isofit.surface.surface_glint_model
==================================

.. py:module:: isofit.surface.surface_glint_model


Classes
-------

.. autoapisummary::

   isofit.surface.surface_glint_model.GlintModelSurface


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

.. py:class:: GlintModelSurface(full_config: Config)

   Bases: :py:obj:`isofit.surface.surface_multicomp.MultiComponentSurface`


   A model of the surface based on a collection of multivariate
   Gaussians, extended with two surface glint terms (sun + sky glint).


   .. py:attribute:: glint_ind


   .. py:attribute:: sky_glint_ind


   .. py:attribute:: sun_glint_ind


   .. py:attribute:: n_state


   .. py:attribute:: idx_surface


   .. py:attribute:: analytical_iv_idx


   .. py:attribute:: sun_glint_sigma


   .. py:attribute:: sky_glint_sigma


   .. py:method:: xa(x_surface, geom)

      Mean of prior distribution, calculated at state x.



   .. py:method:: Sa(x_surface, geom)

      Covariance of prior distribution, calculated at state x.  We find
      the covariance in a normalized space (normalizing by z) and then un-
      normalize the result for the calling function.



   .. py:method:: fit_params(rfl_meas, geom, *args)

      Given a reflectance estimate and one or more emissive parameters,
      fit a state vector.



   .. py:method:: calc_rfl(x_surface, geom)

      Direct and diffuse Reflectance (includes sun and sky glint).

      Inputs:
      x_surface : np.ndarray
          Surface portion of the statevector element
      geom : Geometry
          Isofit geometry object

      Outputs:
      rho_dir_dir : np.ndarray
          Reflectance quantity for downward direct photon paths
      rho_dif_dir : np.ndarray
          Reflectance quantity for downward diffuse photon paths

      .. note::

         Here, we treat direct and diffuse photon path reflectance
         differently. The sun and sky glint magnitudes are statevector
         elements that interact with the two reflectance quantities
         independently.



   .. py:method:: drfl_dsurface(x_surface, geom)

      Partial derivative of reflectance with respect to state vector,
      calculated at x_surface.



   .. py:method:: drdn_dglint(L_tot, L_down_dir, s_alb, rho_dif_dir)

      Derivative of radiance with respect to
      the direct and diffuse glint terms



   .. py:method:: drdn_dsurface(rho_dif_dir, drfl_dsurface, dLs_dsurface, s_alb, t_total_up, L_tot, L_down_dir)

      Derivative of radiance with respect to
      full surface vector



   .. py:method:: analytical_model(background, L_down_dir, L_down_dif, L_tot, geom, L_dir_dir=None, L_dir_dif=None, L_dif_dir=None, L_dif_dif=None)

      Linearization of the glint terms to use in AOE inner loop.
      Function will fetch the linearization of the rho terms and
      add the matrix components for the direct glint term.
      Currently we set the diffuse glint scaling term to constant
      value, which makes the AOE inner loop inversion possible.



   .. py:method:: summarize(x_surface, geom)

      Summary of state vector.



   .. py:method:: fresnel_rf(vza)
      :staticmethod:


      Calculates reflectance factor of sky radiance based on the
      Fresnel equation for unpolarized light as a function of view zenith angle (vza).