opticam.background.local_background
===================================

.. py:module:: opticam.background.local_background


Classes
-------

.. autoapisummary::

   opticam.background.local_background.BaseLocalBackground
   opticam.background.local_background.DefaultLocalBackground


Module Contents
---------------

.. py:class:: BaseLocalBackground(r_in_scale = 5, r_out_scale = 7.5, sigma_clip = SigmaClip(sigma=3, maxiters=10))

   Bases: :py:obj:`abc.ABC`


   Base class for local background estimators.


   .. py:attribute:: r_in_scale
      :value: 5



   .. py:attribute:: r_out_scale
      :value: 7.5



   .. py:attribute:: sigma_clip


   .. py:method:: __call__(data, position, semimajor_axis, semiminor_axis, theta)
      :abstractmethod:


      Compute the local background and its error at a given position (**per pixel**).

      Parameters
      ----------
      data : NDArray
          The image data.
      semimajor_axis : float
          The (unscaled) semi-major axis of the aperture.
      semiminor_axis : float
          The (unscaled) semi-minor axis of the aperture.
      theta : float
          The rotation angle of the PSF.
      position : Tuple[float, float]
          The x, y position at which to compute the local background.

      Returns
      -------
      Tuple[float, float]
          The local background and its error per pixel.



   .. py:method:: get_annulus(position, semimajor_axis, semiminor_axis, theta)
      :abstractmethod:


      Define an annulus at the given position.

      Parameters
      ----------
      position : NDArray
          The centre of the annulus.
      semimajor_axis : float
          The semimajor standard deviation of the PSF.
      semiminor_axis : float
          The semiminor standard deviation of the PSF.
      theta : float
          The orientation of the source **in radians**.

      Returns
      -------
      Aperture
          The annulus.



   .. py:method:: get_stats(data, position, semimajor_axis, semiminor_axis, theta)

      Get the stats of the annulus.

      Parameters
      ----------
      data : NDArray
          The image data.
      position : NDArray
          The centre of the annulus.
      semimajor_axis : float
          The semimajor standard deviation of the PSF.
      semiminor_axis : float
          The semiminor standard deviation of the PSF.
      theta : float
          The orientation of the source **in radians**.

      Returns
      -------
      ApertureStats
          The stats of the annulus.



.. py:class:: DefaultLocalBackground(r_in_scale = 5, r_out_scale = 7.5, sigma_clip = SigmaClip(sigma=3, maxiters=10))

   Bases: :py:obj:`BaseLocalBackground`


   Default local background estimator using an elliptical annulus.


   .. py:method:: get_annulus(position, semimajor_axis, semiminor_axis, theta)

      Define an annulus at the given position.

      Parameters
      ----------
      position : NDArray
          The centre of the annulus.
      semimajor_axis : float
          The semimajor standard deviation of the PSF.
      semiminor_axis : float
          The semiminor standard deviation of the PSF.
      theta : float
          The orientation of the source **in radians**.

      Returns
      -------
      Aperture
          The annulus.



   .. py:method:: __call__(data, position, semimajor_axis, semiminor_axis = None, theta = 0.0)

      Compute the sigma-clipped local background (mean) and its error (standard deviation) at a given position.

      Parameters
      ----------
      data : NDArray
          The image data.
      error : NDArray
          The error in the image data.
      position : NDArray
          The x, y position at which to compute the local background.
      semimajor_axis : float
          The (unscaled) semimajor axis of the aperture.
      semiminor_axis : float | None, optional
          The (unscaled) semiminor axis of the aperture, by default `None`. If `None`, it is assumed to be equal to 
          the semimajor axis (i.e., the annulus is circular).
      theta : float, optional
          The rotation angle of the PSF, by default 0 (i.e., no rotation).

      Returns
      -------
      Tuple[float, float]
          The local background (mean) and its error (standard deviation).