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-rw-r--r--include/astra/ParallelBeamBlobKernelProjector2D.inl310
1 files changed, 164 insertions, 146 deletions
diff --git a/include/astra/ParallelBeamBlobKernelProjector2D.inl b/include/astra/ParallelBeamBlobKernelProjector2D.inl
index c5040b7..ccd2166 100644
--- a/include/astra/ParallelBeamBlobKernelProjector2D.inl
+++ b/include/astra/ParallelBeamBlobKernelProjector2D.inl
@@ -26,186 +26,204 @@ along with the ASTRA Toolbox. If not, see <http://www.gnu.org/licenses/>.
*/
-
-//----------------------------------------------------------------------------------------
-// PROJECT ALL
template <typename Policy>
void CParallelBeamBlobKernelProjector2D::project(Policy& p)
{
- for (int iAngle = 0; iAngle < m_pProjectionGeometry->getProjectionAngleCount(); ++iAngle) {
- for (int iDetector = 0; iDetector < m_pProjectionGeometry->getDetectorCount(); ++iDetector) {
- projectSingleRay(iAngle, iDetector, p);
- }
- }
+ projectBlock_internal(0, m_pProjectionGeometry->getProjectionAngleCount(),
+ 0, m_pProjectionGeometry->getDetectorCount(), p);
}
-
-//----------------------------------------------------------------------------------------
-// PROJECT SINGLE PROJECTION
template <typename Policy>
void CParallelBeamBlobKernelProjector2D::projectSingleProjection(int _iProjection, Policy& p)
{
- for (int iDetector = 0; iDetector < m_pProjectionGeometry->getDetectorCount(); ++iDetector) {
- projectSingleRay(_iProjection, iDetector, p);
- }
+ projectBlock_internal(_iProjection, _iProjection + 1,
+ 0, m_pProjectionGeometry->getDetectorCount(), p);
}
-
-
-//----------------------------------------------------------------------------------------
-// PROJECT SINGLE RAY
template <typename Policy>
void CParallelBeamBlobKernelProjector2D::projectSingleRay(int _iProjection, int _iDetector, Policy& p)
{
- ASTRA_ASSERT(m_bIsInitialized);
+ projectBlock_internal(_iProjection, _iProjection + 1,
+ _iDetector, _iDetector + 1, p);
+}
- int iRayIndex = _iProjection * m_pProjectionGeometry->getDetectorCount() + _iDetector;
+//----------------------------------------------------------------------------------------
+// PROJECT BLOCK - vector projection geometry
+//
+// Kernel limitations: isotropic pixels (PixelLengthX == PixelLengthY)
+//
+// For each angle/detector pair:
+//
+// Let D=(Dx,Dy) denote the centre of the detector (point) in volume coordinates, and
+// let R=(Rx,Ry) denote the direction of the ray (vector).
+//
+// For mainly vertical rays (|Rx|<=|Ry|),
+// let E=(Ex,Ey) denote the centre of the most upper left pixel:
+// E = (WindowMinX + PixelLengthX/2, WindowMaxY - PixelLengthY/2),
+// and let F=(Fx,Fy) denote a vector to the next pixel
+// F = (PixelLengthX, 0)
+//
+// The intersection of the ray (D+aR) with the centre line of the upper row of pixels (E+bF) is
+// { Dx + a*Rx = Ex + b*Fx
+// { Dy + a*Ry = Ey + b*Fy
+// Solving for (a,b) results in:
+// a = (Ey + b*Fy - Dy)/Ry
+// = (Ey - Dy)/Ry
+// b = (Dx + a*Rx - Ex)/Fx
+// = (Dx + (Ey - Dy)*Rx/Ry - Ex)/Fx
+//
+// Define c as the x-value of the intersection of the ray with the upper row in pixel coordinates.
+// c = b
+//
+// The intersection of the ray (D+aR) with the centre line of the second row of pixels (E'+bF) with
+// E'=(WindowMinX + PixelLengthX/2, WindowMaxY - 3*PixelLengthY/2)
+// expressed in x-value pixel coordinates is
+// c' = (Dx + (Ey' - Dy)*Rx/Ry - Ex)/Fx.
+// And thus:
+// deltac = c' - c = (Dx + (Ey' - Dy)*Rx/Ry - Ex)/Fx - (Dx + (Ey - Dy)*Rx/Ry - Ex)/Fx
+// = [(Ey' - Dy)*Rx/Ry - (Ey - Dy)*Rx/Ry]/Fx
+// = [Ey' - Ey]*(Rx/Ry)/Fx
+// = [Ey' - Ey]*(Rx/Ry)/Fx
+// = -PixelLengthY*(Rx/Ry)/Fx.
