find_fwhm_in_image.inl

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//
//
/*
    Copyright (C) 2004- 2009, Hammersmith Imanet
    This file is part of STIR.
 
    SPDX-License-Identifier: Apache-2.0
 
    See STIR/LICENSE.txt for details
*/
#include <algorithm>
#include "stir/warning.h"
 
START_NAMESPACE_STIR
 
template <class RandomAccessIterType>
float
find_level_width(const RandomAccessIterType& begin_iterator,
                 const RandomAccessIterType& current_max_iterator,
                 const RandomAccessIterType& end_iterator,
                 const float level_height)
{
  const int max_position = static_cast<int>(current_max_iterator - begin_iterator + 1);
  RandomAccessIterType current_iter = current_max_iterator;
  while (current_iter != end_iterator && *current_iter > level_height)
    ++current_iter;
  if (current_iter == end_iterator)
    {
      warning("find_level_width: level extends beyond border."
              "Cannot find the real level-width of this point source!");
      // go 1 back to remain inside the range
      --current_iter;
    }
 
  // do linear interpolation to find position of level_height
  float right_level_max = (*current_iter - level_height) / (*current_iter - *(current_iter - 1));
  right_level_max = float(current_iter - (begin_iterator + max_position)) - right_level_max;
 
  current_iter = current_max_iterator;
  while (current_iter != begin_iterator && *current_iter > level_height)
    --current_iter;
  if (current_iter == begin_iterator && *current_iter > level_height)
    {
      warning("find_level_width: level extends beyond border."
              "Cannot find the real level-width of this point source!");
    }
 
  float left_level_max = (*current_iter - level_height) / (*current_iter - *(current_iter + 1));
  left_level_max += float(current_iter - (begin_iterator + max_position));
 
  return right_level_max - left_level_max;
}
 
template <class RandomAccessIterType>
float
find_level_width(const RandomAccessIterType& begin_iterator, const RandomAccessIterType& end_iterator, const float level_height)
{
  return find_level_width(begin_iterator, std::max_element(begin_iterator, end_iterator), end_iterator, level_height);
}
END_NAMESPACE_STIR