weighted_sum_computation
==============================================

.. py:function:: petpal.utils.math_lib.weighted_sum_computation(pet_series: ants.core.ANTsImage | numpy.ndarray, frame_duration: numpy.ndarray, half_life: float, frame_start: numpy.ndarray, decay_correction: numpy.ndarray)

   Weighted sum of a PET image based on time and re-corrected for decay correction.

   :param image_frame_duration: Duration of each frame in pet series
   :type image_frame_duration: np.ndarray
   :param half_life: Half life of tracer radioisotope in seconds.
   :type half_life: float
   :param pet_series: 4D PET image series, as a data array.
   :type pet_series: np.ndarray
   :param image_frame_start: Start time of each frame in pet series,
                             measured with respect to scan TimeZero.
   :type image_frame_start: np.ndarray
   :param image_decay_correction: Decay correction factor that scales
                                  each frame in the pet series.
   :type image_decay_correction: np.ndarray

   :returns: *image_weighted_sum (np.ndarray)* --

             3D PET image computed by reversing decay correction
                 on the PET image series, scaling each frame by the frame duration, then re-applying
                 decay correction and scaling the image to the full duration.

   .. seealso:: * :meth:`petpal.image_operations_4d.weighted_series_sum`: Function where this is implemented.