Line data    Source code

       1             : #pragma once
       2             : 
       3             : #include "elsaDefines.h"
       4             : #include "DetectorDescriptor.h"
       5             : #include "PlanarDetectorDescriptor.h"
       6             : #include "VolumeDescriptor.h"
       7             : #include "DataContainer.h"
       8             : #include "SiddonsMethod.h"
       9             : #include "JosephsMethod.h"
      10             : 
      11             : namespace elsa
      12             : {
      13             :     /**
      14             :      * @brief Class representing a subset sampling method.
      15             :      *
      16             :      * @author Michael Loipführer - initial code
      17             :      *
      18             :      * @tparam DetectorDescriptor_t
      19             :      * @tparam data_t data type for the domain and range of the problem, defaulting to real_t
      20             :      *
      21             :      */
      22             :     template <typename DetectorDescriptor_t, typename data_t = real_t>
      23             :     class SubsetSampler : public Cloneable<SubsetSampler<DetectorDescriptor_t, data_t>>
      24             :     {
      25             :     public:
      26             :         /// enum to differentiate between different subset sampling strategies
      27             :         enum class SamplingStrategy {
      28             :             ROUND_ROBIN, /// (default) divides data points into subsets via simple round-robin
      29             :             ROTATIONAL_CLUSTERING, /// equally spaces the data points based on their rotation
      30             :         };
      31             : 
      32             :         /**
      33             :          * @brief Constructor for SubsetSampler
      34             :          *
      35             :          * @param[in] volumeDescriptor of the problem
      36             :          * @param[in] detectorDescriptor describes the geometry and trajectory of the measurements
      37             :          * @param[in] nSubsets is number of subsets that should be generated
      38             :          * @param[in] samplingStrategy the strategy with which to sample the subsets
      39             :          */
      40             :         SubsetSampler(const VolumeDescriptor& volumeDescriptor,
      41             :                       const DetectorDescriptor_t& detectorDescriptor, index_t nSubsets,
      42             :                       SamplingStrategy samplingStrategy = SamplingStrategy::ROUND_ROBIN);
      43             : 
      44             :         /// default destructor
      45          18 :         ~SubsetSampler() = default;
      46             : 
      47             :         /**
      48             :          * @brief return a new DataContainer with a BlockDescriptor containing the reordered
      49             :          * sinogram data in each block corresponding to a subset
      50             :          *
      51             :          * @param[in] sinogram the original sinogram
      52             :          */
      53             :         DataContainer<data_t> getPartitionedData(const DataContainer<data_t>& sinogram);
      54             : 
      55             :         /**
      56             :          * @brief return
      57             :          *
      58             :          * @tparam projector_t the type of projector to instantiate
      59             :          */
      60             :         template <typename Projector_t>
      61             :         std::unique_ptr<LinearOperator<data_t>> getProjector()
      62           6 :         {
      63           6 :             return std::make_unique<Projector_t>(_volumeDescriptor, _fullDetectorDescriptor);
      64           6 :         }
      65             : 
      66             :         /**
      67             :          * @brief return a list of projectors that correspond to each subset
      68             :          *
      69             :          * @tparam projector_t the type of projector to instantiate
      70             :          */
      71             :         template <typename Projector_t>
      72             :         std::vector<std::unique_ptr<LinearOperator<data_t>>> getSubsetProjectors()
      73           6 :         {
      74           6 :             std::vector<std::unique_ptr<LinearOperator<data_t>>> projectors;
      75             : 
      76          24 :             for (const auto& detectorDescriptor : _detectorDescriptors) {
      77          24 :                 projectors.emplace_back(
      78          24 :                     std::make_unique<Projector_t>(_volumeDescriptor, detectorDescriptor));
      79          24 :             }
      80             : 
      81           6 :             return projectors;
      82           6 :         }
      83             : 
      84             :         /**
      85             :          * @brief Helper method implementing a general round robin splitting of a list of indices.
      86             :          *
      87             :          * @return mapping of data indices to subsets
      88             :          */
      89             :         static std::vector<std::vector<index_t>>
      90             :             splitRoundRobin(const std::vector<index_t>& indices, index_t nSubsets);
      91             : 
      92             :         /**
      93             :          * @brief Helper method implementing rotational distance based sampling. Iteratively loop
      94             :          * through all data points and assign the closest on based on the angle of rotation to the
      95             :          * next subset.
      96             :          *
      97             :          * @return mapping of data indices to subsets
      98             :          */
      99             :         static std::vector<std::vector<index_t>>
     100             :             splitRotationalClustering(const DetectorDescriptor_t& detectorDescriptor,
     101             :                                       index_t nSubsets);
     102             : 
     103             :     protected:
     104             :         /// default copy constructor for cloning
     105             :         SubsetSampler<DetectorDescriptor_t, data_t>(
     106             :             const SubsetSampler<DetectorDescriptor_t, data_t>& other);
     107             :         /// implement the polymorphic comparison operation
     108             :         bool isEqual(const SubsetSampler<DetectorDescriptor_t, data_t>& other) const override;
     109             : 
     110             :         /// implement the polymorphic clone operation
     111             :         SubsetSampler<DetectorDescriptor_t, data_t>* cloneImpl() const override;
     112             : 
     113             :     private:
     114             :         /// mapping of data point indices to respective subsets
     115             :         std::vector<std::vector<index_t>> _indexMapping;
     116             : 
     117             :         /// volume descriptor of the problem
     118             :         VolumeDescriptor _volumeDescriptor;
     119             : 
     120             :         /// the full detector descriptor of the problem
     121             :         DetectorDescriptor_t _fullDetectorDescriptor;
     122             : 
     123             :         /// list of detector descriptors corresponding to each block
     124             :         std::vector<DetectorDescriptor_t> _detectorDescriptors;
     125             : 
     126             :         /// number of subsets
     127             :         index_t _nSubsets;
     128             :     };
     129             : } // namespace elsa