+//
+// Given c on a certain row, its pixel directly on its left (col), and the distance (offset) to it, can be found:
+// col = floor(c)
+// offset = c - col
+//
+// The index of this pixel is
+// volumeIndex = row * colCount + col
+//
+//
+// Mainly horizontal rays (|Rx|<=|Ry|) are handled in a similar fashion:
+//
+// E = (WindowMinX + PixelLengthX/2, WindowMaxY - PixelLengthY/2),
+// F = (0, -PixelLengthX)
+//
+// a = (Ex + b*Fx - Dx)/Rx = (Ex - Dx)/Rx
+// b = (Dy + a*Ry - Ey)/Fy = (Dy + (Ex - Dx)*Ry/Rx - Ey)/Fy
+// r = b
+// deltar = PixelLengthX*(Ry/Rx)/Fy.
+// row = floor(r+1/2)
+// offset = r - row
+//
+template <typename Policy>
+void CParallelBeamBlobKernelProjector2D::projectBlock_internal(int _iProjFrom, int _iProjTo, int _iDetFrom, int _iDetTo, Policy& p)
+{
+ // get vector geometry
+ const CParallelVecProjectionGeometry2D* pVecProjectionGeometry;
+ if (dynamic_cast<CParallelProjectionGeometry2D*>(m_pProjectionGeometry)) {
+ pVecProjectionGeometry = dynamic_cast<CParallelProjectionGeometry2D*>(m_pProjectionGeometry)->toVectorGeometry();
+ } else {
+ pVecProjectionGeometry = dynamic_cast<CParallelVecProjectionGeometry2D*>(m_pProjectionGeometry);
+ }
- // POLICY: RAY PRIOR
- if (!p.rayPrior(iRayIndex)) return;
+ // precomputations
+ const float32 pixelLengthX = m_pVolumeGeometry->getPixelLengthX();
+ const float32 pixelLengthY = m_pVolumeGeometry->getPixelLengthY();
+ const float32 inv_pixelLengthX = 1.0f / m_pVolumeGeometry->getPixelLengthX();
+ const float32 inv_pixelLengthY = 1.0f / m_pVolumeGeometry->getPixelLengthY();
+ const int colCount = m_pVolumeGeometry->getGridColCount();
+ const int rowCount = m_pVolumeGeometry->getGridRowCount();
+
+ // loop angles
+ for (int iAngle = _iProjFrom; iAngle < _iProjTo; ++iAngle) {
+
+ // variables
+ float32 Dx, Dy, Ex, Ey, c, r, deltac, deltar, offset, invBlobExtent, RxOverRy, RyOverRx;
+ int iVolumeIndex, iRayIndex, row, col, iDetector;
+ int col_left, col_right, row_top, row_bottom, index;
+
+ const SParProjection * proj = &pVecProjectionGeometry->getProjectionVectors()[iAngle];
+
+ bool vertical = fabs(proj->fRayX) < fabs(proj->fRayY);
+ if (vertical) {
+ RxOverRy = proj->fRayX/proj->fRayY;
+ deltac = -m_pVolumeGeometry->getPixelLengthY() * (proj->fRayX/proj->fRayY) * inv_pixelLengthX;
+ invBlobExtent = m_pVolumeGeometry->getPixelLengthY() / abs(m_fBlobSize * sqrt(proj->fRayY*proj->fRayY + proj->fRayX*proj->fRayX) / proj->fRayY);
+ } else {
+ RyOverRx = proj->fRayY/proj->fRayX;
+ deltar = -m_pVolumeGeometry->getPixelLengthX() * (proj->fRayY/proj->fRayX) * inv_pixelLengthY;
+ invBlobExtent = m_pVolumeGeometry->getPixelLengthX() / abs(m_fBlobSize * sqrt(proj->fRayY*proj->fRayY + proj->fRayX*proj->fRayX) / proj->fRayX);
+ }
- // get values
- float32 t = m_pProjectionGeometry->indexToDetectorOffset(_iDetector);
- float32 theta = m_pProjectionGeometry->getProjectionAngle(_iProjection);
- if (theta >= 7*PIdiv4) theta -= 2*PI;
+ Ex = m_pVolumeGeometry->getWindowMinX() + pixelLengthX*0.5f;
+ Ey = m_pVolumeGeometry->getWindowMaxY() - pixelLengthY*0.5f;
- bool flip = false;
+ // loop detectors
+ for (iDetector = _iDetFrom; iDetector < _iDetTo; ++iDetector) {
+
