Implementations of two square root Hessian row sum computation methods, as proposed by Tsai et al. (2020). More...
#include "stir/recon_buildblock/SqrtHessianRowSum.h"
Public Member Functions | |
| SqrtHessianRowSum () | |
| Default constructor. More... | |
| SqrtHessianRowSum (const std::string &) | |
| void | set_defaults () override |
| sets default values More... | |
| void | process_data () |
| The main function to compute and save the sqrt of the Hessian row sum volume. More... | |
| shared_ptr< TargetT > | get_output_target_sptr () |
| get method for returning the sqrt row sum image | |
| void | set_up () |
| void | compute_Hessian_row_sum () |
| Computes the objective function Hessian row sum at the current image estimate. Can compute the penalty's Hessian if it exists for the selected prior. | |
| void | compute_approximate_Hessian_row_sum () |
| Computes the approximate Hessian of the objective function. Cannot use penalty's approximate Hessian, see compute_with_penalty. | |
get and set methods for the objective function sptr | |
| GeneralisedObjectiveFunction< TargetT > const & | get_objective_function_sptr () |
| void | set_objective_function_sptr (const shared_ptr< GeneralisedObjectiveFunction< TargetT >> &obj_fun) |
get and set methods for the input image | |
| shared_ptr< TargetT > | get_input_image_sptr () |
| void | set_input_image_sptr (shared_ptr< TargetT > const &image) |
get and set methods for use approximate hessian bool | |
| bool | get_use_approximate_hessian () const |
| void | set_use_approximate_hessian (bool use_approximate) |
get and set methods for the compute with penalty bool | |
| bool | get_compute_with_penalty () const |
| void | set_compute_with_penalty (bool with_penalty) |
 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 Attributes | |
| bool | _already_setup = false |
| Protected Attributes inherited from stir::ParsingObject | |
| KeyParser | parser |
Additional Inherited Members | |
| Protected Member Functions inherited from stir::ParsingObject | |
| virtual void | set_key_values () |
| This will be called before parsing or parameter_info is called. More... | |
Detailed Description
template<typename TargetT>
class stir::SqrtHessianRowSum< TargetT >
Implementations of two square root Hessian row sum computation methods, as proposed by Tsai et al. (2020).
Two methods of computing the sqrt of the Hessian row sum images:
- use an approximation of the Hessian of the log-likelihood from only the measured data sqrt[ backproj( forwproj(ones) / y) ]
- use a current image estimate to compute the Hessian of the objective function (and optionally Hessian of the prior) where y is the measured (input) data, b is the corrections (additive sinogram), lambda is the current image estimate, and ones is an uniform array of ones.sqrt[ backproj( (y / (forwproj(lambda) + b)^2 ) * forwproj(ones)) +beta * prior.Hessian_times_input(lambda, ones)]
For more details, see: Tsai, Y.-J., Schramm, G., Ahn, S., Bousse, A., Arridge, S., Nuyts, J., Hutton, B. F., Stearns, C. W., & Thielemans, K. (2020). Benefits of Using a Spatially-Variant Penalty Strength With Anatomical Priors in PET Reconstruction. IEEE Transactions on Medical Imaging, 39(1), 11-22. https://doi.org/10.1109/TMI.2019.2913889
Constructor & Destructor Documentation
◆ SqrtHessianRowSum()
| stir::SqrtHessianRowSum< TargetT >::SqrtHessianRowSum | ( | ) |
Default constructor.
calls set_defaults().
Member Function Documentation
◆ set_defaults()
|
overridevirtual |
sets default values
Sets use_approximate_hessian to true and compute_with_penalty to false
Reimplemented from stir::ParsingObject.
References stir::error().
◆ process_data()
| void stir::SqrtHessianRowSum< TargetT >::process_data | ( | ) |
The main function to compute and save the sqrt of the Hessian row sum volume.
Different Hessian row sum methods can be used, see compute_Hessian_row_sum() and compute_approximate_Hessian_row_sum().
The documentation for this class was generated from the following files:
- /home/sirfuser/devel/STIRdistrib/STIR/src/include/stir/recon_buildblock/SqrtHessianRowSum.h
- /home/sirfuser/devel/STIRdistrib/STIR/src/recon_buildblock/SqrtHessianRowSum.cxx
