This class implements forward projection using Siddon's algorithm for ray tracing. That is, it computes length of intersection with the voxels. More...
#include "stir/recon_buildblock/ForwardProjectorByBinUsingRayTracing.h"
Inheritance diagram for stir::ForwardProjectorByBinUsingRayTracing:
Public Member Functions | |
| ForwardProjectorByBinUsingRayTracing (const shared_ptr< const ProjDataInfo > &, const shared_ptr< const DiscretisedDensity< 3, float >> &) | |
| Constructor. More... | |
| void | set_up (const shared_ptr< const ProjDataInfo > &proj_data_info_ptr, const shared_ptr< const DiscretisedDensity< 3, float >> &density_info_ptr) override |
| Stores all necessary geometric info. More... | |
| const DataSymmetriesForViewSegmentNumbers * | get_symmetries_used () const override |
| Informs on which symmetries the projector handles. More... | |
 Public Member Functions inherited from stir::RegisteredParsingObject< ForwardProjectorByBinUsingRayTracing, ForwardProjectorByBin > | |
| std::string | get_registered_name () const override |
| Returns Derived::registered_name. | |
| std::string | parameter_info () override |
| Returns a string with all parameters and their values, in a form suitable for parsing again. | |
| Public Member Functions inherited from stir::ForwardProjectorByBin | |
| ForwardProjectorByBin () | |
| Default constructor calls reset_timers() | |
| void | forward_project (ProjData &, const DiscretisedDensity< 3, float > &, int subset_num=0, int num_subsets=1, bool zero=true) |
| project the volume into the whole or a subset of proj_data, optionally zeroing the rest More... | |
| virtual void | forward_project (ProjData &, int subset_num=0, int num_subsets=1, bool zero=true) |
| project the volume into the whole proj_data More... | |
| void | forward_project (RelatedViewgrams< float > &) |
| project the volume into the viewgrams More... | |
| void | forward_project (RelatedViewgrams< float > &, const int min_axial_pos_num, const int max_axial_pos_num) |
| void | forward_project (RelatedViewgrams< float > &, const int min_axial_pos_num, const int max_axial_pos_num, const int min_tangential_pos_num, const int max_tangential_pos_num) |
| virtual void | set_input (const DiscretisedDensity< 3, float > &) |
| Set input. | |
| void | set_pre_data_processor (shared_ptr< DataProcessor< DiscretisedDensity< 3, float >>> pre_data_processor_sptr) |
| Set data processor to use before forward projection. MUST BE CALLED BEFORE SET_INPUT. | |
| Public Member Functions inherited from stir::TimedObject | |
| void | reset_timers () |
| reset all timers kept by this object | |
| void | stop_timers () const |
| stop all timers kept by this object More... | |
| void | start_timers (bool do_reset=false) const |
| start all timers kept by this object More... | |
| double | get_CPU_timer_value () const |
| get current value of the CPU timer (since first use or last reset) | |
| double | get_wall_clock_timer_value () const |
| get current value of the wall-clock timer (since first use or last reset) | |
| Public Member Functions inherited from stir::ParsingObject | |
| ParsingObject (const ParsingObject &) | |
| ParsingObject & | operator= (const ParsingObject &) |
| void | ask_parameters () |
| bool | parse (std::istream &f) |
| bool | parse (const char *const filename) |
Static Public Attributes | |
| static const char *const | registered_name = "Ray Tracing" |
| Name which will be used when parsing a ForwardProjectorByBin object. | |
Protected Attributes | |
| bool | restrict_to_cylindrical_FOV |
| variable that determines if a cylindrical FOV or the whole image will be handled | |
| Protected Attributes inherited from stir::ForwardProjectorByBin | |
| bool | _already_set_up |
| shared_ptr< DiscretisedDensity< 3, float > > | _density_sptr |
| The density ptr set with set_up() | |
| shared_ptr< DataProcessor< DiscretisedDensity< 3, float > > > | _pre_data_processor_sptr |
| shared_ptr< const ProjDataInfo > | _proj_data_info_sptr |
| ProjDataInfo set by set_up() | |
| Protected Attributes inherited from stir::ParsingObject | |
| KeyParser | parser |
Additional Inherited Members | |
| Static Public Member Functions inherited from stir::RegisteredParsingObject< ForwardProjectorByBinUsingRayTracing, ForwardProjectorByBin > | |