+ iRayIndex = iAngle * m_pProjectionGeometry->getDetectorCount() + iDetector;
- if (theta >= 3*PIdiv4) {
- theta -= PI;
- t = -t;
- flip = true;
- }
+ // POLICY: RAY PRIOR
+ if (!p.rayPrior(iRayIndex)) continue;
+
+ Dx = proj->fDetSX + (iDetector+0.5f) * proj->fDetUX;
+ Dy = proj->fDetSY + (iDetector+0.5f) * proj->fDetUY;
+ // vertically
+ if (vertical) {
- if (theta <= PIdiv4) { // -pi/4 <= theta <= pi/4
+ // calculate c for row 0
+ c = (Dx + (Ey - Dy)*RxOverRy - Ex) * inv_pixelLengthX;
- // precalculate sin, cos, 1/cos
- float32 sin_theta = sin(theta);
- float32 cos_theta = cos(theta);
- float32 inv_cos_theta = 1.0f / cos_theta;
+ // loop rows
+ for (row = 0; row < rowCount; ++row, c += deltac) {
- // precalculate other stuff
- float32 lengthPerRow = m_pVolumeGeometry->getPixelLengthY() * inv_cos_theta;
- float32 updatePerRow = sin_theta * lengthPerRow;
- float32 inv_pixelLengthX = 1.0f / m_pVolumeGeometry->getPixelLengthX();
- float32 pixelLengthX_over_blobSize = m_pVolumeGeometry->getPixelLengthX() / m_fBlobSize;
-
- // some variables
- int row, col, xmin, xmax;
- float32 P, x, d;
+ col_left = int(c - 0.5f - m_fBlobSize);
+ col_right = int(c + 0.5f + m_fBlobSize);
- // calculate P and x for row 0
- P = (t - sin_theta * m_pVolumeGeometry->pixelRowToCenterY(0)) * inv_cos_theta;
- x = (P - m_pVolumeGeometry->getWindowMinX()) * inv_pixelLengthX - 0.5f;
+ if (col_left < 0) col_left = 0;
+ if (col_right > colCount-1) col_right = colCount-1;
- // for each row
- for (row = 0; row < m_pVolumeGeometry->getGridRowCount(); ++row) {
-
- // calculate extent
- xmin = (int)ceil((P - m_fBlobSize - m_pVolumeGeometry->getWindowMinX()) * inv_pixelLengthX - 0.5f);
- xmax = (int)floor((P + m_fBlobSize - m_pVolumeGeometry->getWindowMinX()) * inv_pixelLengthX - 0.5f);
-
- // add pixels
- for (col = xmin; col <= xmax; col++) {
- if (col >= 0 && col < m_pVolumeGeometry->getGridColCount()) {
- //d = abs(x - col) * pixelLengthX_over_blobSize;
- //index = (int)(d*m_iBlobSampleCount+0.5f);
- //float32 fWeight = m_pfBlobValues[min(index,m_iBlobSampleCount-1)] * lengthPerRow;
-
- float32 fWeight;
- int index;
- if ((x >= col) ^ flip) {
- d = abs(x - col) * pixelLengthX_over_blobSize * cos_theta;
- index = (int)(d*m_iBlobSampleCount+0.5f);
- fWeight = m_pfBlobValues[min(index,m_iBlobSampleCount-1)];
- } else {
- d = abs(x - col) * pixelLengthX_over_blobSize * cos_theta;
- index = (int)(d*m_iBlobSampleCount+0.5f);
- fWeight = m_pfBlobValuesNeg[min(index,m_iBlobSampleCount-1)];
- }
+ // loop columns
+ for (col = col_left; col <= col_right; ++col) {
- int iVolumeIndex = m_pVolumeGeometry->pixelRowColToIndex(row, col);
- // POLICY: PIXEL PRIOR + ADD + POSTERIOR
- if (p.pixelPrior(iVolumeIndex)) {
- p.addWeight(iRayIndex, iVolumeIndex, fWeight);
- p.pixelPosterior(iVolumeIndex);
+ iVolumeIndex = row * colCount + col;
+ // POLICY: PIXEL PRIOR + ADD + POSTERIOR
+ if (p.pixelPrior(iVolumeIndex)) {
+ offset = abs(c - float32(col)) * invBlobExtent;
+ index = (int)(offset*m_iBlobSampleCount+0.5f);
+ p.addWeight(iRayIndex, iVolumeIndex, m_pfBlobValues[min(index,m_iBlobSampleCount-1)]);
+ p.pixelPosterior(iVolumeIndex);
+ }
}
}
}
- // update P and x
- P += updatePerRow;
- x += updatePerRow * inv_pixelLengthX;
