This section summarizes various useful functions implemented in LumiSpy.
In case several spectra (or spectral images) where subsequently recorded for
different, but overlapping spectral windows, LumiSpy provides a utility
join_spectra() to merge these into a single spectrum. The
main argument is a list of two or more spectral objects. Spectra are joined at
the centre of the overlapping range along the signal axis. To avoid steps in the
intensity, several parameters (see docstring:
allow to tune the scaling of the later signals with respect to the previous ones.
By default, the scaling parameter is determined as average ratio between the two
signals in the range of +/- 50 pixels around the centre of the overlapping region.
>>> import lumispy as lum >>> s = lum.join_spectra((s1,s2))
Exporting text files
LumiSpy includes a function
that exports the data of a signal object
(with not more than two axes) to a simple .txt (or .csv) file. Can facilitate
data transfer to other programs, but no metadata is included. By default,
the axes are saved as first column (and row in 2d case). Set
save the data object only. The function can also
the dataset or take a custom
%.5f) or delimiter (default
>>> import lumispy as lum >>> import numpy as np ... >>> # Spectrum: >>> S = lum.signals.LumiSpectrum(np.arange(5)) >>> lum.savetxt(S, 'spectrum.txt') 0.00000 0.00000 1.00000 1.00000 2.00000 2.00000 3.00000 3.00000 4.00000 4.00000 ... >>> # Linescan: >>> L = lum.signals.LumiSpectrum(np.arange(25).reshape((5,5))) >>> lum.savetxt(L, 'linescan.txt') 0.00000 0.00000 1.00000 2.00000 3.00000 4.00000 0.00000 0.00000 5.00000 10.00000 15.00000 20.00000 1.00000 1.00000 6.00000 11.00000 16.00000 21.00000 2.00000 2.00000 7.00000 12.00000 17.00000 22.00000 3.00000 3.00000 8.00000 13.00000 18.00000 23.00000 4.00000 4.00000 9.00000 14.00000 19.00000 24.00000
For convenience, LumiSpy provides functions that convert between different units commonly used for the signal axis. Namely,
For the energy axis, the conversion uses the wavelength-dependent refractive index of air.
Solving the grating equation
solve_grating_equation() (relationship between
wavelength and pixel position in the detector plane) follows the conventions
described in the tutorial from Horiba Scientific.