refmod.hapke.amsa

Module Contents

refmod.hapke.amsa.__amsa_preprocess(single_scattering_albedo, incidence_direction, emission_direction, surface_orientation, phase_function_type, b_n=None, a_n=None, roughness=0.0, hs=0.0, bs0=0.0, hc=0.0, bc0=0.0, phase_function_args=())

Preprocesses the inputs for the AMSA model.

Parameters:

• single_scattering_albedo (npt.NDArray) – Single scattering albedo.

• incidence_direction (npt.NDArray) – Incidence direction vector(s) of shape (…, 3).

• emission_direction (npt.NDArray) – Emission direction vector(s) of shape (…, 3).

• surface_orientation (npt.NDArray) – Surface orientation vector(s) of shape (…, 3).

• phase_function_type (PhaseFunctionType) – Type of phase function to use.

• b_n (npt.NDArray) – Coefficients of the Legendre expansion.

• a_n (npt.NDArray) – Coefficients of the Legendre expansion.

• roughness (float, optional) – Surface roughness, by default 0.0.

• hs (float, optional) – Shadowing parameter, by default 0.0.

• bs0 (float, optional) – Shadowing parameter, by default 0.0.

• hc (float, optional) – Coherent backscattering parameter, by default 0.0.

• bc0 (float, optional) – Coherent backscattering parameter, by default 0.0.

• phase_function_args (tuple, optional) – Additional arguments for the phase function, by default ().

Returns:

A tuple containing:

• albedo_independentnpt.NDArray

  Albedo-independent term.

• mu_0npt.NDArray

  Cosine of the incidence angle.

• munpt.NDArray

  Cosine of the emission angle.

• p_gnpt.NDArray

  Phase function values.

• mnpt.NDArray

  M term.

• p_mu_0npt.NDArray

  Legendre polynomial values for mu_0.

• p_munpt.NDArray

  Legendre polynomial values for mu.

• pnpt.NDArray

  Legendre polynomial values.

• h_mu_0npt.NDArray

  H-function values for mu_0.

• h_munpt.NDArray

  H-function values for mu.

Return type:

tuple

refmod.hapke.amsa.amsa(single_scattering_albedo, incidence_direction, emission_direction, surface_orientation, phase_function_type, b_n=None, a_n=None, hs=0, bs0=0, roughness=0, hc=0, bc0=0, phase_function_args=(), refl_optimization=None)

Calculates the reflectance using the AMSA model.

Parameters:

• single_scattering_albedo (npt.NDArray) – Single scattering albedo.

• incidence_direction (npt.NDArray) – Incidence direction vector(s) of shape (…, 3).

• emission_direction (npt.NDArray) – Emission direction vector(s) of shape (…, 3).

• surface_orientation (npt.NDArray) – Surface orientation vector(s) of shape (…, 3).

• phase_function_type (PhaseFunctionType) – Type of phase function to use.

• b_n (npt.NDArray) – Coefficients of the Legendre expansion.

• a_n (npt.NDArray) – Coefficients of the Legendre expansion.

• hs (float, optional) – Shadowing parameter, by default 0.

• bs0 (float, optional) – Shadowing parameter, by default 0.

• roughness (float, optional) – Surface roughness, by default 0.

• hc (float, optional) – Coherent backscattering parameter, by default 0.

• bc0 (float, optional) – Coherent backscattering parameter, by default 0.

• phase_function_args (tuple, optional) – Additional arguments for the phase function, by default ().

• refl_optimization (npt.NDArray | None, optional) – Reflectance optimization array, by default None.

Returns:

Reflectance values.

Return type:

npt.NDArray

Raises:

• Exception – If at least one reflectance value is not real.

• References –

• ---------- –

• [AMSAModelPlaceholder] –

refmod.hapke.amsa.amsa_derivative(single_scattering_albedo, incidence_direction, emission_direction, surface_orientation, phase_function_type, b_n=None, a_n=None, roughness=0, hs=0, bs0=0, hc=0, bc0=0, phase_function_args=(), refl_optimization=None)

Calculates the derivative of the reflectance using the AMSA model.

Parameters:

• single_scattering_albedo (npt.NDArray) – Single scattering albedo.

• incidence_direction (npt.NDArray) – Incidence direction vector(s) of shape (…, 3).

• emission_direction (npt.NDArray) – Emission direction vector(s) of shape (…, 3).

• surface_orientation (npt.NDArray) – Surface orientation vector(s) of shape (…, 3).

• phase_function_type (PhaseFunctionType) – Type of phase function to use.

• b_n (npt.NDArray) – Coefficients of the Legendre expansion.

• a_n (npt.NDArray) – Coefficients of the Legendre expansion.

• roughness (float, optional) – Surface roughness, by default 0.

• hs (float, optional) – Shadowing parameter, by default 0.

• bs0 (float, optional) – Shadowing parameter, by default 0.

• hc (float, optional) – Coherent backscattering parameter, by default 0.

• bc0 (float, optional) – Coherent backscattering parameter, by default 0.

• phase_function_args (tuple, optional) – Additional arguments for the phase function, by default ().

• refl_optimization (npt.NDArray | None, optional) – Reflectance optimization array, by default None. This parameter is not used in the derivative calculation.

Returns:

• npt.NDArray – Derivative of the reflectance with respect to single scattering albedo.

• References

• ———-

• [AMSAModelPlaceholder]