# hyperspy.misc.eels.tools module

hyperspy.misc.eels.tools.eels_constant(s, zlp, t)

Calculate the constant of proportionality (k) in the relationship between the EELS signal and the dielectric function. dielectric function from a single scattering distribution (SSD) using the Kramers-Kronig relations.

Parameters
• zlp ({number, BaseSignal}) – If the ZLP is the same for all spectra, the intengral of the ZLP can be provided as a number. Otherwise, if the ZLP intensity is not the same for all spectra, it can be provided as i) a Signal of the same dimensions as the current signal containing the ZLP spectra for each location ii) a Signal of signal dimension 0 and navigation_dimension equal to the current signal containing the integrated ZLP intensity.

• t ({None, number, BaseSignal}) – The sample thickness in nm. If the thickness is the same for all spectra it can be given by a number. Otherwise, it can be provided as a Signal with signal dimension 0 and navigation_dimension equal to the current signal.

Returns

k

Return type

Signal instance

Find the scale and offset of the Poissonian noise

By comparing an SI with its denoised version (i.e. by PCA), this plots an estimation of the variance as a function of the number of counts and fits a polynomy to the result.

Parameters
• noisy_SI (signal1D.Signal1D instances) –

• clean_SI (signal1D.Signal1D instances) –

• mask (numpy bool array) – To define the channels that will be used in the calculation.

• pol_order (int) – The order of the polynomy.

• higher_than (float) – To restrict the fit to counts over the given value.

• return_results (Bool) –

• plot_results (Bool) –

• store_results ({True, False, "ask"}, default "ask") – If True, it stores the result in the signal metadata

Returns

• Dictionary with the result of a linear fit to estimate the offset

• and scale factor

hyperspy.misc.eels.tools.get_edges_near_energy(energy, width=10, only_major=False, order='closest')

Find edges near a given energy that are within the given energy window.

Parameters
• energy (float) – Energy to search, in eV

• width (float) – Width of window, in eV, around energy in which to find nearby energies, i.e. a value of 10 eV (the default) means to search +/- 5 eV. The default is 10.

• only_major (bool) – Whether to show only the major edges. The default is False.

• order (str) – Sort the edges, if ‘closest’, return in the order of energy difference, if ‘ascending’, return in ascending order, similarly for ‘descending’

Returns

edges – All edges that are within the given energy window, sorted by energy difference to the given energy.

Return type

list

hyperspy.misc.eels.tools.get_info_from_edges(edges)

Return the information of a sequence of edges as a list of dictionaries

Parameters

edges (str or iterable) – the sequence of edges, each entry in the format of ‘element_subshell’.

Returns

info – a list of dictionaries with information corresponding to the provided edges.

Return type

list