X-Git-Url: http://git.kpe.io/?p=ctsim.git;a=blobdiff_plain;f=libctsim%2Fbackprojectors.cpp;h=9aa314598a9cc19e69205b3273a39f52d2822e68;hp=1f6e92c1bece4c526d80abdad76e47d1d70a7f75;hb=3fba6928127cd65870bdcd96c8114ad5894247ae;hpb=08f34bf3ba14d4f436f4d2ef0ee5af1d6eb266ac diff --git a/libctsim/backprojectors.cpp b/libctsim/backprojectors.cpp index 1f6e92c..9aa3145 100644 --- a/libctsim/backprojectors.cpp +++ b/libctsim/backprojectors.cpp @@ -8,7 +8,7 @@ ** This is part of the CTSim program ** Copyright (C) 1983-2000 Kevin Rosenberg ** -** $Id: backprojectors.cpp,v 1.4 2000/06/25 17:32:24 kevin Exp $ +** $Id: backprojectors.cpp,v 1.8 2000/07/13 07:03:21 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 @@ -26,18 +26,18 @@ #include "ct.h" -Backprojector::Backprojector (const Projections& proj, ImageFile& im, const char* const backprojName, const char* const interpName) +Backprojector::Backprojector (const Projections& proj, ImageFile& im, const char* const backprojName, const char* const interpName, const int interpFactor) { m_fail = false; m_pBackprojectImplem = NULL; - initBackprojector (proj, im, backprojName, interpName); + initBackprojector (proj, im, backprojName, interpName, interpFactor); } void Backprojector::BackprojectView (const double* const viewData, const double viewAngle) { - if (m_pBackprojectImplem) + if (m_pBackprojectImplem != NULL) m_pBackprojectImplem->BackprojectView (viewData, viewAngle); } @@ -54,7 +54,7 @@ Backprojector::~Backprojector (void) // and initializes the backprojector bool -Backprojector::initBackprojector (const Projections& proj, ImageFile& im, const char* const backprojName, const char* const interpName) +Backprojector::initBackprojector (const Projections& proj, ImageFile& im, const char* const backprojName, const char* const interpName, const int interpFactor) { m_nameBackproject = backprojName; m_nameInterpolation = interpName; @@ -78,15 +78,17 @@ Backprojector::initBackprojector (const Projections& proj, ImageFile& im, const } if (m_idBackproject == BPROJ_TRIG) - m_pBackprojectImplem = static_cast(new BackprojectTrig (proj, im, m_idInterpolation)); + m_pBackprojectImplem = static_cast(new BackprojectTrig (proj, im, m_idInterpolation, interpFactor)); else if (m_idBackproject == BPROJ_TABLE) - m_pBackprojectImplem = static_cast(new BackprojectTable (proj, im, m_idInterpolation)); + m_pBackprojectImplem = static_cast(new BackprojectTable (proj, im, m_idInterpolation, interpFactor)); else if (m_idBackproject == BPROJ_DIFF) - m_pBackprojectImplem = static_cast(new BackprojectDiff (proj, im, m_idInterpolation)); + m_pBackprojectImplem = static_cast(new BackprojectDiff (proj, im, m_idInterpolation, interpFactor)); else if (m_idBackproject == BPROJ_DIFF2) - m_pBackprojectImplem = static_cast(new BackprojectDiff2 (proj, im, m_idInterpolation)); + m_pBackprojectImplem = static_cast(new BackprojectDiff2 (proj, im, m_idInterpolation, interpFactor)); else if (m_idBackproject == BPROJ_IDIFF2) - m_pBackprojectImplem = static_cast(new BackprojectIntDiff2 (proj, im, m_idInterpolation)); + m_pBackprojectImplem = static_cast(new BackprojectIntDiff2 (proj, im, m_idInterpolation, interpFactor)); + else if (m_idBackproject == BPROJ_IDIFF3) + m_pBackprojectImplem = static_cast(new BackprojectIntDiff3 (proj, im, m_idInterpolation, interpFactor)); else { m_fail = true; m_failMessage = "Unable to