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/*
-----------------------------------------------------------------------
Copyright: 2010-2021, imec Vision Lab, University of Antwerp
2014-2021, CWI, Amsterdam
Contact: astra@astra-toolbox.com
Website: http://www.astra-toolbox.com/
This file is part of the 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/>.
-----------------------------------------------------------------------
*/
#ifndef _INC_ASTRA_PARALLELPROJECTIONGEOMETRY2D
#define _INC_ASTRA_PARALLELPROJECTIONGEOMETRY2D
#include "ProjectionGeometry2D.h"
#include "ParallelVecProjectionGeometry2D.h"
namespace astra
{
/**
* This class defines a 2D parallel beam projection geometry.
*
* <img src="../images/par_proj_geom.svg" width="600"/>
* This geometry is defined by a number of parameters:
* - The number of detectors (DetCount).
* The distance between the first detector and the projection of the origin \f$O\f$ is equal to
* the distance between the last detector and the projection of \f$O\f$.
* - The width of each detector (detector width). All detectors are equidistant.
* - A list of projection angles (\f$\theta\f$), measured w.r.t. the y-axis of the volume. In Radians. Should lie in the interval \f$[-\frac{\pi}{4},\frac{7\pi}{4}]\f$.
*
* This class provides functionality to convert between detector index and detector offset \f$t\f$.
*
* \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 w.r.t. the y-axis of the volume in radians.}
*
* \par MATLAB example
* \astra_code{
* proj_geom = astra_struct('parallel');\n
* proj_geom.DetectorCount = 512;\n
* proj_geom.DetectorWidth = 1.0;\n
* proj_geom.ProjectionAngles = linspace(0\,pi\,100);\n
* }
*/
class _AstraExport CParallelProjectionGeometry2D : public CProjectionGeometry2D
{
public:
/** Default constructor. Sets all numeric member variables to 0 and all pointer member variables to NULL.
*
* If an object is constructed using this default constructor, it must always be followed by a call
* to one of the init() methods before the object can be used. Any use before calling init() is not allowed,
* except calling the member function isInitialized().
*
*/
CParallelProjectionGeometry2D();
/** Constructor. Create an instance of the CParallelProjectionGeometry2D class.
*
* @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.
*/
CParallelProjectionGeometry2D(int _iProjectionAngleCount,
int _iDetectorCount,
float32 _fDetectorWidth,
const float32* _pfProjectionAngles);
/** Copy constructor.
*/
CParallelProjectionGeometry2D(const CParallelProjectionGeometry2D& _projGeom);
/** Destructor.
*/
~CParallelProjectionGeometry2D();
/** Assignment operator.
*/
CParallelProjectionGeometry2D& operator=(const CParallelProjectionGeometry2D& _other);
/** Initialize the geometry with a config object.
*
* @param _cfg Configuration Object
* @return initialization successful?
*/
virtual bool initialize(const Config& _cfg);
/** Initialization. Initializes an instance of the CProjectionGeometry2D class. If the object has been
* initialized before, the object is reinitialized and memory is freed and reallocated if necessary.
*
* @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.
*/
bool initialize(int _iProjectionAngleCount,
int _iDetectorCount,
float32 _fDetectorWidth,
const float32* _pfProjectionAngles);
/** Create a hard copy.
*/
virtual CProjectionGeometry2D* clone();
/** 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 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 == "parallel".
*/
virtual bool isOfType(const std::string& _sType);
/** Get all settings in a Config object.
*
* @return Configuration Object.
*/
virtual Config* getConfiguration() const;
/**
* Returns a vector describing the direction of a ray belonging to a certain detector,
* the direction is the same for all detectors in one projection
*
* @param _iProjectionIndex index of projection
* @param _iProjectionIndex index of detector
*
* @return a unit vector describing the direction
*/
virtual CVector3D getProjectionDirection(int _iProjectionIndex, int _iDetectorIndex = 0);
/** Create a vector geom
*/
CParallelVecProjectionGeometry2D* toVectorGeometry();
};
} // namespace astra
#endif /* _INC_ASTRA_PARALLELPROJECTIONGEOMETRY2D */
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