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authorWillem Jan Palenstijn <WillemJan.Palenstijn@uantwerpen.be>2013-07-01 22:34:11 +0000
committerwpalenst <WillemJan.Palenstijn@uantwerpen.be>2013-07-01 22:34:11 +0000
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Update version to 1.3
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+/*
+-----------------------------------------------------------------------
+Copyright 2012 iMinds-Vision Lab, University of Antwerp
+
+Contact: astra@ua.ac.be
+Website: http://astra.ua.ac.be
+
+
+This file is part of the
+All Scale Tomographic Reconstruction Antwerp Toolbox ("ASTRA Toolbox").
+
+The ASTRA Toolbox is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+The ASTRA Toolbox is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with the ASTRA Toolbox. If not, see <http://www.gnu.org/licenses/>.
+
+-----------------------------------------------------------------------
+$Id$
+*/
+
+#ifndef _INC_ASTRA_FANFLATPROJECTIONGEOMETRY2D
+#define _INC_ASTRA_FANFLATPROJECTIONGEOMETRY2D
+
+#include "ProjectionGeometry2D.h"
+
+#include <cmath>
+
+namespace astra
+{
+
+/**
+ * This class defines a 2D fan beam geometry with a flat detector that has equally spaced detector cells.
+ *
+ * \par XML Configuration
+ * \astra_xml_item{DetectorCount, int, Number of detectors for each projection.}
+ * \astra_xml_item{DetectorWidth, float, Width of each detector.}
+ * \astra_xml_item{ProjectionAngles, vector of float, projection angles in radians.}
+ * \astra_xml_item{DistanceOriginDetector, float, Distance between the center of rotation and the detectorarray.}
+ * \astra_xml_item{DistanceOriginSource, float, Distance between the center of rotation the the x-ray source.}
+ *
+ * \par MATLAB example
+ * \astra_code{
+ * proj_geom = astra_struct('fanflat');\n
+ * proj_geom.DetectorCount = 512;\n
+ * proj_geom.DetectorWidth = 1.0;\n
+ * proj_geom.ProjectionAngles = linspace(0,pi,100);\n
+ * proj_geom.DistanceOriginDetector = 300;\n
+ * proj_geom.DistanceOriginSource = 300;\n
+ * }
+ */
+class _AstraExport CFanFlatProjectionGeometry2D : public CProjectionGeometry2D
+{
+ /**
+ * Distance from the origin of the coordinate system to the source.
+ */
+ float32 m_fOriginSourceDistance;
+
+ /**
+ * Distance from the origin of the coordinate system to the detector (i.e., the distance between the origin and its orthogonal projection
+ * onto the detector array).
+ */
+ float32 m_fOriginDetectorDistance;
+
+public:
+
+ /** Default constructor. Sets all variables to zero. Note that this constructor leaves the object in an unusable state and must
+ * be followed by a call to init().
+ */
+ CFanFlatProjectionGeometry2D();
+
+ /** Constructor.
+ *
+ * @param _iProjectionAngleCount Number of projection angles.
+ * @param _iDetectorCount Number of detectors, i.e., the number of detector measurements for each projection angle.
+ * @param _fDetectorWidth Width of a detector cell, in unit lengths. All detector cells are assumed to have equal width.
+ * @param _pfProjectionAngles Pointer to an array of projection angles. The angles will be copied from this array.
+ * All angles are represented in radians.
+ * @param _fOriginSourceDistance Distance from the origin of the coordinate system to the source
+ * @param _fOriginDetectorDistance Distance from the origin of the coordinate system to the detector
+ */
+ CFanFlatProjectionGeometry2D(int _iProjectionAngleCount,
+ int _iDetectorCount,
+ float32 _fDetectorWidth,
+ const float32* _pfProjectionAngles,
+ float32 _fOriginSourceDistance,
+ float32 _fOriginDetectorDistance);
+
+ /** Copy constructor.
+ */
+ CFanFlatProjectionGeometry2D(const CFanFlatProjectionGeometry2D& _projGeom);
+
+ /** Assignment operator.
+ */
+ CFanFlatProjectionGeometry2D& operator=(const CFanFlatProjectionGeometry2D& _other);
+
+ /** Destructor.
+ */
+ virtual ~CFanFlatProjectionGeometry2D();
+
+ /** Initialize the geometry with a config object.
+ *
+ * @param _cfg Configuration Object
+ * @return initialization successful?
+ */
+ virtual bool initialize(const Config& _cfg);
+
+ /** Initialization. This function MUST be called after using the default constructor and MAY be called to
+ * reset a previously initialized object.
+ *
+ * @param _iProjectionAngleCount Number of projection angles.