| static ForwardProjectorByBin * | read_from_stream (std::istream *) |
| Construct a new object (of type Derived) by parsing the istream. More... | |
| Static Public Member Functions inherited from stir::RegisteredObject< ForwardProjectorByBin > | |
| static ForwardProjectorByBin * | 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 ForwardProjectorByBin * | 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< ForwardProjectorByBin > | |
| typedef ForwardProjectorByBin *(* | 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. | |
| Protected Member Functions inherited from stir::ForwardProjectorByBin | |
| virtual void | actual_forward_project (RelatedViewgrams< float > &viewgrams, const int min_axial_pos_num, const int max_axial_pos_num, const int min_tangential_pos_num, const int max_tangential_pos_num) |
| virtual void | check (const ProjDataInfo &proj_data_info) const |
| check if the argument is the same as what was used for set_up() More... | |
| virtual void | check (const ProjDataInfo &proj_data_info, const DiscretisedDensity< 3, float > &density_info) const |
| check if the arguments are the same as what was used for set_up() More... | |
| Protected Member Functions inherited from stir::ParsingObject | |
| 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... | |
| Static Protected Member Functions inherited from stir::RegisteredObject< ForwardProjectorByBin > | |
| static RegistryType & | registry () |
| Static function returning the registry. More... | |
Detailed Description
This class implements forward projection using Siddon's algorithm for ray tracing. That is, it computes length of intersection with the voxels.
Currently, the LOIs are divided by voxel_size.x(), unless NEWSCALE is #defined during compilation time of ForwardProjectorByBinUsingRayTracing_Siddon.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).
- Warning
- Current implementation assumes that x,y voxel sizes are at least as large as the sampling in tangential direction, and that z voxel size is either equal to or exactly twice the sampling in axial direction of the segments.
- For each bin, maximum 3 LORs are 'traced'
- The image forward projected HAS to be of type VoxelsOnCartesianGrid.
- The projection data info HAS to be of type ProjDataInfoCylindrical
-
The implementation assumes that the
s-coordinate is antisymmetric in terms of the tangential_pos_num, i.e.proj_data_info_ptr->get_s(Bin(...,tang_pos_num)) ==- proj_data_info_ptr->get_s(Bin(...,-tang_pos_num))
Constructor & Destructor Documentation
◆ ForwardProjectorByBinUsingRayTracing()
| stir::ForwardProjectorByBinUsingRayTracing::ForwardProjectorByBinUsingRayTracing | ( | const shared_ptr< const ProjDataInfo > & | proj_data_info_sptr, |
| const shared_ptr< const DiscretisedDensity< 3, float >> & | image_info_ptr | ||
| ) |
Constructor.
- Warning
- Obsolete
Member Function Documentation
◆ set_up()
|
overridevirtual |
Stores all necessary geometric info.
Note that the density_info_ptr is not stored in this object. It's only used to get some info on sizes etc.
Implements stir::ForwardProjectorByBin.
References stir::error(), stir::VoxelsOnCartesianGrid< elemT >::get_voxel_size(), stir::round(), and stir::warning().
◆ get_symmetries_used()
|
overridevirtual |
Informs on which symmetries the projector handles.
It should get data related by at least those symmetries. Otherwise, a run-time error will occur (unless the derived class has other behaviour).
Implements stir::ForwardProjectorByBin.
References stir::RelatedViewgrams< elemT >::begin(), stir::error(), stir::RelatedViewgrams< elemT >::get_basic_segment_num(), stir::RelatedViewgrams< elemT >::get_basic_view_num(), stir::RelatedViewgrams< elemT >::get_num_viewgrams(), stir::RelatedViewgrams< elemT >::get_proj_data_info_sptr(), stir::Viewgram< elemT >::get_proj_data_info_sptr(), stir::Viewgram< elemT >::get_segment_num(), and stir::Viewgram< elemT >::get_view_num().
The documentation for this class was generated from the following files:
- /home/sirfuser/devel/STIRdistrib/STIR/src/include/stir/recon_buildblock/ForwardProjectorByBinUsingRayTracing.h
- /home/sirfuser/devel/STIRdistrib/STIR/src/recon_buildblock/ForwardProjectorByBinUsingRayTracing.cxx
- /home/sirfuser/devel/STIRdistrib/STIR/src/recon_buildblock/ForwardProjectorByBinUsingRayTracing_Siddon.cxx
