STIR
6.2.0
|
Computes projection matrix elements for VoxelsOnCartesianGrid images by using a Length of Intersection (LOI) model. More...
#include "stir_experimental/recon_buildblock/ProjMatrixByDenselOnCartesianGridUsingElement.h"
Public Member Functions | |
void | set_up (const shared_ptr< const ProjDataInfo > &proj_data_info_ptr, const shared_ptr< const DiscretisedDensity< 3, float >> &density_info_ptr) override |
Stores necessary geometric info. More... | |
virtual float | get_element (const Bin &bin, const CartesianCoordinate3D< float > &densel_ctr) const =0 |
this member computes a single element of the projection matrix More... | |
Public Member Functions inherited from stir::ProjMatrixByDensel | |
virtual const DataSymmetriesForDensels * | get_symmetries_ptr () const =0 |
get a pointer to an object encoding all symmetries that are used by this ProjMatrixByDensel | |
void | get_proj_matrix_elems_for_one_densel (ProjMatrixElemsForOneDensel &, const Densel &) const |
The main method for getting a column of the matrix. More... | |
void | enable_cache (bool v) |
Public Member Functions inherited from stir::RegisteredObjectBase | |
virtual std::string | get_registered_name () const =0 |
Returns the name of the type of the object. More... | |
Public Member Functions inherited from stir::ParsingObject | |
ParsingObject (const ParsingObject &) | |
ParsingObject & | operator= (const ParsingObject &) |
void | ask_parameters () |
virtual std::string | parameter_info () |
bool | parse (std::istream &f) |
bool | parse (const char *const filename) |
Protected Member Functions | |
void | calculate_proj_matrix_elems_for_one_densel (ProjMatrixElemsForOneDensel &) const override |
Calculates all non-zero elements for a particular densel. More... | |
Protected Member Functions inherited from stir::ProjMatrixByDensel | |
ProjMatrixByDensel () | |
default ctor (enables caching) | |
Succeeded | get_cached_proj_matrix_elems_for_one_densel (ProjMatrixElemsForOneDensel &) const |
The method that tries to get data from the cache. More... | |
void | cache_proj_matrix_elems_for_one_densel (const ProjMatrixElemsForOneDensel &) const |
The method to store data in the cache. More... | |
Protected Member Functions inherited from stir::ParsingObject | |
virtual void | set_defaults () |
Set defaults before parsing. | |
virtual void | initialise_keymap () |
Initialise all keywords. | |
virtual bool | post_processing () |
This will be called at the end of the parsing. More... | |
virtual void | set_key_values () |
This will be called before parsing or parameter_info is called. More... | |
Protected Attributes | |
shared_ptr< const ProjDataInfo > | proj_data_info_ptr |
CartesianCoordinate3D< float > | grid_spacing |
CartesianCoordinate3D< float > | origin |
float | min_z_index |
float | max_z_index |
Protected Attributes inherited from stir::ProjMatrixByDensel | |
bool | cache_disabled |
Protected Attributes inherited from stir::ParsingObject | |
KeyParser | parser |
Additional Inherited Members | |
Static Public Member Functions inherited from stir::RegisteredObject< ProjMatrixByDensel > | |
static ProjMatrixByDensel * | read_registered_object (std::istream *in, const std::string ®istered_name) |
Construct a new object (of a type derived from Root, its actual type determined by the registered_name parameter) by parsing the istream. More... | |
static ProjMatrixByDensel * | ask_type_and_parameters () |
ask the user for the type, and then calls read_registered_object(0, type) More... | |
static void | list_registered_names (std::ostream &stream) |
List all possible registered names to the stream. More... | |
Protected Types inherited from stir::RegisteredObject< ProjMatrixByDensel > | |
typedef ProjMatrixByDensel *(* | RootFactory) (std::istream *) |
The type of a root factory is a function, taking an istream* as argument, and returning a Root*. | |
typedef FactoryRegistry< std::string, RootFactory, interfile_less > | RegistryType |
The type of the registry. | |
Static Protected Member Functions inherited from stir::RegisteredObject< ProjMatrixByDensel > | |
static RegistryType & | registry () |
Static function returning the registry. More... | |
Computes projection matrix elements for VoxelsOnCartesianGrid images by using a Length of Intersection (LOI) model.
Currently, the LOIs are divided by voxel_size.x(), unless NEWSCALE
is #defined
during compilation time of ProjMatrixByDenselOnCartesianGridUsingElement.cxx.
If the z voxel size is exactly twice the sampling in axial direction, multiple LORs are used, to avoid missing voxels. (TODOdoc describe how).
Currently, a FOV is used which is circular, and is slightly 'inside' the image (i.e. the radius is about 1 voxel smaller than the maximum possible).
The implementation uses RayTraceVoxelsOnCartesianGrid().
|
overridevirtual |
Stores necessary geometric info.
This function hsd
to be called by any derived class.
Note that the density_info_ptr is not stored in this object. It's only used to get some info on sizes etc.
Currently, the proj_data_info_ptr argument is not used.
Implements stir::ProjMatrixByDensel.
Reimplemented in stir::ProjMatrixByDenselUsingRayTracing.
References stir::error(), stir::DiscretisedDensityOnCartesianGrid< num_dimensions, elemT >::get_grid_spacing(), stir::VectorWithOffset< Array< num_dimensions - 1, elemT > >::get_max_index(), stir::VectorWithOffset< Array< num_dimensions - 1, elemT > >::get_min_index(), and stir::DiscretisedDensity< num_dimensions, elemT >::get_origin().
|
pure virtual |
this member computes a single element of the projection matrix
bin | The bin-coordinates specifying the row of the projection matrix |
densel_ctr | The densel coordinates specifying the column of the projection matrix |
Ideally, get_element should be implemented such that tiny elements are truncated to 0, to avoid storing (and using) elements that not really contribute to the result.
Implemented in stir::ProjMatrixByDenselUsingRayTracing.
|
overrideprotectedvirtual |
Calculates all non-zero elements for a particular densel.
This implementation uses the get_element() member. It uses a generic way of finding non-zero elements, which is slow but makes only a few assumptions. TODO more doc.
Implements stir::ProjMatrixByDensel.
References stir::ProjMatrixElemsForOneDensel::get_densel(), stir::ProjMatrixElemsForOneDensel::push_back(), stir::Bin::set_bin_value(), stir::ProjMatrixElemsForOneDensel::size(), stir::square(), and stir::Bin::tangential_pos_num().