+ * @param _iDetectorCount Number of detectors, i.e., the number of detector measurements for each projection angle.
+ * @param _fDetectorWidth Width of a detector cell, in unit lengths. All detector cells are assumed to have equal width.
+ * @param _pfProjectionAngles Pointer to an array of projection angles. The angles will be copied from this array.
+ * @param _fOriginSourceDistance Distance from the origin of the coordinate system to the source
+ * @param _fOriginDetectorDistance Distance from the origin of the coordinate system to the detector
+ */
+ bool initialize(int _iProjectionAngleCount,
+ int _iDetectorCount,
+ float32 _fDetectorWidth,
+ const float32* _pfProjectionAngles,
+ float32 _fOriginSourceDistance,
+ float32 _fOriginDetectorDistance);
+
+ /** Create a hard copy.
+ */
+ virtual CProjectionGeometry2D* clone();
+
+ /** Returns true if the type of geometry defined in this class is the one specified in _sType.
+ *
+ * @param _sType geometry type to compare to.
+ * @return true if _sType == "fanflat".
+ */
+ virtual bool isOfType(const std::string& _sType);
+
+ /** Return true if this geometry instance is the same as the one specified.
+ *
+ * @return true if this geometry instance is the same as the one specified.
+ */
+ virtual bool isEqual(CProjectionGeometry2D*) const;
+
+ /** Returns the distance from the origin of the coordinate system to the source.
+ *
+ * @return Distance from the origin of the coordinate system to the source
+ */
+ float32 getOriginSourceDistance() const;
+
+ /** Returns the distance from the origin of the coordinate system to the detector
+ * (i.e., the distance between the origin and its orthogonal projection onto the detector array).
+ *
+ * @return Distance from the origin of the coordinate system to the detector
+ */
+ float32 getOriginDetectorDistance() const;
+
+ /** Returns the distance from the source to the detector
+ * (i.e., the distance between the source and its orthogonal projection onto the detector array).
+ *
+ * @return Distance from the source to the detector
+ */
+ float32 getSourceDetectorDistance() const;
+
+ /** Get the value for t and theta, based upon the row and column index.
+ *
+ * @param _iRow row index
+ * @param _iColumn column index
+ * @param _fT output: value of t
+ * @param _fTheta output: value of theta, always lies within the [0,pi[ interval.
+ */
+ virtual void getRayParams(int _iRow, int _iColumn, float32& _fT, float32& _fTheta) const;
+
+ /**
+ * Returns a vector describing the direction of a ray belonging to a certain detector
+ *
+ * @param _iProjectionIndex index of projection
+ * @param _iProjectionIndex index of detector
+ *
+ * @return a unit vector describing the direction
+ */
+ virtual CVector3D getProjectionDirection(int _iProjectionIndex, int _iDetectorIndex);
+};
+
+
+
+// Returns the distance from the origin of the coordinate system to the source.
+inline float32 CFanFlatProjectionGeometry2D::getOriginSourceDistance() const
+{
+ return m_fOriginSourceDistance;
+}
+
+
+// Returns the distance from the origin of the coordinate system to the detector.
+inline float32 CFanFlatProjectionGeometry2D::getOriginDetectorDistance() const
+{
+ return m_fOriginDetectorDistance;
+}
+
+
+// Returns the distance from the source to the detector.
+inline float32 CFanFlatProjectionGeometry2D::getSourceDetectorDistance() const
+{
+ return (m_fOriginSourceDistance + m_fOriginDetectorDistance);
+}
+
+
+// Get T and Theta
+inline void CFanFlatProjectionGeometry2D::getRayParams(int _iRow, int _iColumn, float32& _fT, float32& _fTheta) const
+{
+ assert(m_bInitialized);
+
+ // get the distance between the center of the detector array and the detector.
+ float32 det_offset = indexToDetectorOffset(_iColumn);
+
+ // get the angle between the center ray of the projection and the projection.
+ float32 alpha = atan(det_offset / getSourceDetectorDistance());
+
+ // calculate t and theta
+ _fT = m_fOriginSourceDistance * sin(alpha);
+ _fTheta = getProjectionAngle(_iRow) + alpha;
+
+ // if theta is larger than pi, flip of the origin
+ if (PI <= _fTheta) {
+ _fTheta -= PI;
+ _fT = -_fT;
+ }
+ // if theta is below 0, flip
+ if (_fTheta < 0) {
+ _fTheta += PI;
+ _fT = -_fT;
+ }
+}
+
+
+
+} // namespace astra
+
+#endif /* _INC_ASTRA_FANFLATPROJECTIONGEOMETRY2D */
+