X-Git-Url: http://git.kpe.io/?a=blobdiff_plain;f=libctsim%2Fbackprojectors.cpp;h=8afe1892054fb7969fdc878b290b1e587e1b55ec;hb=4c687b64a6e11cc735525f9f65f962b53ba6b595;hp=8343314faca95ad774e4a6e3ba87e8cbd5f58a25;hpb=23f5654dacb1952c15bda92c2606fae3a55e48ad;p=ctsim.git diff --git a/libctsim/backprojectors.cpp b/libctsim/backprojectors.cpp index 8343314..8afe189 100644 --- a/libctsim/backprojectors.cpp +++ b/libctsim/backprojectors.cpp @@ -6,9 +6,9 @@ ** Date Started: June 2000 ** ** This is part of the CTSim program -** Copyright (C) 1983-2000 Kevin Rosenberg +** Copyright (c) 1983-2001 Kevin Rosenberg ** -** $Id: backprojectors.cpp,v 1.23 2001/01/04 21:28:41 kevin Exp $ +** $Id: backprojectors.cpp,v 1.25 2001/02/09 01:54:20 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 @@ -59,18 +59,20 @@ const int Backprojector::s_iBackprojectCount = sizeof(s_aszBackprojectName) / si const int Backprojector::INTERP_INVALID = -1; const int Backprojector::INTERP_NEAREST = 0; const int Backprojector::INTERP_LINEAR = 1; -const int Backprojector::INTERP_FREQ_PREINTERPOLATION = 2; +const int Backprojector::INTERP_CUBIC = 2; +const int Backprojector::INTERP_FREQ_PREINTERPOLATION = 3; #if HAVE_BSPLINE_INTERP -const int Backprojector::INTERP_BSPLINE = 3; -const int Backprojector::INTERP_1BSPLINE = 4; -const int Backprojector::INTERP_2BSPLINE = 5; -const int Backprojector::INTERP_3BSPLINE = 6; +const int Backprojector::INTERP_BSPLINE = 4; +const int Backprojector::INTERP_1BSPLINE = 5; +const int Backprojector::INTERP_2BSPLINE = 6; +const int Backprojector::INTERP_3BSPLINE = 7; #endif const char* Backprojector::s_aszInterpName[] = { {"nearest"}, {"linear"}, + {"cubic"}, {"freq_preinterpolationj"}, #if HAVE_BSPLINE_INTERP {"bspline"}, @@ -84,6 +86,7 @@ const char* Backprojector::s_aszInterpTitle[] = { {"Nearest"}, {"Linear"}, + {"Cubic"}, {"Frequency Preinterpolation"}, #if HAVE_BSPLINE_INTERP {"B-Spline"}, @@ -330,6 +333,10 @@ BackprojectTrig::BackprojectView (const double* const filteredProj, const double { double theta = view_angle; + CubicInterpolator* pCubicInterp = NULL; + if (interpType == Backprojector::INTERP_CUBIC) + pCubicInterp = new CubicInterpolator (filteredProj, nDet); + double x = xMin + xInc / 2; // Rectang coords of center of pixel for (int ix = 0; ix < nx; x += xInc, ix++) { double y = yMin + yInc / 2; @@ -341,22 +348,25 @@ BackprojectTrig::BackprojectView (const double* const filteredProj, const double if (interpType == Backprojector::INTERP_NEAREST) { int iDetPos = iDetCenter + nearest (L / detInc); // calc'd index in the filter raysum array - if (iDetPos < 0 || iDetPos >= nDet) // check for impossible: index outside of raysum pos - errorIndexOutsideDetector (ix, iy, theta, r, phi, L, iDetPos); - else + 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 pFloor = floor (p); int iDetPos = iDetCenter + static_cast(pFloor); double frac = p - pFloor; // fraction distance from det - if (iDetPos < 0 || iDetPos >= nDet - 1) // check for impossible: index outside of raysum pos - errorIndexOutsideDetector (ix, iy, theta, r, phi, L, iDetPos); - else + 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 + if (p >= 0 && p < nDet) + v[ix][iy] += rotScale * pCubicInterp->interpolate (p); } } } + + if (interpType == Backprojector::INTERP_CUBIC) + delete pCubicInterp; } @@ -393,6 +403,10 @@ BackprojectTable::BackprojectView (const double* const filteredProj, const doubl { double theta = view_angle; + CubicInterpolator* pCubicInterp = NULL; + if (interpType == Backprojector::INTERP_CUBIC) + pCubicInterp = new CubicInterpolator (filteredProj, nDet); + for (int ix = 0; ix < nx; ix++) { ImageFileColumn pImCol = v[ix]; @@ -402,22 +416,25 @@ BackprojectTable::BackprojectView (const double* const filteredProj, const doubl if (interpType == Backprojector::INTERP_NEAREST) { int iDetPos = iDetCenter + nearest(L / detInc); // calc index in the filtered raysum vector - if (iDetPos < 0 || iDetPos >= nDet) // check for impossible: index outside of raysum pos - errorIndexOutsideDetector (ix, iy, theta, r[ix][iy], phi[ix][iy], L, iDetPos); - else + if (iDetPos >= 0 && iDetPos < nDet) pImCol[iy] += filteredProj[iDetPos]; } else if (interpType == Backprojector::INTERP_LINEAR) { double dPos = L / detInc; // position along detector double dPosFloor = floor (dPos); int iDetPos = iDetCenter + static_cast(dPosFloor); double frac = dPos - dPosFloor; // fraction distance from det - if (iDetPos < 0 || iDetPos >= nDet - 1) - errorIndexOutsideDetector (ix, iy, theta, r[ix][iy], phi[ix][iy], L, iDetPos); - else + 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) + pImCol[iy] += pCubicInterp->interpolate (p); } } // end for y } // end for x + + if (interpType == Backprojector::INTERP_CUBIC) + delete pCubicInterp; } @@ -453,6 +470,10 @@ BackprojectDiff::BackprojectView (const double* const filteredProj, const double double det_dy = yInc * sin (theta); double lColStart = start_r * cos (theta - start_phi); // calculate L for first point in image + CubicInterpolator* pCubicInterp = NULL; + if (interpType == Backprojector::INTERP_CUBIC) + pCubicInterp = new CubicInterpolator (filteredProj, nDet); + for (int ix = 0; ix < nx; ix++, lColStart += det_dx) { double curDetPos = lColStart; ImageFileColumn pImCol = v[ix]; @@ -464,22 +485,25 @@ BackprojectDiff::BackprojectView (const double* const filteredProj, const double if (interpType == Backprojector::INTERP_NEAREST) { int iDetPos = iDetCenter + nearest(curDetPos / detInc); // calc index in the filtered raysum vector - if (iDetPos < 0 || iDetPos >= nDet) // check for impossible: index outside of raysum pos - errorIndexOutsideDetector (ix, iy, theta, curDetPos, iDetPos); - else + if (iDetPos >= 0 && iDetPos < nDet) pImCol[iy] += filteredProj[iDetPos]; } else if (interpType == Backprojector::INTERP_LINEAR) { double detPos = curDetPos / detInc; // position along detector double detPosFloor = floor (detPos); int iDetPos = iDetCenter + static_cast(detPosFloor); double frac = detPos - detPosFloor; // fraction distance from det - if (iDetPos < 0 || iDetPos >= nDet - 1) - errorIndexOutsideDetector (ix, iy, theta, curDetPos, iDetPos); - else + 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 + (curDetPos / detInc); // position along detector + if (p >= 0 && p < nDet) + pImCol[iy] += pCubicInterp->interpolate (p); } } // end for y } // end for x + + if (interpType == Backprojector::INTERP_CUBIC) + delete pCubicInterp; } @@ -494,6 +518,10 @@ BackprojectDiff2::BackprojectView (const double* const filteredProj, const doubl { double theta = view_angle; + CubicInterpolator* pCubicInterp = NULL; + if (interpType == Backprojector::INTERP_CUBIC) + pCubicInterp = new CubicInterpolator (filteredProj, nDet); + // Distance betw. detectors for an angle given in units of detectors double det_dx = xInc * cos (theta) / detInc; double det_dy = yInc * sin (theta) / detInc; @@ -515,21 +543,24 @@ BackprojectDiff2::BackprojectView (const double* const filteredProj, const doubl if (interpType == Backprojector::INTERP_NEAREST) { int iDetPos = iDetCenter + nearest (curDetPos); // calc index in the filtered raysum vector - if (iDetPos < 0 || iDetPos >= nDet) // check for impossible: index outside of raysum pos - errorIndexOutsideDetector (ix, iy, theta, curDetPos, iDetPos); - else + if (iDetPos >= 0 && iDetPos < nDet) *pImCol++ += filteredProj[iDetPos]; } else if (interpType == Backprojector::INTERP_LINEAR) { double detPosFloor = floor (curDetPos); int iDetPos = iDetCenter + static_cast(detPosFloor); double frac = curDetPos - detPosFloor; // fraction distance from det - if (iDetPos < 0 || iDetPos >= nDet - 1) - errorIndexOutsideDetector (ix, iy, theta, curDetPos, iDetPos); - else + if (iDetPos > 0 && iDetPos < nDet - 1) *pImCol++ += filteredProj[iDetPos] + (frac * (filteredProj[iDetPos+1] - filteredProj[iDetPos])); + } else if (interpType = Backprojector::INTERP_CUBIC) { + double p = iDetCenter + curDetPos; // position along detector + if (p >= 0 && p < nDet) + *pImCol++ += pCubicInterp->interpolate (p); } } // end for y } // end for x + + if (interpType == Backprojector::INTERP_CUBIC) + delete pCubicInterp; } // CLASS IDENTICATION @@ -543,6 +574,10 @@ BackprojectIntDiff2::BackprojectView (const double* const filteredProj, const do { double theta = view_angle; + CubicInterpolator* pCubicInterp = NULL; + if (interpType == Backprojector::INTERP_CUBIC) + pCubicInterp = new CubicInterpolator (filteredProj, nDet); + static const kint32 scale = 1 << 16; static const double dScale = scale; static const kint32 halfScale = scale / 2; @@ -579,9 +614,16 @@ BackprojectIntDiff2::BackprojectView (const double* const filteredProj, const do errorIndexOutsideDetector (ix, iy, theta, curDetPos, iDetPos); else *pImCol++ += ((1.-frac) * filteredProj[iDetPos] + frac * filteredProj[iDetPos+1]); + } else if (interpType = Backprojector::INTERP_CUBIC) { + double p = iDetCenter + (static_cast(curDetPos) / scale); // position along detector + if (p >= 0 && p < nDet) + *pImCol++ += pCubicInterp->interpolate (p); } } // end for y } // end for x + + if (interpType == Backprojector::INTERP_CUBIC) + delete pCubicInterp; } // CLASS IDENTICATION @@ -606,13 +648,17 @@ BackprojectIntDiff3::BackprojectView (const double* const filteredProj, const do // calculate L for first point in image (0, 0) kint32 detPosColStart = nearest ((start_r * cos (theta - start_phi) / detInc + iDetCenter) * scale); - // precalculate scaled difference for linear interpolation - double* deltaFilteredProj = new double [nDet]; + double* deltaFilteredProj = NULL; + CubicInterpolator* 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 CubicInterpolator (filteredProj, nDet); } - deltaFilteredProj[nDet - 1] = 0; // last detector int iLastDet = nDet - 1; for (int ix = 0; ix < nx; ix++, detPosColStart += det_dx) { @@ -638,10 +684,17 @@ BackprojectIntDiff3::BackprojectView (const double* const filteredProj, const do if (iDetPos >= 0 && iDetPos <= iLastDet) *pImCol++ += filteredProj[iDetPos] + (detRemainder * deltaFilteredProj[iDetPos]); } // end for iy - } //end linear + } else if (interpType = Backprojector::INTERP_CUBIC) { + for (int iy = 0; iy < ny; iy++, curDetPos += det_dy) { + *pImCol++ += pCubicInterp->interpolate (static_cast(curDetPos) / 65536); + } + } // end cubic } // end for ix - delete deltaFilteredProj; + if (interpType == Backprojector::INTERP_LINEAR) + delete deltaFilteredProj; + else if (interpType == Backprojector::INTERP_CUBIC) + delete pCubicInterp; } @@ -650,6 +703,10 @@ BackprojectEquiangular::BackprojectView (const double* const filteredProj, const { double beta = view_angle; + CubicInterpolator* pCubicInterp = NULL; + if (interpType == Backprojector::INTERP_CUBIC) + pCubicInterp = new CubicInterpolator (filteredProj, nDet); + for (int ix = 0; ix < nx; ix++) { ImageFileColumn pImCol = v[ix]; @@ -659,27 +716,29 @@ BackprojectEquiangular::BackprojectView (const double* const filteredProj, const double rsin_t = r[ix][iy] * sin (dAngleDiff); double dFLPlusSin = m_dFocalLength + rsin_t; 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(gamma / detInc); // calc index in the filtered raysum vector - - if (iDetPos < 0 || iDetPos >= nDet) { // check for impossible: index outside of raysum pos - ; // errorIndexOutsideDetector (ix, iy, beta, r[ix][iy], phi[ix][iy], gamma, iDetPos); - } else + int iDetPos = iDetCenter + nearest(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 dPos = gamma / detInc; // position along detector double dPosFloor = floor (dPos); int iDetPos = iDetCenter + static_cast(dPosFloor); double frac = dPos - dPosFloor; // fraction distance from det - if (iDetPos < 0 || iDetPos >= nDet - 1) { - ; // errorIndexOutsideDetector (ix, iy, beta, r[ix][iy], phi[ix][iy], gamma, iDetPos); - } else + 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 + if (d >= 0 && d < nDet) + pImCol[iy] += pCubicInterp->interpolate (d) / dL2; } } // end for y } // end for x + + if (interpType == Backprojector::INTERP_CUBIC) + delete pCubicInterp; } void @@ -687,6 +746,10 @@ BackprojectEquilinear::BackprojectView (const double* const filteredProj, const { double beta = view_angle; + CubicInterpolator* pCubicInterp = NULL; + if (interpType == Backprojector::INTERP_CUBIC) + pCubicInterp = new CubicInterpolator (filteredProj, nDet); + for (int ix = 0; ix < nx; ix++) { ImageFileColumn pImCol = v[ix]; @@ -698,27 +761,31 @@ 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 + // of phantom, see Kak-Slaney Figure 3.22. This assumes that the detector is also + // located focal-length away from the origin. dDetPos *= 2; - + double dPos = dDetPos / detInc; // position along detector array + if (interpType == Backprojector::INTERP_NEAREST) { - int iDetPos = iDetCenter + nearest(dDetPos / detInc); // calc index in the filtered raysum vector - - if (iDetPos < 0 || iDetPos >= nDet) // check for impossible: index outside of raysum pos - ; /// errorIndexOutsideDetector (ix, iy, beta, r[ix][iy], phi[ix][iy], dDetPos, iDetPos); - else + int iDetPos = iDetCenter + nearest(dPos); // calc index in the filtered raysum vector + if (iDetPos >= 0 && iDetPos < nDet) pImCol[iy] += (filteredProj[iDetPos] / (dU * dU)); } else if (interpType == Backprojector::INTERP_LINEAR) { - double dPos = dDetPos / detInc; // position along detector double dPosFloor = floor (dPos); int iDetPos = iDetCenter + static_cast(dPosFloor); double frac = dPos - dPosFloor; // fraction distance from det - if (iDetPos < 0 || iDetPos >= nDet - 1) - ; // errorIndexOutsideDetector (ix, iy, beta, r[ix][iy], phi[ix][iy], dDetPos, iDetPos); - else - pImCol[iy] += (filteredProj[iDetPos] + frac * (filteredProj[iDetPos+1] - filteredProj[iDetPos])) / (dU * dU); + if (iDetPos >= 0 && iDetPos < nDet - 1) + pImCol[iy] += (filteredProj[iDetPos] + frac * (filteredProj[iDetPos+1] - filteredProj[iDetPos])) + / (dU * dU); + } else if (interpType == Backprojector::INTERP_CUBIC) { + double d = iDetCenter + dPos; // position along detector + if (d >= 0 && d < nDet) + pImCol[iy] += pCubicInterp->interpolate (d) / (dU * dU); } } // end for y } // end for x + + if (interpType == Backprojector::INTERP_CUBIC) + delete pCubicInterp; }