- }
+ // horizontally
+ else {
- } else { // pi/4 < theta < 3pi/4
-
- // precalculate sin cos
- float32 sin_90_theta = sin(PIdiv2-theta);
- float32 cos_90_theta = cos(PIdiv2-theta);
- float32 inv_cos_90_theta = 1.0f / cos_90_theta;
-
- // precalculate other stuff
- float32 lengthPerCol = m_pVolumeGeometry->getPixelLengthX() * inv_cos_90_theta;
- float32 updatePerCol = sin_90_theta * lengthPerCol;
- float32 inv_pixelLengthY = 1.0f / m_pVolumeGeometry->getPixelLengthY();
- float32 pixelLengthY_over_blobSize = m_pVolumeGeometry->getPixelLengthY() / m_fBlobSize;
-
- // some variables
- int row, col, xmin, xmax;
- float32 P,x, d;
-
- // calculate P and x for col 0
- P = (sin_90_theta * m_pVolumeGeometry->pixelColToCenterX(0) - t) * inv_cos_90_theta;
- x = (P - m_pVolumeGeometry->getWindowMinY()) * inv_pixelLengthY - 0.5f;
-
- // for each col
- for (col = 0; col < m_pVolumeGeometry->getGridColCount(); ++col) {
-
- // calculate extent
- xmin = (int)ceil((P - m_fBlobSize - m_pVolumeGeometry->getWindowMinY()) * inv_pixelLengthY - 0.5f);
- xmax = (int)floor((P + m_fBlobSize - m_pVolumeGeometry->getWindowMinY()) * inv_pixelLengthY - 0.5f);
-
- // add pixels
- for (row = xmin; row <= xmax; row++) {
- if (row >= 0 && row < m_pVolumeGeometry->getGridRowCount()) {
- //d = abs(x - row) * pixelLengthY_over_blobSize;
- //int index = (int)(d*m_iBlobSampleCount+0.5f);
- //float32 fWeight = m_pfBlobValues[min(index,m_iBlobSampleCount-1)] * lengthPerCol;
-
- float32 fWeight;
- int index;
- if ((x <= row) ^ flip) {
- d = abs(x - row) * pixelLengthY_over_blobSize * cos_90_theta;
- index = (int)(d*m_iBlobSampleCount+0.5f);
- fWeight = m_pfBlobValues[min(index,m_iBlobSampleCount-1)];
- } else {
- d = abs(x - row) * pixelLengthY_over_blobSize * cos_90_theta;
- index = (int)(d*m_iBlobSampleCount+0.5f);
- fWeight = m_pfBlobValuesNeg[min(index,m_iBlobSampleCount-1)];
- }
-
-
- int iVolumeIndex = m_pVolumeGeometry->pixelRowColToIndex(row, col);
- // POLICY: PIXEL PRIOR + ADD + POSTERIOR
- if (p.pixelPrior(iVolumeIndex)) {
- p.addWeight(iRayIndex, iVolumeIndex, fWeight);
- p.pixelPosterior(iVolumeIndex);
- }
- }
- }
+ // calculate r for col 0
+ r = -(Dy + (Ex - Dx)*RyOverRx - Ey) * inv_pixelLengthY;
- // update P and x
- P += updatePerCol;
- x += updatePerCol * inv_pixelLengthY;
- }
+ // loop columns
+ for (col = 0; col < colCount; ++col, r += deltar) {
- }
+ row_top = int(r - 0.5f - m_fBlobSize);
+ row_bottom = int(r + 0.5f + m_fBlobSize);
- // POLICY: RAY POSTERIOR
- p.rayPosterior(iRayIndex);
+ if (row_top < 0) row_top = 0;
+ if (row_bottom > rowCount-1) row_bottom = rowCount-1;
+ // loop rows
+ for (row = row_top; row <= row_bottom; ++row) {
+ iVolumeIndex = row * colCount + col;
+ // POLICY: PIXEL PRIOR + ADD + POSTERIOR
+ if (p.pixelPrior(iVolumeIndex)) {
+ offset = abs(r - float32(row)) * invBlobExtent;
+ index = (int)(offset*m_iBlobSampleCount+0.5f);
+ p.addWeight(iRayIndex, iVolumeIndex, m_pfBlobValues[min(index,m_iBlobSampleCount-1)]);
+ p.pixelPosterior(iVolumeIndex);
+ }
+ }
+ }
+ }
+
+ // POLICY: RAY POSTERIOR
+ p.rayPosterior(iRayIndex);
+
+ } // end loop detector
+ } // end loop angles
}
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