
start_phi = atan2 (y, x);
BackprojectDiff::BackprojectView (const double* const filteredProj, const double view_angle)
{
double theta = view_angle;
BackprojectDiff::BackprojectView (const double* const filteredProj, const double view_angle)
{
double theta = view_angle;
-
- // calculate detPosition for first point in image (ix=0, iy=0)
- double detPosColStart = iDetCenter + 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;
+
if (interpType == Backprojector::INTERP_LINEAR) {
// precalculate scaled difference for linear interpolation
deltaFilteredProj = new double [nDet];
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 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;
+
+#if HAVE_OPENMP
+ #pragma omp parallel for
+#endif
+ for (int ix = 0; ix < nx; ix++) {
+ double detPos = detPosColBase + (ix * det_dx);
- int iDetPos = 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) {
- double frac = curDetPos - detPosFloor; // fraction distance from det
- if (iDetPos >= 0 && iDetPos <= iLastDet)
- *pImCol++ += filteredProj[iDetPos] + (frac * deltaFilteredProj[iDetPos]);
+ double frac = detPos - detPosFloor; // fraction distance from det
+ if (iDetPos >= 0 && iDetPos <= iLastDet) {
+ *pImCol++ += filteredProj[iDetPos] + (frac * deltaFilteredProj[iDetPos]);
+ }
static const long scaleBitmask = scale - 1;
static const long halfScale = scale / 2;
static const double dInvScale = 1. / scale;
static const long scaleBitmask = scale - 1;
static const long halfScale = scale / 2;
static const double dInvScale = 1. / scale;
const long det_dx = nearest<long> (xInc * cos (theta) / detInc * scale);
const long det_dy = nearest<long> (yInc * sin (theta) / detInc * scale);
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 detPosColStart = nearest<long> ((start_r * cos (theta - start_phi) / detInc + iDetCenter) * scale);
-
- double* deltaFilteredProj = NULL;
+
+ // 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
deltaFilteredProj = new double [nDet];
CubicPolyInterpolator* pCubicInterp = 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]) * dInvScale;
deltaFilteredProj[nDet - 1] = 0; // last detector
} else if (interpType == Backprojector::INTERP_CUBIC) {
pCubicInterp = new CubicPolyInterpolator (filteredProj, nDet);
}
for (int i = 0; i < nDet - 1; i++)
deltaFilteredProj[i] = (filteredProj[i+1] - filteredProj[i]) * dInvScale;
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) {
- long curDetPos = detPosColStart;
+#if HAVE_OPENMP
+ #pragma omp parallel for
+#endif
+ for (int ix = 0; ix < nx; ix++) {
+ long detPos = detPosColBase + (ix * det_dx);
-
- if (interpType == Backprojector::INTERP_NEAREST) {
- for (int iy = 0; iy < ny; iy++, curDetPos += det_dy) {
- const int iDetPos = (curDetPos + halfScale) >> scaleShift;
- 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) {
-
- } // 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) >> scaleShift) * m_interpFactor;
- if (iDetPos >= 0 && iDetPos <= iLastDet)
+ } else if (interpType == Backprojector::INTERP_FREQ_PREINTERPOLATION) {
+ const int iDetPos = ((detPos + halfScale) >> scaleShift) * m_interpFactor;
+ if (iDetPos >= 0 && iDetPos <= iLastDet) {
- } // end for iy
- } else if (interpType == Backprojector::INTERP_LINEAR) {
- for (int iy = 0; iy < ny; iy++, curDetPos += det_dy) {
- const long iDetPos = curDetPos >> scaleShift;
+ } else if (interpType == Backprojector::INTERP_LINEAR) {
+ const long iDetPos = detPos >> scaleShift;
- const long detRemainder = curDetPos & scaleBitmask;
- *pImCol++ += filteredProj[iDetPos] + (detRemainder * deltaFilteredProj[iDetPos]);
- } else
+ const long detRemainder = detPos & scaleBitmask;
+ *pImCol++ += filteredProj[iDetPos] + (detRemainder * deltaFilteredProj[iDetPos]);
+ } else
- } // 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) / scale);
- }
- } // end Cubic
+ } else if (interpType == Backprojector::INTERP_CUBIC) {
+ *pImCol++ += pCubicInterp->interpolate (static_cast<double>(detPos) / scale);
+ } // end Cubic
+ } // end for iy
if (interpType == Backprojector::INTERP_LINEAR)
delete deltaFilteredProj;
else if (interpType == Backprojector::INTERP_CUBIC)
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;
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);
CubicPolyInterpolator* pCubicInterp = NULL;
if (interpType == Backprojector::INTERP_CUBIC)
pCubicInterp = new CubicPolyInterpolator (filteredProj, nDet);
double dAngleDiff = beta - phi[ix][iy];
double rcos_t = r[ix][iy] * cos (dAngleDiff);
double rsin_t = r[ix][iy] * sin (dAngleDiff);
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);
double gamma = atan (rcos_t / dFLPlusSin);
double dPos = gamma / detInc; // position along detector
double dL2 = dFLPlusSin * dFLPlusSin + (rcos_t * rcos_t);
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);
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);
if (iDetPos >= 0 && iDetPos < nDet - 1)
pImCol[iy] += (filteredProj[iDetPos] + frac * (filteredProj[iDetPos+1] - filteredProj[iDetPos])) / dL2;
} else if (interpType == Backprojector::INTERP_CUBIC) {
if (iDetPos >= 0 && iDetPos < nDet - 1)
pImCol[iy] += (filteredProj[iDetPos] + frac * (filteredProj[iDetPos+1] - filteredProj[iDetPos])) / dL2;
} else if (interpType == Backprojector::INTERP_CUBIC) {
BackprojectEquilinear::BackprojectView (const double* const filteredProj, const double view_angle)
{
double beta = view_angle;
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);
CubicPolyInterpolator* pCubicInterp = NULL;
if (interpType == Backprojector::INTERP_CUBIC)
pCubicInterp = new CubicPolyInterpolator (filteredProj, nDet);
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);
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);
- // 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
- 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);
} else if (interpType == Backprojector::INTERP_LINEAR) {
double dPosFloor = floor (dPos);
int iDetPos = iDetCenter + static_cast<int>(dPosFloor);