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Files | |
| file | find_fwhm_in_image.cxx |
| Implementations of functions defined in find_fwhm_in_image.h. | |
| file | find_fwhm_in_image.h |
| A collection of functions to measure resolution. | |
| file | find_fwhm_in_image.inl |
| A collection of functions to measure resolution. | |
Classes | |
| struct | stir::ResolutionIndex< num_dimensions, elemT > |
| a structure that is used to hold the output of the function find_fwhm_in_image. More... | |
Functions | |
| template<class RandomAccessIterType > | |
| float | stir::find_level_width (const RandomAccessIterType &begin_iterator, const RandomAccessIterType &max_iterator, const RandomAccessIterType &end_iterator, const float level_height) |
| find width at a level More... | |
| template<class RandomAccessIterType > | |
| float | stir::find_level_width (const RandomAccessIterType &begin_iterator, const RandomAccessIterType &end_iterator, const float level_height) |
| find width at a level More... | |
| template<class elemT > | |
| BasicCoordinate< 3, int > | stir::maximum_location_per_slice (const Array< 3, elemT > &input_array, const int slice, const int dimension) |
| finds the maximum of the Input_Array in the given slice at the given dimension (z=1, y=2, x=3), and returns its location as a vector in BasicCoordinate Field (only 3D implementation). | |
| template<class elemT > | |
| Array< 1, elemT > | stir::interpolate_line (const Array< 3, elemT > &input_array, const BasicCoordinate< 3, int > &max_location, const BasicCoordinate< 3, bool > &do_direction, const int dimension) |
| extract a line from the given array after determining its locatin with a parabolic fit More... | |
| template<class elemT > | |
| std::list< ResolutionIndex< 3, float > > | stir::find_fwhm_in_image (DiscretisedDensity< 3, elemT > &input_image, const unsigned int num_maxima, const float level, const int dimension, const bool nema) |
| Finds FWHM, FWTM etc (in mm) for a number of point sources or a line source. More... | |
Detailed Description
Function Documentation
◆ find_level_width() [1/2]
|
inline |
find width at a level
- Parameters
-
[in] begin_iterator start of sequence to check [in] max_iterator location from where the search will start, should be close to the location of the (local) maximum you want to investigate [in] end_iterator end of sequence to check [in] level_height intensity level at which to find the width
- Returns
- width of the level set (in pixel units)
The implementation assumes uniform spacing between the samples.
We use linear interpolation between samples to estimate where the function value reaches the level_height value.
If the search runs to the end/start of the sequence, a warning is issued, and the width is estimated using linear extrapolation.
References stir::warning().
Referenced by stir::find_level_width().
◆ find_level_width() [2/2]
|
inline |
find width at a level
- Parameters
-
[in] begin_iterator start of sequence to check [in] end_iterator end of sequence to check [in] level_height intensity level at which to find the width
- Returns
- width of the level set (in pixel units)
This function finds the maximum in the sequence and calls find_level_width(const RandomAccessIterType& begin_iterator, const RandomAccessIterType& max_iterator, const RandomAccessIterType& end_iterator, const float level_height)
References stir::find_level_width().
◆ interpolate_line()
| Array< 1, elemT > stir::interpolate_line | ( | const Array< 3, elemT > & | input_array, |
| const BasicCoordinate< 3, int > & | max_location, | ||
| const BasicCoordinate< 3, bool > & | do_direction, | ||
| const int | dimension | ||
| ) |
extract a line from the given array after determining its locatin with a parabolic fit
It finds the real maximum location, using the 3 points parabolic fit. Then, tri-linear interpolation is used to find the whole line at the given dimension (z:1,y:2,x:3) taking into account the voxels that intersects the voxel which has in its center the point with the real maximum_value.
References stir::error(), stir::extract_line(), and stir::Array< num_dimensions, elemT >::get_regular_range().
◆ find_fwhm_in_image()
| std::list< ResolutionIndex< 3, float > > stir::find_fwhm_in_image | ( | DiscretisedDensity< 3, elemT > & | input_image, |
| const unsigned int | num_maxima, | ||
| const float | level, | ||
| const int | dimension, | ||
| const bool | nema | ||
| ) |
Finds FWHM, FWTM etc (in mm) for a number of point sources or a line source.
- Parameters
-
[in] input_image [in] num_maxima the number of maxima to find (see below) [in] level level at which to compute the width (2 for half maximum, 10 for tenth maximum etc.) [in] dimension the dimension along which the line source is oriented, or 0 for point sources [in] nema enables the calculation based on the NEMA Standards Publication NU 2-2001.
- Returns
- a list containing the maximum_value, its location per slice and resolution. For line sources, sorted by minimum to maximum slice of the requested dimension, or for point sources, sorted by maximum to minimum value.
For line sources, num_maxima slices are sampled (from first to last slice, with steps given by num_slices/(num_maxima+1)
For point sources, if num_maxima is larger than 1, after finding a maximum and the resolution, the data is masked out in a neigbhourhood of half-size (resolution*2/level). This will only ork properly if the point sources are not too close to eachother and have roughly the maximum.
The value of the maximum is computed using a parabolic fit through the 3 points around the maximum as specified in NEMA 2001.
If nema=false, the interpolate_line() function is used to find a line, otherwise we use extract_line().