select a backprojection method [Backprojector::initBackprojector]"; @@ -112,6 +114,8 @@ Backprojector::convertBackprojectNameToID (const char* const backprojName) backprojID = BPROJ_DIFF2; else if (strcasecmp (backprojName, BPROJ_IDIFF2_STR) == 0) backprojID = BPROJ_IDIFF2; + else if (strcasecmp (backprojName, BPROJ_IDIFF3_STR) == 0) + backprojID = BPROJ_IDIFF3; return (backprojID); } @@ -131,6 +135,8 @@ Backprojector::convertBackprojectIDToName (const BackprojectID bprojID) bprojName = BPROJ_DIFF2_STR; else if (bprojID == BPROJ_IDIFF2) bprojName = BPROJ_IDIFF2_STR; + else if (bprojID == BPROJ_IDIFF3) + bprojName = BPROJ_IDIFF3_STR; return (bprojName); } @@ -146,6 +152,8 @@ Backprojector::convertInterpolationNameToID (const char* const interpName) interpID = INTERP_NEAREST; else if (strcasecmp (interpName, INTERP_LINEAR_STR) == 0) interpID = INTERP_LINEAR; + else if (strcasecmp (interpName, INTERP_FREQ_PREINTERPOLATION_STR) == 0) + interpID = INTERP_FREQ_PREINTERPOLATION; #if HAVE_BSPLINE_INTERP else if (strcasecmp (interpName, INTERP_BSPLINE_STR) == 0) interpID = INTERP_BSPLINE; @@ -174,6 +182,8 @@ Backprojector::convertInterpolationIDToName (const InterpolationID interpID) return (INTERP_NEAREST_STR); else if (interpID == INTERP_LINEAR) return (INTERP_LINEAR_STR); + else if (interpID == INTERP_FREQ_PREINTERPOLATION) + return (INTERP_FREQ_PREINTERPOLATION_STR); #if HAVE_BSPLINE_INTERP else if (interpID == INTERP_BSPLINE) return (INTERP_BSPLINE_STR); @@ -189,8 +199,8 @@ Backprojector::convertInterpolationIDToName (const InterpolationID interpID) // PURPOSE // Pure virtual base class for all backprojectors. -Backproject::Backproject (const Projections& proj, ImageFile& im, const Backprojector::InterpolationID interpType) - : proj(proj), im(im), interpType(interpType) +Backproject::Backproject (const Projections& proj, ImageFile& im, const Backprojector::InterpolationID interpType, const int interpFactor) + : proj(proj), im(im), interpType(interpType), m_interpFactor(interpFactor) { detInc = proj.detInc(); nDet = proj.nDet(); @@ -209,9 +219,6 @@ Backproject::Backproject (const Projections& proj, ImageFile& im, const Backproj xInc = (xMax - xMin) / nx; // size of cells yInc = (yMax - yMin) / ny; - - if (interpType != Backprojector::INTERP_NEAREST && interpType != Backprojector::INTERP_LINEAR) - sys_error (ERR_WARNING, "Illegal interpType %d [selectBackprojector]", interpType); } Backproject::~Backproject (void) @@ -288,8 +295,8 @@ BackprojectTrig::BackprojectView (const double* const filteredProj, const double // PURPOSE // Precalculates trigometric function value for each point in image for backprojection. -BackprojectTable::BackprojectTable (const Projections& proj, ImageFile& im, Backprojector::InterpolationID interpType) - : Backproject::Backproject (proj, im, interpType) +BackprojectTable::BackprojectTable (const Projections& proj, ImageFile& im, Backprojector::InterpolationID interpType, const int interpFactor) + : Backproject::Backproject (proj, im, interpType, interpFactor) { arrayR.initSetSize (nx, ny); arrayPhi.initSetSize (nx, ny); @@ -350,8 +357,8 @@ BackprojectTable::BackprojectView (const double* const filteredProj, const doubl // 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, Backprojector::InterpolationID interpType) - : Backproject::Backproject (proj, im, interpType) +BackprojectDiff::BackprojectDiff (const Projections& proj, ImageFile& im, Backprojector::InterpolationID interpType, const int interpFactor) + : Backproject::Backproject (proj, im, interpType, interpFactor) { // calculate center of first pixel v[0][0] double x = xMin + xInc / 2; @@ -448,7 +455,7 @@ BackprojectDiff2::BackprojectView (const double* const filteredProj, const doubl if (iDetPos < 0 || iDetPos >= nDet - 1) errorIndexOutsideDetector (ix, iy, theta, curDetPos, iDetPos); else - *pImCol++ += ((1-frac) * filteredProj[iDetPos] + frac * filteredProj[iDetPos+1]); + *pImCol++ += filteredProj[iDetPos] + (frac * (filteredProj[iDetPos+1] - filteredProj[iDetPos])); } } // end for y } // end for x @@ -465,12 +472,12 @@ BackprojectIntDiff2::BackprojectView (const double* const filteredProj, const do { double theta = - view_angle; // add half PI to view angle to get perpendicular theta angle - kint32 scale = 1 << 16; - double dScale = scale; - kint32 halfScale = scale / 2; + static const kint32 scale = 1 << 16; + static const double dScale = scale; + static const kint32 halfScale = scale / 2; - kint32 det_dx = nearest (xInc * sin (theta) / detInc * scale); - kint32 det_dy = nearest (yInc * cos (theta) / detInc * scale); + const kint32 det_dx = nearest (xInc * sin (theta) / detInc * scale); + const kint32 det_dy = nearest (yInc * cos (theta) / detInc * scale); // calculate L for first point in image (0, 0) kint32 detPosColStart = nearest (start_r * cos (theta - start_phi) / detInc * scale); @@ -500,8 +507,64 @@ BackprojectIntDiff2::BackprojectView (const double* const filteredProj, const do if (iDetPos < 0 || iDetPos >= nDet - 1) errorIndexOutsideDetector (ix, iy, theta, curDetPos, iDetPos); else - *pImCol++ += ((1-frac) * filteredProj[iDetPos] + frac * filteredProj[iDetPos+1]); + *pImCol++ += ((1.-frac) * filteredProj[iDetPos] + frac * filteredProj[iDetPos+1]); } } // end for y } // end for x } + +// CLASS IDENTICATION +// BackprojectIntDiff3 +// +// PURPOSE +// Highly optimized version of BackprojectIntDiff2 + +void +BackprojectIntDiff3::BackprojectView (const double* const filteredProj, const double view_angle) +{ + double theta = - view_angle; // add half PI to view angle to get perpendicular theta angle + static const int scaleShift = 16; + static const kint32 scale = (1 << scaleShift); + static const kint32 scaleBitmask = scale - 1; + static const kint32 halfScale = scale / 2; + static const double dInvScale = 1. / scale; + + const kint32 det_dx = nearest (xInc * sin (theta) / detInc * scale); + const kint32 det_dy = nearest (yInc * cos (theta) / detInc * scale); + + // 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 [nDet - 1]; + if (interpType == Backprojector::INTERP_LINEAR) { + for (int i = 0; i < nDet - 1; i++) + deltaFilteredProj[i] = (filteredProj[i+1] - filteredProj[i]) * dInvScale; + } + + for (int ix = 0; ix < nx; ix++, detPosColStart += det_dx) { + kint32 curDetPos = detPosColStart; + 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; + assert(iDetPos >= 0 && iDetPos < nDet); + *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; + assert(iDetPos >= 0 && iDetPos < nDet); + *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; + assert(iDetPos >= 0 && iDetPos < nDet - 1); + *pImCol++ += filteredProj[iDetPos] + (detRemainder * deltaFilteredProj[iDetPos]); + } // end for iy + } //end linear + } // end for ix +}