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![]() ![]() The Chebyshev and Chebyshev2 baselines fit a Chebyshev series of the first and second kind, respectively. The temperature (in kelvin) that best fits the data is stored in W_Coef and in the wavenotes of output waves. Select the x-units of your data from nm, μm, wavenumbers, and Å. ![]() The Planck function uses Planck's law to fit a black-body radiation spectrum. The fit coefficients are described in the help for built-in curve fitting functions. When the 'Peak' checkbox is checked, the first coefficient of the fit function is set to the baseline reference value, meaning that these are peak functions with no vertical offset. Some baseline functions have a 'peak' option. These are described in the following sections. Some additional functions are selectable in the masked- and automatic-fitting tabs. The fit coefficients are stored in the wave W_Coef, in case you need them for further processing. ![]() Most of Igor Pro's built-in curve fitting functions can be selected as a baseline fit function. Note that baselines uses cursors C through J, so don't try to use them for other purposes in the baseline fitting graph window. Close the main 'Baseline Controls' panel to clean up after fitting. Clicking on the cog icon opens a control panel where you can adjust the settings for baseline fitting. Baselines works with both waveform and x-y traces, but not with 2D waves. The four tabs select between four 'families' of baseline algorithms: masked function fitting, manual function fitting, automatic baselines that process the input data to estimate a baseline, and spline baselines that are interpolated between node positions selected by the user. Select a spectrum and baseline type from the popup menus in the control panel. Traces are reset to their original colors when the 'Baseline Controls' panel is closed. Traces in the graph will be recolored (unless the trace recoloring option is turned off in the settings panel) so that the selected trace, together with a preview of the baseline and baseline-subtracted waves, are the only non-grey traces. Select 'Baselines' from the analysis menu to attach the 'Baseline Controls' panel to the top graph. The waves may be vertically offset as you please. To get started, plot all of the waves that need baseline correction in a graph window.
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